Abstract:

In order to clarify the changes of stalk lodging resistance and mechanical grain harvesting quality of maize under different planting densities and the correlations between them, ‘Xianyu 1171’ and ‘Zhongyu 3’ were used as experimental materials, and six planting densities, including 3.0×10⁴, 4.5×10⁴, 6.0×10⁴, 7.5×10⁴, 9.0×10⁴, and 10.5×10⁴ plants/hm², were set to carry out field experiments to study the effects of different planting densities on maize stalk morphology, mechanical strength, lodging rate and mechanical grain harvesting quality. The results showed that with the increase of planting density, the plant height and ear position of maize increased, the basal internodes became longer and thinner, the rind penetration strength and stalk breaking strength decreased, and the lodging risk increased greatly. Correlation analysis found that the stalk breaking strength could be used as a judgment index of anti-lodging mechanical grain harvesting. The lodging rate, grain moisture content, impurity rate, breakage rate and total yield loss rate of maize also increased with the increase of planting density, and the suitable range of grain moisture content for mechanical harvesting was 17.83%-25.76%. As the planting density increased, the maize yield first increased then decreased, and the relationship between planting density and maize yield was quadratic function. Under this experimental condition, the suitable planting density of ‘Xianyu 1171’ was 70800 plants/hm², while the suitable planting density of ‘Zhongyu 3’ was 79900 plants/hm². According to climatic conditions and cropping scheme, the harvest can be delayed properly to improve the mechanical grain harvesting quality of maize in hilly areas of Sichuan.

Key words: density, maize, Sichuan hilly areas, lodging resistance, mechanical grain harvesting