By-Plant Nitrogen Response as a Function of Delayed Emergence in Corn (Zea mays L.)

Abstract

Determining the correct nitrogen (N) rate for plants of uneven emergence should prove to be beneficial for increasing nitrogen use efficiency and crop yields. Delayed plants were planted 4, 7, and 10 days after initial planting, along with receiving varying amounts of by-plant N fertilizer to assess nitrogen response. At Lake Carl Blackwell (1), for each day delay in planting corn grain yields decreased by 1,034 kg ha-1, when 67 kg N/ha was applied preplant. At Lake Carl Blackwell (2), a yield reduction of 178 kg ha-1 for every day delay in planting for the 67 kg N/ha preplant N rate was observed. When sidedress N was applied, with addition preplant N, yield reductions due to delayed planting were less pronounced. Over all sites, delayed emergence decreased average grain yields thus highlighting the need to homogenize plant emergence.