Influence of Tillage and Cover Crop on Soil Nitrous Oxide Emission in Corn and Winter Cereal Rye PDF Download
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Author: Madhabi Tiwari
Publisher:
ISBN:
Category : Corn
Languages : en
Pages : 0
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Book Description
Food production security and resiliency require combination of agricultural management practices that are environmentally friendly and economically viable. Cover crops and tillage are two typical management practices that influence corn (Zea mays L.) and soybean (Glycine max L.) production in Illinois and the Midwest, USA. Finding practices that could potentially reduce nitrous oxide (N2O) emissions and sequester carbon (C) in the soil can improve agricultural resiliency to climate change. Generally, shifting from reduced tillage (RT) to no-till (NT) improves soil structure and decreases C emissions or sequesters soil C but might increase N2O emissions. Including a legume cover crop such as hairy vetch (Vicia villosa L.) before corn is preferred to winter cereal cover crops (WCCCs) to avoid yield penalty in corn and ensure high grain production. Winter cereal cover crops such as winter cereal rye (Secale cereale) (WCR) could potentially decrease soil N2O emissions during fallow period by capturing residual N and reducing soil moisture. These conditions could change in soils with legacy tillage (RT vs. NT) effects due to changes in soil physical, chemical, and biological over time. We utilized a medium-term (six-year-old) trial to test several hypotheses. We hypothesized that RT increases the soil temperature, accelerates soil organic matter mineralization, and especially in combination with hairy vetch could increase soil N in the soil leading to increased corn grain yield and N2O emission (Chapter 1). We also hypothesized that WCR takes up residual N after harvesting corn, decrease soil N, use soil moisture, and therefore, could decrease soil N2O emission (Chapter 2). For study 1 (Chapter 1), our objective was to evaluate the influence of cover crop (hairy vetch) vs. a no CC control and tillage systems (RT vs. NT) on (i) corn yield, N uptake, removal, and N balance; (ii) N2O emissions during corn season; (iii) yield scaled N2O emissions on a long-term (eight years) tillage × cover cropping system during the corn growing season in 2019 and 2021. We also analyzed factors that influence N2O emissions via principal component analysis in corn season. In corn growing seasons, we found that corn grain yield was higher in RT than NT reflecting on more N in the soil in RT than NT. Hairy vetch increased corn grain yield, soil N, and N2O-N indicating increased corn grain yield by hairy vetch N contribution let to higher N loss. Yield-scaled N2O-N emissions in NT-2019 (3696.4 g N2O-N Mg-1) were twofold higher than RT-2019 (1872.7 g N2O-N Mg-1) and almost fourfold higher than NT-2021 and RT-2021 indicating in a wet year like 2019, yield-scaled N2O-N emissions were higher in NT than RT. Principal component analysis indicated N2O-N fluxes were less driven by soil N and more by environmental conditions and N balances reflecting on N application at planting in this trial. The objectives for chapter 2 were to evaluate the legacy effect of tillage (RT vs. NT) and cover crops (WCR vs. a no cover crop control) on soil nitrate-N (NO3-N), volumetric water content (VWC), temperature, and N2O emission trends during a fallow period after corn in a six-yr trial. In spring 2020 we also estimated WCR biomass and N uptake as affected by tillage practices and compared WCR biomass to weeds in the no cover crop treatment. In rye growing season, winter cereal rye biomass was 55% higher than weeds in the fallow treatment. A linear positive relation between WCR biomass and N uptake (R2= 0.93) and C accumulation (R2 = 0.99) indicates WCR captures more N and adds more C inputs than weeds. Winter cereal rye biomass was also higher in RT than NT reflecting on higher soil temperature and N availability in RT than NT. Soil VWC was lower in WCR plots and there was a negative linear relation between days of the year (DOY) and VWC (R2 = 0.6). Despite all these differences, soil N2O-N values were mainly less than 5 g N2O-N ha-1d-1 in all sampling dates regardless of tillage or cover crop treatment. We conclude that in poorly drained Alfisols with claypan and fragipans, NT is not an effective strategy to decrease N2O-N fluxes. Hairy vetch benefits corn grain yield and supplement N but that increases N loss through N2O-N emissions. We concluded that we should focus on decreasing N2O emissions early in corn season since majority of N is lost during that time sometimes 300 times higher than those reported during the WCR phase. Some changes in management practices that could reduce N2O losses are shifting from upfront N application to sidedress N management, terminating hairy vetch at or even after corn planting, and combine these efforts with enhanced efficiency fertilizers that control nitrification and denitrification.
