1. A 6-year comparison of nitrate leaching from grass/clover and N-fertilized grass pastures grazed by sheep.
Cuttle, S. P.; Scurlock, R. V.; and Davies, B. M. S.
Journal of Agricultural Science 131(1): 39-50. (1998)
NAL Call #:   10 J822; ISSN: 0021-8596
Descriptors:   grazing/ pastures
Abstract: Nitrate leaching was measured over a 3-year period from rotationally grazed perennial ryegrass (Lolium perenne L.) pasture receiving 200 kg fertilizer-N/ha and from similarly grazed ryegrass/white clover (Trifolium repens L.) pasture that received no N fertilizer. The results are discussed together with those from the same plots in the preceding 3 years when. they were stocked continuously. Under both managements, the numbers of grazing sheep were adjusted on the basis of the quantity of herbage available on the plots. During the whole 6 years, mean nitrate concentrations in soil water collected by porous cup samplers remained below the European Union limit of 11.3 mg N/l except for the fertilized grass plots in year 5 of the study. Quantities of nitrate leached ranged from 6 to 34 kg/ha per year from the grass/clover plots and 2-46 kg/ha from the fertilized plots. Leaching losses from both types of pasture were positively correlated with the numbers of lamb grazing days in the later part of the grazing season. This relationship and the high spatial variability associated with the measurements indicated that N derived from excreta was the main source of leached nitrate. It was concluded that, where pastures of equal productivity are compared, similar quantities of N are likely to be leached from grass/clover swards as from grass swards receiving N fertilizer.
© The Thompson Corporation

2. Acidification under grazed annual and perennial grass based pastures.
Ridley, A. M.; Slattery, W. J.; Helyar, K. R.; and Cowling, A.
Australian Journal of Experimental Agriculture 30(4): 539-544. (1990)
NAL Call #:   23 Au792; ISSN: 0816-1089
Descriptors:   Phalaris tuberosa/ plant/ nitrate leaching/ aluminum sensitive species/ soil management/ crop industry/ agriculture/ Australia
Abstract: Soil samples to a depth of 60 cm were collected from adjacent, 39-year-old, phalaris-[Phalaris tuberosa] based and annual pasture fields on an acid soil at Rutherglen, north-eastern Victoria [Australia]. The fields had similar histories of fertiliser application and stock enterprise. Minimum net acid addition rates were determined under both pasture types, and the soil under annual pasture showed greater acidification. Carbon cycle acid addition contributed 1.31 and 1.36 kmol H+/ha.year to net acid addition on annual and phalaris pastures, respectively. Because slow alkaline soil reactions in the field contribute to buffering capacity on an acid soil and lead to underestimation of net acid addition rate and nitrate leaching, estimates of such reactions were made for both pasture types. If correct assumptions were used nitrate leaching was substantial under both pasture types but was reduced by 1.01 kmol H+/ha.year under phalaris pasture. This suggests that perennial grass based pastures can be used to reduce acification on pastoral soils. Alkali addition to counteract net acidification may be necessary on acid soils to maintain management options for growing aluminium-sensitive species.
© The Thompson Corporation

3. Agricultural impacts on bacterial water quality in karst groundwater.
Pasquarell, G. C. and Boyer, D. G.
Journal of Environmental Quality 24(5): 959-969. (1995)
NAL Call #:   QH540.J6; ISSN: 0047-2425
Descriptors:   water quality/ karst/ groundwater pollution/ agricultural practices/ cattle/ bacteria/ coliforms/ feces/ seasonal variations/ soil water/ springs/ karstic environments/ ground water/ fecal coliforms/ agricultural pollution/ USA, West Virginia/ karstic environments/ ground water/ fecal coliforms/ agricultural pollution/ karst/ cattle/ soil water/ agricultural practices/ feces/ springs
Abstract: A 2-yr study (1991-1992) was conducted in a karst region in southeast West Virginia to determine the impact of agriculture on groundwater quality. The primary agriculture is characterized by seasonal cattle grazing. Fecal coliform densities were measured weekly in the resurgences of three karst basins possessing different degrees of agricultural intensity (79, 51, and 16% land use in agriculture). Fecal coliforms were also measured in a creek at sites upstream and downstream of the known resurgences from the most agriculturally intensive (79%) basin. The fecal coliform densities in the resurgences peaked in the summer and declined in the fall, with a recovery in late winter before the introduction of new cattle. The timing of the recovery indicated that significant storage of fecal material had taken place, which was transported to the groundwater when soil water conditions permitted. For most of each year, soil water effects appeared to have a greater bearing on the fecal coliform densities than did the presence or absence of cattle. The data did not generally support a strong relationship with percent land use in agriculture. This was attributed to the high variability in the data and to low soil moisture during periods of recession that inhibited the transport of fecal material to the groundwater. The karst resurgence springs of the most intensively agricultural basin were contaminated with fecal bacteria. Fecal bacteria concentrations were observed to significantly increase, in the receiving surface stream, from a point upstream of the resurgence springs to a point downstream of the resurgence springs.
© CSA

4. Agricultural land-use effects on the indicator bacterial quality of an upland stream in the Derbyshire Peak District in the U.K.
Hunter, Colin; Perkins, Joy; Tranter, Jamie; and Gunn, John
Water Research 33(17): 3577-3586. (1999)
NAL Call #:   TD420.W3; ISSN: 0043-1354
Descriptors:   agricultural land use intensification/ bacterial contamination/ catchment soils/ ecotoxicology/ health risk/ hydrological transport/ limestone karst system/ precipitation related output/ recreational caving/ seasonal variation/ sheep grazing/ spatial changes/ stream channel/ streamwater quality/ survival/ upland stream/ water inflow sampling sites
Abstract: Concentrations of indicator bacteria - faecal coliforms (FC) and faecal streptococci (FS) - were monitored at stream and water inflow sampling sites over a 21 month period within a small upland catchment in north Derbyshire, England. Agricultural land-use within the catchment included rough, semi-improved and improved pastures for sheep grazing. During its passage through the catchment, the stream became significantly contaminated by faecal bacteria, suggesting the existence of a semi-permanent store of faecal bacteria in catchment soils, combined with hydrological transport mechanisms capable of moving bacteria from the land to the stream channel. Spatial changes in the bacterial quality of streamwater could be explained by the influence of a number of monitored water inflows to the stream, although a clear and consistent relationship between the bacterial quality of catchment waters and the intensity of adjacent agricultural land-use was not apparent. This is explained in terms ofa trade-off between practices which allow land-use intensification and a consequent reduction in the potential for bacterial survival in soils and efficient hydrological transport via surface-water flows. A consistent seasonal pattern of bacterial concentration change was observed, with the highest concentrations occurring during summer months as stocking density increased and the bacterial land store recovered from high precipitation-related outputs during the winter. The extent of faecal bacterial contamination of the stream, particularly during summer months, may constitute a real health risk to recreational cavers using parts of the limestone karst system into which the stream drains.
© The Thompson Corporation

5. An analysis of environmental and economic implications of nil and restricted grazing systems designed to reduce nitrate leaching from New Zealand dairy farms: Pasture production and cost/benefit analysis.
De Klein, C. A. M. and Ledgard, S. F.
New Zealand Journal of Agricultural Research 44(2-3): 217-235. (2001)
NAL Call #:   23 N4892; ISSN: 0028-8233
Descriptors:   cost/ benefit analysis/ grazing systems: dairy farms, economic aspects, environmental aspects/ nitrogen loss/  pasture production
Abstract: Nitrate leaching from animal urine is perceived to be a serious consequence of dairy farming. Previous results suggested that nil and restricted grazing systems could reduce nitrate leaching by up to 50%. It is likely that such systems may also increase pasture production. However, potential disadvantages include reduction in the clover content of pastures and increase in capital and/or operating costs. This paper examines the economic implications of nil and restricted grazing systems based on data from an average New Zealand dairy farm and from a long-term farmlet study. The analyses suggested that pasture production increased by about 20% and 2-8%, respectively, compared with a conventional grazing system. Based on the average New Zealand dairy farm, the costs/benefit analysis of the nil grazing system suggested a negative return on capital of about-10%. For the restricted grazing system, the average return on capital was about 9% (range: -4 to 25%) and depended largely on the efficiency of animal excreta use. On farms where an effluent application system is already in place, the average return on capital was 17% (range: 2 to 50%). Based on the farmlet study, the cost/benefit analysis of both grazing systems suggested a small negative return on capital, except when the costs of an effluent application system were excluded. It is concluded that a restricted grazing system for the average New Zealand dairy farm is likely to be economically viable, on farms where an effluent application system or a feed pad is already in place.
© The Thompson Corporation

6. An analysis of the physical condition of two intensively grazed Southland soils.
Greenwood, P. B. and McNamara, R. M.
Proceedings of the New Zealand Grassland Association 54: 71-75. (1992)
NAL Call #:   60.19 N48; ISSN: 0369-3902
Descriptors:   bulk density/ porosity/ macropores/ hydraulic conductivity/ permeability/ resistance to penetration/ grazing/ physical properties/ soil compaction/ trampling/ soil degradation/ silt loam soils/ soil physical properties/ soil/ physics  
Abstract: The physical properties of two Southland, New Zealand silt loam soils (a yellow-grey earth and a yellow-brown earth) with histories of high and low winter stocking densities of sheep were compared. Assessments were made of mechanical impedance, bulk density, porosity, air permeability and hydraulic conductivity. Results showed that winter treading by sheep on all-grass wintering systems (800-2000 sheep/ha) caused significant soil physical degradation by reducing hydraulically effective soil macroporosity, restricting the transmission of water through the topsoil. This led to waterlogging and root-zone oxygen deficiencies after rain. Soil compaction occurred to nearly the full depth of the A horizon probably as a result of damage over several winters. Measurements of mechanical impedance and bulk density were insensitive to small changes in soil porosity. Air permeability and hydraulic conductivity were good indicators of the relative degree of compactness and both were sensitive to small changes in effective macroporosity .
© CAB International/CABI Publishing

7. Animal trampling effects on soil physical properties of two Southeastern U.S. Ultisols.
Tollner, E. W.; Calvert, G. V.; and Langdale, G.
Agriculture, Ecosystems & Environment 33(1): 75-87. (1990)
NAL Call #:   S601 .A34; ISSN: 0167-8809
Descriptors:   soil physics/ physical properties/ grazing/ animal husbandry/ soil/ soil fertility/ productivity  
Abstract: Several selected soil physical properties and plant growth indicators thought to be affected by animal trampling were measurd in three experiments ranging over 8 years. Crops studied included lucerne (Medicago sativa), Bermudagrass (Cynodon dactylon), and soyabeans (Glycine max) following wheat (Triticum aestivum) or rye (Secale cereale). Stocking rates for the experiments ranged from 5 to 18 animals/ha. Cone penetrometer measurements were consistently higher in grazed areas than in areas protected from grazing. Other physical parameters (infiltration rate, bulk density, water release curve) measurements were sometimes significantly influenced by trampling. Natural densification explained increased bulk densities within protected areas. Trampling altered surface soil structure; however, productivity (root biomass, forage growth) was not significantly reduced .
© CAB International/CABI Publishing

8. Assessing the effect of management intensive grazing on water quality in the Northeast US.
Stout, W. L.; Fales, S. L.; Muller, L. D.; Schnabel, R. R.; Elwinger, G. F.; and Weaver, S. R.
Journal of Soil and Water Conservation 55(2): 238-243. (2000)
NAL Call #:   56.8 J822; ISSN: 0022-4561
Descriptors:   grazing/ animal husbandry/ water quality/ environmental impact/ stocking rate/ dairy farming/ profitability/ nitrates/ leaching/ pastures/ excretion/ soil erosion/ groundwater/ leachates/ Pennsylvania
This citation is from AGRICOLA.

