The Effect of Nitrogen Rates on The Growth and Yield of Maize in Agricultural Fields with the Stream

Abstract

This study was conducted to investigate the effect of nitrogen rates on the growth characteristics and yield of maize in agricultural fields with the stream. This indicates the necessity and optimal level of nitrous fertilization to examine the possibilities of quantity enhancement. Plant height and ear height of maize were not significantly different among the nitrogen rates. Stem diameter and leaf area index increased in the nitrogen treatment compared to untreated control. Changes of photosynthetic rate in maize leaves depending on nitrogen treatments increased as much as nitrogen rates were increased up to the highest level, 36 kg per 10a. NDF and ADF content levels of maize were investigated with different nitrogen rates regardless of treatments. In the case of NDF, it showed a tendency to decrease after 8 days of tasseling date. ADF had also decreased after 15 days of tasseling date. Nitrogen uptake of maize leaves with different nitrogen rates showed the highest level, 4.9 g kg -1 with 36 kg per 10a on the tasseling date. Ear length and 100-kernel weight, there were no significant differences according to yield and the components with different nitrogen rates. Ear diameter and kernel number, nitrogen rates of 18 kg and 36 kg were increased compared to nitrogen rate of 9 kg per 10a and untreated control. The pericarps in 9 kg nitrogen rate and control were thicker than those of 18 kg and 36 kg treatment. The yield, 18 kg, 36 kg, and 9 kg treatments were increased by 10.96%, 9.27%, and 3.31%, compared to control. The component analysis on maize kernel with different nitrogen rates, starch showed no significant differences among treatments.Total sugar in 18 kg nitrogen treatment represented the highest content level, 6.37%. In addition, Amylopectin in 18 kg treatment showed the highest content level of 90.38%. However, amylose in 18 kg treatment showed the lowest level, 9.62% which drew a conclusion that waxy of 18 kg treatment is considered to be the strongest one. From the results described above, nitrous fertilization is essential to grow maize in agricultural fields with the stream. The optimum level of nitrous fertilization is considered 18 kg per 10a.