Author: Madhabi Tiwari
Publisher:
ISBN:
Category : Corn
Languages : en
Pages : 0
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Book Description
Food production security and resiliency require combination of agricultural management practices that are environmentally friendly and economically viable. Cover crops and tillage are two typical management practices that influence corn (Zea mays L.) and soybean (Glycine max L.) production in Illinois and the Midwest, USA. Finding practices that could potentially reduce nitrous oxide (N2O) emissions and sequester carbon (C) in the soil can improve agricultural resiliency to climate change. Generally, shifting from reduced tillage (RT) to no-till (NT) improves soil structure and decreases C emissions or sequesters soil C but might increase N2O emissions. Including a legume cover crop such as hairy vetch (Vicia villosa L.) before corn is preferred to winter cereal cover crops (WCCCs) to avoid yield penalty in corn and ensure high grain production. Winter cereal cover crops such as winter cereal rye (Secale cereale) (WCR) could potentially decrease soil N2O emissions during fallow period by capturing residual N and reducing soil moisture. These conditions could change in soils with legacy tillage (RT vs. NT) effects due to changes in soil physical, chemical, and biological over time. We utilized a medium-term (six-year-old) trial to test several hypotheses. We hypothesized that RT increases the soil temperature, accelerates soil organic matter mineralization, and especially in combination with hairy vetch could increase soil N in the soil leading to increased corn grain yield and N2O emission (Chapter 1). We also hypothesized that WCR takes up residual N after harvesting corn, decrease soil N, use soil moisture, and therefore, could decrease soil N2O emission (Chapter 2). For study 1 (Chapter 1), our objective was to evaluate the influence of cover crop (hairy vetch) vs. a no CC control and tillage systems (RT vs. NT) on (i) corn yield, N uptake, removal, and N balance; (ii) N2O emissions during corn season; (iii) yield scaled N2O emissions on a long-term (eight years) tillage × cover cropping system during the corn growing season in 2019 and 2021. We also analyzed factors that influence N2O emissions via principal component analysis in corn season. In corn growing seasons, we found that corn grain yield was higher in RT than NT reflecting on more N in the soil in RT than NT. Hairy vetch increased corn grain yield, soil N, and N2O-N indicating increased corn grain yield by hairy vetch N contribution let to higher N loss. Yield-scaled N2O-N emissions in NT-2019 (3696.4 g N2O-N Mg-1) were twofold higher than RT-2019 (1872.7 g N2O-N Mg-1) and almost fourfold higher than NT-2021 and RT-2021 indicating in a wet year like 2019, yield-scaled N2O-N emissions were higher in NT than RT. Principal component analysis indicated N2O-N fluxes were less driven by soil N and more by environmental conditions and N balances reflecting on N application at planting in this trial. The objectives for chapter 2 were to evaluate the legacy effect of tillage (RT vs. NT) and cover crops (WCR vs. a no cover crop control) on soil nitrate-N (NO3-N), volumetric water content (VWC), temperature, and N2O emission trends during a fallow period after corn in a six-yr trial. In spring 2020 we also estimated WCR biomass and N uptake as affected by tillage practices and compared WCR biomass to weeds in the no cover crop treatment. In rye growing season, winter cereal rye biomass was 55% higher than weeds in the fallow treatment. A linear positive relation between WCR biomass and N uptake (R2= 0.93) and C accumulation (R2 = 0.99) indicates WCR captures more N and adds more C inputs than weeds. Winter cereal rye biomass was also higher in RT than NT reflecting on higher soil temperature and N availability in RT than NT. Soil VWC was lower in WCR plots and there was a negative linear relation between days of the year (DOY) and VWC (R2 = 0.6). Despite all these differences, soil N2O-N values were mainly less than 5 g N2O-N ha-1d-1 in all sampling dates regardless of tillage or cover crop treatment. We conclude that in poorly drained Alfisols with claypan and fragipans, NT is not an effective strategy to decrease N2O-N fluxes. Hairy vetch benefits corn grain yield and supplement N but that increases N loss through N2O-N emissions. We concluded that we should focus on decreasing N2O emissions early in corn season since majority of N is lost during that time sometimes 300 times higher than those reported during the WCR phase. Some changes in management practices that could reduce N2O losses are shifting from upfront N application to sidedress N management, terminating hairy vetch at or even after corn planting, and combine these efforts with enhanced efficiency fertilizers that control nitrification and denitrification.
