Winter Nitrate Leaching under Different Tillage and Winter Cover Crop Management Practices

2013 ◽  
Vol 77 (4) ◽  
pp. 1391-1401 ◽  
Author(s):  
P. M. Fraser ◽  
D. Curtin ◽  
T. Harrison-Kirk ◽  
E. D. Meenken ◽  
M. H. Beare ◽  
...  
2014 ◽  
Vol 18 (12) ◽  
pp. 5239-5253 ◽  
Author(s):  
I.-Y. Yeo ◽  
S. Lee ◽  
A. M. Sadeghi ◽  
P. C. Beeson ◽  
W. D. Hively ◽  
...  

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.


2013 ◽  
Vol 10 (11) ◽  
pp. 14229-14263 ◽  
Author(s):  
I.-Y. Yeo ◽  
S. Lee ◽  
A. M. Sadeghi ◽  
P. C. Beeson ◽  
W. D. Hively ◽  
...  

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 winter cover crop establishment. The objective of this study was to assess the long-term effect of planting winter cover crops at the watershed scale 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 and satellite-based estimates of winter cover crop species performance to simulate hydrological processes and nutrient cycling over the period of 1991–2000. Multiple scenarios were developed to obtain baseline information on nitrate loading without winter cover crops planted and to investigate how nitrate loading could change with different winter cover crop planting scenarios, including different species, planting times, and implementation areas. The results indicate that winter cover crops had a negligible impact on water budget, but significantly reduced nitrate leaching to groundwater and delivery to the waterways. Without winter cover crops, annual nitrate loading was approximately 14 kg ha−1, but it decreased to 4.6–10.1 kg ha−1 with winter cover crops resulting in a reduction rate of 27–67% at the watershed scale. Rye was most effective, with a potential to reduce nitrate leaching by up to 93% with early planting at the field scale. Early planting of winter 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 winter 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 implement of winter cover crop programs, in part by helping to target critical pollution source areas for winter cover crop implementation.


2015 ◽  
Vol 35 (2) ◽  
pp. 280-292 ◽  
Author(s):  
DIEGO DOS SANTOS ◽  
EDUARDO G. DE SOUZA ◽  
LÚCIA H. P. NÓBREGA ◽  
CLAUDIO L. BAZZI ◽  
FERNANDO N. DE QUEIROZ

Cover crops are important for improving soil quality. However, soil properties usually have some spatial dependence. Thus, this study aimed to evaluate the effect of winter cover crops on physical properties of soil and soybean yields using thematic maps. Five winter treatments were used: black oats; intercropping 1 (forage turnips and black oats); intercropping 2 (forage turnips, black oats and common vetch); wheat; and control. Macroporosity, microporosity, total porosity, bulk density and water content of the soil from 0 - 0.1 m depths were evaluated after the winter cover crop management. Soybeans were sown over the entire area in the summer after the winter cover crop management, and the soybean yield was determined for each treatment. Maps for each treatment were created and compared to the control treatment using the relative deviation coefficient (RDC). The cover crops improved the total macroporosity of the soil in some regions of the study area. The black oats were more efficient at maintaining higher water content of the soil, and it can be used to decrease the bulk density.


2008 ◽  
Vol 51 (5) ◽  
pp. 1575-1583 ◽  
Author(s):  
L. Li ◽  
R. W. Malone ◽  
L. Ma ◽  
T. C. Kaspar ◽  
D. B. Jaynes ◽  
...  

2006 ◽  
Vol 98 (4) ◽  
pp. 946-950 ◽  
Author(s):  
Dennis E. Rowe ◽  
Timothy E. Fairbrother ◽  
Karamat A. Sistani

Weed Science ◽  
2015 ◽  
Vol 63 (2) ◽  
pp. 477-490 ◽  
Author(s):  
John R. Teasdale ◽  
Steven B. Mirsky

Insufficient weed control is a major constraint to adoption of reduced-tillage practices for organic grain production. Tillage, cover crop management, and crop planting date are factors that influence emergence periodicity and growth potential of important weed species in these systems. We assessed two hairy vetch cover crop management practices, disk-kill and roll-kill, across a range of corn planting dates from early May to late June in three experiments in Beltsville, MD. Patterns of seed dormancy, emergence, and early weed growth were determined for overseeded populations of common ragweed, giant foxtail, and smooth pigweed, three important species in the Mid-Atlantic states that represent early to late emergence. Common ragweed emergence was lowest and dormancy was highest of the three species across all planting dates. Giant foxtail emergence was higher than the other species in roll-killed hairy vetch and included a significant number of seeds that germinated before rolling operations in late June. Smooth pigweed had the highest emergence and lowest dormancy in disk-killed hairy vetch in June. Individual giant foxtail plant weight was higher in roll-killed than disk-killed hairy vetch in 2 of 3 yr, whereas that of smooth pigweed plants was higher in disk-killed than roll-killed vetch in 2 of 3 yr. Giant foxtail was the dominant species in roll-killed hairy vetch (averaged 79% of total weed biomass at corn silking), probably because of early germination and establishment before rolling operations. Smooth pigweed was the dominant species in disk-killed hairy vetch at June planting dates (averaged 77% of total weed biomass), probably because of high growth rates under warm conditions in tilled soil. This research demonstrated that cover crop management practices and the timing of planting operations can shift the dominant species of weed communities in organic farming systems and must be considered in long-term weed management planning.


2018 ◽  
Vol 47 (2) ◽  
pp. 292-299 ◽  
Author(s):  
Amanda L Buchanan ◽  
Cerruti R R Hooks

2019 ◽  
Vol 10 ◽  
Author(s):  
Sana Romdhane ◽  
Aymé Spor ◽  
Hugues Busset ◽  
Laurent Falchetto ◽  
Juliette Martin ◽  
...  

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