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United States Department of Agriculture

Agricultural Research Service

2011 Annual Report

1a.Objectives (from AD-416)
Overall Project Goal: Develop long-term sustainable soil and crop management practices for the Central Great Plains Region (CGPR) and identify technologies that maximize the use of the region’s soil and water resources with minimal negative environmental impact. Objectives: 1. Develop adaptive management practices and document their benefits to optimize yield and enhance ecosystem services for CGPR dryland agricultural systems most vulnerable to potential adverse climate changes with an emphasis on precipitation and temperature. 2. Quantify microbial plant associations and their effects on plant productivity in no-till dryland cropping systems. 3. Develop best management practices for remediation/restoration of degraded soils in the CGPR. 4. Development of alternative bio-fuel specialty crops for incorporation into alternative dryland cropping systems. 5. Quantify how localized climate, topography, soils and management that vary across landscapes affect crop yields, carbon sequestration, and nutrient cycling for dryland agricultural systems and to develop adaptation options to mitigate risks for dryland cropping systems associated with climate change.

1b.Approach (from AD-416)
Field, and laboratory experiments and modeling efforts will be conducted to determine the adaptability of current dryland cropping systems to potential changes in climate (primarily drought the result of declining precipitation and/or increases in evaporative demand) in the region. These experiments and modeling efforts will include studies to evaluate and test the adaptability of dryland crop rotations across a regional site network that varies in soil type, climate and elevation (topography). Experiments will include the effects of residue management, nutrient management and crop ecological management to maximize carbon fixation/sequestration and crop yield and to reduce dependence on pesticides and other ag-chemicals. The effect of rotation and soil management on soil chemical, physical and biological quality will be also quantified. Crop and soil simulation models will be calibrated/evaluated for prediction accuracy of yield and soil transformations using 102 years of climate data and multiple years of crop rotation results to extrapolate research at CGPRS to other locations in the region. Economic risk assessment of intensive dryland rotations will be calibrated to determine economic feasibility.

3.Progress Report
This is the final report for project 5407-12130-006-00D terminated in 2011. ARS scientists at Akron, Colorado in collaboration with the ARS scientists in Ft. Collins used crop production and water use data from the dryland alternative crop rotation experiment to develop new crop response models for spring canola, corn, proso millet and wheat. Farmers use the risk analysis tools developed for risk assessment when considering these crops in dryland rotations. Risk analysis tools using these data were provided to farmers on compact disc and a website to assist in crop rotation planning. Production functions of triticale and foxtail millet were developed to inform farmers and ranchers on the quantity and quality of these forage crops as a supplement to rangeland grass production in mixed crop – livestock systems. Research on improving degraded soils continued, with coordinated studies at Akron, CO, Hays, KS, and Bowling Green, KY. The effects of manure applications on the long-term soil fertility and soil physical properties were evaluated for restoring soils degraded by erosion. This research evaluated soil management practices on soil aggregation, carbon sequestration, and potential greenhouse gas emissions. Evaluation of soil physical properties on the root environment continued and a method was developed for estimating relative suitability of the soil environment for root and crop growth. The method was tested against data accumulated during the project. Soil spectroscopy work continued for evaluating crop management factors on transient organic compounds contained in organic matter. Additionally, soil spectroscopy was used to identify transient and stable fractions of organic compounds in biochar. Biochar may improve soil properties and provide a source of stable organic matter for carbon sequestration. Eight refereed journal publications were produced this fiscal year. The topics included papers on: dryland rotation selection based on stored soil water and projected rainfall; the detrimental effects of fallow on soil quality; modeling dryland crop rotations; effects of crop rotations on soil aggregation and carbon sequestration; use of cover crops in no-till; and using spectroscopy for evaluating chemical compounds in soil organic matter. This project will continue under the project 5407-12210-001-00D, Sustainable Dryland Cropping Systems for the Central Great Plains.

1. Enhancing canola production. Canola oil is in high demand because its oil has health benefits. This consumer demand is sparking an expansion in acreage. Hence, spring canola is a new crop across dryland cropping system in the Central Great Plains. To enhance canola production across locations with varying soil moisture, ARS scientist in Akron, CO, used weather records to model canola yield. Additional models were developed for spring triticale, proso millet, and foxtail millet. Yield distribution maps and models for canola that incorporate rotational crops allow farmers to access production risks and net returns of cropping systems involving canola. This research enhances the production of canola decreasing the need for foreign import.