Author: Sowmya Surapur
Publisher:
ISBN: 9781321441031
Category : Electronic dissertations
Languages : en
Pages : 174
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Author: Oladapo Adeyemi
Publisher:
ISBN:
Category : Agricultural ecology
Languages : en
Pages : 0
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Book Description
Winter cereal cover crops (WCCCs) could provide extra profit by being harvested as forage or for biofuel purposes, could benefit soil, and the following cash crops, and are considered an effective practice in reducing the nitrate-N (NO3-N) leaching especially in corn (Zea mays L.) and soybean (Glycine max L.) fields. The extend at which WCCCs and their residue management (e.g. harvesting vs. terminating at different times) improve farm profit, influence the following cash crop, especially corn is less studied. Also, literature is scant on the residue management effects on NO3-N leaching potential and its tradeoff with soil nitrous oxide (N2O) emissions especially in Alfisols with claypans. Two trials (chapter 1-2) were conducted to evaluate the time of harvest of winter wheat (Triticum aestivum L.) or winter cereal rye (WCR; Secale cereale L.) to determine the best time of harvest for maximizing profit through improving biomass production at high quality. In chapter 1, a five site-yr trial was conducted in Colorado (CO) and Illinois (IL) to evaluate the effect of harvest date on WCR forage yield, quality, and its economic performance. From March to April, WCR dry matter (DM) yield increased exponentially in CO and linearly in IL. The DM yield at DOY 112-116 in CO was 6.9, 5.0, and 5.2 Mg ha-1 in 2018, 2019, and 2020, respectively compared to 4.7 and 2.7 Mg ha-1 in IL in 2019 and 2020. Delayed harvesting increased acid detergent fiber (ADF) and neutral detergent fiber (NDF) concentrations and decreased crude protein (CP), total digestible nutrients (TDN), and relative feed quality (RFQ). Yield-quality trade-off showed that forage yield increased rapidly but forage quality declined after DOY 105-108. Economic analysis, including cost of nutrient removal and 10% corn yield penalty following WCR production revealed harvesting WCR biomass as forage was economically feasible in four out of five site-yrs at hay price over 132 $ Mg-1. Eliminating corn yield penalty indicated profitability in four site-yrs at hay price of ≥110 $ Mg-1 and removing nutrient removal costs made all site-yrs profitable at hay price of ≥110 $ Mg-1. It was concluded that harvesting WCR biomass can be a profitable and effective strategy for sustainable intensification that can offer environmental stewardship and economic benefit. In chapter 2, a four-year trial was conducted in the 2017-2018, 2018-2029, 2019-2020, and 2020- 2021 growing seasons to evaluate the effect of harvesting time (late-March to mid-May considering the growth stage) on winter wheat biomass yield, quality, and farm profit in single season corn vs. wheat-corn rotation. A delay in harvest of wheat resulted in increased DM biomass and lower CP and RFQ. The RFQ that was suitable for dairy production occurred at GDD of 1849 in which the DM biomass was 6.2 Mg ha-1 leading to $1526.46 ha-1 income. The RFQ for heifer production was 126 at 2013 GDD in which the DM biomass was 6.8 Mg ha-1 leading to $1290.85 ha-1 income. These results suggested that wheat-corn rotation could provide extra income while covering the soil year-round. A series of trials were conducted to evaluate the effects of cover crop (CC) and nitrogen (N) management on (i) corn growth, (ii) grain yield and yield components, (iii) the economic optimum N rate (EONR) for corn and farm profit, (iv) N removal, and balances, (v) N use metrics, (vi) soil NO3-N and ammonium-N (NH4-N), along with (vii) N2O emissions and factors associated with it. In chapter 3, an experiment was conducted as a randomized complete block design with split plot arrangement and four replicates to study winter wheat cover crop management practices on corn growth, production, N requirement, soil N, and farm profit. The main plots were four CC treatments: no CC (control), early terminated wheat CC (four weeks to corn planting; ET), late terminated wheat CC (just prior to corn planting; LT), and harvested wheat CC (residue removal; RR), and the subplots were six N fertilizer application rates (0-280 kg N ha-1 ) for 2018 and 2019 and seven N fertilizer application rates (0-336 kg N ha-1 ) for 2020 and 2021. Wheat cover crop management influenced corn grain yield where fallow was consistently high yielding while RR decreased corn grain yield drastically due to its negative effects on the corn plant population. All cover crop treatments immobilized N as shown by lower corn grain yields at zero-N control compared to the fallow treatment. The EONR generally ranged from 