Influence of Nitrogen Fertilizer Application Rate and Time on Winter Wheat Yields

摘要

Nitrogen (N) fertilizer is required on most soils in Arkansas to produce high-yielding soft red winter wheat (Triticum aestivwn L.). The time and rate of N application are critical management decisions because they can influence the N-fertilizer uptake efficiency (Alcoz et al., 1993) and tillering (Weisz et al., 2001), which are highly correlated with wheat yields. In Arkansas, N fertilizer is usually applied in February when wheat plants are at Feekes stage 4 or 5, which coincides with the end of tillering. A small amount (-40 lbs N/acre) of N fertilizer is also recommended at planting for winter wheat following corn (Zea mayes L.), grain sorghum (Sorghum bicolor L.), and rice (Oryza sativa L.) to stimulate tillering. These crop residues have widecarbon to N ratios that may immobilize inorganic soil and fertilizer N.