In order to determine the regulating effects of wide sowing and planting density on chemical indices and lodging resistance of oat stem, the experiment was conducted at the experimental station of Ulanqab Agricultural and Animal Husbandry Research Institute in Inner Mongolia in 2019-2020, using Mengnongdayan 1 as the experimental material. Two seeding methods of wide sowing and conventional sowing and three seeding densities of 3 million plants ·hm-2, 4.5 million plants ·hm-2 and 6 million plants ·hm-2 were performed. The contents of lignin, cellulose, hemicellulose, and potassium, lodging resistance index and lodging rate in oat stem under different sowing methods and densities were analyzed. The results showed that the lodging rate and lodging grade of oat increased with the increase of planting density, and the contents of lignin, cellulose, hemicellulose, potassium, and lodging resistance index of oat stem all decreased. The contents of lignin, cellulose, hemicellulose, potassium, and lodging resistance index in stem of oat under wide sowing at different densities were higher than those under conventional sowing. The correlation analysis showed that the cellulose content in oat stem had the greatest correlation with lodging resistance index. Among them, the cellulose content of wide sowing was increased by 5.7%-16.3% compared with that of conventional sowing, and the increase rate was the largest under high planting density. Hemicellulose content, lignin content and potassium content were increased by 10.9%-20.3%, 13.6%-23.3% and 1.6%-25.5%, respectively. The lodging resistance index of stem was increased by 12.7%-56.5%. In conclusion, wide sowing could effectively reduce the content of related chemical indices in stem and lodging resistance index of stem after the planting density increased, ultimately reducing the lodging rate and lodging degree of oats, and promoting high and stable yield of oats. |