Combined effect of water and nitrogen application on yield and silage quality of silage maize

This research was conducted to investigate the effect of combining water and nitrogen supplementation on yield, nutritional value, and silage quality of silage maize (Zea may, improving its comprehensive utilization value. The silage maize hybrid cultivar Beinong silage 368 was used as experimental material. The experimental design included three water irrigation application rates, i.e., 2 250, 2 025, and 1 800 m³·ha⁻¹ (designated as W₁, W₂, and W₃, respectively), and three nitrogen application rates, i.e., 420, 378, and 336 kg·ha⁻¹ (designated as N₁, N₂, and N₃, respectively). The results showed that the highest yields of silage maize were obtained when W₂ and N₂ treatments were combined; this yield was 5.02% higher than that obtained with the traditional water and fertilizer application volumes (W₁N₁). The dry matter loss rate of silage resulting from W₁N₁, W₂N₂, or W₂N₃ treatments was less than 1.0% after a year. However, there were significant differences in neutral and acid detergent fiber content, starch content, and crude ash of whole maize plants between treatments (P < 0.05) but not in ether extract concentration. After the first anniversary, the pH of the maize silage was stable at about 4.0, its relative feed value was 136.04 ~ 164.35, and its lactic and acetic acid contents were 3.33 ~ 4.34% and 1.63% ~ 2.29%, respectively. The lactic acid content resulting from the treatments was higher than that of W₁N₁, and the acetic acid content resulting from W₂N₂ and W₃N₃ treatments was significantly lower than that from other treatments (P < 0.05). In conclusion, considering the yield, dry matter content loss rate, and silage quality, W₂N₂ was the best treatment for producing high quality silage.