Effect of Nitrogen Levels on Spring Maize in Relation to Mulching Materials in Central Inner Tarai of Nepal

Abstract

The effect of different mulching materials and varying nitrogen fertilizer levels on growth, yield attributes, and yield of open-pollinated maize variety aiming at yield improvement was studied in inner Terai of Nepal through a field experimentation in 2019. The treatments included were the combinations of three mulching materials, (a) plastic mulch, (b) straw mulch, and (c) no mulching; and four nitrogen levels (0, 50, 100, and 150 kg ha-1) arranged in a split-plot design with four replications. Data on growth, yield attributes, and yield were taken and analyzed by using R Studio. The higher (p<0.05) heat use efficiency was recorded under plastic mulch and the higher levels of nitrogen application. The number of kernels per cob and thousand kernel weight were higher (p<0.05) in mulch treatments and higher nitrogen levels. Both the barrenness and sterility percentage were higher (p<0.05) for the 0 kg N ha^-1 and reduced (p<0.05) by the nitrogen application of ≥100 kg ha^-1. Increased tasseling-silking interval increased (p<0.05) the sterility and grain filling duration and increased (p<0.05) the grain yield. Due to the better yield attributes, the grain yield of mulch applied treatments and application of ≥100 kg N ha^-1 were higher (p<0.05) than the no mulch and ≤50 kg N ha^-1, respectively. The yield was hampered more by barrenness than by sterility. The effect of nitrogen levels on grain yield followed the quadratic relationship; 104 kg and 129-130 kg N ha^-1, respectively for no mulch and mulching treatments which are estimated as economic levels of nitrogen fertilizers for open-pollinated spring maize under the central inner Terai environment.