Evaluating decomposition trends and effects of fall planted annual CC on spring soil active carbon in the Northeast

View the project final report

Commodities

• Agronomic: oats, peas (field, cowpeas), radish (oilseed, daikon, forage)

Practices

• Crop Production: cover crops, nutrient cycling
• Natural Resources/Environment: indicators
• Production Systems: agroecosystems
• Soil Management: nutrient mineralization, soil quality/health

Many Northeast farmers plant cover crops to build soil health, provide benefits to subsequent crops, and mitigate the negative environmental impacts of agriculture. Although the long-term benefits of CC are well established, additional research is needed to examine short-term, species-mediated impacts of CC on soil health and nutrient cycling. These species-mediated influences on soil health parameters must be better understood to translate soil health concepts into the development of soil health best management practices. Decomposing CC residues impact nutrient turnover in soils by directly altering active carbon (C), which is the portion of soil C that is immediately available as a microbial food source; active C serves as fuel for the microbial soil engine. This project characterizes the different rates of decomposition, measured by C and nitrogen (N) release, of aerial and root residues of winter-killed oat, forage radish, and field pea CC (monocultures and mixed plantings) as they decompose from April-July. Changes to active soil C during CC decomposition are quantified in each treatment. New knowledge generated by this project will be integrated into the results of a larger, pre-existing study. This will facilitate the comprehensive assessment of relationships between active soil C, microbial respiration, soil moisture, and soil food web functioning, and the associated implications for soil health and nutrient cycling.  The results of this project, disseminated via factsheets, Extension publications, and presentations at annual conferences, will provide growers with new knowledge that can help inform both short-term management decisions and long-term soil health goals.

Objective 1 – Classify the C and N release of three annual, fall-planted CC common in the Northeast (oat, field pea, forage radish) and their mixture during spring residue decomposition

Objective 2 – Quantify changes in soil active C during spring residue decomposition of the three CC species, representing different C:N compositions, compared to a mixture of all three species over the course of two years

Objective 3 – Characterize the relationships between cover crop residue decomposition, active soil C, microbial respiration, soil food web status, and soil moisture over the course of two years