Corn Era Hybrid Macronutrient and Dry Matter Accumulation in Plant Components

Core Ideas We compared 1960 and 2000 era hybrid DM and macronutrient partitioning. Similar DM, N, P, and K accumulation patterns occurred for 1960 and 2000 era hybrids. Nutrient concentrations (g kg −1 ) were lower for 2000 than 1960 era hybrids. Plant component N, P, and K contents (kg ha −1 ) were greatest for 2000 era hybrids. Greater modern hybrid nutrient uptake was mainly due to greater DM and yield. As corn ( Zea mays L.) hybrids change over time, and with increased use of different plant components for feed, bedding, and energy production, it is important to know macronutrient distribution within plants and how nutrient concentration and accumulation varies during plant development. This field study was conducted in 2007 and 2008 to evaluate dry matter (DM) biomass, macronutrient concentration, and macronutrient content in corn plant fractions (stalk, leaf, tassel, ear shoot, cob, and grain) across developmental stages with two hybrids from 1960 and 2000 eras. Concentrations of N, P, and K were generally lower in all plant fractions for the 2000 compared to 1960 era hybrids, except P concentration in stalks and grain and K concentration in leaves and ear shoots. In contrast, N, P, and K content was consistently higher in 2000 era hybrids for whole plants, leaves, and grain; a reflection of greater DM production. Nitrogen, P, K, and DM content in tassels was lower for 2000 than 1960 era hybrids. From the 1960s to 2000s, hybrid development brought about an increase in plant biomass and grain yield resulting in greater total nutrient content. However, macronutrient concentrations in vegetative plant fractions and grain decreased, thus moderating increase in plant total and grain nutrient content. This research shows the importance for analysis of newer hybrid vegetative and grain biomass on an ongoing basis to provide reliable estimates of macronutrient uptake patterns and removal with harvest of specific vegetative material and grain.