Advancing Intensive Management of Corn Systems in Minnesota (Rainfed)

This experiment was conducted on a Mollisol in a continuous maize system to determine yield differences between farmer practice (FP) and ecological intensification (EI) management. The FP standard was determined through discussions with growers, crop advisers and researchers. Both management systems incorporated the following: chopping stalks in the fall after grain harvest; disk-ripping in the Fall after harvest, and field cultivating in the Spring before planting; pre-plant application of 17 kg S/ha; 6 kg N/ha and 8 kg P/ha applied in the seed furrow at planting; and the use of pre-emergence and post-emergence herbicides. Ecological intensification management differed from FP in the following ways: removal of 40% of the maize stover remaining after harvest; use of a longer-season hybrid (more growing degree days until maturity); and a 26% higher seeding rate. In both management systems, two nutrient management approaches were tested: 1) standard practice that followed current university extension recommendations, and 2) advanced practice that used a 24% higher total N rate, P and K application rates that replaced nutrients removed by grain harvest, a portion of the N co-applied with additional S as a surface band located 5 cm to the side of the row, and another portion of the N applied at an early vegetative (V6) growth stage.

The highest average grain yield (12,353 kg dry matter (DM)/ha) was measured with the advanced nutrient management approach in the EI system. This yield was significantly greater than the 11,398 kg DM/ha yield with advanced nutrient management in the FP system (8% increase). In both management systems, advanced nutrient management practice produced significantly greater yields than standard practice. Nitrogen recovery efficiency as well as agronomic efficiency were greatest for standard nutrient management practice in the EI system. Physiological N use efficiency was greatest for standard nutrient practice in the FP management system. Thus, in 2013, advanced nutrient practice using the EI approach resulted in the greatest yield but not the greatest N use efficiency.