Mark Pokorny is one of 10 farmers working with Iowa Learning Farms and Practical Farmers of Iowa on a project comparing corn and soybean yields following a winter rye cover crop. Located near Clutier in Tama County, he began hosting a demonstration site in fall 2009 for the cover crop working group.
The Iowa Learning Farms program works with many farmers across Iowa who are implementing conservation farming practices while remaining profitable. Farmer partners, such as Pokorny, help ILF by sharing their experiences to help build a Culture of Conservation. They host field days, speak at workshops, or chat one on one with other farmers interested in making changes on their own farms.
“I had seen some cover crops around the area, but had limited personal experience with them. I was interested in trying a winter rye cover crop for the erosion benefits over winter and in early spring,” says Mark. “I hadn’t considered the nutrient capture, organic matter increases and reduced weed pressure benefits that I saw in 2011.” This past harvest, Pokorny reported higher soybean yield following the cover crop and also saw reduced common waterhemp and lambsquarter weed pressure.
Establishing cover crops
Pokorny rotates soybeans with one or two years of corn or seed corn production. Spring full-width tillage with a soil finisher precedes corn planting, and soybeans are no-till planted into standing cornstalks. After bean harvest in November 2009, he drilled replicated side-by-side treatment strips of winter rye cover next to “no cover” treatment strips. In April 2010, he used a disk and soil finisher to terminate the rye and prepare a seedbed for corn planted a few days later.
Pokorny’s 2010 corn yields were not affected by the preceding rye cover crop (176 bushel per acre following rye cover, 177 bushel per acre in “no cover” strips). Rye cover and no cover treatment strips were re-established in fall 2010.
In spring 2011, he terminated the winter rye with a preemerge herbicide tank-mix of glyphosate, Authority and First Rate. Non-GMO soybeans were planted in May in 30-inch rows at 150,000 seeds per acre. Control of waterhemp and lambsquarter weeds was less than desired in “no cover” soybeans; however, the beans planted into the rye cover showed significantly less weed pressure. Over four replications, soybean yields averaged 68 bushels per acre following rye cover and 60 bushels per acre in “no cover” strips.
Fertilizer management in Pokorny’s cropping system includes an annual fall dribbled application of maintenance rates of liquid P and K with micronutrients. Soils are sampled every three years. Much of his acreage has a history of swine manure application, although no manure has been applied in the past five years. Corn nitrogen fertilization includes 32% UAN applied preemerge with herbicide and a foliar-applied nitrogen product accompanying postemerge herbicides.
Pokorny hasn’t experienced increased insect or disease pressure in corn or soybean crops planted into winter rye cover. “I plan to expand my use of rye cover crops following seed corn production,” he says. “Any non-GMO soybean acres with a history of significant weed pressure will be planted into winter rye cover based on the results I experienced in 2011.”
Pokorny divides his working hours as a conservation-minded farmer and Tama County NRCS technician. “Conservation is a mindset every farmer should strive towards to ensure soil productivity for future generations,” he says. “Mulch till, strip till and no-till can be implemented without sacrificing yield; it just takes a little different approach towards fertilization and residue management.”
Lundvall is with Iowa Learning Farms.
This article published in the February, 2012 edition of WALLACES FARMER.
All rights reserved. Copyright Farm Progress Cos. 2012.