Influence of planting density on yield and quality of forage maize in the Yinda Irrigation District

【Objective】 Forage maize is a crop cultivated in the Yinda Irrigation District in Gansu province, China. This paper investigates the influence of planting density on its growth, yield and quality. 【Method】 The variety of Long Silage No.1 was used as the model plant. The field experiments compared five planting densities: 5.6×104 plants/hm2 (M1), 6.8×104 plants/hm2 (M2), 8.0×104 plants/hm2 (M3), 9.2×104 plants/hm2 (M4), and 10.4×104 plants/hm2 (M5). In each treatment, we measured plant traits, yield and quality of the plant at its maturity stage. 【Result】 ① Plant height and stem thickness both varied with planting density parabolically. With the increase in planting density, cob length, cob thickness, fresh cob weight, the number of rows of grains and the number of rows in cobs all increased first and then decreased when planting density exceeded 8.0×104 plants/hm2. ② With the increase in planting density, fresh grass, hay and kernel yields increased to 182 146.72 kg/hm2, 91 054.35 kg/hm2, and 24 278.68 kg/hm2, respectively, when planting density was 8.0×104 plants/hm2, and then decreased after planting density exceeded 8.0×104 plants/hm2. ③ Compared with M4 and M5, M3 increased the crude protein by 8.31% and 12.49%, the crude starch by 10.58% and 15.71%, and the fat contents by 10.38 and 19.71%, respectively. It was found that the neutral washing fiber was the highest in M5 and the least in M3. Compared to M3, M5 increased the neutral detergent fiber by 7.78%. 【Conclusion】 A planting density of 8.0×104 plants/hm2 is optimal for yield and quality of forage maize cultivated in the Yinda Irrigation District.