151.4 kg ha-1 to 206.4 kg ha-1 in fallow, 192.8 kg ha-1 to 275.8 kg ha-1 in ET, 225 kg ha-1 to 325 kg ha-1 in LT, and 175.3 kg ha-1 to 257.5 kg ha-1 in RR. At the EONR, corn grain yields ranged from 12.2 Mg ha-1 to 13.7 Mg ha-1 in the fallow treatment, 9.7 Mg ha-1 to 13.0 Mg ha-1 in the ET, 9.51 Mg ha-1 to 13.3 Mg ha-1 in the LT, and 8.2 Mg ha-1 to 10.5 Mg ha-1 in the RR treatment. Adding N beyond EONR resulted in a drastic increase in end of season soil N which could be subject to leaching emphasizing targeting EONR is critical for avoiding high N leaching and that if N is applied at rates beyond EONR, then cover cropping becomes even a more critical practice to avoid N losses. In chapter 4 and 5, we evaluated whether splitting N fertilization along with the two (no-cover crop vs. early termination; ET) (chapter 4) or four above-mentioned cover crops treatments (chapter 5) could improve corn production and farm profit through improved N use efficiency (NUE). Therefore, for chapter 4, a two-yr field trail was implemented at the Agronomy Research Center in Carbondale, IL in 2018 and 2019 to evaluate whether split N application to corn changes N use efficiency (NUE) in no-cover crop vs. following an early terminated (ET) wheat cover crop. A four-replicated randomized completed block design with split plot arrangements were used. Main treatments were a no cover crop (control) vs. ET and subplots were five N timing applications to succeeding corn: (1) 168 kg N ha-1 at planting; (2) 56 kg N ha-1 at planting + 112 kg N ha-1 at sidedress; (3) 112 kg N ha-1 at planting + 56 kg N ha-1 at sidedress (4) 168 kg N ha-1 at sidedress, and (5) zero kg N ha-1 (control). Corn yield was higher in 2018 than 2019 reflecting more timely precipitation in that year. Grain yield declined by 12.6% following the wheat cover crop compared to no cover crop control indicating corn yield penalty when wheat was planted prior to corn. In 2018, a year with timely and sufficient rainfall, there were no differences among N application timing while in 2019, delaying the N addition improved NUE and corn grain yield due to excessive rainfall early in the season reflecting on N losses. Overall, our findings elucidate necessity of revisiting guidelines for current N management practices in Midwestern United States and incorporating cover crop component into MRTN prediction tool. For chapter 5, a four-year trial conducted with a split plot arrangement and four replicates. Main plots were four cover crop management [no cover crop control (fallow); ET, late termination (LT), and residue removal at late termination (RR) and five N fertilizer application timings (all at planting, most at planting + sidedress; half-half; less at planting and more at sidedress; and all sidedress). Our results indicated that RR resulted in corn population and grain yield reduction compared to other treatments. Fallow was consistently high-yielding and 112-56 N management during the first two years for fallow worked the best (10.1 Mg ha-1 ). In 2020 and 2021, both applying all N upfront or sidedressing yielded similar for fallow giving growers options with N timing. For both ET and LT, in all years, delaying the N addition to sidedress timing resulted in high yields (9.1 - 11.7 Mg ha-1 ). Some N addition upfront plus sidedressing the rest (56-168) resulted in the highest yield in ET in 2021 (11.6 Mg ha-1 ). For RR, split application of N (56-112 or 56-168) was consistently most productive in all years (8.7 Mg ha-1 ) suggesting that there is an advantage to sidedressing than upfront N application in cover crop systems. The high productive N management practices generally resulted in higher NUE (24.0 - 38.6 kg grain kg N-1 ) and lower N balance (20.6 - 50.2 kg ha-1 for 2018-2019, and 74 - 106.4 kg ha-1 for 2020-2021) which are critical to achieve not only for farm profit but also minimizing environmental footprints. Except for N0, N balance was positive in all treatments in all years indicating the inefficiency of fertilizer N that was corroborated by low NUE and PFP data. We concluded that to optimize corn production and reducing nutrient loss, split N addition or sidedressing N is most suitable especially in cover cropping systems. For chapter six, a four-times replicated randomized complete block design trial was conducted to evaluate the effects of winter wheat cover crop management practices (ET, LT, and RR) vs. a no-cover crop control (fallow) on corn grain yield, N removal and balances, soil N dynamics, soil volumetric water content (VWC) and temperature dynamics, N2O-N emissions, yield-scaled N2O-N emissions, and factors that drive N2O-N and corn grain yield in 2019-2020 and 2020-2021 growing seasons in a silt loam soil with clay and fragipans. Our results indicated that corn grain yield decreased by both ET and RR as