9. Cattle and sheep grazing effects on soil organisms, fertility and compaction in a smooth-stalked meadowgrass-dominant white clover sward.
Murphy, W. M.; Mena Barreto, A. D.; Silman, J. P.; and Dindal, D. L.
Grass and Forage Science 50(3): 191-194. (1995)
NAL Call #:   60.19 B773; ISSN: 0142-5242
Descriptors:   Poa pratensis/ Trifolium repens/ cattle/ sheep/ rotational grazing/ pastures/ range management/ forbs/ soil fertility/ soil compaction/ free-living nematodes/ Rotifera/ earthworms/ nitrogen/ potassium/ phosphorus/ topping/ Vermont
This citation is from AGRICOLA.

10. Cattle grazing impact on surface water quality in a Colorado front range stream.
Gary, H. L.; Johnson, S. R.; and Ponce, S. L.
Journal of Soil and Water Conservation 38(2): 124-126. (1983)
NAL Call #:   56.8 J822; ISSN: 0022-4561
Descriptors:   grazing/ environmental impact/ surface water/ water quality/ streams/  microbial pollution/ freshwater pollution/ agriculture/ microbial contamination/ USA, Colorado/ cattle/ microbial contamination/ streams/ microbial pollution
Abstract: Cattle grazing in pastures bisected by a small perennial in central Colorado had only minor effects on water quality during two years of study. Suspended solids and nitrate nitrogen did not increase significantly, and ammonia nitrogen increased significantly only once under moderate rates of grazing. Indicator bacteria densities in the stream water significantly higher when at least 150 cattle were grazing. After removal of cattle or when 40 head of cattle were grazing, bacterial counts dropped to levels similar to those in an adjacent, ungrazed pasture. About 5 percent of the total manure produced by cattle contributed to pollution and/or enrichment of the stream.
© CSA

11. Cattle grazing influences on percentage corn residue cover.
Shelton, D. P.; Schroeder, M. A.; Kachman, S. D.; Gosey, J. A.; and Jasa, P. J.
Journal of Soil and Water Conservation 52(3): 203-206. (1997)
NAL Call #:   56.8 J822; ISSN: 0022-4561
Descriptors:   soil conservation/ erosion control/ Zea mays/ crop residues/ surface layers/ cattle/ grazing/ no-tillage/ fertilizers/ application methods/ sowing/ planters/ crop residue management/ Nebraska
This citation is from AGRICOLA.

12. Cattle treading and phosphorus and sediment loss in overland flow from grazed cropland.
Mcdowell, R. W.; Drewry, J. J.; Muirhead, R. W.; and Paton, R. J.
Australian Journal of Soil Research 41(8): 1521-1532. (2003)
NAL Call #:   56.8 Au7; ISSN: 0004-9573
Descriptors:   cattle dung/ cattle treading/ cultivated paddocks/ cultivated soil/ dairy cow treading/ grazed cropland/ overland flow: events, mean suspended sediment concentration/ overland flow volume/ pasture/ sediment loss/ slope positions/ soil disturbance/ soil macroporosity/ soil physical properties
Abstract: This 1-year study investigated the effect of dairy cow treading on soil physical properties and sediment and phosphorus (P) loss via overland flow from pasture and cultivated soil used for wintering dairy cows in southern New Zealand. Treading decreased soil macroporosity and Ksat, and increased overland flow volumes. Treading increased mean suspended sediment concentration in overland flow in the cultivated + trodden treatment (2.6 g/L) compared with ungrazed pasture (0.44 g/L) and ungrazed cultivated (0.98 g/L) treatments over 2 slope positions. Following grazing in the cultivated + trodden treatment, only 25% more sediment was lost in subsequent overland flow events (2.09 and 2.63 g before and after grazing, respectively), and mean total P (TP) losses increased by >250% (from 0.7 to 2.5 mg P). Meanwhile in the cultivated but ungrazed treatment, sediment and TP loss decreased. The increased loss of sediment and P following grazing in the cultivated + trodden treatment was attributed to P from cattle dung, and soil disturbance. Consequently, wintering of animals on cultivated paddocks with forage crops increases the risk of losing much P, especially in particulate form.
© The Thompson Corporation

13. Change in the balance of ammonium-N and nitrate-N content in soil under grazed grass swards over 7 years.
Watson, C. J. and Poland, P.
Grass and Forage Science 54(3): 248-254. (1999)
NAL Call #:   60.19 B773; ISSN: 0142-5242
Descriptors:   sward/ ammonium nitrogen/ nitrate nitrogen/ soil fertility/ grazing/ range management/ nitrification/ Lolium perenne/ Trifolium repens/ calcium ammonium nitrate/ steers/ soil microorganisms/ microorganisms/ grassland soils/ application rate/ Northern Ireland
Abstract: The pool of nitrate-N (NO3(-)-N) in the soil is more prone to losses than that of ammonium-N (NH4+ -N) so any shift towards NO3(-)-N dominance in the soil pools, caused by management intensity, could have environmental implications. The change in the balance of soil NH4+ -N and NO3(-)-N content with time was studied using grazed grass swards receiving different fertilizer N inputs. In addition, the effects of past management on net nitrification of 400 microgram NH4+ -N g-1 was investigated in a soil incubation study. Mineral N was determined at frequent intervals (at least every 2 weeks) throughout the year in the top 5 or 7.5 cm of a sandy clay-loam soil at the Agricultural Research Institute of Northern Ireland at Hillsborough, County Down, for a 7-year period (1989-90 to 1995-96). The treatments were a perennial ryegrass-white clover sward receiving no fertilizer N, together with perennial ryegrass swards receiving 100, 200, 300, 400 or 500 kg N ha-1 year-1 as calcium ammonium nitrate. The plots were continuously grazed by beef steers from April to October to maintain a constant sward height of 7 cm. There was little or no change in average soil NO3(-)-N and NH4+ -N content from 1989-90 to 1995-96 on the grass-clover sward and plots receiving 100 and 200 kg N ha-1 year-1. However, with the plots receiving 300, 400 and 500 kg N ha-1 year-1 NO3(-)-N became progressively more dominant with time. The incubation study confirmed that this was due to an increase in net nitrification rate. There was evidence that rapid microbial assimilation of NO3(-)-N occurred during the soil incubations. Past management history can play an important role in determining soil NO3(-)-N content and hence potential losses of N to the environment.
This citation is from AGRICOLA.

14. Changes in a stream's physical and biological conditions following livestock exclusion.
Line, D. E.
Transactions of the ASAE 46(2): 287-293. (2003)
NAL Call #:   290.9 Am32T; ISSN: 0001-2351
Descriptors:   BMP/ fecal coliform/ livestock exclusion/ water quality
Abstract: Runoff from dairy cow pastures can degrade the quality of surface waters. Weekly grab samples were collected for 7.5 years from a small stream draining a 56.7-ha, mostly dairy cow pasture and analyzed for fecal coliform and enterococci (streptococci). In situ measurements of pH, dissolved oxygen, temperature, conductivity, and turbidity were made during most grab sampling events. Fecal coliform and enterococci levels for samples collected during the 2.25 years prior to the installation of livestock exclusion fencing were more than 300% greater at the downstream monitoring station compared to the upstream station. After fencing, fecal coliform and enterococci levels decreased 65.9% and 57.0%, respectively. The decreased bacteria levels were significantly different, indicating that livestock exclusion fencing was effective at reducing bacteria levels in the stream. While the levels of dissolved oxygen, pH, temperature, and specific conductivity downstream relative to upstream following fencing generally documented improved water quality, the changes were not statistically significant. Conversely, decreases in turbidity and suspended sediment levels following fencing were significantly different. Levels of most of the physical parameters and bacteria were not significantly different at the upstream monitoring site following the installation of the alternate water supply in the pasture upstream. Thus, the alternate water supply, without fencing, was not effective at improving water quality in the upper pasture.
© 2006 Elsevier B.V. All rights reserved.

15. Changes in soil fungal:bacterial biomass ratios following reductions in the intensity of management of an upland grassland.
Bardgett, R. D.; Hobbs, P. J.; and Frostegard, A.
Biology and Fertility of Soils 22(3): 261-264. (1996)
NAL Call #:   QH84.8.B46; ISSN: 0178-2762
Descriptors:   soil fungi/ soil bacteria/  biomass/ grassland soils/ upland soils/ range management/ soil management/ sheep/ grazing/ NPK fertilizers/ liming/ soil pH/ community ecology/ biological activity in soil/  estimation/ methodology/ community structure
Abstract: In this study we examined the effect on soil fungal:bacterial biomass ratios of withholding fertiliser, lime, and sheep-grazing from reseeded upland grassland. The cessation of fertiliser applications on limed and grazed grassland resulted in a reduction in soil pH from 5.4 to 5.1. The cessation of fertiliser applications and liming on grazed grassland resulted in a fall in pH from 5.4 to 4.7, whereas withholding fertiliser and lime and the removal of grazing resulted in a further reduction to pH 4.5. Substrate-induced respiration was reduced in the unfertilised grazed (21%; P<0.01) and unfertilised ungrazed (36%; P<0.001) treatments. Bacterial substrate-induced respiration and bacterial fatty acids were unaffected by the treatments. The relative abundance of the fungal fatty acid 18:2 omega 6 increased by 39 and 72% (P<0.05) in the limed grazed and unfertilised grazed treatments, respectively. Fungal substrate-induced respiration increased in the limed grazed (18%) and unfertilised grazed (65%; P<0.05) treatments. The ratio of 18:2 omega 6: bacterial fatty acids was correlated with the ratio of fungal:bacterial substrate-induced respiration (r=0.69; P<0.001).
This citation is from AGRICOLA.

