Factors affecting nitrate leaching from a calcareous loam in East Anglia

SUMMARYThe effects of overwinter cover cropping, delayed ploughing and method of straw disposal on the quantities of nitrate leached (averaged over three winters during 1989–93) from a chalk loam in Eastern England were examined. The recovery of ‘retained’ nitrogen (retained through cover crop uptake, delayed ploughing and immobilization by straw) in a following spring crop was also assessed. In the first two winters, the rye cover crop decreased nitrate leaching by > 90% (28 kg N/ha per year), as compared with bare fallow treatments. In 1992/93 this decrease was only 23% (10 kg/ha), due to the early onset of drainage before cover was well established. Delayed ploughing on bare treatments, to decrease autumn N mineralization and subsequent nitrate leaching, was ineffectual in 1989/90 but had substantial effects in 1990/91 and 1992/93; N mineralization, inferred from soil mineral nitrogen content, and nitrate leaching were decreased by 31 and 35% in 1990/91 and by 36 and 61% in 1992/93, respectively. Nitrate leaching (averaged over three winters) was unaffected by straw incorporation. There was no evidence of recovery of cover crop N in the spring sown test crops (barley or sugarbeet). In the low soil N input situation encountered in this experiment, it was unnecessary to sow cover crops before early September in years of average or below average rainfall to ensure that the average soil solution concentrations remained below the EU drinking water limit of 11 mg NO3-N/1. However, in wetter seasons substantial N leaching occurred before cover had taken up much N. In 1992/93 N retained against leaching by a rye cover crop in previous years was apparently being remobilized and lost through leaching, although if cover was grown again there was less leaching than from bare land. In the future, an increase in the extent of cover cropping might increase transpiration rates and therefore lead to a decrease in aquifer recharge.

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NLEAP Computer Model and Multiple Linear Regression Prediction of Nitrate Leaching in Vegetable Systems

HortTechnology ◽

10.21273/horttech.12.2.250 ◽

2002 ◽

Vol 12 (2) ◽

pp. 250-256 ◽

Cited By ~ 2

Author(s):

Hudson Minshew ◽

John Selker ◽

Delbert Hemphill ◽

Richard P. Dick

Keyword(s):

Linear Regression ◽

Multiple Linear Regression ◽

Nitrate Leaching ◽

Cover Crops ◽

N Uptake ◽

N Leaching ◽

Residual Soil ◽

Vegetable Crops ◽

Crop N Uptake ◽

Mlr Model

Predicting leaching of residual soil nitrate-nitrogen (NO3-N) in wet climates is important for reducing risks of groundwater contamination and conserving soil N. The goal of this research was to determine the potential to use easily measurable or readily available soilclimatic-plant data that could be put into simple computer models and used to predict NO3 leaching under various management systems. Two computer programs were compared for their potential to predict monthly NO3-N leaching losses in western Oregon vegetable systems with or without cover crops. The models were a statistical multiple linear regression (MLR) model and the commercially available Nitrate Leaching and Economical Analysis Package model (NLEAP 1.13). The best MLR model found using stepwise regression to predict annual leachate NO3-N had four independent variables (log transformed fall soil NO3-N, leachate volume, summer crop N uptake, and N fertilizer rate) (P < 0.001, R2 = 0.57). Comparisons were made between NLEAP and field data for mass of NO3-N leached between the months of September and May from 1992 to 1997. Predictions with NLEAP showed greater correlation to observed data during high-rainfall years compared to dry or averagerainfall years. The model was found to be sensitive to yield estimates, but vegetation management choices were limiting for vegetable crops and for systems that included a cover crop.

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Effect of Winter Cover Crops on Soil Nitrogen Availability, Corn Yield, and Nitrate Leaching

The Scientific World JOURNAL ◽

10.1100/tsw.2001.267 ◽

2001 ◽

Vol 1 ◽

pp. 22-29 ◽

Cited By ~ 19

Author(s):

S. Kuo ◽

B. Huang ◽

R. Bembenek

Keyword(s):

