Location: Agroecosystems Management Research2010 Annual Report
1a. Objectives (from AD-416)
Overall objective: To develop and transfer technologies to manage Midwestern cropping systems which enhance soil and water quality and maintain profitability. Objective 1: Develop strategies for incorporating annual and perennial cover crops into continuous corn and corn-soybean management systems. Objective 2: Quantify changes in C and N cycling resulting from inclusion of cover crops within corn-soybean based cropping systems. Objective 3: Assess erosion and soil quality impacts and production risk associated with using cover crops, complex rotations, and bioenergy production in Midwestern cropping systems.
1b. Approach (from AD-416)
A combination of controlled environment, plot, and watershed-scale studies will quantify functional components of cover crops to develop enhanced Midwestern cropping systems. Up to fifteen winter rye, triticale, and wheat cultivars will be obtained from commercial sources and planted with a grain drill following soybean harvest. Results will quantify corn grain yield response to cultivars of winter rye, wheat, and triticale used as winter cover crops in a corn-soybean rotation. Perennial cover crop research using various herbicide and strip tillage management systems in continuous corn with stover removal will quantify C inputs from cover crops and their effect on corn yield. Inter-species differences in plant growth parameters may affect a cover crop’s potential to sequester soil C. Research will quantify total aboveground and belowground C and N allocation, rhizosphere respiration, and net mineralized N for selected cover crops grown under controlled conditions, quantify changes in surface residue, root, and soil C and N pools and cumulative net mineralized N and respired C during decomposition of cover crop biomass under controlled conditions, and field experiments to quantify the effects of the cover crop on soil C cycling and storage within extended corn-soybean based crop rotations with and without compost amendment. Field studies will evaluate the impact of corn stover removal with and without rye and perennial cover crops on soil quality. A modeling study will evaluate the effect of a winter rye cover crop on soil erosion in corn-soybean rotations using georeferenced terrain and cropping system data from two western Iowa watersheds. Evaluation of risk to crop yield induced by the removal of soil water by cover crops will be assessed with a combination of simulation models and experimental observations. Simulation results will be obtained with the Precision Agricultural-Landscape Modeling System (PALMS) model. The simulation model allows for an extension of the results to different soil types and climates and will be used to assess the degree of risk imposed on the main crop through soil water removal patterns.
3. Progress Report
The second year of the project coincided with a laboratory reorganization. Consequently, nine research projects were merged into five. During the reorganization, some work on specific objectives was delayed or terminated. Nevertheless, progress was documented in all four objectives of the reorganized project. In Objective 1, winter small grain cultivars were planted and spring cover crop shoot dry weight, corn harvest plant populations, and yield data were collected. All data were collected in the perennial groundcover experiment and the data are being analyzed. In Objective 2, plant species were identified that will be used for the carbon and nitrogen cycling experiments. In Objective 3, field plots were established for the winter rye and corn silage experiment and surface cores were collected for soil carbon, potentially mineralizable nitrogen, and particulate organic matter. In Objective 4, soil fertility data are being collected in the large biomass study in Field 70/71 at the Agronomy Farm. Additionally, tile should be installed in the organic research plots this summer and the plots should be ready to initiate the rotations next year.
Hatfield, J.L., Prueger, J.H. 2010. Value of Using Different Vegetative Indices to Quantify Agricultural Crop Characteristics at Different Growth Stages under Varying Management Practices. Remote Sensing. 2:562-578.