Corn Management Following Cereal Rye Cover Crop with Strip Tillage and In-Row Fertilization
Cover crop adoption is a key practice promoted to reach the Iowa Nutrient Reduction Strategy (INRS) goals of 45% nitrogen and 29% phosphorus reduction in surface waters. It is estimated 12 million acres of cover crops are needed in Iowa to meet INRS goals, yet only 720,000 acres were planted in 2017, about 3% of the corn and soybean acres planted in Iowa annually. Farmer evaluations show corn yield drag and poor return on investment are the biggest barriers to adoption. Most cover crop research for corn production systems is focused on the management of the cover crop. This research focuses on management of the corn crop following winter cereal rye.
Evaluate the effects of a winter rye cover crop-free zone and starter fertilizer to improve seedling vigor and eliminate yield drag associated with winter cereal rye. This objective will be reached by determining treatment effects on corn growth and development throughout the growing season; disease, insect and weed incidence, severity, and prevalence; and winter cereal rye biomass growth and nutrient uptake.
This project includes a field trial at the ISU Agricultural Engineering and Agronomy Farm, supplemented by companion trials at one outlying research farm. Eight treatments will be used. Cover crops will be broadcast seeded in the fall, and terminated 10-14 days ahead of corn planting for all treatments. Cover crop biomass and nitrogen uptake will be determined with two fall and two spring biomass sampling periods each year. Corn growth and development will include stand establishment; root and shoot biomass, nutrient uptake, and staging at approximately 10 and 20 days after emergence; date of silking and physiological maturity; and grain yield and moisture at harvest. Corn roots will be evaluated for root rot pathogens, and stand establishment observations will be used to detect noticeable seedling death. Insect incidence and weed density/community notes will be determined in every plot. These data will help researchers develop improved management recommendations for corn production following winter cereal rye cover crops.
Cover crop plots were seeded at Kanawha (October 30) and Ames (October 29). The fall strip-tillage treatment occurred at Kanawha and Ames (November 16). Soil samples were taken for baseline fertility at the Ames site (November 16). No soil samples were collected from Kanawha because of wet conditions followed by frozen soil. Neither site had cover crops emerge so fall cover crop biomass and stand counts were not able to be determined.
A post-doc has been placed on the project. The field locations have been identified at the ISU Northern Research and Demonstration Farm, Kanawha, and at the Ag Engineering Agronomy Research Farm, Boone. Plot layouts have been generated and Elbon cereal rye has been secured. The cereal rye will be drill seeded-soon after the soybean are harvested; weather permitting by mid-October.
The project was discussed at a September 2018 field day at the ISU Southeast Research and Demonstration Farm, Crawfordsville.