The Effect of Cover Crop Choice on Nitrous Oxide Emissions and Soil N Dynamics in a California Vineyard Agroecosystem PDF Download
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Author: Jonathan Vick Publisher: ISBN: 9781369795554 Category : Languages : en Pages :
Book Description
Nitrous oxide (N2O) is a potent greenhouse gas (GHG) with a global warming potential (GWP) 298 times greater than CO2. Cover crops, those crops grown other than the cash crop, offer a range of benefits for growers. However, cover crops also serve as inputs of carbon (C) and nitrogen (N), that can stimulate microbial N2O emissions. Vineyard agroecosystems represent a unique case for studying the effects of cover crops on N2O emissions as vineyard cover crops are generally non-fertilized and rain-fed. A two-year field study and accompanying laboratory incubation was conducted to examine the effects of three cover crop treatments (a legume mix, a ‘soil builder’ mix, and perennial ryegrass) and a fallow control on soil GHG emissions and soil N-dynamics. N2O emissions over the course of the study period did not show significant differences, with emissions ranging from 550 ± 202 g N2O-N ha−1 from the fallow soil to 951 ± 135 g N2O-N ha−1 from the ryegrass planted soil. Precipitation patterns were an important driver of N2O emissions. The laboratory incubation results showed N2O emissions from the legume mix planted soil to be an order of magnitude higher than the other treatments, with denitrification as the pathway responsible for the observed differences in gaseous N production rates. Additionally, patterns of N-transformations exhibited treatment differences, suggesting that two years of cover cropping influenced soil microbial community behavior.
Author: Jonathan Vick Publisher: ISBN: 9781369795554 Category : Languages : en Pages :
Book Description
Nitrous oxide (N2O) is a potent greenhouse gas (GHG) with a global warming potential (GWP) 298 times greater than CO2. Cover crops, those crops grown other than the cash crop, offer a range of benefits for growers. However, cover crops also serve as inputs of carbon (C) and nitrogen (N), that can stimulate microbial N2O emissions. Vineyard agroecosystems represent a unique case for studying the effects of cover crops on N2O emissions as vineyard cover crops are generally non-fertilized and rain-fed. A two-year field study and accompanying laboratory incubation was conducted to examine the effects of three cover crop treatments (a legume mix, a ‘soil builder’ mix, and perennial ryegrass) and a fallow control on soil GHG emissions and soil N-dynamics. N2O emissions over the course of the study period did not show significant differences, with emissions ranging from 550 ± 202 g N2O-N ha−1 from the fallow soil to 951 ± 135 g N2O-N ha−1 from the ryegrass planted soil. Precipitation patterns were an important driver of N2O emissions. The laboratory incubation results showed N2O emissions from the legume mix planted soil to be an order of magnitude higher than the other treatments, with denitrification as the pathway responsible for the observed differences in gaseous N production rates. Additionally, patterns of N-transformations exhibited treatment differences, suggesting that two years of cover cropping influenced soil microbial community behavior.
Author: Gina Marie Garland Publisher: ISBN: 9781267023544 Category : Languages : en Pages :
Book Description
Nitrous oxide (N2O) is a powerful greenhouse gas (GHG) produced from soils. It is a natural component of the nitrogen (N) cycle, but emissions are rising due to the increased use of both organic and synthetic N fertilizers in agricultural production systems over the past century. As atmospheric concentrations of N2O continue to climb, its influence on global warming and climate change cannot be denied. Because N2O is produced during soil microbial processes, agricultural production has a great influence on these processes by shaping the soil environment and thus how the microbes are able to process available N. Therefore, knowing the underlying practices responsible for current GHG emissions is necessary to develop best management practices aimed at reducing N2O emissions. Two studies were conducted in a vineyard in Northern California in order to determine how management practices (both conventional and alternative) as well as climatic conditions affect annual and seasonal nitrous oxide emissions within Mediterranean vineyard cropping systems. N2O fluxes were measured using a closed flux chamber method for several days following each management and precipitation event. Furthermore, soil samples were collected to relate N2O emissions with water-filled pore space (WFPS), inorganic N concentration (NO3 and NH4), dissolved organic carbon (DOC), and pH. Cumulative N2O emissions in the no-till (NT) system were greater under both the vine and the tractor row compared to conventional till (CT), with 0.15 ± 0.026 kg N2O-N ha−1 growing