In order to clarify the regulation of wide sowing and planting density on photosynthetic characteristics and dry matter accumulation of oat, the differences of photosynthetic capacity, dry matter accumulation, and yield of oat(Mengnongdayan 1) under different sowing methods and densities were compared and analyzed at the experimental station of Ulanqab Academy of Agriculture and Animal Husbandry, Inner Mongolia, in 2019-2020, with two sowing methods: wide sowing(K) and conventional sowing(C) and three sowing densities(3 million plants·hm-2(D1), 4.5 million plants·hm-2(D2) and 6 million plants·hm-2(D3). The results showed that photosynthetic parameters SPAD values and dry matter accumulation per plant decreased with the increase of planting density. The photosynthetic parameters and dry matter accumulation of oat leaves in wide sowing were higher than those in conventional sowing at all densities. Among them, the net photosynthetic rate of wide sowing oats was increased by 7.2%-24.8% compared with that of conventional sowing, and the increase rate was the largest under D3. Transpiration rate, intercellular CO2 concentration and SPAD were increased by 1.8%-24.1%, 1.7%-25.5%, and 2.2%-11.5%, respectively. The dry matter accumulation per plant was increased by 4.9%-56.2%. Wide sowing significantly increased the ear number, grain number per ear, 1000-grain weight, and yield of oat. The yield was significantly increased by 8.6%, 9.3%, and 14.5% under D1, D2, and D3,respectively. It can be seen that wide sowing effectively promoted the coordinated growth of photosynthesis, dry matter accumulation, and yield components of oat, and finally achieved yield increase. In particular, it can effectively alleviate the impact of oat population photosynthesis, dry matter production and yield formation under high planting density. |