Effects of nitrogen and nhosphate fertilizer application on production performance and forage quality for Sorghum bicolor×S. sudanense in Haihe lowland plain

This study analyzed the effects of nitrogen and phosphate fertilizer application on production performance and forage quality for Sorghum bicolor×S. sudanense in Haihe lowland plain. In this study, we conducted a small-plot field experiment in which ‘Jicao 2’ was used as experimental material, and analyzed grass yield, forage quality, and soil fertility under N and P fertilizer treatment(N:0, 90, 180, 270, 360, 450 kg·ha-1; P: 0, 45, 90, 135, 180, 225 kg·ha-1). Our results showed that the total dry yield at the N270P180(270 kg·ha-1 N fertiler, 180 kg·ha-1 P fertiler) level was significantly higher than the yield of a control group. However, there was no significant difference in total dry yield from different phosphate fertilizer levels and the control. There were also no significant differences in content of crude protein, acid detergent fiber, neutral detergent fiber, brix, or relative feed value under the nitrogen and phosphate fertilizer treatment, whereas the average of content of nitrate-N was increased 62.6% under nitrogen fertilizer treatment when compared with the control. There were no significant differences in the contents of total N or available N at different levels of nitrogen fertilizer and the control, and the content of available P was higher or significantly higher than CK under phosphate fertilizer treatment. We posit that the optimal fertilizer levels for planting Sorghum bicolor×S. sudanense in Haihe lowland plain are N at 180~270 kg·hm-2 and P2O5 at 90~135 kg·hm-2.