Improving Maize Nutrient Use Efficiency With Plant Growth Regulators.

The application of nitrogen fertilizers is an essential component of modern agriculture; however, excess fertilization can result in environmental degradation and unnecessary costs for growers. Improving plant nutrient use efficiency (NUE) has been suggested as a means to maximize yield while minimizing fertilizer inputs. NUE is usually divided into nutrient uptake from the soil into plants and internal nutrient transport to harvestable organs (e.g. grains). Regulation of internal plant nutrient levels occurs both directly (via nutrient based signaling) and indirectly (via hormones and other secondary signaling). The interaction between plant nutrient status and plant hormone activity is of interest to us as a possible means of modifying plant NUE. An initial set of field trials were conducted to examine the effect of plant growth regulators (PGR) on NUE for maize grown in Weslaco, Texas in 2012. These trials included an examination of nitrogen use efficiency with variable nitrogen application rates and a PGR application program. We report significant positive yield increases with the PGR treatments. Increased kernel size, increased kernel nutrient concentration and increased nutrient use efficiency were also noted. Based on the positive initial field results, repeated trials are underway in Weslaco, Texas and additional trials were initiated in Iowa and Illinois for 2013.