compared to the fallow and LT. Soil temperature was similar among all treatments, but soil VWC was higher in LT and ET than fallow and RR. The LT treatment always had lower soil NO3-N than the other treatments in both years. In 2021, the ET also had less soil nitrate-N than fallow and RR. Averaged over the two years, cumulative soil N2O-N was higher in LT (14.85 kg ha-1 ) and ET (12.85 kg ha-1 ) than RR (11.10 kg ha-1 ) and fallow (7.65 kg ha-1 ) indicating while these treatments are effective in reducing NO3-N leaching, they could increase soil N2O-N emissions. Principal component analysis indicated that higher N2O-N emissions in LT and ET was related to higher VWC suggesting at optimal N management scenarios, other factors than soil N drive N2O-N emissions. In this study, fallow had the least yield-scaled N2O-N emissions followed by RR. The yield-scaled emissions were similar between ET and LT. These results indicate the importance of evaluating N2O-N emissions in cereal cover crops prior to corn for informing best management practice for winter cereal cover crop adoption. Future studies should focus on manipulating cover crop management to capture residual N without creating microclimates with high VWC to avoid increase of N2O-N emissions. While a lot is known about CC effects on the following cash crop, less is known about rotational benefits of late terminated (planting green) wheat and nitrogen (N) management on the following WCR and soybean in rotation. Therefore, for chapter 7, a trial was conducted with a split plot arrangement in a randomized complete block design set up. The main plots were two cover crop treatments (a no cover crop control vs. LT) and the subplots were three N rates [0 (N0), 224 (N224), and 336 (N336) kg N ha-1 ). Each treatment was replicated four times and rye and soybean was planted in all of the plots in rotation. Our results indicated wheat, when terminated late, can uptake 50-80 kg N ha-1 and result in belowground:aboveground ratio of 0.18 in which belowground had much higher C:N than the aboveground biomass. The soil NO3-N was affected by wheat presence and often reduced due to wheat N uptake and also N immobilization negatively affecting the following corn especially at both N0 and N224. Nitrogen fertilization at 336 kg N ha-1 resulted in high end of season N, reduced NUE, increased N balance, and thus, potential for N loss especially in the fallow treatment. The end of season N was lower and NUE was higher in LT which was coincided with reduced rye N uptake in LT suggesting wheat effect lingers longer than just during the corn season and could potentially reduce N loss potential during the fallow period following corn harvest. Soybean yields were higher in LT than the fallow which could be due to (i) higher rye biomass in fallow or (ii) positive legacy effect of wheat in rotation. Improved soybean yields could offset some of the economic loss during the corn phase and push growers in the Midwestern USA to be willing to adopt cover cropping to minimize N loss while protecting soil and stay profitable. Our results from chapter 3-7, indicate a need to change in cover crop management strategy to make it more user friendly with lower costs. In general, in the Midwestern USA, growers are reluctant to plant WCR especially prior to corn due to N immobilization and establishment issues. Precision planting of WCR or --Skipping the corn row‖ (STCR) can minimize some issues associated with WCR ahead of corn while reducing cover crop seed costs. The objective of this study was to compare the effectiveness of --STCR‖ vs. normal planting of WCR at full seeding rate (NP) on WCR biomass, nutrient uptake, and composition in three site-yrs (ARC2019, ARC2020, BRC2020). Our results indicated no differences in cover crop dry matter (DM) biomass production between the STCR (2.40 Mg ha-1 ) and NP (2.41 Mg ha-1 ) supported by similar normalized difference vegetative index (NDVI) and plant height for both treatments. Phosphorus, potassium (K), calcium (Ca), and magnesium (Mg) accumulation in aboveground biomass was only influenced by site-yr and both STCR and NP removed similar amount of P, K, Ca, and Mg indicating STCR could be as effective as NP in accumulating nutrients. Aboveground carbon (C) content (1086.26 kg h-1 average over the two treatments) was similar between the two treatments and only influenced by site-yr differences. Lignin, lignin:N, and C:N ratios were higher in STCR than NP in one out of three site-years (ARC2019) indicating greater chance of N immobilization when WCR was planted later than usual. Implementing STCR saved 8.4 $ ha-1 for growers and could incentivize growers to adopt this practice. Future research should evaluate corn response to STCR compared with NP and assess if soil quality declines by STCR practice over time.