Cover Crops ◽

Cover Crop ◽

N Fertilizer ◽

N Leaching ◽

Corn Yield ◽

N Availability ◽

Soil N ◽

Soil N Availability ◽

N Concentration ◽

Fertilizer Rates

Biculture of nonlegumes and legumes could serve as cover crops for increasing main crop yield, while reducing NO3leaching. This study, conducted from 1994 to 1999, determined the effect of monocultured cereal rye (Secale cereale L.), annual ryegrass (Lolium multiflorum), and hairy vetch (Vicia villosa), and bicultured rye/vetch and ryegrass/vetch on N availability in soil, corn (Zea mays L.) yield, and NO3-N leaching in a silt loam soil. The field had been in corn and cover crop rotation since 1987. In addition to the cover crop treatments, there were four N fertilizer rates (0, 67, 134, and 201 kg N ha-1, referred to as N0, N1, N2, and N3, respectively) applied to corn. The experiment was a randomized split-block design with three replications for each treatment. Lysimeters were installed in 1987 at 0.75 m below the soil surface for leachate collection for the N0, N2, and N3treatments. The result showed that vetch monoculture had the most influence on soil N availability and corn yield, followed by the bicultures. Rye or ryegrass monoculture had either no effect or an adverse effect on corn yield and soil N availability. Leachate NO3-N concentration was highest where vetch cover crop was planted regardless of N rates, which suggests that N mineralization of vetch N continued well into the fall and winter. Leachate NO3-N concentration increased with increasing N fertilizer rates and exceeded the U.S. Environmental Protection Agency’s drinking water standard of 10 mg N l�1 even at recommended N rate for corn in this region (coastal Pacific Northwest). In comparisons of the average NO3-N concentration during the period of high N leaching, monocultured rye and ryegrass or bicultured rye/vetch and ryegrass/vetch very effectively decreased N leaching in 1998 with dry fall weather. The amount of N available for leaching (determined based on the presidedress nitrate test, the amount of N fertilizer applied, and N uptake) correlated well with average NO3-N during the high N leaching period for vetch cover crop treatment and for the control without the cover crops. The correlation, however, failed for other cover crops largely because of variable effectiveness of the cover crops in reducing NO3leaching during the 5 years of this study. Further research is needed to determine if relay cover crops planted into standing summer crops is a more appropriate approach than fall seeding in this region to gain sufficient growth of the cover crop by fall. Testing with other main crops that have earlier harvest dates than corn is also needed to further validate the effectiveness of the bicultures to increase soil N availability while protecting the water quality.

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Mustard Cover Crop Growth and Weed Suppression in Organic, Strawberry Furrows in California

HortScience ◽

10.21273/hortsci12576-17 ◽

2018 ◽

Vol 53 (4) ◽

pp. 432-440 ◽

Cited By ~ 1

Author(s):

Eric B. Brennan ◽

Richard F. Smith

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Sinapis Alba ◽

Weed Suppression ◽

Shoot Biomass ◽

Plastic Mulch ◽

Seeding Rate ◽

Crop Cover ◽

Cover Cropping ◽

Growing Seasons

Strawberry (Fragaria ×ananassa Duch.) production in California uses plastic mulch–covered beds that provide many benefits such as moisture conservation and weed control. Unfortunately, the mulch can also cause environmental problems by increasing runoff and soil erosion and reducing groundwater recharge. Planting cover crops in bare furrows between the plastic cover beds can help minimize these problems. Furrow cover cropping was evaluated during two growing seasons in organic strawberries in Salinas, CA, using a mustard (Sinapis alba L.) cover crop planted at two seeding rates (1× and 3×). Mustard was planted in November or December after strawberry transplanting and it resulted in average densities per meter of furrow of 54 and 162 mustard plants for the 1× and 3× rates, respectively. The mustard was mowed in February before it shaded the strawberry plants. Increasing the seeding rate increased mustard shoot biomass and height, and reduced the concentration of P in the mustard shoots. Compared with furrows with no cover crop, cover-cropped furrows reduced weed biomass by 29% and 40% in the 1× and 3× seeding rates, respectively, although weeds still accounted for at least 28% of the furrow biomass in the cover-cropped furrows. These results show that growing mustard cover crops in furrows without irrigating the furrows worked well even during years with relatively minimal precipitation. We conclude that 1) mustard densities of ≈150 plants/m furrow will likely provide the most benefits due to greater biomass production, N scavenging, and weed suppression; 2) mowing was an effective way to kill the mustard; and 3) high seeding rates of mustard alone are insufficient to provide adequate weed suppression in strawberry furrows.