16. Changes of surface oil nutrients and sustainability of pastoralism on grazed hilly and steep land, South Island, New Zealand.
Mcintosh, P. D.; Ogle, G. I.; Patterson, R. G.; Aubrey, B.; Morriss, J.; and Giddens, K.
Journal of Range Management 49(4): 361-367. (1996)
NAL Call #:   60.18 J82; ISSN: 0022-409X
http://jrm.library.arizona.edu/data/1996/494/361-367_mcintosh.pdf
Descriptors:   sheep/ grazing/ upland soils/ cation exchange capacity/ topsoil/ pH/ highlands/ New Zealand
Abstract: Soil nutrients in topsoils (0-7.5 cm) on grazed hilly and steep land on 2 high country sheep farms with contrasting climate in the upper Waitaki district, South Island, New Zealand, were compared before and after a 14-15 year period. In addition, effects on soils of 2 farm management systems were compared by sampling similar soils on adjacent farms. On a farm with mean annual rainfall of 700-1,000 mm (study area A) that had been fertilised and oversown, and grazed with about 1.6 ewe equivalents per hectare for 14 years, levels of exchangeable cations (Ca, K, Mg) increased in topsoils on sunny slopes, but there was little change on shady slopes. The Ca increase on sunny slopes was the increase to be expected from the amount of Ca contained in the superphosphate applied but increases of exchangeable K and Mg could not be explained by fertiliser additions. There was an overall 29% increase of CEC, 7.5% decline of base saturation, and decline of soil pH by 0.4 units over the 14 year period. On a farm with mean annual rainfall of 500-600 mm (study area B) that had been grazed for 15 years with about 0.6 ewe equivalents per hectare but not fertilised or oversown, levels of exchangeable cations in topsoils declined. Base saturation values declined from 98% to 73% and pH declined by 0.4 units. Losses of Ca and Mg were greater than could be explained by direct effects of sheep grazing and we conclude that processes such as erosion or removal of vegetation and nutrients by rabbits are important loss pathways. In the spatial comparison on land with mean annual rainfall of approximately 1,000 mm, oversown and fertilised soils (grazed with about 1.6 ewe equivalents per hectare) had higher levels of exchangeable cations, organic C and total N than soils that had neither been oversown or fertilised (grazed with about 0.6 ewe equivalents per hectare). Questions of ecological and economic sustainability arise both on the moister and drier high country. On moister land like area A, if lime can be applied economically, and fertiliser can continue to be applied with positive financial returns, oversowing and fertilising may be sustainable on sunny slopes. The sustainability of pastoralism on shady slopes is more problematical. If on drier land losses of topsoil nutrients such as those measured on area B are widespread, they are considered to be unsustainable. Although the nutrients lost could be readily replenished using modest amounts of fertiliser and lime, the changes have occurred concurrently with declines of organic C and total N. Restoration of organic matter levels is likely to require either reduced grazing, or oversowing and application of fertiliser. Because oversowing and fertilising the drier high country is not financially viable except during periods of high commodity prices, both these options would require major changes in farm management and/or financial assistance with soil conservation measures.
This citation is from AGRICOLA.

17. Changes to soil physical properties after grazing exclusion.
Greenwood, K. L.; MacLeod, D. A.; Scott, J. M.; and Hutchinson, K. J.
Soil Use and Management 14(1): 19-24. (1998)
NAL Call #:   S590.S68; ISSN: 0266-0032
Descriptors:   pastures/ soil degradation/ bulk density/ unsaturated hydraulic conductivity/ sheep/ grazing/ stocking rate/ rain/ evaporation/ New South Wales
Abstract: The potential for degraded physical properties of soil to regenerate naturally after exclusion of grazing animals was examined at a long-term stocking rate trial near Armidale, New South Wales, Australia. Unsaturated hydraulic conductivity was measured before grazing was excluded, and after 7 months and 2.5 years' grazing exclusion. These data were compared with controls grazed at 10,l5 and 20 sheep/ha. After 2.5 years, there were significant increases in unsaturated hydraulic conductivity at 5 and 15 mm tension in the ungrazed treatments compared with the grazed controls. The unsaturated hydraulic conductivities and bulk density of surface soils under pasture which had been ungrazed for 2.5 years were comparable to those where the pasture had been ungrazed for 27 years. We speculate that the natural amelioration of soil physical properties in these soils was due to biological activity and wetting and drying cycles, in the absence of the compactive effect of animal treading.
This citation is from AGRICOLA.

18. Channel changes over 12 years on grazed and ungrazed reaches of Wickiup Creek in eastern Oregon.
Nagle, G. N. and Clifton, C. F.
Physical Geography 24(1): 77-95. (2003); ISSN: 0272-3646
Descriptors:   channels/ streams/ grazing/ pastures/ geography/ reach/ livestock
Abstract: Stream channel cross sections were first compared in 1986 in grazed reaches and inside a 47-yr.-old grazing exclosure along Wickiup Creek in eastern Oregon. Significant differences between grazed and ungrazed channels were found at that time. In 1998, we measured 49 cross sections placed at a similar spacing inside the exclosure and in three grazed reaches in order to examine changes over 12 yr. Although the grazed channels were still significantly different than the ungrazed, in two out of three grazed reaches, the channels showed improvement in all parameters since 1985 although not all of these were statistically significant at the 90% level. Since 1990, the Wickiup riparian pasture has been managed more cautiously than many other streamside pastures in eastern Oregon and our results indicate that under careful grazing management, stream channels may show improvement from destructive past grazing without complete exclusion of livestock. As an alternative to the intensive method of measuring channel cross sections that was used in this study, we propose a rapid method of measuring stream channels that might be more useful in future studies of riparian grazing impacts.
© CSA

19. Chemical water quality of runoff from grazing land in Nebraska: Contributing factors.
Schepers, J. S.; Hackes, B. L.; and Francis, D. D.
Journal of Environmental Quality 11(3): 355-359. (1982)
NAL Call #:   QH540.J6; ISSN: 0047-2425
Descriptors:   farm management/ livestock/ pastures/ precipitation/ runoff/ agricultural runoff/ water quality/ animal wastes/  manure/ vegetation/ wildlife/ nutrients/ organic matter/ nitrates/ phosphorus/ chlorides/ ammonium/ water pollution sources/ fate of pollutants/ grazing/ farm wastes/ nonpoint pollution sources/ Nebraska
Abstract: The effects of climatic factors, hydrologic factors, and management practices on the chemical quality of runoff from a 32.5 ha cow and calf pasture in Nebraska were studied in 1976-78. Precipitation and hydrologic characteristics, stocking rates, and sediment contents in the runoff were used to predict the average concentrations of ammonium-N, nitrate-N, Kjeldahl N, soluble P, total P, total organic carbon, COD, and chloride. Animal stocking density significantly influenced the predicted concentrations of ammonium-N, nitrate-N, total P, total organic carbon, and COD in the runoff. However, dilution was the dominant process. Likely sources of pollutants were standing plant material and manure. Chloride appeared to be an indicator of wildlife activity.
© NISC

20. Chemical water quality of runoff from grazing land in Nebraska: Influence of grazing livestock.
Schepers, J. S. and Francis, D. D.
Journal of Environmental Quality 11(3): 351-354. (1982)
NAL Call #:   QH540.J6; ISSN: 0047-2425
Descriptors:   pastures/ runoff/ water quality/ farm management/ animal wastes/ manure/ vegetation/ wildlife/ nutrients/ organic matter/ nitrates/ phosphorus/ chlorides/ ammonium/ water pollution sources/ fate of pollutants/ livestock/ grazing/ farm wastes/ nonpoint pollution sources/ Nebraska
Abstract: The quality of runoff water from a 32.5 ha cow and calf pasture in Nebraska was studied for three years, 1976-78. Three types of pastures were included: ungrazed pasture (control), grazed pasture with livestock actively grazing, and grazed pasture with livestock absent. The runoff water from pasture with actively grazing livestock had higher concentrations of all water quality parameters with respect to the grazed pasture with no livestock present, with the exception of Kjeldahl N, which decreased by 19%. The increases were: total solids, 52%; total organic carbon, 11%; COD, 7%, ammonium-N, 6%, nitrate-N, 45%; total P, 37%; soluble P, 48% and chloride, 78%. Runoff from the control area was tea-colored and had the poorest quality, with 1.94 to 10.8 times greater concentrations of pollutants. This was attributed to wildlife activity and leaching of nutrients and organic matter from vegetation.
© NISC

21. A comparison between continuous and controlled grazing on a red duplex soil: Effects on soil physical characteristics.
Proffitt, A. P. B.; Bendotti, S.; and Mcgarry, D.
Soil and Tillage Research 35(4): 199-210. (1995)
NAL Call #:   S590.S48; ISSN: 0167-1987
Descriptors:   controlled grazing/ hardsetting/ no grazing/ plastic limit/ set stocking/ structural deterioration/ trampling
Abstract: The effect of sheep trampling and grazing management practice on soil physical characteristics was examined over one pasture season. The soil studied was a fragile sandy clay loam (red duplex soil) located in a dryland agricultural area (307 mm average annual rainfall) of Western Australia. The pasture was predominantly Serena medic (Medicago polymorpha). The three grazing management practices investigated were: (i) traditional set-stocking (where sheep were grazed continuously for 17 weeks, beginning soon after the start of the early winter rains); (ii) controlled grazing (where sheep were temporarily removed from the enclosure when the topsoil was close to its plastic limit); (iii) no grazing (where the pasture was mown to simulate grazing without trampling). Topsoil structure was assessed in several ways: dry bulk density, infiltration rate and tensile strength measurements, and image analysis of resin-impregnated soil blocks. At the end of the grazing period, all soil structure attributes measured showed that topsoil structure under the controlled grazing practice was not only superior to that found under the traditional set-stocking practice, but similar to that found in the ungrazed treatment. Soil remoulding appeared to be a significant process contributing to the deterioration in topsoil structure. The plastic limit was used diagnostically and found to be an important soil property which should be routinely determined in order to aid management decisions. Continuous (or set-stocking) grazing practices in the pasture phase of wheat (Triticum aestivum): pasture rotations can exacerbate the susceptibility of red duplex soils to structure deterioration and hardsetting. However, the degree of structure deterioration inflicted by stock can be minimized by removing stock for brief periods when the soil is close to its plastic limit.
© The Thompson Corporation

22. Curtailing grazing-induced erosion in a small catchment and its environs, the Peak District, Central England.
Evans, R.
Applied Geography 25(1): 81-95. (2005); ISSN: 0143-6228
Descriptors:   erosion/ grazing/ peat/ sheep/ vegetation colonisation
Abstract: Eroding slopes within a small catchment in the Peak District, Central England, and its environs have been monitored since 1966. A reduction in sheep grazing pressure in the late 1960s, due to a harsh winter and a poor crop of lambs, led to colonisation of bare soil on lower slopes, but not on higher exposed slopes. Sheep grazing pressure was permanently reduced in the 1980s as part of a new grazing regime. Many formerly eroding sheep scars in the small catchment have over time become completely colonised by vegetation and only those scars still actively used by sheep remain. It took two decades before vegetation began to invade the bare soil on the higher slopes. There, it was not until all the peat and the underlying leached (Ea) soil horizon was stripped off that vegetation was re-established. Colonisation is a rapid process and c.80% of the bare soil is covered within 5-10 years. Factors other than sheep grazing pressure that exacerbated erosion were a cooling climate in the 1960s and the presence of cattle on the slopes. Temperatures have risen since then and cattle no longer graze the slopes. © 2004 Elsevier Ltd. All rights reserved.
© 2006 Elsevier B.V. All rights reserved.

