New Tools to Make Organic No-till Soybeans and Corn a Reality

New Tools to Make Organic No-till Soybeans and Corn a Reality

Summary

The demand for organic grains is increasing. Farmers making the transition to organic production cite weed management as their biggest challenge. The objective of the project was to determine if an organic no-till system was feasible in the Southeast US. Experiments were held throughout the state. A rye (Secale cereal) cover crop (‘Rymin’) was planted in late fall and rolled/crimped or flail-mowed prior to planting to create a weed suppressing mulch with potential allelopathic properties. To augment weed control, one pre-emergence and two post-emergence weed management tactics were evaluated. Compared with conventionally treated check plots, the rolled rye system resulted in equivalent soybean yields at most of our locations. Rye biomass levels played a critical role in weed suppression.

Objectives/Performance Targets

We utilized research stations and on farm trials to compare no-till organic soybean systems utilizing different combinations of the following tactics: planting soybeans into a rye cover crop compared to planting into no cover crop; planting soybeans into a rolled down rye cover crop compared to planting into an undercut rye cover crop; planting soy with a 7 inch band of corn gluten over the crop row, use of post crop emergence clove oil organic herbicides with sprays directed under crop foliage and the use of one pass of a high residue cultivator to control weeds between crop rows.

We also proposed a multi-location investigation of nitrogen contribution by crimson clover and hairy vetch cover crops grown on poorly drained soils preceding corn as part of the no-till organic grain rotation.

Accomplishments/Milestones

The use of rye cover crops for weed suppression was successful. Rolled rye resulted in pigweed (Amaranthus retroflexus L.) cover of 3% vs. 13% in flail-mowed rye. Corn gluten meal increased weed coverage at most locations and reduced yield by 208 kg ha-1 on average across locations. Compared with conventionally treated check plots, the rolled rye system resulted in equivalent soybean yields at Goldsboro and Plymouth where biomass was 10854 kg ha-1 and 9526 kg ha-1, respectively. Additionally, rolled rye in combination with clove oil resulted in slightly higher soybean yields than conventional check plots at both sites. In Kinston, a low rye biomass of 6606 kg ha-1 was insufficient for adequate weed control and soybeans from rolled rye plots yielded 853 kg ha-1 less than those from conventional plots. Rye biomass levels played a critical role in weed suppression.

The 2009 season has started. All treatments will be repeated.

Impacts and Contributions/Outcomes

A field day event was held in mid August to demonstrate various organic grain systems. This field day hosted local farmers from Hyde and neighboring counties. Many farmers have expressed much interest in the success of the system.

The organic grains program also held an out-of-state organic grains bus tour. Surrounding farmers, researchers, and students traveled to the Rodale Institute and neighboring organic farmers to explore new options for organic growers.

Collaborators: