Location:
2022 Annual Report
Objectives
Objective 1: Develop management practices incorporating the latest technology developments for a field size aspirational four year, dryland crop rotation system with precision nutrient, agrichemical, weed control and crop population management.
Sub-objective 1a. Identify and quantify production parameters most important in affecting economic yields across a dryland field-scape.
Sub-objective 1b. Develop methods for quantifying optimal precision N management for specific management zones in wheat-based dryland rotation.
Sub-objective 1c. Develop methods to quantify optimal corn populations for specific management zones in a four-year aspirational rotation.
Sub-objective 1d. Develop and evaluate new tools for assessing soil quality across a field-scape using spectral scanning (FTIR) and other quick methods.
Sub-objective 1e. Evaluate the use of drone based data for the quantification of crop water stress in dryland crop rotations.
Objective 2: Compare yields, economic returns, and environmental impacts of the aspirational rotation system, to a dryland rotation system currently used by producers of the region.
Sub-objective 2a. Quantify and compare grain yields and economic returns from a precision-managed four-year aspirational no-till rotation with a “business as usual” reduced-till wheat-fallow rotation.
Sub-objective 2b. Quantify and evaluate changes in soil quality as affected by both management systems across the field-scape.
Objective 3: Evaluate potential alternative crops and management practices for introduction into the aspirational wheat based dryland rotation system.
Sub-objective 3a. Continue evaluations of germplasm and potential alternative crops for inclusion into wheat-based dryland systems.
Sub-objective 3b. Evaluate new agronomic practices for inclusion into aspirational wheat-based dryland rotations.
Approach
Dryland farmers in the central Great Plains have the technical means to collect much of the field data needed for precision farm/field management. These data often available in a map format or “data layer” include field grain-yield maps, soil-color maps, electrical conductivity (EC), pH, topographical-elevation field maps, and soil-series maps. However, most dryland producers do not have a science-based, unbiased collection of quantitative recommendations for interpreting how to best use those field data layers. The lack of reliable quantitative recommendations makes it difficult to manage field-scape variability for maximizing net returns. In this project, researchers will use a replicated set of field sized plots that show substantial variability in productivity as one moves through a given field. Using this large field experiment we will develop the mathematical relationships between yield, and inherent field variability and climate variability that are key to a field’s annual productivity. This research will provide a quantitative understanding of how N inputs in dryland rotations can best be optimized across variable field landscapes and variable climate for improving farm gate income. With that science based knowledge researchers will build reliable decision support tools to help guide producers on precision farm management in semi-arid wheat base dryland rotations. This research will also focus on precision optimization of dryland corn populations that match inherent field and climate variability. Soil health monitoring of the rotation treatments and the testing and development of quick methods for assessing soil quality will also be included as important research aspects of the project.
Progress Report
Objective 1: Crop yield and topography were used to develop management zones (high, medium, and low yield potential) in each aspirational (ASP) and business-as-usual (BAU) crop-rotation field and are being used to make fertilizer decisions. Soil water data continue to be collected using neutron probe access tubes located along transects across management zones in each ASP and BAU field. Thousands of soil samples collected on 30-m grids in each BAU and ASP field have been analyzed for general soil chemical properties, which has allowed the creation of geospatial maps showing distributions of soil physical and chemical variables. Detailed elevation data were collected to create a uniform, high-resolution topographic map to quantify water accumulation patterns within and across fields. Preliminary analyses using random forest machine learning (ML) and principal component analysis (PCA) statistics were used to explore interactions of grain quality and yield, topography, and gridded soil physical and chemical variables. Results will establish the factors that best predict crop yields, which will improve management-zone delineation and management-decision recommendations. Unmanned aerial vehicles (UAVs) collected a second year of detailed spatial data in each field to document crop condition at different times during the growing season. Normalized Difference Vegetation Index (NDVI) using red and near-infrared bands and Green Normalized Difference Vegetation Index (GNDVI) using green and near-infrared bands were highest when plants were at the reproductive stage and may provide useful data to monitor crop growth, nitrogen (N), and water status and provide reliable information for decision-making in dryland crop production. A new study was initiated to assess both NDVI and GNDVI to determine which might be more appropriate to predict the N fertilizer required to meet crop yield potential, when we should collect these data to provide the best estimate of yield potential, and what data spatial resolution is suitable. With installation of a second eddy covariance tower in 2021, we are measuring evapotranspiration over both BAU and ASP field conditions. A National Aeronautics and Space Administration (NASA) Solar Induced Fluorescence tower was co-located with the eddy flux tower on a BAU wheat field during spring. All these activities are setting the stage for a long-term comparison of BAU wheat-fallow crop production to more-intense, precision-managed, multi-crop ASP rotations under dryland conditions. Data and preliminary results were disseminated to producers and stakeholders at the 2022 Customer Focus Group meeting, 2022 Field Day, and to the scientific community in conference presentations. Research continued to evaluate yield stability as influenced by environmental conditions throughout the duration of the project.
Objective 2: Field management data, including crop inputs, field operations, operational costs, and crop yields, were compiled in a database for the first 4 years of the project. A new collaborative agreement was established with economics researchers at Colorado State University to compile all input, management, yield, and market data needed to evaluate economics of the ASP and BAU rotations. Final gridded soil sampling is planned for the end of the complete 4-year crop-rotation cycle (end the growing season of 2022). Data and preliminary results were disseminated to producers and stakeholders at the 2022 Customer Focus Group meeting, 2022 Field Day, and to the scientific community in conference presentations.