23. Dissolved organic carbon losses from grazed grasslands under different management regimes.
Mctiernan, K. B.; Jarvis, S. C.; Scholefield, D.; and Hayes, M. H. B.
Water Research 35(10): 2565-2569. (2001)
NAL Call #:   TD420.W3; ISSN: 0043-1354
Descriptors:   grasslands/ grazing/ fertilizers/ drainage/ watershed management/ organic carbon/ on-site investigations/ dissolved organic matter/ dissolved organic carbon/ soils/ drainage water/ nitrogen/ resource management/ waterlogged/ land (grass and pasture)/ land/ organic matter/ biogeochemistry/ soil/ glazed grassland
Abstract: Dissolved organic matter (DOM) is fundamental to many biogeochemical processes in soils and natural waters. Despite the large number of studies reporting on DOM losses from forest soils and in surface waters there is little published data on exports from managed grasslands. The objective of our study was to determine the extent of short-term exports of dissolved organic carbon (DOC) from managed grazed grasslands and to evaluate the influence of fertilizer management and drainage regime. DOC discharged from grazed grassland plots, with a range of management strategies, was determined over 2 months. Total export varied from 42 to 118 kg C ha super(-1), and was greater from some plots than literature estimates for annual losses from all catchment types. There was a significant (P = 0.048) positive correlation between DOC export and rates of nitrogen application for treatments with no artificial drainage. Increased dry matter production arising from increased fertilizer-N inputs is suggested as an important factor in this relationship. DOC export was significantly (P = 0.032) reduced by artificial drainage and adsorption of DOC to soil surfaces and the restriction of decomposition due to waterlogging are suggested as two possible explanations.
© CSA

24. A drained plot study of the impact of cutting and/or grazing management and N fertilization on nitrate leaching under grassland.
Decau, M. L. and Le Corre, L.
In: Grassland and Society: 15th General Meeting of the European Grassland Federation. (Held 6 Jun 1994-9 Jun 1994 at Wageningen, Netherlands.)
Wageningen, Netherlands: Wageningen Pers; pp. 382-386; 1994.
NAL Call #:  QK938.P7E97 1994; ISBN: 9074134157
Descriptors:   book chapter/ meeting poster/ nitrogen/ pollution/ soil
© The Thompson Corporation

25. Economic and environmental impacts of pasture nutrient management.
Osei, E.; Gassman, P. W.; Hauck, L. M.; Neitsch, S.; Jones, R. D.; McNitt, J.; and Jones, H.
Journal of Range Management 56(3): 218-226. (2003)
NAL Call #:   60.18 J82; ISSN: 0022-409X
Descriptors:   dairy cows/ grazing/ stocking rate/ soil nutrient balance/ nutrient management/ nitrogen/ phosphorus/ simulation models/ dairy farm management/ production costs/ farm size/ fertilizer application/ application rate/ agricultural runoff/ costs and returns/ pollution control/ Texas
Abstract: Highly intensive stocking of dairy cattle on continuously grazed pasture coupled with liberal applications of commercial fertilizer can lead to increased losses of agricultural nutrients, which is a concern for water quality of receiving lakes and surface water resources. Integrated economic-environmental model simulations performed for the Lake Fork Reservoir Watershed in northeast Texas indicate that appropriate pasture nutrient management including stocking density adjustments and more efficient commercial fertilizer use could lead to significant reductions in nutrient losses. Soluble and organic P losses were predicted to decline by 54 and 13% relative to baseline conditions when manure P was assumed totally plant available (Low P scenario). The soluble and organic P loss reductions declined to 33 and 7% when only inorganic P was assumed plant available (High P scenario). Simulation of an N-based manure management plan resulted in the smallest predicted soluble and organic P loss reductions of 18 and 3%. Nitrogen loss predictions ranged from a 7% decline to a 1% increase for the 3 scenarios as compared to the baseline. The High P and Low P scenarios resulted in estimated aggregate profit reductions of 6 and 18% relative to the baseline. These profit declines occurred because the dairies had to acquire additional pasture land to accommodate the expanded area required for the P-based scenarios. In contrast, the N-based stocking density and nutrient management scenario resulted in an aggregate profit increase of 3% across all dairies. Variations in economic impacts were also predicted across farm sizes.
This citation is from AGRICOLA.

26. Effect of cattle and sheep treading on surface configuration of a sedimentary hill soil.
Betteridge, K.; Mackay, A. D.; Shepherd, T. G.; Barker, D. J.; Budding, P. J.; Devantier, B. P.; and Costall, D. A.
Australian Journal of Soil Research 37(4): 743-760. (1999)
NAL Call #:   56.8 Au7; ISSN: 0004-9573
Descriptors:   downward movement/ grazing/  pastures/ disturbed soils/ grassland soils/ soil types/ soil compaction/ soil physical properties/ upland soils/ livestock/ soil mechanics/ trampling/ surface roughness
Abstract: Pastures with a 6-year history of grazing by cattle (cattle pasture) and sheep (sheep pasture) in New Zealand were used to measure the effects on soil disturbance of a single severe grazing/treading event by sheep (S), one by cattle (C1), or 2 events within 3 weeks by cattle (C2). Treatments were stocked at 35 500 kg LW [liveweight]0.9/ha (? 200 cattle/ha) for 48 h when the soil was wetter than the plastic limit. A control plot (untrodden, U) was grazed only lightly by sheep to control pasture cover while causing minimal observable surface damage. Change in surface contour, random roughness, soil surface damage, and pasture cover were determined with a 'contometer'. The construction and use of the contometer to measure change in microtopography and to describe the soil surface and vegetative state by grazing is described. Disturbance was calculated as the change in height (mm) of soil level at fixed positions along transects within treatment plots. Both sheep and cattle pastures were affected similarly (P >0.05) in relation to absolute and net disturbance of soils. Averaged across both pasture types, very little absolute surface soil disturbance was measured on S, whereas cattle-treading caused significant upward and downward movement of soil. Mean (+or-s.d.) absolute surface disturbance (sum of upward and downward movement on a transect) was greater by cattle (C1, 11.2 +or-8.1; C2, 9.9 +or-5.0 mm) than by sheep (5.1 +or-1.8 mm) (P <0.01) after the single treading and 9.0 +or-4.1 mm for C2 after the second treading. Net disturbance (average of upward and downward movement on a transect) was 1.9 +or-4.0, 1.8 +or-4.0, and 3.0 +or-1.8 mm for C1, C2, and S (P >0.05), respectively, after the first treading and 4.1 +or-3.7 mm for C2 after the second treading. Cumulative net disturbance resulting from C2 on sheep pasture was greater than cattle pasture (P <0.05), especially after the first treading, which suggested sheep pasture was more susceptible to compaction than the previously damaged cattle pasture. Random roughness and percentage of surface soil penetrated by hooves, based on observation, was greater with cattle than sheep treading. Random roughness increased (P <0.07) following treading of sheep than of cattle pastures. It was concluded that the effect on soil surface configuration of severe short-term treading events on wet soils was greater by cattle than by sheep stocked at the same metabolic liveweight per hectare and that this occurred irrespective of the previous grazing history. Although absolute disturbance in each of the 2 cattle treadings in C2 was similar, net disturbance (compaction) on sheep pasture was more than twice that on cattle pasture (P <0.05) .
© CAB International/CABI Publishing

27. Effect of grassland management on nitrogen mineralization potential, microbial biomass and nitrogen yield in the following year.
Hassink, J.
Netherlands Journal of Agricultural Science 40(2): 173-185. (1992)
NAL Call #:   12 N3892; ISSN: 0028-2928
Descriptors:   fertilizer/ grazing/ herbage dry matter production/ mowing
Abstract: The effect of mowing or grazing and mineral fertilizer level on N mineralization potential and microbial biomass N (N flush) was studied in 1988 on a sandy soil and a sedimentary calcareous silty loam (loam). On the loam the residual effect of the treatments on N yield and herbage dry matter accumulation in the following year was also studied. The different management practices were started in 1985 on the sandy soil and in 1986 on the loam. The amount of microbial biomass N was larger under grazing than under mowing. The increase in the amount of microbial biomass N due to grazing was larger for the loam than for the sandy soil. The N-mineralization rate was higher under grazing than under mowing. The difference in N-mineralization rates between grazed and mown fields was 20-30% in April for both soils, but increased considerably in the sandy soil during the growing season. It was estimated that the difference in N-mineralization between mown and grazed plots under field conditions was 110 and 40 kg N ha-1 year-1 in the sandy soil and the loam, respectively. Thus the optimus N fertilizer application rate should be considerably lower under grazing conditions than under mowing conditions, especially on sandy soil. Fertilizer level had no effect on the amount of microbial biomass and rates of N-mineralization. Both grazing compared to moving and increasing N fertilizer levels above 550 kg N ha-1 year-1 affected the N yield and dry matter accumulation in the following year (= residual effects) on the loam. These effects were greater for N yield than for dry matter accumulation. The residual effect of previous fertilizer input was proably caused by the presence of different amounts of N in roots and stubble. The residual effect on N yield under grazing exceeded that under mowing by 28%.
© The Thompson Corporation

28. Effect of grassland management on the amounts of soil organic nitrogen and carbon.
Hassink, J. and Neeteson, J. J.
Netherlands Journal of Agricultural Science 39(4): 225-236. (1991)
NAL Call #:   12 N3892; ISSN: 0028-2928
Descriptors:   grazing/ mowing/ fertilizer
Abstract: In the period 1985-1990 field trials with N fertilization, grazing and mowing were conducted on a sandy soil and a loamy soil to investigate the accumulation of organic N and C in intensively managed grassland systems. Annual fertilizer rates of N varied from 250 to 700 kg ha-1 under grazing and from 0 to 700 kg ha-1 under mowing. On the grazed plots no significant accumulation of soil organic N occurred in the sandy oil, whereas in the loamy soil an average N accumulation of 245 kg ha-1 yr-1 was found. The accumulation in the loamy soil was probably caused by the marine history of the soil and the fact that the soil was recently plowed and resown. The accumulation was independent of the level of fertilizer N applied, indicating that increased biomass production does not necessarily increase the return of dead organic material to the soil. These results confirm the suggestion that the surplus of fertilizer N is largely lost to the environment. About four years after the start of the experiment the amounts of soil N and C were considerably higher under grazing than under mowing. In spite of the higher amount of soil N under grazing compared to mowing, approximately 71% and 57% of the extra amount of N returned to the soil by grazing is lost to the environment on the sandy and the loamy soil, respectively. The C/N ratio of the soil organiz matter was lower in plots with fertilizer N application than in plots without fertilizer N. This difference was probably caused by a difference in C/N ratio of dead grass and roots that were returned to the soil.
© The Thompson Corporation

29. The effect of grazing on soil microbial biomass and community on alpin pastures.
Insam, H.; Rangger, A.; Henrich, M.; and Hitzl, W.
Phyton (Horn) 36(3): 205-216. (1996)
NAL Call #:   450 P565; ISSN: 0079-2047
Descriptors:   agronomy/ alpine pasture/ animal husbandry/ ecophysiology/ grazing/ litter quality/ respiration/ soil microbial biomass/ sol conditions/ terrestrial ecology
Abstract: Within in a multidisciplinary project the effect of termination of cattle grazing on grassland and forest on soil microbial properties was investigated. The changes of microbial biomass (C-mic), basal respiration and the ecophysiological parameters (metabolic quotient and the C-mic:C-org ratio) were small. Mainly in the dry summer of 1993 an increase of basal respiration, microbial biomass and the C-mic:C-org ratio was observed for the fenced in sites. The effects were not observed in the moist summer of 1995. For the pasture site, a substrate utilization assay employing 95 different C sources (Biolog) indicated some changes in the functional abilities of the bacterial communities after 9 years of protecting the site from grazing. The changes were attributed to a change of litter quality.
© The Thompson Corporation