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The Correct Cover Crop Species Integrated with Slurry Can Increase Biomass, Quality and Nitrogen Cycling to Positively Affect Yields in a Subsequent Spring Barley Rotation

Agronomy ◽

10.3390/agronomy10111760 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1760

Author(s):

Paul Cottney ◽

Lisa Black ◽

Ethel White ◽

Paul N. Williams

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Crop Yields ◽

Spring Barley ◽

C:N Ratio ◽

Brassica Species ◽

Carbon Accumulation ◽

Soil Mineral Nitrogen ◽

Crop Species ◽

N Accumulation

The aim of this study is to identify species of cover crops that cause an increase in biomass and total nutrient accumulation in response to manure/slurry. This could improve nutrient efficiency and intensify the benefits from over-winter cover crops in arable rotations and improve following commercial crop yields. In a pot experiment, sixteen cover crops were grown for 100 days in response to slurry. Growth and nutrient (N, P, K, Mg and S) accumulation were measured, and then residue was reincorporated into the soil with spring barley (Hodeum vulgare L.) sown and harvested for yield. In response to slurry, tillage radish (Raphanus sativus L.) increased N accumulation by 101% due to a significant increase in biomass and % N (p < 0.05) over its relative control plots. Significant interactions between species and the application of slurry were found in cover crop biomass, cover crop and spring barley nutrient uptake, as well as cover crop carbon accumulation, particularly in the brassica species used. Slurry integrated with cover crops both reduced the cover crop C:N ratio and enhanced nutrient cycling compared to the control when soil mineral nitrogen (SMN) and spring barley crop N offtake were pooled. However, this was not observed in the legumes. This study shows that slurry integration with cover crops is a promising sustainable farming practice to sequester N and other macro-nutrients whilst providing a range of synergistic benefits to spring barley production when compared to unplanted/fallow land rotations. However, this advantage is subject to use of responsive cover crop species identified in this study.

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Assessing winter cover crop nutrient uptake efficiency using a water quality simulation model

Hydrology and Earth System Sciences ◽

10.5194/hess-18-5239-2014 ◽

2014 ◽

Vol 18 (12) ◽

pp. 5239-5253 ◽

Cited By ~ 28

Author(s):

I.-Y. Yeo ◽

S. Lee ◽

A. M. Sadeghi ◽

P. C. Beeson ◽

W. D. Hively ◽

...

Keyword(s):

Water Quality ◽

Nitrate Leaching ◽

Cover Crops ◽

Cover Crop ◽

Watershed Scale ◽

Source Areas ◽

Winter Cover Crop ◽

Nitrate Export ◽

Winter Cover ◽

Winter Cover Crops

Abstract. Winter cover crops are an effective conservation management practice with potential to improve water quality. Throughout the Chesapeake Bay watershed (CBW), which is located in the mid-Atlantic US, winter cover crop use has been emphasized, and federal and state cost-share programs are available to farmers to subsidize the cost of cover crop establishment. The objective of this study was to assess the long-term effect of planting winter cover crops to improve water quality at the watershed scale (~ 50 km2) and to identify critical source areas of high nitrate export. A physically based watershed simulation model, Soil and Water Assessment Tool (SWAT), was calibrated and validated using water quality monitoring data to simulate hydrological processes and agricultural nutrient cycling over the period of 1990–2000. To accurately simulate winter cover crop biomass in relation to growing conditions, a new approach was developed to further calibrate plant growth parameters that control the leaf area development curve using multitemporal satellite-based measurements of species-specific winter cover crop performance. Multiple SWAT scenarios were developed to obtain baseline information on nitrate loading without winter cover crops and to investigate how nitrate loading could change under different winter cover crop planting scenarios, including different species, planting dates, and implementation areas. The simulation results indicate that winter cover crops have a negligible impact on the water budget but significantly reduce nitrate leaching to groundwater and delivery to the waterways. Without winter cover crops, annual nitrate loading from agricultural lands was approximately 14 kg ha−1, but decreased to 4.6–10.1 kg ha−1 with cover crops resulting in a reduction rate of 27–67% at the watershed scale. Rye was the most effective species, with a potential to reduce nitrate leaching by up to 93% with early planting at the field scale. Early planting of cover crops (~ 30 days of additional growing days) was crucial, as it lowered nitrate export by an additional ~ 2 kg ha−1 when compared to late planting scenarios. The effectiveness of cover cropping increased with increasing extent of cover crop implementation. Agricultural fields with well-drained soils and those that were more frequently used to grow corn had a higher potential for nitrate leaching and export to the waterways. This study supports the effective implementation of cover crop programs, in part by helping to target critical pollution source areas for cover crop implementation.

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Cover cropping in Vitis vinifera L. cv. Manto Negro vineyards under Mediterranean conditions: effects on plant vigour, yield and grape quality

OENO One ◽

10.20870/oeno-one.2011.45.4.1501 ◽

2011 ◽

Vol 45 (4) ◽

pp. 223 ◽

Cited By ~ 5

Author(s):

Alícia Pou ◽

Javier Gulías ◽

Maria Moreno ◽

Magdalena Tomàs ◽

Hipolito Medrano ◽

...