Author: Humberto Blanco
Publisher: John Wiley & Sons
ISBN: 0891186395
Category : Technology & Engineering
Languages : en
Pages : 260
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Book Description
Cover Crops and Soil Ecosystem Services A comprehensive resource on cover crops and their role in soil ecosystems Cover crops are a reemerging strategy to improve and maintain the services that soils provide. They can have an enormous affect on agricultural outcomes, preventing soil erosion, restoring vital soil nutrients, sequestering C from the atmosphere, and more. The successful management and use of cover crops is therefore critical to ensure soil ecosystem services are maintained or improved not only to meet our demands for food, fuel, fiber, and feed but also to reduce pollution and improve the soil. Cover Crops and Soil Ecosystem Services provides a heavily researched and highly readable introduction to cover crops and their role in soil ecosystems. It ranges from a detailed discussion of cover crop biomass production to a thorough treatment of soil ecosystems and their vulnerabilities. The result is an essential guide to a critical area of agricultural science. Cover Crops and Soil Ecosystem Services readers will also find: Detailed treatment of cover crop biomass production, soil erosion, greenhouse gas fluxes, nitrate leaching, soil C sequestration, and more Discussion of emerging issues, including extreme weather events and the economics of cover crop farming Wide-ranging summaries of interdisciplinary soil and cover crop research Cover Crops and Soil Ecosystem Services is a useful reference for students and researchers at all levels of study relating to cover crop agriculture.
Author: Carinthia Alden Grayson
Publisher:
ISBN:
Category : Conservation tillage
Languages : en
Pages : 232
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Author: James Stuart Schepers
Publisher: ASA-CSSA-SSSA
ISBN: 9780891181644
Category : Technology & Engineering
Languages : en
Pages : 994
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Book Description
Review of the principles and management implications related to nitrogen in the soil-plant-water system.
Author: Ram Swaroop Meena
Publisher: Academic Press
ISBN: 0323886000
Category : Technology & Engineering
Languages : en
Pages : 730
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Book Description
Advances in Legume-based Agroecoystem for Sustainable Intensification explores current research and future strategies for ensuring capacity growth and socioeconomic improvement through the utilization of legume crop cultivation and production in the achievement of sustainability development goals (SDGs). Sections cover the role of legumes in addressing issues of food security, improving nitrogen in the environment, environmental sustainability, economic-environmentally optimized systems, the importance and impact of nitrogen, organic production, and biomass potential, legume production, biology, breeding improvement, cropping systems, and the use of legumes for eco-friendly weed management. This book is an important resource for scientists, researchers and advanced students interested in championing the effective utilization of legumes for agronomic and ecological benefit. Focuses on opportunities for agricultural impact and sustainability Presents insights into both agricultural sustainability and eco-intensification Includes the impact of legume production on societal impacts such as health and wealth management
Author: William T. Deppe
Publisher:
ISBN: 9781339876016
Category :
Languages : en
Pages : 165
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The pairing of cover crops with spring application of nitrogen has shown improved nitrogen efficiency in corn production systems. However, studies have shown that only 50% of central Illinois farmers practice spring application of nitrogen. Furthermore, the literature demonstrates that in years with above average rainfall, fall applied N management systems are more susceptible to N loading relative to spring systems. Therefore, the objective of this research was to determine the efficacy of winter cover crops to impact the distribution of soil inorganic N following fall applied anhydrous ammonium. The experimental site is located at the Illinois State University Research and Teaching Farm in Lexington, IL. The treatments consisted of a control, daikon radish, cereal rye and a cereal rye/daikon radish mixture. All treatments received a fall application of 200 kg N ha-1 in the form of anhydrous ammonia. Soil samples were collected in the spring at four separate depths and were analyzed for inorganic N. At the 0-5cm depth, we determined that tillage radish resulted in 18% greater soil NO3- relative to the control. In the environmental depth of 20-80cm, we observed that fall applying N into a living cover crop resulted in 35% (cereal rye) and 22% (daikon radish) less soil NO3- when compared to the control. In 2014 and 2015, each treatment was further divided into three nitrogen rate subplots: 200, 145 and 90 kg N ha-1. However, no obvious trend within the rate applied (90, 145 and 200 kg ha-1) was observed. After four consecutive years of established cover crops, corn uptake and yield data was collected. On average the addition of daikon radish at 200 kg N ha-1 increased total crop uptake by 20%; while the inclusion of cereal rye despite application rate significantly (P= 0.0021) increased total N at R6. Consequently, sampling at harvest (2014) demonstrated the capacity of the cover crops (cereal rye, P= 0.0323) despite rate to increase the crop yielding potential 3-6%. Over a four year period, winter cover crops reduced nitrate leaching and stabilized a greater concentration of soil NO3- in the agronomic depths following fall applied N, relative to the control. The results of this study also suggest that cover crop inclusion into a fall applied system has the potential to advance nitrogen use efficiency, yield and profitability.