30. The effect of improved pastures and grazing management on soil water storage on a basaltic plains site in south-west Victoria.
Bird, P. R.; Jackson, T. T.; Kearney, G. A.; Saul, G. R.; Waller, R. A.; and Whipp, G.
Australian Journal of Experimental Agriculture 44(6): 559-569. (2004)
NAL Call #:   23 Au792; ISSN: 0816-1089
Descriptors:   rotational grazing: applied and field techniques/ basalt/ grazing management/ groundwater recharge/ pasture/ rainfall/ soil salinity
Abstract: Soil salinity of non-irrigated farmlands in Australia has been largely attributed to tree clearing and their replacement by annual pasture and crop species. This paper deals with the effects of sowing perennial ryegrass and greater inputs of fertiliser, and the effect of grazing management, on water use and the potential to improve recharge control on a gravelly soil derived from basalt. In 1991, neutron access tubes were inserted into plots on a project established in 1989 to examine the impact of upgrading the pasture on sheep productivity. These plots were subdivided in 1996 to examine the impact of grazing management (tactical v. set-stocking) and pasture type (pastures dominated by annual species v. upgraded pastures) on productivity. Neutron probe readings were taken periodically from tubes in each plot, at depth intervals of 25 cm (December 1991-March 1995) or 20 cm (August 1995-April 1999) to 170 cm. There was no effect of treatment on soil moisture. Data for 2 wet years (1995 and 1996) indicate that the effective soil water storage capacity to 170 cm depth for these pastures was a mean of 125 mm of water. This represents the potential buffer before winter rainfall exceeds the water use by the pasture, fills the soil profile to capacity and then either runs off or allows deep drainage to occur. We did not achieve a significant reduction in soil water storage, and therefore potential recharge of groundwater, by re-sowing the pasture with perennial ryegrass and applying more fertiliser, or by altering the grazing management to a form of rotational grazing. Compared with set-stocked annual pasture, the impact of such treatments was to reduce soil water storage to a depth of 170 cm in autumn by less than 20 mm/year. There was no association between total herbage production and soil water storage, however, an increased percentage of perennial ryegrass in the pasture was associated with a small reduction in soil water storage in 1 year. Greater use of soil water may depend upon using deeper-rooted perennials or maintaining a higher proportion of perennial species in the sward (the perennial ryegrass in the re-sown pastures declined from 53% in October 1996 to 4% in October 1998).
© The Thompson Corporation

31. The effect of livestock grazing on surface runoff and soil erosion from sloping pasture lands in the Ethiopian highlands.
Mwendera, E. J.; Saleem, M. A. Mohamed; and Dibabe, A.
Australian Journal of Experimental Agriculture 37(4): 421-430. (1997)
NAL Call #:   23 Au792; ISSN: 0816-1089
Descriptors:   livestock industry/ animal husbandry/ biobusiness/ grazing/ pasture land/ slope/ soil erosion/ soil science/ surface runoff
Abstract: Effects of livestock grazing on surface runoff and soil erosion at varying slopes were studied in pasture lands within Ginchi watershed, Ethiopia. The results showed that livestock grazing in the watershed followed distinct seasonal and spatial patterns. During the rainy season, grazing pressure was greatest on the upper slopes (gt 5% slope) while the pressure shifted to the lower slopes during part of the dry season. Seasonal grazing pressure in different parts of the watershed was further complicated by the fact that during the rainy season and immediately after the rains, grazing was limited to individually designated pasture lands while during most part of the dry season, the entire watershed became a common grazing resource for livestock of watershed residents as well as those farmers outside the watershed. It was observed that, on pastures above 4.2% slope, there is the risk of erosion rates exceeding the estimated soil loss tolerable limit under the current grazing pressures (heavy grazing), while slopes exceeding 5.8% are likely to suffer soil erosion under moderate grazing pressure at the current level of biomass productivity. Since livestock are mobile, farmers tend to take advantage of this attribute by seasonally moving the livestock to different parts of the watershed. This study has demonstrated the need for better understanding of the resource use patterns beyond the individual farmlands, most preferably at watershed level, so that on-site and off-site effects of seasonal concentration of livestock can be incorporated into developing feed production and management strategies for improving the system productivity and environmental protection.
© The Thompson Corporation

32. Effect of retention of run-off water and grazing on soil and on vegetation of a temperate humid grassland.
Alconada, M.; Ansin, O. E.; Lavado, R. S.; Deregibus, V. A.; Rubio, G.; and Gutierrez Boem, F. H.
Agricultural Water Management 23(3): 233-246. (1993)
NAL Call #:   S494.5.W3A3; ISSN: 0378-3774
Descriptors:   temperate zones/ grasslands/ runoff farming/ grazing/ water management/ animal husbandry/ temperate grasslands/ water relations/ trampling  
Abstract: A 4-year field trial was carried out on a Typic Natraqualf to modify surface runoff, to change the soil water regime and improve forage productivity. Water was retained by earth banks which were built along contour lines. The area was grazed by cattle at a density of six animal units per hectare during five or six occupation periods per year. To study the effect of cattle trampling, 1 ha within the water retention area was excluded from grazing. It was found that surface accumulation of water led to higher soil water contents and prevented salt rising by capillarity from the water table (electrical conductivity of A1 horizon, 1.4 dS/m against 3.4 dS/m in the control area). Soil salinization in the control area was associated with soil water evaporative losses and a water table depth <1.5 m. Soil alkalinity (pH and SAR) showed variations closely related to salinity. The already impaired soil physical properties were not significantly affected by livestock trampling in the water retention area. A marked change in plant community composition was observed. Most halophytic species disappeared and the area was covered by hydrophilous grasses. This contributed to the fourfold increase forage. Runoff water retention proved to be a promising way to change temporarily the status of the soil and to cause a large change in grassland characteristics and productivity .
© CAB International/CABI Publishing

33. Effect of rotational grazing on selected physical properties of a gleyed brunisolic gray luvisol loam in Nova Scotia.
Rodd, A. V.; Papadopoulos, Y. A.; Laflamme, L. F.; Mcrae, K. B.; Fillmore, S. A. E.; and Wilson, R. W.
Canadian Journal of Soil Science 79(1): 117-125. (1999)
NAL Call #:   56.8 C162; ISSN: 0008-4271
Descriptors:   bulk density/ hydraulic conductivity/ penetration resistance/ physical properties/ rotational grazing/ gleyed brunisolic gray luvisol loam
Abstract: Low organic matter content and weak soil structure, combined with high annual precipitation, make the soils of the Maritime Provinces extremely susceptible to compaction. Although many pasture studies have been conducted in the Maritime Provinces, none has investigated the impact of pasturing cattle on soil physical properties. Soil properties such as resistance to penetration, bulk density and hydraulic conductivity were monitored on pasture swards receiving various rotational-grazing intensities. These parameters were measured concomitantly on traffic-free areas that had been harvested as conserved forage. Resistance to penetration measurements indicate that a significant amount of compaction by cattle occurred during the 1990, 1991 and 1992 grazing seasons. Penetration resistance was generally greatest in the top 6 cm of soil, but was alleviated by frost action during the subsequent winter and spring. The other soil parameters measured were either more variable (surface and subsurface saturated hydraulic conductivity) or less sensitive (bulk density) to compaction. Although more variable, surface hydraulic conductivity was significantly higher in the traffic-free conserved forage areas than in the pasture paddocks. Rest intervals between grazings had no significant effect on saturated hydraulic conductivity. Seasonal change in resistance to penetration generally increased as rest interval decreased. The timothy/alfalfa swards (little alfalfa was left in the pastures by 1992) had the least seasonal change in resistance to penetration.
© The Thompson Corporation

34. Effect of short term pastures on soil nitrogen status under contrasting management practices.
Williams, P. H. and Wright, C. E.
Proceedings Annual Conference Agronomy Society of New Zealand 27: 139-143. (1997)
NAL Call #:   S3.A37; ISSN: 0110-6589
Descriptors:   nitrogen fertilizers/ application rates/ grazing/ mineral uptake/ nutrient uptake/ seed production/ straw/ wheat/ nitrogen fixation/ residual effects
Abstract: In a field trial in 1993-95 at Lincoln, New Zealand, mixtures of Lolium perenne cv. Grasslands Supernui and Trifolium repens cv. Grasslands Tahora were grazed by sheep or managed for seed production. Under grazing, T. repens fixed 55 kg N ha-1 year-1, and the net input to the soil was 84 kg N ha-1 over the two years. In the first year under seed production when L. perenne seed was harvested, T. repens fixed only 21 kg N ha-1, but 100 kg N ha-1 was applied in fertilizer. In the second year, when L. perenne was killed by herbicide and T. repens seed harvested, 134 kg N ha-1 was fixed and 25 kg N ha-1 fertilizer was applied. However, N was removed in harvested seed (15 kg N ha-1 in L. perenne seed and 30 kg N ha-1 in T. repens seed) and L. perenne straw (65 kg N ha-1). Overall, the net input of N to the soil under seed production (157 kg N ha-1) was greater than under grazing (84 kg N ha-1). Despite the higher net N input to the soil under seed production, there was no evidence that this had a beneficial effect on wheat cv. Sapphire in a subsequent greenhouse pot trial, and there was a higher dry matter yield and N uptake from the wheat following grazing than seed production. The carryover effect of the two management practices on the wheat appeared to be linked to the form of N added to the soil, rather than the total amount of N added .
© CAB International/CABI Publishing

35. Effect of two different grazing intensities on the rotational methods with dairy cattle: Nutrients recycling in the soil from the dairy cattle feces.
Reyes, J.; Vidal, Ibis; Gonzalez, Maria R.; Gonzalez, Rosa M.; and Fonte, Damaris
Cuban Journal of Agricultural Science 37(2): 161-166. (2003)
NAL Call #:   S1.R4; ISSN: 0864-0408
Descriptors:   grazing rotation method: applied and field techniques/ dung patches/ red ferrallic soil
Abstract: For determining the contribution of cattle feces to the soil in each grazing intensity with low inputs, a study was conducted for four years on a red ferrallic soil planted with star grass (Cynodon nlemfuensis) and submitted to two grazing intensities (high (HI), 184.4 LAU/ha and low intensity (LI), 101.2 LAU/ha, as average). High stocking rates, 3.7 and 3.2 LAU/ha/year, for HI and LI, respectively, were used. The statistical analysis used was a linear model of fixed effect. Treatment, season, year and their interaction were controlled. The results showed that the number of dung patches deposited in the paddocks (dung patches/animal/d) did not differ between treatments; while the highest (P<0.05) number of dung patches was reported in the rainy season. The deposition of total dung patches (dung patches/ha/year) was higher (P<0.01) in the four years with HI, in 37.2, 30.4, 18.3 and 15.0%, respectively, compared to LI. The percentage of the area covered by the dung patches did not surpass 10.5% in any case. However, the method of HI surpassed (P<0.001) to that of LI in all the years (2.7, 1.4, 1.2 and 1.2 more from the first to the fourth year, respectively). The contribution of organic matter was higher in the four years (P<0.01) in the HI method (868.2, 698.3, 692.9 and 1104.9 kg of organic matter/ha/year), while the contribution of nitrogen, phosphorus and potassium by total feces (dung patches and urine) was higher (P<0.001) in HI, which represented 29.1, 40.9 and 24.6% for nitrogen, phosphorous and potassium, respectively, as average. The results confirmed that the contribution of nutrients to the soil is higher by using higher grazing intensities. However, further studies are suggested to prove that there is a balance in the system, in general, and in the soil, in particular, with thees intensities.
© The Thompson Corporation

36. Effect of urine volume on nitrate leaching in the northeast USA.
Stout, W. L.
Nutrient Cycling in Agroecosystems 67(2): 197-203. (2003)
NAL Call #:   S631 .F422; ISSN: 1385-1314
Descriptors:   field experiment: applied and field techniques/ large drainage lysimeter: field equipment/ Hagerstown silt loam soil: fine, mesic typic hapludalf, mixed/ grazing/ nitrate leaching: urine volume effects/ water quality
Abstract: To investigate how the urine volume (i.e. size of cow) affects how much NO3-N is leached from a urine deposition in the climatic conditions of the northeast USA, a field study using large drainage lysimeters to measure NO3-N leaching loss from synthetic urine applied in spring, summer and fall in 1-, 2-, and 3-1 volumes to an orchardgrass (Dactyls glomerata L., c.v. 'Pennlate') sward was conducted from April 1997 to March 1999. The study site was located in central Pennsylvania on a Hagerstown silt loam soil (fine, mixed, mesic Typic Hapludalf). It was found that increasing urine volume increased the amount of urine N leached but had no significant effect on the apparent percent of urine N leached. The apparent percent of urine N leached was 25% averaged over all treatment times and volumes and was 21% for spring and summer applied urine and 32% for fall applied urine.
© The Thompson Corporation

37. The effects of agricultural management on the soil biota of some upland grasslands.
Bardgett, R. D.; Frankland, J. C.; and Whittaker, J. B.
Agriculture, Ecosystems & Environment 45(1-2): 25-45. (1993)
NAL Call #:   S601 .A34; ISSN: 0167-8809
Abstract: Soil Collembola, in particular the fungal-feeding Onychiurus procampatus, were selected for further study. Field sampling revealed simultaneous trends of decreasing Collembola numbers and increasing total hyphal length and biomass of fungi in the surface soil, together with differences in chemical and physical soil properties, along a gradient of reduced sheep management intensity. Similar changes occurred when sheep grazing was removed by fenced exclosures. The relative abundance of the seven most commonly isolated species of litter fungi varied along the same gradient of sheep management. -from Authors
© 2006 Elsevier B.V. All rights reserved.

