In order to investigate the effects of long term continuous full straw returning to the field in the Huabei Plain lime concretion black soil area of Anhui Province on the grain setting characteristics of winter wheat, four different models were set up from 2021-2022 based on 13 years of long term positioning experiments at the Crop Cultivation Observatory of the Ministry of Agriculture and Rural Affairs in East China, including wheat single season full straw crushing and mulching (T1), wheat and maize full straw crushing and returning to the field (T2), maize full straw crushing and burying and returning to the field (T3) and no straw returning to the field throughout the year (CK) to explore the effects of long term continuous full straw returning on the number of grains and grain weight at different spikelets of wheat. The results showed that T1, T2, and T3 treatments increased the total number of grains per spike in the main stem by 21.21%, 7.50%, and 12.55%, respectively, compared to CK treatments. The number of grains in the second grain position (G2) was increased by 7.71%, 7.71%, and 5.79%, respectively. The number of grains setting in the upper spikelets was increased by 57.23%, 10.75%, and 32.15%, respectively, and the number of grains setting in G2 was increased by 30.95%, 30.95%, and 23.09%, respectively. Among them, T1 treatment had the best effect on improving the number of wheat grains. Under different straw returning treatments in different seasons, the grain weight of wheat main stem and its G2, tillering ear and its third grain position(G3) were higher than CK. The grain weight of main stem and ear in T1, T2, and T3 treatments were increased by 16.06%, 4.14%, and 16.06%, respectively, and the increase rate of tillering ear was 9.86%, 0.71%, and 8.87%, respectively. Under T1, T2, and T3 treatments, the increase rate in grain weight of G2 in the main stem was 20.69%, 10.34%, and 17.24%, respectively, while that of G3 in tillering was 4.55%, 2.27%, and 6.82%. Among them, T1 treatment had the best effect on improving grain weight, followed by T3 treatment. Overall, long term straw returning to the field The results showed that T1, T2, and T3 treatments increased the total number of grains per spike in the main stem by 21.21%, 7.50%, and 12.55%, respectively, compared to CK treatments; The number of grains in G2 increased by 7.71%, 7.71%, and 5.79%, respectively; The number of grains set in the upper spikelets increased by 51.41%, 22.79%, and 31.36%, respectively, and the number of grains set in G2 increased by 30.95%, 30.95%, and 23.09%, respectively. Among them, T1 treatment had the best effect on improving the number of wheat grains. Under different straw returning treatments in different seasons, the grain weight of wheat main stem and its G2, tillering ear and its G3 were higher than CK. The grain weight increase of main stem and ear in T1, T2, and T3 treatments were 16.06%, 4.14%, and 16.06%, respectively, and the increase of tillering ear was 9.86%, 0.71%, and 8.87%, respectively; Under T1, T2, and T3 treatments, the increase in grain weight of G2 in the main stem was 20.69%, 10.34%, and 17.24%, respectively, while that of G3 in tillering was 4.55%, 2.27%, and 6.82%. Among them, T1 treatment had the best effect on improving grain weight, followed by T3 treatment. Overall, long term straw returning to the field in the lime concretion black soil area of the Huaibei Plain in Anhui Province can increase the number and weight of wheat grains per ear, thereby promoting yield improvement. Among them, T1 treatment had the best effect on improving the number and weight of wheat grains, making it a suitable straw returning model for promotion in the region. |