Biodiversity Effects on Soil carbon Gain in Annual and Perennial Cropping Systems

View the project final report

Commodities

• Agronomic: corn, rye, soybeans, wheat, grass (misc. perennial), hay
• Fruits: apples, berries (strawberries)

Practices

• Animal Production: feed/forage
• Crop Production: application rate management, catch crops, conservation tillage, continuous cropping, cover crops, crop rotation, no-till, nutrient cycling
• Education and Training: extension, on-farm/ranch research, participatory research, study circle, workshop
• Energy: bioenergy and biofuels
• Natural Resources/Environment: biodiversity, carbon sequestration, indicators
• Production Systems: agroecosystems, holistic management
• Soil Management: nutrient mineralization, organic matter, soil analysis, soil chemistry, soil microbiology, soil physics, soil quality/health

Soil carbon is the most important variable in sustaining annual and perennial cropping systems, and can be increased through biodiversity. Farms in the North Central region have annual row crops and perennial landscapes that are currently used for forage or pasture. In the future perennial landscapes could also be used for cellulosic bioenergy feedstocks. Soil organic matter (SOM) has declined in both annual and perennial cropping systems, due to increased intensification and overuse, which threatens their overall productivity and profitability. The objectives of our proposed research are 1) to determine the extent that biodiversity accelerates SOM accrual in both annual and perennial cropping systems and 2) to give farmers practical information about biodiversity that will lead to opportunities for better management of soil carbon. To address our first objective, we will us an existing experimental trial at the Kellogg Biological Station, located in Hickory Corners MI, which has two biodiversity gradients. The annual gradient consists of annual monocultures, annual row crops in rotations and annual crops in rotation + cover crops. The perennial gradient consists of a perennial monoculture, a perennial mixed grass, and a native prairie. Plant and soil samples were collected in the fall of 2013. Root:shoot ratios, SOM pools and root carbon content will be analyzed . Additionally, on-farm experimentation will be conducted to determine if the active fraction of SOM, an important predictor of crop nutrient availability, can be a useful tool for predicting agronomic performance and for tracking C dynamics under different crops and treatments. Our second objective will be addressed by providing farmers information about biodiversity that will guide them towards better soil C management. We will soil sample on 10-12 Michigan farms that have both annual and perennial cropping systems. We will measure the ‘active fraction’ of SOM, which is an important predictor of nutrient availability and agronomic performance. We will discuss results individually with farmers, and provide information that will guide them toward better soil carbon management. We will also hold facilitative workshops to engage a wider group of farmers and discuss soil carbon in its relation to soil health and cropping productivity. Both the interviews and facilitative workshop will help structure an MSU Extension bulletin regarding biodiversity impacts on soil carbon. This work will also be presented at scientific meetings and will be published in peer-reviewed journals.

The goal of this work is to document the effect of biodiversity on soil organic matter accrual in annual and perennial cropping systems and provide farmers with practical information regarding soil carbon that will aid in making more effective management decisions. Short-term outcomes will include a better understanding of how biodiversity management can influence the most active pool of soil organic matter, which is important for nutrient availability to the crop. Long-term outcomes include understanding how biodiversity stabilizes the slow and passive SOM pools to increase carbon sequestration. In addition, this project seeks to make soil organic matter tests results more accessible and useful to farmers. In the short-term, farmer knowledge regarding soil organic matter will increase due to on-farm sampling and one-on-one consultations as well as facilitative workshops discussing soil carbon in relation to different management practices and cropping systems. Long-term outcomes will include more effective management practices on-farm due to increased knowledge gained from soil tests, which will ultimately lead to increases in soil health.