Analysis of production performance and economic benefit of different forage multiple cropping modes in Ningxia irrigation area

In view of the present situation of low forage yield, backward cultivation techniques, and extreme shortage of seasonal green fodder in the Ningxia Yellow River Diversion Irrigation Area, the conflict between grass and livestock is sharp. In this study, × Triticosecale Wittmack + Sorghum bicolor × S. sudanense (T-SS), × Triticosecale Wittmack + S. bicolor (T-FS), × Triticosecale Wittmack + Setaria italica (T-FM) and × Triticosecale Wittmack + Zea mays (T-FM) were used for autumn sowing. The growth index, grass yield, nutritional quality, economic benefits, and soil nutrient content of the different treatments were determined and analyzed. This study aimed to determine the production performance and comprehensive benefits of four different multiple forage cropping modes and to provide a theoretical basis for multiple forage cropping technology in this area. The results showed that there were significant differences in plant height, stem diameter, and SPAD of the four multiple-cropping grasses, and the different multiple-cropping systems had significant effects on fresh grass, hay yield, branch number, crude protein yield, quality, soil physical and chemical properties, and economic benefits. The yield of grass, number of branches, and crude protein of the sorghum bicolor multiple cropping systems were the highest, the crude protein content of forage millet was the highest, the acid and neutral washing fiber content of corn silage was the lowest, and the relative feeding value was the highest. The effects on soil organic matter, total salt, and pH were not significant, but the available potassium and alkali-hydrolyzable nitrogen contents were significant, whereas the available phosphorus content was extremely significant. The output-input ratio of the S. bicolor multiple cropping system was the highest. Through principal component analysis and comprehensive evaluation, the planting mode of forage rye multiple-cropping, forage millet, and sorghum grass could be extended to the annual planting mode of forage in the Ningxia Yellow River irrigation area.