2013 Annual Report
1a.Objectives (from AD-416):
Determine the amount of corn stover residue needed to maintain soil C content (soil quality) and crop productivity.
1b.Approach (from AD-416):
The field experiment will include replicated plots established at three sites using continuous corn management practices, two corn stover harvest treatments will consist of 0%, ~50%, and ~100% residue removal. The stover harvest treatments will be imposed using a single pass grain and stover harvester. At the beginning and end of the study, soil samples will be collected to approximately 4-5 feet to document soil C and N distribution and other soil properties needed to define soil quality. Soil samples will be collected at depths of 0-6 inches, 6-12 inches, and one foot increments following. The minimum data to be collected at all depths for each plot are: total organic C and N, bulk density, oil-test P and K (i.e. Mehlich III, NH4OAc, Olson, etc.), pH and EC. Also, to be collected for the surface 12 inches are: Particulate organic matter, water stable aggregate size distribution. Each year data will be collected on grain and stover yield (after physiological maturity) and N content. The amount of crop residue remaining on the soil surface after each stover harvest treatment will also be determined. The following minimum data will be collected on the crop (corn) in each plot: Planting and harvest date, grain yield, N content and moisture content, corn stover yield, moisture content and N-P-K concentrations, dry matter retained in field, and fraction soil cover.
A graduate student under the direction of collaborator set up a database to contain all data collected in this project. Student also assisted in collecting the soil and plant data, and in submitting the quarterly reports to the Sun Grant Initiative. Progress was monitored on a quarterly basis with a meeting followed by a report, supplemented by telephone conversations as needed.
Collaborator and a graduate student under his direction collected soil and plant data at all three field sites, and assisted in submitting the quarterly reports to the Sun Grant Initiative. Collaborator collected soil and plant data at all three field sites, assisted in submitting the required progress reports to the Sun Grant Initiative, and helped prepare a presentation for the Sun Grant Conference. The results showed no treatment difference in corn yields; i.e. - as a function of stover removal level. However, yields in all treatments declined in the final two years, probably due to increased insect problems associated with continuous corn production. This relates to objective 1a of Project Number 3640-12000-007-00D: “Determine the impact of different levels of stover removal from highly productive continuous corn systems on soil C levels, soil respiration and N2O emissions.”