Location: Soil Management Research2013 Annual Report
1a. Objectives (from AD-416):
1. Determine crop residue needs to protect soil resources and identify management strategies that enable sustainable production of food, feed, and biofuel. 2. Develop options for managing crop systems to reduce GHG emissions and increase C storage. 3. Evaluate impacts of environmental changes (water, CO2, temperature) on traditional, biofuel and alternative crops to develop a model-based risk assessment of crop production under the most likely medium-term (10-30 yr) climate change scenario for the upper Midwest. 4. Evaluate availability of N in organic production systems across different crops and soils and as compared to relevant conventional practices.
1b. Approach (from AD-416):
The project will generate information for balancing crop production goals with harvest of biomass for biofuel; develop management options to decrease greenhouse gas emissions and increase C storage in soil; evaluate an approach to remediate eroded soils; and provide information on crop response to climate change. Plot and on-farm approaches will be used to assess changes in soil carbon, greenhouse gas emission, soil quality indicators and production as a consequence of crop biomass harvest. This information will be identified locally and contribute to the national GRACEnet database on greenhouse gas emission and carbon storage. It will also contribute to national recommendations and guidelines through the REAP project. A farm-scale evaluation of field-scale soil movement (conducted to decrease soil spatial variability) will be used to develop improved management practices that restore productivity to eroded soils. This information will improve predictions of water and agrochemical transport in eroded soils, the response of soil biological communities to soil disturbance, and the short-term impact of soil erosion on soil C dynamics and soil productivity. This project will identify physiological and biochemical markers to develop or select cultivars adapted to climate change to develop environmentally- and economically-sustainable and diversified cropping systems that reduce risk and increase the probability of profitable crop production.
3. Progress Report:
Made substantial progress toward developing soil and crop management systems that sustain agricultural production, readily adapt to climate change, minimize greenhouse gas emission, sequester carbon, and safeguard soil productivity while protecting environmental quality in the upper Midwest (Obj. 1 and 2). Completed 4 full harvest cycles (8 years) studying the impact of stover removal rate in a corn-soybean rotation. The impact of stover harvest rate on soil biology, soil erosion risk, and soil organic matter content is being assessed. We added published data on crop response to stover harvest to the publically available Resilient Economic Agricultural Practices database (nrrc.ars.usda.gov/slreap/#/Home). The 2013 season marks the 6th year of the alternative biomass production system rotation evaluating the incorporation of annual and perennial grasses into a traditional corn-soybean rotation. We will anticipate a final assessment of particulate organic matter and soil carbon for the first phase of the rotation in fall 2013. To date we determined that a winter rye cover crop establishes better with the removal of corn stover, but biomass production is far less than the stover biomass removed. We replanted perennial grasses to improve weed management in a long-term study. Statistical analysis and summarization of changes in soil organic carbon and greenhouse gas emission is in progress. Completed data collection and modeling to quantify risk associated with climate change predictions (Obj. 3). Under controlled conditions, we subjected plants of 6 physiologically diverse crops, producing different combinations of carbohydrates, oil and protein, to factorial combinations of water, carbon dioxide and temperature. We monitored and recorded growth and development, and then at full maturity collected plant chemical and biochemical composition data. Also evaluated these crops under field conditions as to their response to length of growing season and competition for water and nutrient resources; by manipulating crop-specific planting dates and seeding densities. We collected data from field and growth chamber experiments, developed a relational database and prepared data for statistical analyses and modeling. We expect to identify crop-specific and non-specific adaptation strategies to climate change components (water, temperature and carbon dioxide). Upon completion of the statistical and simulation studies, we expect to generate and make available a database that can be integrated with similar regional databases and used for local and regional planning purposes. We continued an assessment of the mineralization potential of soil under conventional and organic cropping systems (Obj. 4) to compensate for a poor assessment year affected by drought in 2012. Early season rains prevented timely planting of crops; crop comparisons were reduced from 3 to 2 so it is likely the study will continue for another year. A companion was stated to assess impacts of fertilization and residue removal on nitrogen mineralization potential in a perennial biomass production system.
1. Protect the soil resource and meet the expanding demands for food, feed and fuel. Corn stover (material other than grain) is a potential bioenergy feedstock, but little is known about the impacts of reducing stover return on yield and soil quality in the Northern US Corn Belt. The objective of this research is to determine the amount of crop residue that is needed to prevent a loss of soil organic matter or exacerbate soil erosion. Plot scale and process-based modeling were used to address this objective; furthermore, this work contributes to ARS' multi-location Resilient Economic Agricultural Practices project. ARS researchers at Morris, MN, found that three cycles of stover treatments had inconclusive short-term impacts on crop yield, but caused soil changes that indicate repeated harvests may have negative environmental consequences if stover removal makes the soil less resilient against erosive forces (e.g., wind or water). A modeling exercise suggests that management that did not till the soil is necessary for preserving soil organic matter. This research contributes to ensuring that the soil resource is protected and can meet the expanding demands for food, feed and fuel.
2. High quality maize for food and feed. Farmers and the food and feed industries will continue to demand high-yielding maize varieties with improved nutritional and industrial qualities. It has been long recognized that breeding maize varieties with high levels of protein, oil, starch, and essential amino acid contents, while maintaining high grain yield, is a challenge. ARS researchers at Morris, MN, evaluated 1,348 maize collections belonging to 13 populations from a breeding program for high protein content. These populations were comprised of germplasm from stiff and non-stiff stalk groups at different stages of inbreeding and different seed qualities. We measured 31 physical, biochemical, nutrients, and color traits on seeds from each collection. The objective was to find out how much variation in these quality traits is available for selection and how these traits are interrelated. We developed a visual procedure to help explain the relationships between and within physical and quality traits and identify which populations have larger variation for specific traits that could respond positively to climate change. The analytical procedures, germplasm and information will help researchers choose appropriate accessions to meet specific objectives such as yield and quality requirements of farmers and industry under changing climates.
Johnson, J.M., Acosta Martinez, V., Cambardella, C.A., Barbour, N.W. 2013. Crop and soil responses to using corn stover as a bioenergy feedstock: Observations from the Northern US Corn Belt. Agriculture. 3:72-89.