Features from the Farm
The University of Minnesota West Central Research and Outreach Center (WCROC) in Morris established an organic dairy herd in 2008, and subsequently began transitioning selected fields from conventional crop production to organic crop production in effort to support the organic dairy herd. Approximately 300 acres are under organic management with the goal of producing 1) forages: alfalfa haylage, wheatlage, and corn silage, 2) corn and wheat feed grains, and 3) straw for livestock bedding.
One of the biggest challenges with organic production is weed management and its impact on yield. In organic systems, repetitive tillage is required for successful weed control. While our crop production is mostly successful, it is also tillage intensive and counterproductive to promoting soil sustainability, a tenet embedded within the organic production philosophy. Repetitive tillage leads to increased fuel consumption, soil carbon loss/organic matter decomposition and promotes soil erosion. Our goal is to produce organic crops in a sustainable manner while adhering to organic production principles; thus, a revised, less tillage (LT) intensive production system was initiated, and is being compared to our more tillage (MT) intensive system.
The more tillage system utilizes mostly tillage for weed management and crop production. The less tillage system will increase the utilization of minimal soil disturbance, crop competition, and continuous residue cover operations in its weed management and crop production system. Both the MT and LT systems are in the same diverse six-year crop rotation.
• Year 1: corn is chopped for corn silage and ground is seeded to winter wheat.
• Year 2: winter wheat is chopped for wheatlage, and then seeded to soybeans.
• Year 3: corn is seeded for grain harvest.
• Year 4: alfalfa is seeded with spring wheat (the spring wheat is chopped for wheatlage along with the alfalfa at first cutting).
• Years 5 and 6: remain as alfalfa, all chopped as haylage.
In the MT system, fall tillage separates the crops in rotation. In the LT system, more crop competition and reduced/no tillage seeding operations are used for weed management. Weed pressure and yield are assessed in both systems where they differ operationally, for example, within the first three years of the six-year rotation the MT and LT systems are identical in year one, while they differ in years two and three.
For annual crops in our organic production system, two spring tillage (field cultivation) operations are used prior to seeding crops. The first tillage operation occurs as early as practical in the spring (coinciding with conventional corn spring tillage) and then a second tillage operation 7 to 10 days later to eliminate the early spring flush of weeds. Early in-season weed control is achieved with a rotary hoeing, harrowing, or a row flaming operation prior to or closely after crop emergence for germinating or just emerged weeds. Later season weeds are controlled with row cultivation when the crop is well established.
Differences between the MT and LT systems at the WCROC were recorded; results can be found by visiting the WCROC website at http://wcroc.cfans.umn.edu.