Optimisation of Whole-Plant Corn Silage Harvesting Methods Based on Silage Quality in Northeast China: Interaction of Latitude, Harvesting Time, and Stubble Height

Factors such as latitude, harvesting stage, and stubble height influence silage quality and harvesting decisions. We aimed to examine how harvest stage and stubble height affect the quality of whole-plant corn silage across different latitudes in Northeast China. Experiments were conducted in five different latitude regions (Shenyang, Changchun, Tongliao, Harbin, and Qiqihar) and assessed three stubble heights (20, 40, and 60 cm) at each harvest maturity stage: milk, initial wax, middle wax, late wax, and full maturity. After fermentation, whole-plant corn silage samples were collected and evaluated for nutritional content, fermentation quality, and toxin levels. Increasing the stubble height increased the dry matter (DM), crude protein, starch, and deoxynivalenol content in the whole-plant corn silage (p < 0.01), but decreased the acid detergent fibre and neutral detergent fibre concentrations (p < 0.01). Delayed harvest increased the DM and vomitoxin content (p < 0.01). The pH decreased initially and then increased as the harvest was delayed (p < 0.01). Meanwhile, NH3–N and acetic acid content did not differ significantly with delayed harvesting (p > 0.05). At higher latitudes, the optimal harvest period is correspondingly delayed, shortening the harvest time. To maintain silage quality without affecting yield or economics, a 40 cm stubble height is recommended. If delayed, incrementally increasing the stubble height to 60 cm may be warranted to maintain silage quality. We provide data-driven insights to optimise silage production and ruminant nutrition.