Kernel Breakage and Density of Normal and Opaque‐2 Maize Grain as Influenced by Irrigation and Nitrogen

Abstract

Grain quality is important to farmers, grain elevators, millers, and domestic and foreign buyers. Excessive broken kernels can reduce the grade of grain, lower the selling price farmers receive, decrease production from dry and wet milling processes, reduce artificial drying efficiency, and increase potential dust hazards. However, little attention has been focused on the influence of production practices on grain quality. This study was conducted to determine whether irrigation and soil N levels would affect the quality of maize (Zea mays L.) grain. Two water regimes and five N fertilization levels ranging from zero to 360 kg ha−1 i were applied to two normal and two opaque‐2 hybrids. The experimental site was a Sharpsburg silty clay loam (fine, montmorillinitic, mesic, Typic Argiudoll) near Mead, NE. Opaque‐2 grain was 2.4 times more susceptible to breakage, and 8% lower in density than normal grain. Irrigation increased kernel breakage susceptibility (KBS) from 13.5 to 17.9, 3.2 to 3.8, and 5.4 to 7.3% in 1985, 1986, and 1987, respectively. Increasing soil N levels decreased KBS for all hybrids. Kernel density (KD) of opaque‐2 grain was increased with irrigation but decreased with higher N levels. In contrast, KD of normal grain decreased with irrigation but increased with higher N levels. Average grain yields were 9.4, 7.3, and 5.5 Mg ha−1, with irrigation increasing yields 28, 9, and 27% over nonirrigation in 1985, 1986, and 1987, respectively. Normal hybrids averaged 5% greater yields than opaque‐2 hybrids. Yield increased quadratically with N rate within each moisture regime in each year. Results indicate production practices influence KBS and KD as well as yield, and may become important considerations in the future.