Dynamic changes in biomass accumulation and forage quality of silage corn after tasseling stage

In order to reveal the dynamic changes in biological accumulation and forage quality of silage corn (Zea mays) after tasseling stage, three silage corn varieties ‘Zhengdan958’ (grain type), ‘Beinongqingzhu 368’ (silage type) and ‘Jiqingzhu 1’ (grain and silage type) which were used as experimental materials were tested and analyzed the dynamic changes in dry matter accumulation and forage quality of silage corn after tasseling stage from 2018 to 2020. The result showed that the biological yield of silage corn increased gradually from 8 559.2 kg·ha⁻¹ in tasseling stage to 24 380.7 kg·ha⁻¹ in ripe stage, and there was significant difference between different growth stages ( P < 0.05 ). The content of CP, ADF and NDF with whole plant had a trend of gradual decline, while starch content showed a trend of gradual increase from tasseling stage to ripe stage. WSC and milk yield per ton of dry matter increased first and then decreased, and the highest of milk yield per ton of dry matter was in 1/2 milk line stage (1 446.5 kg·t⁻¹). The dynamic changes in biological accumulation and forage quality of stem, leaf and ear showed that the proportion of stem and leaf were significantly decreased, while the proportion of ear and the biological accumulation were significantly increased as the silage corn developed and matured (P < 0.05). The content of CP in stem and leaf decreased gradually, while the content of ADF and NDF increased gradually. The content of CP in ear was no significant, ADF and NDF content in ear decreased gradually, while the content of starch in ear increased significantly (P < 0.05). Comprehensive analysis of the change trend of milk yield per hectare showed that silage corn had the highest milk yield per hectare (32 027.5 kg·ha⁻¹) in the 1/2 milk line stage. 1/2 milk line stage was the best growth stage for the comprehensive evaluation of biological yield and forage quality of silage corn. It is recommended to harvest silage corn at the 1/2 milk line stage.