38. Effects of animal traffic on soil compaction in wheat pastures.
Krenzer, E. G.; Chee, C. F.; and Stone, J. F.
Journal of Production Agriculture 2(3): 246-249. (1989)
NAL Call #:   S539.5.J68; ISSN: 0890-8524
Descriptors:   Triticum aestivum/ Bos taurus/ conservation tillage/ grazing seasons/ agriculture/ agribusiness/ crop industry/ yield growth/ Great Plains, USA/ bulk density/ gravimetric soil moisture/ soil strength
Abstract: Grazing of hard red winter wheat (Triticum aestivum L.) in the U.S. southern Great Plains during the fall and winter, followed in the summer by the harvesting of grain, has been of great economic importance. With the increase in conservation tillage, however, there is growing concern that the compaction effects grazing has on the soil may not be eliminated by subsequent tillage. This study was conducted to quantify the extent to which soil compaction occurs as a result of animal traffic on wheat pasture. Of the three locations that were evaluated in the 1986-1987 growing season, two were on a silt loam soil and the third a sandy loam. Cattle (Bos taurus) grazed wheat until the early joint stage of growth, and measurements of soil strength, soil moisture, and bulk density were taken before initiation of grazing and immediately after grazing termination. Bulk density measurements and gravimetric soil moisture evaluations were made at 1.2 in. increments through the soil profile to a depth of 16.5 in. Data for soil strength evaluation, using a mechanical cone penetrometer, were collected at 0.8 in. increments also to a depth of 16.5 in. Increases in both the bulk density and the soil strength of the grazed areas were found in all three sites, although the depth to which the differences were measured varied from site to site. Animal traffic increased bulk density by as much as 16% and soil strength by 270% in surface zones. In the sandy loam soil, the bulk density was increased to a depth of 8 in. and the soil strength to 12 in.; while in the silt loam soils, the bulk density was increased only 5 in. These data indicate that compaction does result from grazing wheat pasture and may extend to a depth where some tillage practices may not eliminate it. The possible effects that this compaction may have on wheat growth and its yield, and the tillage practices necessary to alleviate this compaction require further study.
© The Thompson Corporation

39. Effects of cattle grazing and BMPs on stream water quality.
Agouridis, C. T.; Edwards, D. R.; Workman, S. R.; Bicudo, J. R.; Taraba, J. L.; Vanzant, E. S.; and Gates, R. S.
In: 2004 ASAE Annual International Meeting. (Held 1 Aug 2004-4 Aug 2004 at Ottawa, Ontario, Canada .); pp. 2251-2277; 2004.
NAL Call #:  S671.3 .A54
Descriptors:   bacteria/ best management practices/ nutrients/ stream
Abstract:  Cattle production is a major component of Kentucky's agricultural economy, accounting for approximately 15% of the total agricultural sales in 2000. There are over 2.2 million beef cattle and calves in the state making Kentucky the number one beef producer east of the Mississippi River. Research into the effects of cattle grazing on stream water quality has been well documented in the western portion of the United States with some estimates indicating that 80% of the damage to riparian areas was caused by grazing livestock. However, the impacts of grazing cattle in a humid environment may differ significantly from those witnessed in the arid West. Furthermore, relatively little information exists regarding the effectiveness of grazing best management practices (BMPs), such as alternate water sources, alternate shade sources, supplemental feeding, and riparian buffers, for improving the water quality of streams in grazed watersheds of the humid region. As part of a larger research endeavor into cattle production practices in the humid region, water samples were collected over a two year period at the project site located on the University of Kentucky's Animal Research Center. The project sites consisted of two replications of three treatments: control, selected BMPs with free access to the stream, and selected BMPs with limited access to the stream. Grab samples were collected at the upstream and downstream pasture edges. Samples were analyzed for nitrate-nitrogen, ammonium-nitrogen, total Kjeldahl nitrogen, dissolved orthophosphate, total phosphorus, total suspended solids, pH, chemical oxygen demand, five-day biochemical oxygen demand, fecal conforms, and fecal streptococci. Results indicated that minimal water quality benefits were incurred by implementing the BMP systems (i.e. treatments). One of the most substantial understandings gleaned from the project was the importance of upstream land use, and to some degree soils, when attempting to identify significant treatment effects within a small reach. Additionally, the karst geology, which is characteristic of the Bluegrass Region of Kentucky, influenced the rate of transport (i.e. flashy system with quick response time to rainfall) of nutrients from upland areas (i.e. row crops), especially along Pin Oak. These external factors may have resulted in the lack of uniformity in significant constituent concentration differences between the two streams when cattle were present. Furthermore, the background constituent concentration levels may have prohibited the identification of treatment effects. Results from this project indicated that minimal water quality benefits were incurred by implementing a BMP system (with or without a partially excluded riparian zone). However, these results may differ if cattle were completely excluded from the stream or if the BMP system was implemented at a site with larger pastures, different geology (nonkarst), soils (low in phosphorus), or stream morphology (nonbedrock bottom channel).
© 2006 Elsevier B.V. All rights reserved.

40. Effects of cattle treading and natural amelioration on soil physical properties and pasture under dairy farming in Southland, New Zealand.
Drewry, J. J. and Paton, R. J.
New Zealand Journal of Agricultural Research 43(3): 377-386. (2000)
NAL Call #:   23 N4892; ISSN: 0028-8233
Descriptors:   air permeability/ cattle/ compaction/ hydraulic conductivity/ macropores/ pugging/ treading
Abstract: The effects of current dairy cow grazing practice, reduced levels of grazing, and stock exclusion on soil physical properties and pasture dry matter production were investigated under dairy farming in Southland. Current grazing practice involves rotational grazing with dairy cows from September to May each year, with no grazing during winter. For the reduced grazing treatments, cattle were excluded during the 3rd, or combined 3rd, 4th, and 5th grazing cycles, or for half-day grazing intervals to reduce grazing intensity. Macroporosity increased by 70% in the ungrazed treatment compared with current grazing practice (control) within four months of dairy cow exclusion. Air permeability was increased by over two orders of magnitude 18 months after trial commencement, and saturated hydraulic conductivity increased by 200% to the 10-cm soil depth. Macroporosity, air permeability, and hydraulic conductivity for the reduced grazing treatments were intermediate between the control and ungrazed treatments. Relationships between macroporosity and pasture relative yield are presented. At 97% relative pasture yield, the level of macroporosity was 11.5-11.7% (v/v) in three silt loams.
© 2006 Elsevier B.V. All rights reserved.

41. Effects of exclosure and management on biomass and soil nutrient pools in seasonally dry high country, New Zealand.
McIntosh, Peter D.; Allen, Ralph B.; and Scott, Neal
Journal of Environmental Management 51(2): 169-186. (1997)
NAL Call #:   HC75.E5J6; ISSN: 0301-4797
Descriptors:   benmore range/ calcium/ carbon/ conservation/ fertilization/ grazing/ magnesium/ nitrogen/ nutrient/ nutrient pools/ phosphorus/ potassium/ rainfall/ root biomass/ soil acidification/ soil quality/ South Island/ sustainable pastoral use/ tussock grasslands
Abstract: We examined the effects of grazing and three exclosure treatments (no grazing, no-grazing plus oversowing, and no grazing plus oversowing plus fertilizer) on soils (Ustochrepts) and biomass of tussock grasslands on hill country under a mean annual rainfall of about 500-600 mm in the Benmore Range, South Island, New Zealand. Excluding grazing by sheep and rabbits for 15 years, with no oversowing or fertilizer, resulted in a two- to three-fold increase in the total biomass (roots+litter+herbage) relative to the grazed treatment. On all three exclosure treatments root biomass was approximately doubled in relation to root biomass on the grazed treatment. With the exception of Mg, total nutrient pools in biomass plus soil were lowest in the grazed treatment. Oversowing alone, without added fertilizer, maintained soil pH at pre-exclosure values and prevented exchangeable Ca, Mg and K decline, but had no significant effect on soil C, N or P. In contrast, oversowing and fertilizing had the effect of increasing soil C and N by 5.7 t/ha and 0.6 t/ha respectively, relative to the ungrazed treatment, and by 8.7 t/ha and 0.87 t/ha respectively, relative to the grazed treatment. Under ungrazed, grazed, and the oversown +fertilizer treatments pH declined relative to pre-exclosure values and values on the oversown treatment. The lower pH under the oversown +fertilizer treatment was attributed to the direct and indirect acidifying effects of elemental S fertilizer, while the lower pH of the ungrazed treatment was attributed, in part, to the acidifying effect of Hieracium pilosella, with both cation removal by animals and Hieracium effects likely to have lowered pH in the grazed treatment. A positive balance of 425 kg/ha of Ca, 680 kg/ha of K and 1900 kg/ha of N remained in total biomass plus soil on the oversown +fertilizer treatment, after fertilizer additions and previous herbage removals were taken into account. The positive Ca and K balance was attributed to release of nutrients by soil weathering, and the N balance to N fixation by legumes. Grazing of seasonally dry South Island tussock grasslands on hilly land, even at the present low levels, without fertilizing, appears incompatible with the maintenance of soil pH and carbon and total soil and biomass nutrients.
© The Thompson Corporation

42. Effects of grassland management practices and environmental conditions on nutrient concentrations in overland flow.
Kurz, I.; Coxon, C.; Tunney, H.; and Ryan, D.
Journal of Hydrology 304(1-4): 35-50. (2005)
NAL Call #:   292.8 J82; ISSN: 0022-1694
Descriptors:   grasslands/ grassland soils/ overland flow/ nitrogen/ phosphorus/ losses from soil/ nonpoint source pollution/ agricultural runoff/ soil fertility/ grazing/ nitrogen fertilizers/ fertilizer application/  Irish Republic
Abstract: The loss of nutrients from agricultural land to water bodies is a serious concern in river basin management in many countries. To gain information on the contributions of agricultural grassland to the eutrophication of water bodies, this study set out to assess phosphorus (P) loss from grassland areas on poorly drained soils. A second aim was to look at the impact of grassland management practices on nutrient concentrations in overland flow. Edge-of-field measurements of overland flow quantity and of P and nitrogen (N) concentrations in overland flow were carried out at three study sites with different soil P levels. The amounts of overland flow and the P concentrations in overland flow varied considerably during events, and among sites and events. Despite this variability, there was a clear increase in P loss in overland flow from the low to the medium and high soil P sites. The inter-site variability of the P concentrations in overland flow greatly exceeded the variability of the amounts of overland flow from the different sites. Thus, P concentrations had a larger impact than the volume of overland flow on the differences in P exports from the three sites. Management practices which, at times, influenced the P and N concentrations in overland flow were grazing and N fertilisation.
This citation is from AGRICOLA.