season−1 emitted from the CT vine compared to 0.22 ± 0.032 kg N2O-N ha−1 growing season−1 emitted from the NT vine and 0.13 ± 0.048 kg N2O-N ha−1 growing season−1 emitted from the CT row compared to 0.19 ± 0.019 kg N2O-N ha−1 growing season−1 from the NT row. Yet these variations were not significant, indicating no differences in seasonal N2O emissions following conversion from CT to NT compared to long-term CT management. Total annual emissions in the first year, when a leguminous cover crop was planted in the tractor row, totaled 3.92 kg N2O-N ha−1, while emissions in the second year when the tractor rows were fallow showed a 7-fold reduction, reaching only 0.56 kg N2O-N ha−1. During the growing season, fertilization events produced slightly increased emissions compared to the low background values. However, the largest fluxes occurred during the fallow season, in response to the first precipitation event of the year, especially in the tractor rows. Surprisingly, precipitation events in the second year, when the tractor rows were fallow, did not follow the same pattern, indicating the significant influence of the cover crop-derived N on annual N2O emissions. By and large, these studies show that agricultural management practices do have a direct influence on N2O emissions, and that their interaction with climatic conditions greatly influences total N2O emissions within a Mediterranean vineyard cropping system. Furthermore, the vastly increased N2O emissions following leguminous cover crop addition highlights the need to assess the environmental impacts of leguminous cover crops in systems where a crop does not directly follow legume incorporation.
Author: Joshua Smith Publisher: ISBN: Category : Languages : en Pages : 109
Book Description
In the United States, there is renewed interest in incorporating cover crops into agricultural systems to provide a variety of potential benefits related to soil quality, water quality, and greenhouse gas emissions. This study focused on assessing whether cover crops influence N 2 O and CO2 emissions in a central Illinois agricultural research field over two years (2011-2013) of cover crop growing seasons. Three winter cover crop systems, annual ryegrass (Lolium multiflorum ), cereal rye (Secale cereale ), and a cereal rye (2011)/ hairy vetch (Vicia villosa ) (2012) rotation were planted after fall 2011 and 2012 harvests. The field included a total of eight main plots, two of each treatment, and two no cover crop control plots. Soil carbon dioxide (CO 2 ) and nitrous oxide (N2 O) fluxes were measured from the plots in a single corn (Zea mays ) - soybean (Glycine max ) system for two cover crop growing seasons. Fluxes of CO 2 and CO2 were measured in March 2012, August 2012, and February 2013. The CO2 flux measurements were performed by using an infrared gas analyzer. The N2 O fluxes were analyzed from samples collected at 0, 10, 20, 30 min intervals from the same closed dynamic chamber system. Both CO2 and N2 O fluxes were computed from respective gas concentrations over time. Data were analyzed with a repeated measures mixed model procedure. N2 O fluxes from the cereal rye/hairy vetch plots were greater than the no cover control and annual ryegrass plots, suggesting that cover crops may not decrease N2 O fluxes immediately after being incorporated into a cropping system. In contrast, CO2 fluxes did not significantly differ among the treatments, but the cereal rye/hairy vetch plot sequestered ~100 kg C ha-1 of soil organic carbon (SOC). Overall, it was observed that some cover crop plots can have higher N2 O fluxes than plots without cover crops, but cover crops have the long-term potential to sequester C in croplands demonstrating that their use should still be considered a sustainable agriculture practice.
Author: Andy Clark Publisher: DIANE Publishing ISBN: 1437903797 Category : Technology & Engineering Languages : en Pages : 248
Book Description
Cover crops slow erosion, improve soil, smother weeds, enhance nutrient and moisture availability, help control many pests and bring a host of other benefits to your farm. At the same time, they can reduce costs, increase profits and even create new sources of income. You¿ll reap dividends on your cover crop investments for years, since their benefits accumulate over the long term. This book will help you find which ones are right for you. Captures farmer and other research results from the past ten years. The authors verified the info. from the 2nd ed., added new results and updated farmer profiles and research data, and added 2 chap. Includes maps and charts, detailed narratives about individual cover crop species, and chap. about aspects of cover cropping.
Author: Jonathan Vick
Author: Jonathan Vick
Author: Simone Priori
Author: Gina Marie Garland
Author: Joshua Smith
Author: Kaden Blue Koffler
Author: Richard Douglas Smith
Author: Andy Clark
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Author: Danielle Lee Pierce