1a. Objectives (from AD-416):
1. Develop adaptive management practices and document their benefits to optimize yield and enhance ecosystem services for CGPR dryland agricultural systems most vulnerable to adverse changes in climate. 2. Extend the applicability of adaptive management practices across the CGPR using the development and evaluation of site-specific technologies and process modeling for field scales. 3. Develop and evaluate practices for remediation/restoration of degraded soils in the CGPR.
1b. Approach (from AD-416):
There are 27 million acres of cultivated dryland in the Central Great Plains region (CGPR). The primary limitation for cropping in the CGPR is a variable drought dominated climate. Despite system improvements toward more intensive cropping, 58% of the region’s dryland is still winter wheat-summer fallow (WF). Unfortunately, WF is not economically /environmentally sustainable. Our objective is to develop sustainable dryland systems for the CGPR. A central research theme is adapting the region’s cropping systems to the ever-changing semi-arid climate. The unit works to achieve that objective using a long-term “core experiment,” the Alternative Crop Rotation (ACR) study. This field study compares 23 rotations for their economic, agronomic, and drought-mitigating effects and their effects on soil quality. In support of the core experiment, several satellite experiments evaluate the agronomic and economic potential of alternative crop species; quantify crop water use; evaluate changes in soil quality; develop management for remediating degraded soils; and evaluate nutrient use efficiency in these systems. The combined efforts of the “core” and “satellite” experiments will result in sustainable, climate-adaptive cropping systems for the region and will provide a quantitative knowledge of production limitations of the CGPR to climate change. Introducing biological and market diversity with broadleaf bio-diesel/oilseeds will reduce pest pressures inherent to the current grass-dominated rotations. Economic savings from improved cropping systems, reductions in agri-chemical use, and reductions in soil loss resulting from this research are estimated at $6-$35 per acre annually. Assuming 25% adoption of this technology will result in annual regional savings of $40 -$236 million.
3. Progress Report:
Progress of project approved June, 2011: Sustainable Dryland Cropping Systems for the Central Great Plains. Scientists at the USDA-ARS Central Great Plains Research Station (Akron, CO) with ARS and University Collaborators have begun several experiments to reach objectives of the approved project. Objective 1: Develop adaptive management practices to optimize yield and enhance dryland systems most vulnerable to changes in climate. The team has established new simulation modeling exercises, crop water use and N use efficiency experiments, modified alternative rotation plots, and established new crop residue management studies (stripper header management). A new canola rotation was established in 2012 to determine how to best fit canola into wheat rotations. To quantify water use by alternative crops, scientists are analyzing water use data sets of millet, sorghum (both new and old data sets). To improve wheat nitrogen use efficiency (NUE) a wheat cultivar by N management experiment was established with university collaborators (CSU). A grant was funded this summer 2012, to evaluate oilseed germplasm and to evaluate select cultivars in an oilseed stress trial. The Sunflower sequencing experiment is in its second year and will be planted this fall to winter wheat. Scientists are monitoring soil water recharge and will have an assessment of how well wheat performs after various summer crops in 2013. We finished the skip-row sorghum experiments. The graduate student has just written up and defended her thesis this past April. The slot tillage experiment was established in 2011. Progress was made evaluating soil organic matter quality (measured mid-IR spectroscopy) resulting in a published manuscript. Scientists made progress in publishing manuscripts evaluating soil organic carbon as influenced by tillage, and organic amendment. An organic wheat rotation experiment was established in 2011. Biochar experiments were established with USGS collaborators in 2012. Objective 2: Extend the applicability of adaptive management practices across the CGPR using site-specific technologies and process modeling for field scales. Progress is in learning software and purchasing hardware to conduct site specific N management across a landscape. We have grid sampled (for chemical/physical properties) land intended for the research. Several simulation models have been used to extend data gathered at Akron, CO to other soils and climates in the CGPR. This resulted in one peer reviewed manuscript published this past year. Objective 3: Develop and evaluate practices for remediation of degraded soils in the CGPR. Because of the 2012 summer drought no decisions about the direction of the experiment will be made until after the 2013 growing season. In the initial experimental design, 8 manure amendments were applied at rates large enough to provide adequate nutrients for dryland crops for 6 years. Because of the drought we need one more year to complete one cycle of the experiment. Preliminary analyses of yields and soil parameters have been summarized in station annual reports. Two manuscripts have been published.
Calderon, F.J., Mikha, M.M., Vigil, M.F., Nielsen, D.C., Benjamin, J.G., Reeves III, J.B. 2012. Diffuse-reflectance mid-infrared spectral properties of soils under alternative crop rotations in a semiarid climate. Communications in Soil Science and Plant Analysis. 42:17, 2143-2159.