2. Irrigation water use efficiency. Improving water use efficiency for irrigated agriculture in the central Great Plains maximizes the benefit of this limited and expensive input for crop production. A water use-crop yield production function was established by ARS researchers at Akron, CO for irrigated corn, which uses available initial soil water estimates and expected growing season precipitation to estimate irrigation water requirements. The same (or similar) function for forage soybean can determine yield probability for several Central Great Plains locations. Additionally, data on corn, triticale and wheat growth, development, and yield were used to calibrate and evaluate simulation model for making dryland cropping decisions based on soil water at planting. The yield estimates provide guidance for farmers to diversify their cropping systems for maximum return.

3. Analysis of factors affecting proso millet production. Proso millet is an important, well-adapted, minor crop in the central Great Plains, yet little is known about the response of the crop to weather conditions. An analysis of 14 years of proso millet yields from many different cropping systems identified the most important factors influencing yield were water use, rain received from August 12-18, soil water content at planting, days with temperatures exceeding 36 C, and high winds the week before harvest. The regression model developed from this analysis used existing weather data sets from Great Plains locations to estimate proso millet yields and probabilities of achieving break-even yields. Producers use this information in designing more intensive rotations that include millet in the rotation.

4. Degraded soils require inputs for restoration. Soil degradation from previous soil management practices reduces potential crop production. ARS scientists in Akron, CO, in collaboration with scientists at Kansas State University and the University of Kentucky, demonstrated that adding manure to degraded soil improves soil properties. Additionally, a high amount of manure provides sufficient plant nutrients to replace commercial fertilizer in wheat, proso millet and grain sorghum and has the capacity to supply nutrient for up to five years. A high manure application rate reduces the expense of annual manure applications and can replace yearly commercial fertilizer applications. A commercial composting operation has been established adjacent to a local feedlot and farmers are implementing high manure and compost applications to replace commercial fertilizers.

5. Modeling soil effects on plant root growth. Most crop production models lack a root system sub model that is responsive to changing soil physical conditions. ARS scientists in Akron, CO developed a new mathematical model to evaluate soil management changes on soil physical properties and showed the effect soil management has on root distribution. They demonstrated that the new model improved root growth estimates compared with current models. The new model provides a logical framework for developing species-dependent root growth models that are more responsive to soil physical changes caused by changing tillage, irrigation and compaction management.

6. Measuring soil organic matter quality. The chemistry of soil organic matter determines organic matter storage and oxidation, influencing both nutrient release and potential sequestration. ARS scientists in Akron, in collaboration with scientists at Colorado State University, Texas Tech University, and the US Geological Survey developed new spectroscopic techniques that are both quick and inexpensive to identify chemical constituents in soil organic matter. The techniques were used to evaluate soil quality changes from the time native grass was tilled and placed into crop production and can be used for determining the contribution of soil carbon to greenhouse gas emissions from changes in tillage or cropping systems.

Review Publications
Nielsen, D.C., Vigil, M.F., Benjamin, J.G. 2011. Evaluating decision rules for dryland rotation crop selection. Field Crops Research. 120:254-261.

Nielsen, D.C., Calderon, F.J. 2011. Fallow Effects on Soil. p. 287-300 In J.L. Hatfield and T.J. Sauer (ed) Soil Management:building a stable base for agriculture. ASA and SSSA, Madison, WI.

Sistani, K.R., Mikha, M.M., Warren, J.G., Gilfillen, B., Acosta Martinez, V. 2011. Nutrient source and tillage impact on corn grain yield and soil properties. Soil Science. 175(12):593-600.

Saseendran, S.A., D.C. Nielsen, Liwang Ma, L.R. Ahuja, M.F. Vigil, 2010. Simulating Alternative Dryland Rotational Cropping Systems in the Central Great Plains with RZWQM2. Agronomy Journal. 102:1521-1534. doi:10.2134/agronj2010.0141.

Mikha, M.M., Benjamin, J.G., Vigil, M.F., Nielsen, D.C. 2010. Cropping Intensity Impacts on Soil Aggregation and Carbon Sequestration in the Central Great Plains. Soil Science Society of America Journal. 74(5):1712-1719. doi:10.2136/sssaj2009.0335.

Calderon, F.J., Reeves III, J.B., Collins, H.P., Eldor, P.A. 2011. Chemical differences in soil organic matter fractions determined by diffuse-reflectance mid-infrared spectroscopy. Soil Science Society of America Journal. 75(2)568-579.

Saseendran, S.A., Nielsen, D.C., Ma, L., Ahuja, L.R. 2010. Adapting CROPGRO for Simulating Spring Canola Growth with Both RZWQM2 and DSSAT 4.0. Agronomy Journal 102:1606-1621. Doi:10.2134/agronj2010.0277.

Blanco, H., Mikha, M.M., Presley, D.R., Claassen, M.M. 2011. Addition of cover crops enhances no-till potential for improving soil physical properties. Soil Science Society of America Journal. 75(4):1471-1482.

Last Modified: 7/28/2015
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