Corn Residue Removal Impacts on Soil, Water, and Air Resources for Biofuel Production

Corn Residue Removal Impacts on Soil, Water, and Air Resources for Biofuel Production

Summary

The objective of this project is to establish coordinated field studies to determine the short-term and long-term impacts of different corn residue removal, N fertilization rates, and tillage systems on soil, air, and water resources. Study was established in fall of 2008 on Iowa State University Agronomy Research Farm west of Ames, IA and Armstrong Research and Demonstration Farm southwest of Atlantic, IA. The main treatment is tillage practice (no-till and chisel plow), which was split into three different corn residue removal rates (0, 50, and 100%), The N rates were the split- split treatments vary from none to 250 lb N/acre in spring of 2009. Soil measurements were conducted in spring after planting and fertilizer applications, which include soil C, N, P, K, bulk density, water infiltrations, residue cover, microbial biomass, and weekly carbon dioxide (CO2) and nitrous oxide (N2O) gases field measurements. After harvest, crop measurements will include harvested corn for grain yield, and N, P, and K uptake. The study will be conducted and sampled for three years (by seeking additional funding) under continuous corn. Laboratory analyses for various soil parameters will also be conducted such as, soil carbon analysis, plant carbon analysis, nutrients analyses, lab incubation studies, and aggregate stability.

Objectives/Performance Targets

In the second year of this project and through other outreach train-the-trainer project, several workshops and field days were conducted on residue management and its impact on soil and water quality. Several classroom setting presentations and hands on field training sessions were conducted. Audience included farmers, agricultural professionals, and extension educators. In addition, undergraduate student participated in this project by conducting lab residue decomposition study as part of his study curriculum. Evaluation surveys were handed out during most presentations to qualitatively and quntatively measure farmers’ and other agriculture professionals’ familiarity with project’s stated short and long-term outcomes during field days and workshops. Analysis of these surveys are currently being done.

Accomplishments/Milestones

We are currently analyzing data from 2009 and 2010. Preliminary findings include:
• Leaving residue on the surface tends to lower yields in the Ames Research farm but not in Armstrong. This was more prevalent in cold wet years such as in 2010. Figs 1 & 2
• There were no significant difference in corn stover left over at 150 and 250 N lbs/ac. Fig 3
• There were no significant difference in root biomass at 150 and 250 N lbs/ac. Fig 4
• There were no differences in annual C losses due to different corn stover removal rates. Fig 5
• There were no differences in annual C losses due to different N fertilization rates. Fig 6
• No-till has significant lower soil C losses compared to chisel plow. Fig 7
• Removal of 50% and greater of corn residue can potentially lead to soil carbon losses. Fig 8
• No-till under sufficient N fertilization leads to C being sequestrated. Fig 8
• Under chisel plow, greater than 150 N lbs/ac is needed for net increases in C sequestration. Fig 8
Annual field days, training workshops, and other educational events were organized in September of 2010 for agricultural professionals and farmers at the Iowa State University Armstrong Research and Demonstration Farm (Southwest Iowa) and Boone (North Central Iowa). Training, PowerPoint presentations, and educational materials presented during these events. In addition to field days, initial findings of this research shared with other colleagues and agricultural professionals through newsletter articles, presentation at regional committee meeting, presentation to extension educators and other agricultural professionals during various events, such the integrated crop management conference in Iowa that is organized annually and approximately a 1,000 agricultural professionals attended that conference.

• Fig 2
• FIg 3
• FIg 6
• Fig 7
• Fig 1
• Fig 5
• FIg 4
• FIg 8

Impacts and Contributions/Outcomes

This research is in its second year and will continue for another year to provide critical information that is not available or deficient at this time to researchers, nutrient management and soil conservation planners, producers, agriculture industry, and government agencies responsible for establishing nutrient management and soil conservation or environmental regulations. Important project outcomes will include reliable estimates of (1) amount of C and nutrients removed and returned to the soil with different amounts of biomass removal and return to the soil, (2) change in soil C and crop nutrients, and effect on nutrient processes and cycling due to different levels of crop biomass removal, (3) soil C sequestration potential with different levels of crop biomass management, (4) soil CO2 emission in-situ with different crop biomass management (5) crop residue level effects on decomposition in the field and nutrient release to soil, and (6) changes in N, P, and K use and fertilization requirements as affected by crop biomass harvest systems.

Collaborators: