Comparison of production capacity of different corn and sorghum varieties for silage

In order to promote the trial of the “Replace Grain Crop Cultivation with Feed Crop Cultivation” and improve the economic benefits of planting and breeding, eight varieties of maize and sweet sorghum were analyzed for agronomic traits and the yield of whole plant silage to screen out high-yield and excellent silage varieties suitable for planting in the Guanzhong area. The results showed that there were significant differences in agronomic traits and yield among varieties within or between species (P < 0.05). The growth period was 99～116 days for maize and 124～175 days or more for sweet sorghum. The number of leaves was approximately 14 for maize and 8～23 for sweet sorghum. The height interval was 225.8～281.5 cm for maize and 165.3～338.8 cm for sweet sorghum. The silage yield was 40.2～83.9 t·ha⁻¹ for maize and 35.6～125.3 t·ha⁻¹ for sweet sorghum. The dry matter yield was 12.0～25.1 t·ha⁻¹ for maize and 10.7～37.7 t·ha⁻¹ for sweet sorghum. The variety with the highest yield for corn was ‘DB08’, while that for sweet sorghum was ‘Aurora’, which increased the yield by 84.5% and 211.6%, respectively, over the yield of the control grain-type corn variety ‘Qiangsheng 58’. Further nutritional analysis found that there were significant differences in contents of nutrients such as crude protein, crude fiber, crude fat, ash, and nitrogen-free extract between corn and sweet sorghum species or varieties, and the single optimal nutrient indices did not converge in the same variety. Considering the silage production and the nutritional requirements of ruminants, we suggest that the maize ‘DB08’ and sweet sorghum ‘Aurora’ are the most suitable for promotion and planting as silage in the Guanzhong area.