1a. Objectives (from AD-416):
Determine effects of crop residue removal on soil quality.
1b. Approach (from AD-416):
On-going studies at the ISU Agronomy and Agricultural Engineering Research Center (AAERC) will be enhanced by providing more rapid soil quality analyses and interpretation of information. An increased amount of crop response, nutrient uptake, and nutrient removal data will be collected. This study will complement the ARS Renewable Energy Assessment Project (REAP) team efforts with similar resources going to Morris, MN; St. Paul, MN; Lincoln, NE; Brookings, SD; University Park, PA; Akron, CO; and Florence, SC; Equal resources per the SunGrant program guidelines will go to university partners at each location to strengthen the research and technology transfer relationships.
3. Progress Report:
This multi-location project consists of both University and USDA-ARS collaborators at each site. The goal of the project is to determine the amount of corn stover residue needed to maintain soil C content (soil quality) and crop productivity. Cooperators are each responsible for managing the site within their region. Overall progress of the multi-location project was monitored through an annual meeting in Ames IA in February with the University Park progress monitored through periodic meetings, conference calls, site visits, and emails with University collaborator. We successfully established the annual crops for the feedstock experiment, consisting of five rotation treatments 1) continuous corn, 2) continuous corn with rye cover crop, 3) corn/soybean with rye cover crop, 4) soybean/corn with rye cover crop, and 5) continuous corn planted in twin rows with a higher plant population. For each these rotation treatments, there are three stover removal rates, 0, 50% and 100%. A summary of 2012 crop grain yield, corn stover biomass harvested, and nutrient analysis of corn grain and stover and soils were completed. Analysis of the five year data set at University Park indicated that although yields varied significantly over time, there was not a significant difference in yield due to removal. However, 50% stover removal was typically higher yielding with higher soil carbon levels. There was variation in response to the treatments over years. For example, in the cold wet spring in year 2 there appeared to be some advantage to stover removal. In the dry year in year 4 the high populations in the twin row management appeared to negatively impact yields.