Irrigated Corn Nutrient Accumulation and Partitioning in Response to High Nitrogen Rate and Plant Population.

Modern corn hybrids exhibit higher grain yield, increased total biomass production, are more responsive to higher plant densities (PD) and are more efficient in using nitrogen (N). The higher potential for biomass accumulation in modern hybrids influences nutrient uptake and assimilation and may be associated with increased nutrient removal. This study aims to establish if N assimilation and partitioning dynamics differ among hybrids at optimal and high PD with excessive and zero fertilizer N. Furthermore, these treatments will identify differences in kernel N removal, whole plant N uptake and distribution and their effect on yield components. Two hybrids in 2015 and six in 2016 were tested at 74 0000 (optimal PD) and 148 000 plants ha-1 at fertilizer N rates of 0 and 390 kg ha-1. Plants were harvested at V7, V14, R3, R5 and R6 and separated for nutrient determination into vegetative and reproductive fractions. Understanding the dynamics that influence N uptake and partitioning at different crop growth stages in modern corn hybrids will help improve management practices and sustainability in cropping systems.