Environment and Nitrogen Influence on Rainfed Maize Yield and Quality

Abstract

Kernel quality is determined by environmental conditions and fertilization practices. However, the effect of those factors needs to be studied for maize (Zea mays L.) grown in rainfed conditions in permanent‐raised beds as planting system. Long‐term plots in rotation with wheat (Triticum aestivum L.) were established in 2002 with this planting technology. The objective was to assess the effect of crop seasons and three N rates (0, 60, and 120 kg N ha–1) on yield and kernel quality. Results indicated that yield and kernel quality were mostly affected by the effect of crop seasons, except yield and kernel protein (KP) that improved 7.3 and 10.4% respectively, as N application increased from 0 to 60 kg ha–1. Effect of crop season was estimated by means of rainfall and growing degree days (GDD). Seasonal rainfall accounted for 66% of yield variation. Amount of rainfall from tasseling to physiological maturity was associated to 1000‐kernel weight (KW) and floating index (FI). Similarly, as GDD increased from 1310 to 1475, FI improved from 84 to 40% Even though the effect of crop seasons was significant on test weight (TW), no relationship was identified with rainfall and GDD likely due to an outlier data point. In average, environment contributed more heavily to measured parameters than N management. Normalized difference vegetative index (NDVI) readings collected at early growth stages showed to be a potential tool to predict final TW.