What we're doing

Our research is designed to improve our understanding of how plant-soil interactions influence nutrient cycling and availability in organic and limited-resource cropping systems, with an emphasis on the rhizobia-legume symbiosis.

Soil health and nutrient management training for immigrant and minority farming communities

Immigrant and minority farming communities

Photo credit: Shared Ground Farmer Cooperative

Grant cycle: 2015-2017

Immigrant farmers represent a growing population of food producers in Minnesota and elsewhere in the Upper Midwest. Feedback from these farmers demonstrates interest in learning how to calculate nutrient rates for organic crops, as well as manage inputs such as cover crops and organic fertilizers. Currently, there is no comprehensive resource for soil management training for either immigrant farming organization educators or farmers. This project will develop hands-on courses and online resources to teach soil and nutrient management to diverse audiences, with an emphasis on immigrant farmers. Soil science topics will include cover crops, nutrient management for small fruit and vegetable crops, signs of nutrient stress, soil test interpretation, irrigation/fertigation system design and operation, season extension, and tillage equipment operation and maintenance. We will partner with The Good Acre NGO, serving as a food hub to immigrant and low-resource farmers, to deliver experiential, on-site training to 40 agriculture leaders who work with immigrant farmers, including extension educators, NRCS personnel and immigrant farmer leaders. 

This project is funded through the Sustainable Agriculture Research and Education Professional Development Program (SARE-PDP; $74,760)

Optimizing soil health in season extension environments through innovative cover crop management

High tunnel

Grant cycle: 2014-2017

High tunnels in cold climates, such as Minnesota, are in great demand, in part spurred by a national NRCS cost share program promoting their use. Yet, most sit empty in the winter, providing an opportunity to add soil-enhancing cover crops to the rotation. Most high tunnel producers that utilize carbon-based inputs do so using composts made from animal manures. Anecdotal information combined with recent studies indicate that high tunnels regularly using composted manures suffer from over-application of phosphorus (P) in the manure and are at risk of P runoff into sensitive waterways. This project seeks to increase adoption of winter annual legume cover crop use in high tunnels by identifying species of interest to producers and timing requirements, then transferring evidence-based information to growers, including improvements in both soil quality and cash crop productivity. Our aim is to determine ‘best bets’ species or mixtures of cover crops that meet the unique needs of growers utilizing high tunnels in cold environments.  Upon completion this study will offer growers options for enhancing soil health and crop productivity through cover crop inclusion in their high tunnel rotations. Visit West Central Research and Outreach Center (WCROC) - Morris, MN for more information about cover crop managment in high tunnels.

This project is a federal NRCS Conservation Innovation Grant (CIG) funded collaboration with the laboratory of Dr. Mary Rogers at the University of Minnesota ($192,000).

Bringing the benefits of legume cover cropping to northern Midwest climates

Vetch nodule

Grant cycle: 2014-2017

The purpose of this project is to provide legume cover crop options to growers in the upper Midwest by examining the key  microbial process of nitrogen fixation that regulates nitrogen (N) cycling in select winter-hardy legumes, and by designing an innovative set of educational tools showcasing exemplary farmers who successfully utilize legume cover crops in colder climates, or face challenges in doing so.  In particular we will investigate the need for legumes to be inoculated in midwestern soils that may already have competitive rhizobia strains present. Competitive indigenous populations of rhizobia present in farm soils have been shown in many regions to impact the success of rhizobia inoculants added at legume planting. Since rhizobia are present in almost all soils, we hypothesize that legumes may form relationships with indigenous rhizobia that may affect nitrogen fixation rates, either increasing or decreasing its performance.  We will develop a replicated field experiment assessing five legume cover crop species or mixes, and three inoculation treatments to determine if inoculation provides plant growth benefits to legume cover crops in Minnesota soils.

This project is a NC-SARE funded collaboration with the laboratories of Drs. Craig Sheaffer and Nancy Ehlke in the Department of Agronomy and Plant Genetics at the University of Minnesota ($114,000).

