Effect of Nitrogen Fertilization Levels and its Split Application of Nitrogen on Growth Characters and Productivity in Sorghum × Sudangrass Hybrids [Sorghum bicolor (L.) Moench]
2016
Jung, J.S., National Institute of Animal Science, Rural Development Administration, Cheonan, Republic of Korea | Kim, Y.J., National Institute of Animal Science, Rural Development Administration, Cheonan, Republic of Korea | Kim, W.H., National Institute of Animal Science, Rural Development Administration, Cheonan, Republic of Korea | Lee, S.H., National Institute of Animal Science, Wanju, Republic of Korea | Park, H.S., National Institute of Animal Science, Rural Development Administration, Cheonan, Republic of Korea | Choi, K.C., National Institute of Animal Science, Rural Development Administration, Cheonan, Republic of Korea | Lee, K.W., National Institute of Animal Science, Rural Development Administration, Cheonan, Republic of Korea | Hwang, T.Y., National Institute of Animal Science, Rural Development Administration, Cheonan, Republic of Korea | Choi, G.J., National Institute of Animal Science, Rural Development Administration, Cheonan, Republic of Korea
Nitrogen (N) fertilizer management is one of the important aspects of economic production of sorghums in sustainable agriculture. The aim of the study was to evaluate the effects of different N application rates and its split N application methods on productivity, growth characteristics, N accumulation, N use efficiency (NUE), and feed value of Sorghum x Sudangrass hybrids. Treatments consisted of five N application rates (0, 150, 200, 250, and 300 kg ha-¹) and two split N application methods (40% in basal N, 30% at the growing stage, and 30% after the first harvest vs. 50% in basal N and 50% after the first harvest). Plant height, leaf width, and stem diameter were increased (p less than equal to 0.05) with increasing N fertility rates at each harvest. Chlorophyll content (expressed as SPAD values) was the highest at a rate of 300 kg N ha 1 (first harvest, 46.32; second harvest, 33.09). It was the lowest at zero N (first harvest, 21.56; second harvest, 18.5). Total N, N uptake, and NUE were increased with higher N rates. Split N application had little effect on total N, amount of N uptake, or NUE. Total dry matter yields were the highest (21,715 kg ha-¹) at a rate of 300 kg N ha-¹. It was the lowest (10,054 kg ha 1) at zero N. Our results suggest that more than 300 kg N ha-¹ can improve dry matter yield to be above 116% compared to zero N, thus enhancing the agronomic characters of sorghums. However, no significant effect had been found for split N application. Further work is needed to determine the optimal N levels and the effect of split N application rates.
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