43. Effects of riparian grazing and channelisation on streams in Southland, New Zealand: Channel form and stability.
Williamson, R. B.; Smith, R. K.; and Quinn, J. M.
New Zealand Journal of Marine and Freshwater Research 26(2): 241-258. (1992)
NAL Call #:   QH91.57.A1N4; ISSN: 0028-8330
Descriptors:   river banks/ grazing/ erosion/ agriculture/ channels/ vegetation cover/ riparian environments/ geomorphology/ streams/ New Zealand, South I., Southland/ New Zealand/ sheep and cattle grazing/ channelisation/ streams/ vegetation cover
Abstract: The effects of mixed sheep and cattle grazing of stream margins, channelisation, and the benefits of riparian retirement were assessed through a survey of five streams in Southland, New Zealand. There is no evidence that grazing streambanks in floodplain streams of northern Southland will lead to rapid and severe deterioration of channel form, except in small streams (< 2 m wide) under intensive grazing of wet streamside soils. Generally, the dominant erosion mechanism--the undercutting of banks--is largely unaffected by grazing stream margins. In contrast, channelisation has led to severe streambank and streambed erosion in two of the three streams examined. The major factor in this degradation appears to be straightening and deepening the channel so that underlying uncohesive shingle is exposed to high flows. Riparian retirement had variable effects depending on the stability of the stream channel. On smaller, relatively inactive channels, it reduced localised bank erosion from livestock trampling, especially at cattle crossings. However, this damage (which sometimes can be quite visible) did not lead to significant change in average channel form or width in the 7-15 years since the land has been converted to intensive agriculture from extensively grazed tussock.
© CSA

44. Effects of sheep grazing episodes on sediment and nutrient loss in overland flow.
Elliott, A. H. and Carlson, W. T.
Australian Journal of Soil Research 42(2): 213-220. (2004)
NAL Call #:   56.8 Au7; ISSN: 0004-9573
Descriptors:   runoff/ sediments/ nutrient loading/ rainfall/ infiltration/ phosphorus/ particulates/ nutrient loss/ growth/ agriculture/ nitrogen/ grasses/ grazing/ nutrients/ overland flow/ infiltration rate/ rainfall simulators/ sheep/ risk/ growth rates/ farms/ pollution load/ baseline studies/ sediment load/ nitrogen compounds/ New Zealand, North I., Waikato/ grazing
Abstract: The effect of sheep grazing on the loss of sediment and nutrients in overland flow was investigated on a hill-country farm in the Waikato, New Zealand. The losses were measured in runoff produced artificially with small (0.5 m super(2)) and large (1050 m super(2)) rainfall simulators. Immediately after intensive winter grazing, rainfall applied at high intensity increased concentrations by a factor of 13-16 for sediment and particulate nutrients, 33-76 for dissolved reactive phosphorus and ammonium-nitrogen, and 5-7 for dissolved organic nitrogen and phosphorus. During summer, when there was less removal of vegetative cover, there was a smaller effect of grazing. The concentrations of sediment and particulate nutrients in overland flow were strongly correlated with the percentage of bare ground. The concentrations returned to background levels within 6 weeks after grazing, and the infiltration rate and ground cover also recovered from grazing in this time. The small rainfall simulator experiments showed that the infiltration rate decreases with grazing, which results in greater runoff after grazing. The greater runoff combines with the increased concentrations to give higher loads after grazing. In late winter, the infiltration rates were approximately half the summer values and the soil erodibility was approximately double, so the risk of high sediment and nutrient loads is greatest in winter, especially considering the higher rainfall and lower grass growth. The management implications are that exposure of bare ground associated with intensive grazing should be avoided, especially in winter.
© CSA

45. Effects of soil texture and grassland management on soil organic C and N and rates of C and N mineralization.
Hassink, J.
Soil Biology and Biochemistry 26(9): 1221-1231. (1994)
NAL Call #:   S592.7.A1S6; ISSN: 0038-0717
Descriptors:   grassland soils/ soil organic matter/ carbon/ nitrogen/ mineralization/ soil texture/ range management/ age/ nitrogen fertilizers/ mowing/ grazing/ carbon nitrogen ratio/ application rate
Abstract: The effects of soil texture and grassland management, i.e. rate of fertilizer N input, mowing vs grazing, and the number of years the site is under grass, on the amounts of soil organic C and N and on the rates of C and N mineralization were investigated. A positive relationship was found between the amount of organic N in the soil and the clay + silt content.  The relationship was affected by the groundwater table.  There was a negative relationship between the percentage of soil N mineralizing during incubation and the clay + silt content of the soil. The amount of organic C was only positively correlated with soil texture in the soils with a high water table, but the relationship was less clear.  Except for the groundwater table, differences in the C-to-N ratio of the soil organic matter in sandy soils confused the relationship of soil organic C with soil texture. Organic matter in podzol soils had C-to-N ratios between 15 and 20 while in other sandy soils the C-to-N ratio ranged from 10 to 18; in loams and clays the C-to-N ratio was ca 10.  The percentage of soil C mineralizing in sandy soils was negatively correlated with the C-to-N ratio of the soil organic matter.  The sandy soils with a C-to-N ratio > 16 that were used for incubation contained black humus including small charcoal particles; both other sandy soils with a lower C-to-N ratio contained brown humus without visible charcoal particles.  So we hypothesize that sandy soils with a high C-to-N ratio contained more inert C than sandy soils with a low C-to-N ratio. The rate of N fertilization had no effect on soil organic C and N nor on the rates of C and N mineralization. Differences between the effects of grazing and mowing on soil organic C and N and the rate of C and N mineralization were very small and not very consistent. Both the amounts of soil organic C and N found and the rates of C and N mineralization were significantly higher in old grassland (10 yr) than in young grassland (1-3 yr).  The increases in the mineralization rates were larger than the increases in soil organic C and N.
This citation is from AGRICOLA.

46. Effects of the nitrification inhibitor dicyandiamide on potassium, magnesium and calcium leaching in grazed grassland.
Di, H. J. and Cameron, K. C.
Soil Use and Management 20(1): 2-7. (Mar. 2004)
NAL Call #:   S590.S68; ISSN: 0266-0032
This citation is from AGRICOLA.

47. Effects of trampling by cattle on the hydraulic and mechanical properties of soil.
Pietola, L.; Horn, R.; and Yli Halla, M.
Soil and Tillage Research 82(1): 99-108. (2005)
NAL Call #:   S590.S48; ISSN: 0167-1987
Descriptors:   clay/ deformation/ Entisols/ environmental impact/ grassland soils/ grazing/ hydraulics/ Inceptisols/ infiltration/ macropores/ pastures/ porosity/ runoff/ runoff water/ sandy loam soils/ soil compaction/ soil mechanics/ soil structure/ soil types/ trampling  
Abstract: Destroyed soil structure can increase surface runoff water, with adverse environmental impacts. The effects of trampling by cattle on physical parameters of a heavy clay (a Typic Cryaquept) were studied at the followings four Site types of a pasture after grazing for three seasons: (1) grass with no visible trampling; (2) pasture with some trampling; (3) vicinity of a drinking site with some signs of penetrated hooves, and; (4) a drinking site with totally homogenized surface soil and destroyed vegetation. Additionally, Site types 1 and 4 were studied on sandy loam (an Aquic Cryothent) derived from glacial till after one grazing season. Steady state infiltration rates were reached after 15-35 min of infiltration, depending on the degree of trampling and soil texture. On the sandy loam the infiltration rate at the drinking site was only 20% of that under natural pasture with no visible trampling. When the trampling occurred for longer periods in a soil with higher clay content, the infiltration rate of drinking site was only 10-15% of that in non-trampled pastures. These findings could be explained by a reduced porosity for both soils. In heavy clay at the depth of 10-15 cm, macropores (O>30 micro m) decreased from 5 to 1.5% (v/v) by the most severe trampling and mechanical strength was lost near the soil surface (cohesion ~1 kPa). Deeper at 10-13 cm, cohesion (at water potential of -6 kPa) was near 30 kPa at the drinking site but around 20 kPa in non-trampled sites. At the 20-23 cm depth of Site 4, the angle of internal friction value (35) for smaller stresses (<150 kPa) was reduced to smaller values (9) at greater strengths (150-300 kPa) due to a stress dependent aggregate strength and the conversion of a structured soil system to a mostly texture dependent one. The data showed that even a low intensity of grazing will reduce infiltration and hence increase susceptibility to erosion at the drinking sites .
© CAB International/CABI Publishing

48. The efficacy of controlling phosphorus loading: The case of management-intensive grazing.
Winsten, J. R. and Stokes, J. R.
Agricultural Systems 79(3): 283-303. (Mar. 2004)
NAL Call #:   HD1.A3; ISSN: 0308-521X
Abstract: Consolidation in US agriculture has led to fewer, larger farms. In the case of dairy in the Northeastern US, higher concentrations of animals near large population centers pose water quality problems that can be attributed to excessive soil nutrient levels. While new environmental policies and regulations are being developed and implemented to help manage such problems, research to determine the efficacy of alternative dairy production systems is needed. The research reported in this paper makes use of stochastic dynamic programming to determine optimal stocking densities, milk production levels, and feed rations for a hypothetical dairy farm using management-intensive grazing. A key feature of the model is that financial disincentives are placed on excessive accumulation of phosphorus in the farm's soils. The results show that under optimal management the cost of reducing soil phosphorus to acceptable levels across all states of nature modeled is approximately $524 per hectare per year. The optimal farm management strategy is to rapidly reduce the size of the dairy herd (as opposed to feeding for a lower level of milk production per cow) until soil phosphorus levels are under control.
This citation is from AGRICOLA.