Optimizing establishment of corn in cover crops and living mulches to maintain yield while reducing nitrate losses

Corn field

Grant cycle: 2014-2017

Full-width tillage is well known to reduce soil carbon stocks and overall soil quality in systems where it is used continuously, stimulating the investigation of alternative tillage options.  When combined with reduced tillage, systems that utilize legume cover crops on a regular basis have been shown to contain twice as much soil carbon as systems that do not, and four times as much microbial biomass, an important indicator of soil quality and nutrient mineralization potential. Strip tillage, also known as zone tillage, is a potentially attractive alternative to full-width tillage  in which tilled strips are created, typically on 30 inch spacing, while the interrow areas are left untilled.  This preserves surface cover for erosion protection while creating bare soil rows into which the row crops are planted. This study will investigate the role of strip tillage with living perennial mulches in reducing N losses and improving soils and water quality in row crop production.

This project is a Minnesota Department of Agriculture (MDA) funded project in collaboration with Drs. John Baker in the Department of Soil, Water and Climate, and Scott Wells in the Department of Agronomy and Plant Genetics at the University of Minnesota ($232,444).

Innovative conservation tillage strategies in organic cropping systems for improving soil health and microbial activity

Soil Sampling

Year: 2014-2016

Intensive tillage is known to impair soil structure and accelerate decomposition, both of which have negative effects on soil health and quality. Maintaining ground cover is an essential management practice that reduces soil erosion, increases infiltration, and builds soil organic matter. For this reason, many growers now preserve ground cover through no-till management, but this has proven challenging in organic cropping systems where tillage is heavily relied on for warming soil in the spring and controlling weed pressure. The purpose of our research is to evaluate the efficacy and soil biological effects of two different zone tillage methods. Zone tillage is an overlooked reduced tillage strategy where rows are tilled and interrows are maintained with ground cover. We are evaluating these methods in both a field corn system using a kura clover living mulch as well as a vegetable system with a winter rye and hairy vetch biculture. Several soil microbial and organic matter assays will be performed over the course of the growing season to serve as indicators of soil health. Results will enable organic growers to maximize cover crop advantages, both as ground cover and fertility sources, while also conserving soil structure, tightening the N cycle, and reducing environmental pollution from sediment and nutrient losses.

This Graduate Student Grant was awarded to Peyton Ginakes from the Ceres Trust ($9,914).

Improving soil health and microbial activity through zone tillage and innovative cover cropping strategies

Year: 2014-2016

WeedingOrganic growers face a challenging set of guidelines, both prohibiting them from using synthetic herbicides and encouraging them to utilize cover crops in order to maintain ground cover and meet crop nutrient needs. The resulting intensive tillage that organic farmers often use to control weeds, incorporate cover crop residue, and prepare seedbeds is detrimental to soil structure and biology, as well as to the greater environment by accelerating nutrient losses and soil erosion to sensitive water bodies. Zone tillage is an attractive middle ground between intensive tillage and no tillage that involves tilling only narrow row areas where crops will be planted, maintaining the benefits of ground cover in interrow areas. This project seeks to evaluate the viability of and soil biological responses to zone tillage for two cover cropping systems (a winter rye and hairy vetch mix, and a biennial red clover living mulch) as a reduced tillage strategy for organic vegetable growers in the North Central US, with the goal of reconciling organic systems with reduced tillage. Our learning and action outcomes emphasize understanding how zone tillage impacts microbial and organic matter assays, and extending learned information to growers and students.

Peyton Ginakes was ALSO awarded funds for this project (GNC14-187) through the North Central Region Sustainable Agriculture Research and Education (NCR-SARE) Graduate Student Grant Program ($9,995). Go, Peyton!

Understanding rhizobia ecology in legume cover crops

Year: Ongoing

BOXBiological nitrogen fixation (BNF) is the major source of new nitrogen in organic agriculture, yet there has been almost no research devoted to understanding how organic management practices impact this process. Furthermore, few widely used, temperate green manures have been characterized in terms of their nitrogen fixing traits and the ecology of the bacteria responsible for legume BNF, called rhizobia. The goal of this project is to improve understanding of biological nitrogen fixation and rhizobia ecology within organic cropping systems so that this process can be most effectively managed. We are using molecular techniques to ‘fingerprint’ and genetically characterize rhizobia strains that have been both extracted from nodules of legume cover crops and ‘trapped’ from NC farm soils. We are interested in how history of organic management affects the efficiency of rhizobia inoculants, commonly used when farmers plant legume cover crops. We hope that our research will show us how specific management practices are impacting the ecology of rhizobia found in symbiosis with commonly grown legumes in organic systems.