Abstract: To investigate nutritional quality and nutrient requirements of silage crops in the semiarid area of western Liaoning Province, a field experiment was carried out with three silage crops including silage corn, sweet sorghum, and Sorghum bicolor ×S. sudanense in Fuxin Mongolian Autonomous County, Liaoning Province. Crop yield, nutritional quality, feed value, and plant mineral nutrients were determined. The results showed that: (1) Under the same cultivation management conditions, fresh and dry yields of S. bicolor ×S. sudanense were significantly higher than those of silage corn and sweet sorghum, with the highest dry matter yield reaching 34.22 t·hm^-2. (2) Silage fermentation increased the contents of crude protein and crude fat in silage crops, while reduced that of crude fiber, neutral detergent fiber, acid detergent fiber and lignin. Silage corn demonstrated superior nutritional quality than sweet sorghum and S. bicolor ×S. sudanense. (3) Silage fermentation enhanced the forage value of silage crops, with silage corn showing significantly higher digestible dry matter, dry matter intake, and relative forage value than sweet sorghum and S. bicolor ×S. sudanense. (4) There were no significant differences in nitrogen (N), phosphorus (P), and potassium (K) contents of the three silage crops, with N, P, and K requirements being about 200-300, 60-90 and 320-580 kg·hm^-2, respectively. S. bicolor ×S. sudanense exhibited significantly higher N, P, and K uptake compared to silage corn and sweet sorghum, with a notable demand for K. In conclusion, silage fermentation effectively improved nutritional quality of silage crops, and silage corn would be a more suitable silage crop in western Liaoning Province. Our results provide important support for the high-yield cultivation and promotion of silage crops in western Liaoning.

Key words: silage corn, sweet sorghum, Sorghum bicolor ×S. sudanense, nutrient characteristics, straw feed utilization