49. Emission of nitrous oxide from some grazed pasture soils in New Zealand.
Carran, R. A.; Theobald, P. W.; and Evans, J. P.
Australian Journal of Soil Research 33(2): 341-352. (1995)
NAL Call #:   56.8 Au7; ISSN: 0004-9573
Descriptors:   grazing/ grassland soils/ trampling/ nitrogen/ nitrous oxide/ emission/ soil/ grasslands/ pastures  
Abstract: Nitrous oxide emissions from grazed pastures were measured at four sites in North Island, New Zealand, for a 2 year period. Sites differed in drainage class and N cycle characteristics. At two intensively farmed sites on Kairanga silt loam, which is poorly drained, daily emissions ranged from 0 to 100 g N/ha per day and annual emission was in the range 3-5 kg N2O-N/ha. Emissions occurred when the soil was near or above field capacity indicating denitrification was the probable source of N2O. Multiple regression analysis, using soil water content, NO3-, NH4+ and temperature, gave rsuperscript 2 = 0.44 and 0.57 at sites 1 and 2 respectively. Soil water content and NH4+ were significant variables. Emissions at a low fertility hillside site were low and an annual emission of 0.5 kg/N2O-N per yr, or less, was indicated. The highly fertile hillside site showed low emission values. It is suggested that grazing animals may have a significant impact on emissions through hoof damage on wet soils .
© CAB International/CABI Publishing

50. The environmental impact of nitrogen fertiliser use on dairy pastures.
Eckard, R. J.; Chapman, D. F.; White, R. E.; and Chen, D.
Australian Journal of Dairy Technology 59(2): 145-148. (2004)
NAL Call #:   44.8 Au74; ISSN: 0004-9433
Descriptors:   nitrogen abatement management: applied and field techniques/ climatic factors/ denitrification/ grazed dairy pasture/ seasonal variation/ volatilisation loss
Abstract: The use of fertiliser nitrogen (N) on dairy pastures in southeastern Australia has increased exponentially over the past 20 years, with more than 60% of dairy farmers applying between 25 and 50 kg N/ha at least once a year (Eckard and Franks 1998; Eckard et al. 2000). This increase in N use is of environmental concern due to the gaseous losses of NH3 and N2O and the leaching of NO3. Over the past 10 years, there has been an estimated 140% increase in N2O emissions from agricultural systems in Australia (AGO 2003). The application of both N fertiliser and urinary N to intensively grazed pasture can contribute to significant losses of NO3 during periods of high rainfall and drainage (Cameron and Scotter 1987). Few data are available quantifying N losses from intensive pasture-based dairy production systems in south-eastern Australia (Eckard 1998). This paper reviews the recent data of Eckard et al. (2003) and Eckard et al. (2004) reporting N losses through gaseous and leaching pathways from grazed dairy pastures, respectively, and proposes abatement management practices.
© The Thompson Corporation

51. Erosional effects of cattle on streambanks in Tennessee, U.S.A.
Trimble, S. W.
Earth Surface Processes and Landforms 19(5): 451-464. (1994)
NAL Call #:   GB400.E2; ISSN: 0197-9337
Descriptors:   bank erosion/ streams/ geomorphology/ livestock/ watershed management/ riparian vegetation/ agriculture/ grazing/ soil erosion/ river banks/ environmental impact/ vegetation cover/ ecosystem disturbance/ USA, Tennessee
Abstract: The geomorphological effects of cattle on streambanks in a humid region, which have consequent potential effects on water quality, are examined. Field observations suggest that cattle are important agents in causing streambanks to erode, but so many variables are involved that it is difficult to isolate the role of cattle. Instead, an empirical approach based on long-term controlled experiment was adopted along a small perennial stream in the central basin of Tennessee. The results showed that uncontrolled grazing caused about six times as much gross bank erosion as occurred on the protected control stretch. However, most of this difference was due to breakdown of banks by trampling and consequent erosion, rather than by bank scour caused by removal of bank vegetation by grazing. That is, bank vegetation alone did not appear to be a primary control. A relatively inexpensive grade-control structure reduced the gross bank erosion by about 50 per cent. The rapid destruction of streambanks observed in this study suggests that reduction of geomorphic resistance by uncontrolled stock access to streambanks has been an important factor in the stream widening that has taken place during historical time in the eastern United States.
© CSA

52. Evaluation of soil compaction in an irrigated short-duration grazing system.
Silva, A. P.; Imhoff, S.; and Corsi, M.
Soil and Tillage Research 70(1): 83-90. (2003)
NAL Call #:   S590.S48; ISSN: 0167-1987
Descriptors:   grazing/ grazing intensity/ grazing systems/ irrigation/ pastures/ resistance to penetration/ rotational grazing/ soil compaction/ soil degradation/ soil fertility/ soil physical properties/ soil water content/ stocking rate/ trampling  
Abstract: Reduction in pasture productivity is generally attributed to alterations in soil quality. Soil compaction due to animal trampling is one of the factors responsible for the degradation of the physical quality of soils under pasture. The objective of the study was to evaluate penetrometer resistance (PR) in an irrigated short-duration grazing system at three post-graze residue levels. PR and moisture were simultaneously measured in plots containing three different post-graze residue levels (1000, 2500 and 4000 kg dry material ha-1). The influence of soil moisture on PR was taken into account using regression analysis techniques. PR was significantly higher for the treatments characterized by a small amount of post-graze residue, while similar values were obtained for the other two treatments. From a management perspective, adopting an irrigated short-duration grazing system with high stocking rate may adversely affect the soil physical quality .
© CAB International/CABI Publishing

53. Faecal contamination over flood events in a pastoral agricultural stream in New Zealand.
Nagels, J. W.; Davies-Colley, R. J.; Donnison, A. M.; and Muirhead, R. W.
Water Science and Technology 45(12): 45-52. (2002)
NAL Call #:   TD420.A1P7; ISSN: 0273-1223.
Notes: Conference: 5. International Symposium on Waste Management Probelms in Agro-Industries, Shiga [Japan], 16-18 Nov 2001ISBN: 1843394197
Descriptors:   water pollution sources/ nonpoint pollution sources/ agricultural watersheds/ livestock/ flood flow/ bacterial analysis/ Escherichia coli/ experimental data/ data collections/ model studies/ streams/ fecal coliforms/ floods/ pollution (water)/ pollution (nonpoint sources)/ catchment areas/ livestock (see also individual animals)/ floods and flooding/ microbiological analysis/ bacteria (Enterobacteriaceae) (Escherichia)/ Escherichia coli/ New Zealand/ New Zealand, Morrinsville/ cattle
Abstract: Faecal bacterial dynamics during flood events were studied in the Topehaehae Stream near Morrinsville, New Zealand, in a catchment used for grazing dairy and beef cattle. During the rising limb of a natural flood event, E. coli bacterial concentration rose by more than 2 orders of magnitude and peaked at 41,000 cfu/100 mL. E. coli correlated closely with turbidity over the flood event, and both variables peaked close to the time of maximum flow acceleration rather than peak flow. An artificial flood on the same stream, created by releasing water from a supply reservoir during fine weather with no wash-in from the catchment, produced a broadly similar pattern of faecal contamination (peak E. coli = 12,500 cfu/100 mL). This and other evidence suggests that direct deposition of faecal matter by cattle in the stream channel may be of similar or greater importance than wash-in from land. The flood experiments have been useful for constructing a model of faecal bacterial yields, and they imply that exclusion of livestock from stream channels may appreciably improve water quality.
© CSA

54. Fecal bacteria in agricultural waters of the bluegrass region of Kentucky.
Howell, J. M.; Coyne, M. S.; and Cornelius, P.
Journal of Environmental Quality 24(3): 411-419. (1995)
NAL Call #:   QH540.J6; ISSN: 0047-2425
Descriptors:   karst/ cattle/ groundwater pollution/ coliforms/ feces/ Streptococcus/ agricultural runoff/ sampling/ nonpoint pollution sources/ surface-groundwater relations/ animal wastes/ livestock/ water pollution/ water supply/ fecal microflora/ fecal coliforms/ ground water/ agricultural pollution/ microbial contamination/ hazard assessment/ Enterococcus/ USA, Kentucky/ FC/ FS/ USEPA
Abstract: Agricultural runoff influenced by nonpoint pollution frequently exceeds the USEPA standards for bacterial contamination of primary contact water (200 fecal coliforms/100 mL). Few studies have evaluated the effect of cattle (Bos taurus) grazing on fecal contamination of groundwater in the karst topography of central Kentucky. Our objectives were to: (i) observe the extent and pattern of fecal bacteria in agricultural waters from two central Kentucky watersheds; (ii) determine if monthly sampling accurately assessed the extent and variability of fecal contamination; and (iii) assess the fecal coliform/fecal streptococci ratio (FC/FS) as an indicator of fecal bacteria source. Springs, streams, and wells in two agricultural watersheds typical of central Kentucky were monitored for fecal coliform and fecal streptococci from December 1991 to January 1993. Springs and wells exceeded primary contact water standards, between 28 and 74% of the time; streams exceeded water quality standards between 87 and 100% of the time. When fecal bacteria were present, rainfall rapidly moved them from the soil surface into spring and well water. At two springs in Fleming county, only 29% of samples exceeded primary contact standards before cattle were present; 80% exceeded standards after cattle began grazing the surrounding pasture. Monthly sampling adequately reflected the extent of fecal contamination in our study, which had relatively continuous cattle grazing. Although the FC/FS ratio identified domestic animal contamination sources, it did not distinguish between domestic animal and human sources of contamination.
© CSA

55. Fecal coliform and streptococcus concentrations in runoff from grazed pastures in northwest Arkansas.
Edwards, D. R.; Coyne, M. S.; Vendrell, P. F.; Daniel, T. C.; Moore, P. A.; and Murdoch, J. F.
Water Resources Bulletin 33(2): 413-422. (1997)
NAL Call #:   292.9 Am34; ISSN: 0043-1370
Descriptors:   agricultural runoff/ cattle/ coliforms/ Streptococcus/ pastures/ manure/ water quality standards/ grazing/ seasonal variations/ agricultural practices/ fecal coliforms/ fecal microflora/ pasture/ USA, Arkansas, Northwest
Abstract: Agricultural practices such as cattle grazing and animal manure application can contribute to relatively high runoff concentrations of fecal coliform (FC) and fecal streptococcus (FS). Available information, however, is inconsistent with respect to the effects of such practices as well as to measures that can discriminate among candidate sources of FC and FS. The objective of this study was to assess the effects of grazing, time of year, and runoff amounts on FC and FS concentrations and to evaluate whether FC/FS concentration ratios are consistent with earlier values reported as characteristic of animal sources. Runoff from four Northwest Arkansas fields was sampled and analyzed for fecal coliform (FC) and fecal streptococcus (FS) for nearly three years (1991-1994). Each field was grazed and fertilized, with two fields receiving inorganic fertilizer and two receiving animal manure. Runoff amount had no effect on runoff concentrations of FC or FS. There were no consistent relationships between the presence of cattle and FC and FS runoff concentrations. Both FC and FS concentrations were affected by the season during which the runoff occurred. Higher concentrations were observed during warmer months. Runoff FC concentrations exceeded the primary contact standard of 200 cfu/100 mL during at least 89 percent of all runoff events and the secondary contact standard of 1000 cfu/100 mL during at least 70 percent of the events. Ratios of FC to FS concentrations varied widely (from near zero to more than 100), confirming earlier findings that FC/FS ratios are not a reliable indicator of the source of FC and FS.
© CSA

56. Fecal contamination of pastoral wetlands.
Collins, R.
Journal of Environmental Quality 33(5): 1912-1918. (2004)
NAL Call #:   QH540.J6; ISSN: 0047-2425
Descriptors:   wetlands/ cattle/ solar radiation/ contamination/ bacteria/ grazing/ bacteria (enterobacteriaceae) (escherichia)/ catchment areas/ storms/ temperature/ rainfall/ high flow/ excretion/ statistical models/ storm seepage/ feces/ survival/ water quality control/ livestock/ water quality/  catchments/ seasonal variations/ mathematical models/ environmental quality/ Escherichia coli/ New Zealand
Abstract: Near-channel hill-country wetlands draining steep pastoral land in New Zealand exhibit high levels of fecal contamination at a range of flows. This contamination is attributed to both the transport of