Author: Ashani Thilakarathne
Publisher:
ISBN:
Category : Agricultural systems
Languages : en
Pages : 0
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Book Description
Corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) production in Illinois has a significant impact on the economy and environmental footprint in the state and the Midwest region. Nutrient leaching from Midwestern agricultural fields is one of the major reasons for the hypoxic zone developed in the Gulf of Mexico. Winter-fallow and early spring (after fertilizer application) are the two most critical periods for nutrient leaching due to increased precipitation and availability of nutrients. Cover crops (CCs) in these seasons are a promising best management practice (BMP) to reduce nutrient leaching in the winter-fallow season. No-till (NT) and reduced tillage (RT) are some other BMPs that farmers in Illinois adopt to reduce erosion. The adoption of CCs is limited due to the lack of knowledge and data on the yield and environmental benefits of CCs in different climatic and soil regimes. Thereby, this doctoral dissertation addresses several critical questions about CC and tillage impacts in claypan soils of southern Illinois with four principal projects with multiple objectives. Research study 1 was a field experiment conducted from 2013-to 2021 to understand the effect of CCs (CCs vs. noCC) and two tillage (NT and RT) practices on soil nitrate-N leaching. The experimental design was a complete randomized design with CC treatments that had two levels (two crop rotations) corn-cereal rye (Secale cereale L.)-soybean-hairy vetch (Vicia villosa R.) [CcrShv] and corn-noCC-soybean-noCC [CncSnc] and tillage treatments with two levels (NT and RT) replicated three times in the field. Each plot had a pan lysimeter installed below the A horizon (22-30 cm depth) to collect water samples weekly or biweekly depending on the rainfall. The corn yield was significantly greater in RT rotations compared to NT rotations with a 36% increase in the yield in 2019 and 2021 corn rotations. The yield was significantly greater in CcrShv rotations compared to the CncSnc rotations. The greatest yield was observed in the interaction of CcrShv-RT in all years. This increase in yield is inversely correlated to the remaining soil N values when the N credit from CCs was not accounted for. Soil nitrate-N leaching was significantly greater in CcrShv rotations compared to the CncSnc rotation in 2021 indicating vetch CC biomass decomposition can lead to increased leaching losses if the window between CC termination and corn planting is not minimized. Precipitation during the early spring can play a vital role in flushing the newly applied fertilizer as well as the N released from decomposing CC residue. The excessively wet year of 2019 showed that N losses are dominated by both nitrate-N leaching and nitrous oxide emissions, but in a typical growing season N losses are dominated by leaching compared to emissions. Research study 2 was designed to better understand the N cycling and fate of applied N in a complete corn-soybean rotation in southern Illinois with CCs and tillage practices. The research was overlayed in the same field with the same crop rotation and tillage practices. In this study, 15N labeled urea fertilizer (9.2% atom) was applied before the corn and soybean seasons. Soil, water, and biomass samples were collected to understand N distribution in each pool. In the corn season in 2017 a significantly greater 15N recovery was observed in CC (CcrShv) plots compared to the noCC plots in the sample collected seven days after planting (DAP). In the CC and depth interaction, a significantly greater 15N recovery was observed in 15-30 cm depth showing that the increased macropores due to CCs can lead to subsurface movement of N through the topsoil. The 15N recovery in water samples was high in CncSnc rotations in the cereal rye season but was significantly greater in CcrShv rotations (8.95 kg ha-1) in hairy vetch seasons. In the two years of complete rotation, the cumulative 15N recovery (quantity derived from fertilizer in water) was significantly greater in CC rotation. In the corn plants, the 15N recovered from the soil was greater than the 15N recovered from fertilizer. This shows the importance of the residual N from prior fertilizer and organic matter input. In the cereal rye season, CCs recovered