Project Number: 5440-12210-050-00
Project Type: Appropriated

Start Date: Oct 01, 2006
End Date: Sep 30, 2011

Objective:
Objective 1: Determine the role of spatial variability in affecting management outcomes in dryland and irrigated systems. a. Develop sensors for in-season nutrient management. b. Determine management zones for efficient use of inputs. c. Residue management to maintain or enhance critical soil functions. Objective 2: Improve understanding of N and C dynamics in cropping and tillage systems commonly used in the Western Corn Belt and Central Great Plains. a. N index - Assist NRCS efforts to develop a N index for identifying BMP's that minimize N losses in runoff and leaching. b. Develop an algorithm for in-season N management. c. Soil C dynamics to enhance C sequestration. Objective 3: Implement and expand the Soil Management Assessment Framework (SMAF) a. Develop additional scoring curves for the SMAF. b. Implement the SMAF. Objective 4: Determine the impact residue removal for biofuel production has on the soil resource.

Approach:
Objective 1 a. A network of field sites managed by ARS and University scientists will collect common types of data on corn and wheat receiving different rates and timings of N fertilizer. Guidelines and algorithms for producer use of sensors will be developed. b. Apparent electrical conductivity, aerial photography, and yield maps will be assessed for their potential in delineating spatial variability in soil properties that affect plant productivity, nutrient availability, and water status. c. Experiments with factors including tillage, crop sequence, nitrogen fertilizer application, and residue removal are being conducted under contrasting environments (dryland and irrigated); measures of biomass production, grain yield, N removal, change in soil organic carbon, and soil quality indicators will be used to estimate the impact of residue amount and placement on productivity and soil function. Objective 2 a. A team of ARS and University experts will evaluate existing models, develop a strategy, and build an N-Index based on documented requirements, intended delivery method, and applications described by NRCS. b. Chlorophyll meter and grain yield data from a long-term field experiment comparing irrigated cropping systems (continuous corn and corn-soybean rotation), corn hybrids, and N fertilizer rates conducted at the Nebraska Management Systems Evaluation Area (MSEA) will be integrated to develop the algorithm. c. Data on biomass production, grain yield, and change in soil organic carbon with time from an existing experiment with treatment factors of tillage and crop sequence will be used to estimate the impact of residue source and placement on productivity and soil function. Objective 3 a. Soil indicators have been identified and a protocol for creating scoring curves has been developed for use in expanding the SMAF. b.Studies measuring soil properties under various management practices will be identified and evaluated using the SMAF. Objective 4 Two experiments, one including factors of tillage and crop residue removal conducted under irrigation and a second with factors of crop (corn or switchgrass) and residue removal under rainfed conditions have been established. Data from this study and those of other CLEAR CRIS participating locations will be combined to create recommendations for residue retention based on cropping system, climate, and production level.