Effects of sowing rate and nitrogen rate on productivity of summer sowing Sudangrass

The effect of sowing rate and nitrogen fertilizing rate on productivity of Sudangrass (Sorghum sudanense ‘Xinsu No.2’) were studied in this research. The results showed that when the phosphate fertilizing rate was fixed, the highest plant height obtained at B1 (sowing rate 22.5 kg·ha-1) and N3 (nitrogen feritilizing rate 550 kg·ha-1), the biggest stem diameter and maximum tillers number obtained at B1 (sowing rate 22.5 kg·ha-1 ), the highest hay yield obtained at B2 (sowing rate 45 kg·ha-1) and N2 (nitrogen fertilizing rate 415 kg·ha-1), the total hay yield respectively reached 19 200.0 and 19 744.5 kg·ha-1, the highest crude protein yield obtained at B3 (sowing rate 67.5 kg·ha-1) and N2 (nitrogen fertilizing rate 415 kg·ha-1), the total crude protein yield respectively reached 1 607.03 kg·ha-1 and 1 572.00 kg·ha-1. Taking the hay and crude protein yield into consideration, the best treatment combination was B3 (sowing rate 67.5 kg·ha-1) + N2 (nitrogen fertilizing rate 415 kg·ha-1).