Objective 3: We continued data collection and analysis of the wheat and rye variety trials, the 2nd year of the genetics by environment by management (GxExM) study, a stakeholder-driven study on persistence of volunteer triticale in alternative dryland rotations. Kernza (intermediate wheatgrass) management and yields are being evaluated in a new variety trial. A new cowpea crop was introduced to replace fallow in wheat-corn-fallow rotation (wheat-corn-cowpea) at the long-term (30 years) Alternative Crop Rotation study (ACR). In addition, we continue evaluating soil health parameters on the ACR plots that were sampled in 2021. Selected pairs of wheat-rotation-plot data from the ACR study are being evaluated with datasets of air temperature and precipitation to better understand climate impacts on yields in dryland agroecosystems. Analysis of the influence on yields of key ACR data (e.g., precipitation density and frequency, ambient temperatures during critical growth stages, and exposure to temperatures above a threshold) is underway.
Accomplishments
1. Soil quality improved by USDA Conservation Reserve Program after 10-40 years. High quality soils have highly functioning biological, physical, chemical, and nutrient characteristics, which produce more food and have more environmental benefits. Good management improves soil quality, while soil erosion degrades it. ARS scientists at Akron, Colorado, ocompared soil quality of business-as-usual croplands to pasture or cropland converted to native grasses, such as through the USDA Conservation Reserve Program (CRP). Farmers were directly engaged in this research, providing samples from 38 different fields for analysis. Pasture and grasslands improved soil structure stability by 38% and soil organic carbon (SOC) by 47% compared with business-as-usual cropland. Improving soil structure stability of cropland in the U.S. (895 million acres) by just 1% could reduce soil water erosion up to 0.75 tons/acre/decade and wind erosion up to 1.5 tons/acre/decade. Using a soil quality index that integrates key soil quality characteristics, we found old CRP (10-40 years after conversion from cropland) increased the overall level of soil function from 78% for business-as-usual cropland to 84% for CRP, where 100% indicates optimal soil function. We also found that a goal of full recovery soil structure stability and SOC to prairie levels may take 10-40 years using CRP. These promising findings provide new confirmation of the impacts of the long-standing USDA CRP program and point to the need to reestablish grassland on highly sloping croplands that are susceptible to excessive soil erosion. Conversion to grassland could also provide cellulosic feedstocks for bioenergy or other bioproducts.
Review Publications
Jones-Diamond, S., Asfeld, E., Johnson, J., Cabot, P., Fry, J., Tanabe, K., Bartolo, M., Mankin, K.R., Difonzo, C., Roberts, R., Gutierrez-Castillo, D.E. 2022. 2021 Colorado corn variety performance trials. Colorado State University Technical Report. https://webdoc.agsci.colostate.edu/csucrops/reports/corn/cornreport_2021.pdf
Mikha, M.M., Wills, S. 2021. Water-stable soil aggregate assessment. In: Karlen, D.L., Stott, D.E., Mikha, M.M., editors. Soil Health Series: Volume 2 Laboratory Methods for Soil Health Analysis. Madison, WI: Soil Science Society of America. p. 52-68.
Karlen, D.L., Stott, D.E., Mikha, M.M., Moebius-Clune, B.N. 2021. Soil health: An overview and goals for these volumes. In: Karlen, D.L., Stott, D.E., Mikha, M.M., editors. Approaches to Soil Health Analysis, Volume 1. Madison, WI: Soil Science Society of America. p. 1-20.
Jones-Diamond, S., Johnson, J., Mason, E., Asfeld, E., Stromberger, J., Tyler, R., Meyer, R., Trujillo, W., Kaan, D., Ballard, T., Fickenscher, B., Larson, K., Mankin, K.R., Pettinger, B., Nachappa, P., Peirce, E., Roberts, R., LoGrasso, O., Pottorff, L., Miner, G.S., Delgado, J.A., Ippolito, J., Kluth, D., Stewart, C.E., Erker, B., Westra, E., Gaines, T. 2022. 2021 Colorado winter wheat variety performance trials. Technical Report TR 21-3 2021 Wheat Field Days Edition. Fort Collins, CO: Colorado State University Extension. 56p.
Avera, B.N., Rhoades, C., Calderon, F.J., Cotrufo, M.F. 2020. Soil C storage following salvage logging and residue management in bark beetle-infested lodgepole pine forests. Forest Ecology and Management. 472. Article e118251. https://doi.org/10.1016/j.foreco.2020.118251.
Moiser, S., Apfelbaum, S., Byck, P., Calderon, F.J., Teague, R., Thompson, R., Cotrufo, M.F. 2021. Adaptive multi-paddock grazing enhances soil carbon and nitrogen stocks and stabilization through mineral association in southeastern U.S. grazing lands. Journal of Environmental Management. 288. Article e112409. https://doi.org/10.1016/j.jenvman.2021.112409.
Li, L., Jin, V.L., Kettler, T.A., Karlen, D.L., Nunes, M., Lehman, R.M., Johnson, J.M., Mikha, M.M. 2021. Decreased land use intensity improves surface soil quality on marginal lands. Agrosystems, Geosciences & Environment. 4(4). Article e20226. https://doi.org/10.1002/agg2.20226.
Mikha, M.M., Jin, V.L., Johnson, J.M., Lehman, R.M., Karlen, D.L., Jabro, J.D. 2021. Land management effects on wet aggregate stability and carbon content. Soil Science Society of America Journal. 85(6):2149-2168. https://doi.org/10.1002/saj2.20333.