Keyword(s):

Stomatal Conductance ◽

Cover Crops ◽

Cover Crop ◽

Yield Reduction ◽

Growth Stages ◽

Plant Vigour ◽

Cover Cropping ◽

Permanent Resident ◽

Grape Quality ◽

Intrinsic Water Use Efficiency

Aims: In temperate climates, cover crops are mainly used to reduce excess soil water and nutrient availability to grapevines, which otherwise could decrease grape quality. In Mediterranean climates, where water is a limiting factor, the use of cover crops is not as straightforward. However, in this scenario, summer senescent and self-seeding herbaceous cover crops could also help to decrease soil erosion as well as to reduce excessive early vegetative vigour, which could restrict grape water availability at later phenological stages. The aim of this experiment was to study the effects of particular cover crops in Mediterranean vineyards on grapevine vegetative growth, gas exchange, yield and grape quality.Methods and results: The experiment was carried out over three consecutive years in an organic vineyard (cv. Manto Negro) in central Majorca, Spain. Three treatments (three cover cropping rows per treatment) were established: perennial grass and legume mixture (PM), no tillage, i.e., with permanent resident vegetation (NT), and traditional tillage or ploughed soil (TT). The grapevines were rain fed until veraison, and then drip irrigation was applied (30% potential evapotranspiration; ETP) until harvest. Plant water status was established according to a defined value of maximum daily leaf stomatal conductance (gs). Cover crops reduced total leaf area (LA), gs and grapevine vigour at early growth stages. gs and net photosynthesis (AN) were higher in cover crop treatments during the veraison and ripening stages, likely because of the reductions in LA. Intrinsic water use efficiency increased from flowering to veraison-maturity in all treatments. Yield was lower in the cover crop treatments (PM and NT) compared to TT for all years, but these differences were only significant in 2007. However, grape quality parameters slightly improved in the PM treatment.Conclusion: The use of cover crops decreased LA, helping to avoid dramatic reductions of stomatal conductance in mid-summer, but decreased yield and only slightly increased grape quality.Significance and impact of the study: This study showed that the use of specific cover crops in vineyards under Mediterranean climates helps to reduce vegetative vigour. Nevertheless, yield reduction and slight quality improvement suggest that cover crops should be adjusted in order to reduce competition for water and thus prevent these negative effects of water scarcity.

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A survey of cover crop practices and perceptions of sustainable farmers in North Carolina and the surrounding region

Renewable Agriculture and Food Systems ◽

10.1017/s1742170514000398 ◽

2014 ◽

Vol 30 (6) ◽

pp. 550-562 ◽

Cited By ~ 10

Author(s):

S. O'Connell ◽

J.M. Grossman ◽

G.D. Hoyt ◽

W. Shi ◽

S. Bowen ◽

...

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Crop Production ◽

Warm Season ◽

Organic Production ◽

Environmental Benefits ◽

Cover Cropping ◽

Survey Population ◽

Potential Benefits ◽

Production Areas

AbstractThe environmental benefits of cover cropping are widely recognized but there is a general consensus that adoption levels are still quite low among US farmers. A survey was developed and distributed to more than 200 farmers engaged in two sustainable farming organizations in NC and the surrounding region to determine their level of utilization, current practices and perceptions related to cover cropping. The majority of farms surveyed had diverse crop production, production areas <8 ha, and total gross farm incomes <US$50,000. Approximately one-third of the survey population had an organic production component. Eighty-nine percent of participants had a crop rotation plan and 79% of the total survey population utilized cover cropping. More than 25 different cool- and warm-season cover crops were reported. The statements that generated the strongest agreement about cover crop benefits were that cover crops: increase soil organic matter, decrease soil erosion, increase soil moisture, contribute nitrogen to subsequent cash crops, suppress weeds, provide beneficial insect habitat and break hard pans with their roots. Economic costs associated with cover cropping were not viewed as an obstacle to implementation. A factor analysis was conducted to identify underlying themes from a series of positive and negative statements about cover crops. Pre- and post-management challenges were able to explain the most variability (30%) among participant responses. Overall, participants indicated that the incorporation of residues was their greatest challenge and that a lack of equipment, especially for no-till systems, influenced their decisions about cover cropping. Farmers did not always appear to implement practices that would maximize potential benefits from cover crops.