significantly greater 15N from fertilizer compared to noCC rotations, assuring that cereal rye is an effective nutrient scavenger. A similar pattern was observed in the hairy vetch season as well. However, the soybean 15N recovery was greater in noCC rotations compared to CC rotations. The third study was a field trial on CCs and tillage to understand their individual and combined impact on soil physical parameters. Soil physical parameters were first measured in 2014 and were repeated in 2021. Bulk density at the 0-5 cm depth was 5% lower in 2021 compared to 2014 with the lowest BD in CC rotations with RT practices. For the depth of 0-15 cm, the lowest BD was observed in CC rotation with RT but, the largest reduction was observed in the CC rotation with NT. The wet aggregate stability was improved from 15-28 % over the years in all rotations. The lowest percentage improvement was observed in noCC rotation with RT practice. Penetration resistance was significantly lower in CC plots for the depth of 0-2.5 cm. CCs further improved the time to runoff in plots even though the infiltration rates were not affected. Chemical soil health indices were not significant overtime for CCs or tillage practices. However, a large number of earthworm counts were observed in NT systems compared to RT systems. The final project was a field trial to identify the soil P response to the CC and tillage practices. For this study, three different CC rotations, [corn-cereal rye-soybean-hairy vetch / corn-cereal rye-soybean-oats+radish / corn-noCC-soybean-noCC] and two tillage practices (NT and RT) were used. Soil samples were collected after the corn harvest in 2015 and 2021 and were analyzed for soil Phosphorus (P), inorganic P fractions by Chan and Jackson method, and dissolved reactive phosphorus (DRP) in leachate. The soil Mehlich-3 and Bray-1 P values indicate a great concentration of P in 0-15 cm depth for both years. More refined sampling in 2021 showed that the majority of P in 0-15 cm depth concentrates at the near-surface soil, in 0-5 cm depth irrespective of the CC and tillage treatment. Inorganic soil P fractions were not significantly different between CCs or tillage practices over time. Yet, irrespective of the treatment the non- labile P forms increased in 2021in the soil compared to 2015. The average and cumulative DRP values were highly dependent on the precipitation amounts and timing. However, in general, NT systems had greater average and cumulative DRP leaching compared to RT in both years. In general, CCs in the winter-fallow season is a good recommendation for farms that seek to maximize their production with a minimal environmental footprint. In the long run, CCs can improve soil physical and chemical properties which ultimately can increase the yield potential for corn and soybean. The added benefit of N credit due to leguminous CCs can reduce the fertilizer inputs. The CC benefits including the reduction in nutrient leaching depend on the type of CCs used in the field. More importantly, the CC termination time will be critical to obtain the maximum benefit of CCs. Even though the NT practices improve soil physical properties, long-term NT can increase the risk of soil P stratification in near-surface soils and can ultimately lead to more P loss via erosion, runoff, and soil water leaching. However, the combined use of CC and NT practices can help minimize the potential for erosion and runoff.
Author: Takuji Ohyama
Publisher: BoD – Books on Demand
ISBN: 1839684887
Category : Technology & Engineering
Languages : en
Pages : 218
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Book Description
Nitrogen is the most important nutrient in agricultural practice because the availability of nitrogen from the soil is generally not enough to support crop yields. To maintain soil fertility, the application of organic matters and crop rotation have been practiced. Farmers can use convenient chemical nitrogen fertilizers to obtain high crop yields. However, the inappropriate use of nitrogen fertilizers causes environmental problems such as nitrate leaching, contamination in groundwater, and the emission of N2O gas. This book is divided into the following four sections: “Ecology and Environmental Aspects of Nitrogen in Agriculture”, “Nitrogen Fertilizers and Nitrogen Management in Agriculture”, “N Utilization and Metabolism in Crops”, “Plant-Microbe Interactions”.
