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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Research Project #443750

Research Project: Managing Alfalfa for Climate Smart Agriculture

Location: Plant Science Research

Project Number: 5062-21500-001-013-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Apr 1, 2023
End Date: Dec 31, 2025

The goals of this project are 1) to evaluate and demonstrate innovative establishment and termination strategies for alfalfa to improve soil health and field carbon (C) balances. Project objectives are to: 1). Evaluate the impacts of tillage, nurse crops, and alfalfa-grass mixtures on field-scale carbon dioxide (CO2) fluxes, mineralizable carbon, and soil organic carbon during the establishment and termination periods using on-farm alfalfa stands. Management practices to evaluate include: Cover or nurse crops for alfalfa establishment (e.g. oat, barley, triticale, Italian ryegrass) and tillage management for alfalfa establishment and termination (no-till/herbicide, chisel till, undercutting, strip tillage).

Research will be conducted at two on-farm locations in Minnesota and Wisconsin. At each measurement site, two adjacent fields with at least 200 m fetch (~40 acres) in the prevailing wind direction will be identified for establishment of the experiment. One field will be managed with a "business as usual" (BAU) approach that represents standard approaches to establishment or termination of alfalfa with respect to tillage, grass mixtures, and cover/nurse cropping. As a contrast to the BAU field, a second field at each site will be managed as the "treatment" field where alternative approaches to establishment and termination are employed with a goal of improving the field C balance relative to the BAU approach. Practices that may be evaluated include no-till or strip-till seeding and herbicide/no-till termination of alfalfa; cover or nurse crops for alfalfa establishment such as oat, barley, tritcale, or Italian ryegrass; alfalfa-grass mixtures (e.g, seeded in biculture with meadow fescue). The specific management practices chosen for the treatment field will be selected based on each producer's ability to implement the selected practices at the field scale. Treatments may be combined for an individual field (e.g. no-till + cover crop). In this case, the impacts of individual management practices may be confounded, so the treatments will be considered as a "system" for comparison with the BAU approach. All other management practices will be held consistent between fields to the extent possible. This "paired-field" design will allow for a treatment vs BAU contrast at each farm.