Assessing High Tunnel Soil Health Under Prolonged Cover Cropping Methods

Commodities

• Vegetables: peppers

Practices

• Crop Production: cover crops
• Production Systems: organic agriculture
• Soil Management: organic matter, soil analysis, soil microbiology

High tunnels (HT) are being rapidly adopted by vegetable producers in Minnesota due to resulting increases in vegetable crop production and economic gains. However, in recent years HT sustainability has been called into question, driven by intensive agricultural practices that strain the soil’s productive capacity. Nutrient cycling dynamics have been shown to differ greatly from the open field, due to lack of natural rainfall, temperature differentials, and increased photosynthetic activity. These challenges could offset the economic gains that HT production offers.

The goal of this proposal is to understand the degree to which winter cover crops impact key long-term soil-health factors in HT environments. My objectives are based on the extensive research of the effects of cover crops on soil health and crop productivity, with the aim to quantify and compare soil health metrics between HT soils under long-term cover crop management practices, and those that have never been cover cropped. Specific objectives include 1) Measure and interpret physical, biological and chemical soil health assessment indicators associated with long term winter cover crop production, and 2) Create educational resources and disseminate via in-person events, with an emphasis on emerging farmers. HTs are a particularly appealing approach to enable emerging farmers, such as immigrant and Black, Indigenous, People of Color (BIPOC) farmers, to tap into high-value niche markets, since cost-share payments for HT construction are increased for this population. Implementation of activities targeting emerging farmers will cross-cut all project activities. Outreach activities include 1) a hands-on workshop for emerging farmers to learn about general principles of cover crops, and 2) a presentation of final research results to a farmer audience at a regional conference. Tangible outcomes include practical, research-based information that farmers can use to increase long-term economic gains by making cover crops a part of their HT rotations, and associated educational resources to extend our findings.

This project leverages an existing Minnesota Department of Agriculture (MDA) AGRI-Crop Research Grant aimed at engaging emerging HT farmers in winter cover crop rotations. Under this currently funded project, optimal management of timing of fall planting and spring termination is being investigated to maximize economic and soil health building benefits, such as plant-available mineral N. This proposed SARE project will build off of the information obtained from the MDA AGRI-Crop Research Grant (explained further in the Approach and Methods section).

Objective 1. Measure and interpret physical, biological and chemical soil health assessment indicators associated with long term winter cover crop production. Learning Outcome #1: At least 50 HT Farmers will learn about the impact extended cover cropping has on soil health factors that play a central role in crop productivity. Action outcome #1: At least 20 farmers will plant cover crops in their HT as a way to build and maintain soil health.

Objective 2. Create educational resources and disseminate via hands-on field presentations, farmer conference poster sessions, and University of Minnesota Extension articles. Learning Outcome #2: At least 50 farmers will learn to weigh long term impacts on soil health in their decision to adopt winter cover crop rotations. Action outcomes #2: At least 20 HT farmers will use soil health indicators in their decision to adopt a winter cover crop species that contribute to increases in sustainable practices and decreases in soil degradation.