Project Overview
Commodities
- Agronomic: corn
Practices
- Crop Production: conservation tillage, cover crops, no-till
- Production Systems: agroecosystems
- Soil Management: nutrient mineralization, soil microbiology, soil quality/health
Abstract:
Cover crop adoption in the Upper Mississippi Basin has increased by 212% over the last 5 years, and farmers have a working understanding of how cover crops can be used as tool to increase soil health and reduce nitrate loading from tile-drained fields to surface waters. However, little is understood about how the inclusion of cover crops influences the soil microbial community, their efficiency in facilitating nitrogen (N) release from cover crop residue, and the relationship between the soil microbiome and cover crop carbon (C) and N release over the cover crop decomposition period. Therefore, the proposed objectives of this study are to i.) Determine the impact of cover crop species and reduced tillage treatments on soil inorganic N following cover crop termination in a corn cropping system, ii.) Evaluate the impact of cover crop species and reduced tillage treatments on soil enzyme activity dynamics as it relates to N mineralization among treatments, and iii.) Evaluate the impact of cover crop species and reduced tillage treatments on the short term dynamics of the soil microbiome during winter cover crop decomposition. The research treatments were established in 2015, thus our analysis will consist of a one-year effect. Systematic soil sampling occurred post cover crop termination during the spring and summer, which detected changes in soil inorganic N concentrations and the facilitating soil microbial community over time. Results indicate that soil β-glucosidase activity at the V6 growth stage was significantly greater for cereal rye dominated treatments relative to hairy vetch treatments, but was similar to the control (p < 0.05). This elevated soil β-glucosidase activity was related to a subsequent increase in soil inorganic N at the following sample date. Soil inorganic N trended higher from the V6 to R2 growth stages in the spring tillage cover crop treatments compared to the spring tillage no cover crop control. Permutational multivariate analysis of variance (PerMANOVA) of phylogenetic based distance matrices revealed that the main effects of cover crop treatment, tillage system, and sampling date (p < 0.05) were significant determinants of soil microbial community composition over the decomposition period.
Project objectives:
Description
The overarching goal of this study is to develop a comprehensive understanding of how cover crop species, reduced tillage treatments, and soil microbial community diversity are related to soil inorganic nitrogen availability and cover crop carbon release over the cover crop decomposition period.
Objectives
- Determine the impact of cover crop species and reduced tillage treatments on soil inorganic N following cover crop termination in a corn cropping system
- Evaluate the impact of cover crop species and reduced tillage treatments on soil enzyme activity dynamics as it relates to N mineralization among treatments
- Evaluate the impact of cover crop species and reduced tillage treatments on the short term dynamics of the soil microbiome during winter cover crop decomposition