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Alternative performance targets for integrating cover crops as a proactive herbicide-resistance management tool

Weed Science ◽

10.1017/wsc.2020.49 ◽

2020 ◽

Vol 68 (5) ◽

pp. 534-544 ◽

Cited By ~ 1

Author(s):

Jess M. Bunchek ◽

John M. Wallace ◽

William S. Curran ◽

David A. Mortensen ◽

Mark J. VanGessel ◽

...

Keyword(s):

Biomass Production ◽

Herbicide Resistance ◽

Cover Crops ◽

Cover Crop ◽

Selection Pressure ◽

Resistance Management ◽

Management Tool ◽

Performance Targets ◽

Cover Cropping ◽

Management Concepts

AbstractIntensified cover-cropping practices are increasingly viewed as a herbicide-resistance management tool but clear distinction between reactive and proactive resistance management performance targets is needed. We evaluated two proactive performance targets for integrating cover-cropping tactics, including (1) facilitation of reduced herbicide inputs and (2) reduced herbicide selection pressure. We conducted corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] field experiments in Pennsylvania and Delaware using synthetic weed seedbanks of horseweed [Conyza canadensis (L.) Cronquist] and smooth pigweed (Amaranthus hybridus L.) to assess winter and summer annual population dynamics, respectively. The effect of alternative cover crops was evaluated across a range of herbicide inputs. Cover crop biomass production ranged from 2,000 to 8,500 kg ha−1 in corn and 3,000 to 5,500 kg ha−1 in soybean. Experimental results demonstrated that herbicide-based tactics were the primary drivers of total weed biomass production, with cover-cropping tactics providing an additive weed-suppression benefit. Substitution of cover crops for PRE or POST herbicide programs did not reduce total weed control levels or cash crop yields but did result in lower net returns due to higher input costs. Cover-cropping tactics significantly reduced C. canadensis populations in three of four cover crop treatments and decreased the number of large rosettes (>7.6-cm diameter) at the time of preplant herbicide exposure. Substitution of cover crops for PRE herbicides resulted in increased selection pressure on POST herbicides, but reduced the number of large individuals (>10 cm) at POST applications. Collectively, our findings suggest that cover crops can reduce the intensity of selection pressure on POST herbicides, but the magnitude of the effect varies based on weed life-history traits. Additional work is needed to describe proactive resistance management concepts and performance targets for integrating cover crops so producers can apply these concepts in site-specific, within-field management practices.

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Mustard and Other Cover Crop Effects Vary on Lettuce Drop Caused by Sclerotinia minor and on Weeds

Plant Disease ◽

10.1094/pdis-93-10-1019 ◽

2009 ◽

Vol 93 (10) ◽

pp. 1019-1027 ◽

Cited By ~ 8

Author(s):

Tiffany A. Bensen ◽

Richard F. Smith ◽

Krishna V. Subbarao ◽

Steven T. Koike ◽

Steven A. Fennimore ◽

...

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Seed Viability ◽

Weed Seed ◽

Short Term ◽

Sclerotinia Minor ◽

Cover Cropping ◽

Long Term Study ◽

Lettuce Drop

Mustard cover crops have been suggested as a potential biofumigant for managing soilborne agricultural pests and weeds. We conducted several experiments in commercial lettuce fields in the Salinas Valley, CA, to evaluate the effects of mustard cover crops on lettuce drop caused by Sclerotinia minor and on weed density and seed viability. In a long-term study, we measured the effects of white and Indian mustard cover crops on the density of S. minor sclerotia in soil, lettuce drop incidence, weed densities, weed seed viability, and crop yield in head lettuce. We also tested broccoli and rye cover crop treatments and a fallow control. Across several short-term studies, we evaluated the density of S. minor sclerotia in soil, lettuce drop incidence, weed densities, and weed seed viability following cover cropping with a mustard species blend. Numbers of sclerotia in soil were low in most experimental locations and were not affected by cover cropping. Mustard cover crops did not reduce disease incidence in the long-term experiment but the incidence of lettuce drop was lower in mustard-cover-cropped plots across the short-term experiments. With the exception of common purslane and hairy nightshade, weed densities and weed seed viability were not significantly reduced by cover cropping with mustard. Head lettuce yield was significantly higher in mustard-cover-cropped plots compared with a fallow control. Glucosinolate content in the two mustard species was similar to those measured in other studies but, when converted to an equivalent of a commercial fumigant, the concentrations were much lower than the labeled rate for lettuce production. Although mustard cover cropping resulted in yield benefits in this study, there was little to no disease or weed suppression.

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