Start Date: 2013
Principal Investigator: Jeff Coulter
Organization: University of Minnesota, Department of Agronomy and Plant Genetics
Corn yield and its response to fertilizers are largely influenced by weather, leading to challenges and uncertainty in corn management. Research is being conducted on a tile-drained Nicollet clay loam soil in southern Minnesota to determine the maximum corn yields that are possible and the role of fertilizer management in attaining these yields. This study compares two management systems: 1) current farmer practice; and 2) a high-yield system that is also environmentally responsible (ecological intensification). For each system, current university nutrient recommendations are being compared to advanced nutrient management. The performance of each management system and nutrient intensity regime is being evaluated with corn yield and nutrient uptake, nitrogen use efficiency, soil nitrogen content, soil carbon content, and soil fertility levels (both macro- and micronutrients). This study is a companion to the AFREC-funded high-yield irrigated continuous corn study established at Becker, MN in 2014. Results from this study will be combined with those from 19 other locations in 9 countries as part of an International Plant Nutrition Institute project, allowing the results from Minnesota to be placed in both U.S. and global contexts.
With timely rainfall in 2013, corn yields in this study ranged from 193 to 233 bushels/acre. In comparison, 2014 had excessive rainfall in June (12.9 inches) and dry conditions during the remainder of the season and corn yields ranged from 92 to 156 bushels/acre. High-yield management practices, including a longer-season hybrid (104 vs. 99 day) and a greater planting rate (41,000 vs. 36,000 seeds/acre), increased corn yield by 18 bushels/acre in 2013 and 35 bushels/acre in 2014. These intensive practices also enhanced the efficiency of applied N fertilizer (0.66 vs. 0.71 pounds N/bushel in 2013; 1.32 vs. 1.74 pounds N/bushel in 2014). When compared to standard practices, a fertilizer management program that included phosphorus and potassium fertility based on grain nutrient removal, surface-dribbled N near the row at planting, and an additional 40 pounds N/acre as a sidedress application increased corn yield by 23 bushels/acre in 2013 and 31 bushels/acre in 2014. These yield increases with advanced fertilizer management were consistent with both standard and high-yield management. These results from two contrasting growing seasons demonstrate the potential for growers to close the corn yield gap by pairing advanced fertilizer management with intensified cropping systems that include longer-season hybrids and greater planting rates.
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