Responses of dry matter accumulation and yield in a following maize crop to spring wheat straw returning

Dry matter accumulation is the highest form of photosynthetic products in crops, and its accumulation dynamic characteristics are closely related to grain yield. Therefore, it is important to identify the effects of different straw retention methods on dry matter accumulation and crop yield with plastic film mulching. In this study, a field experiment was carried out in a typical irrigated inland region with an arid climate, to determine the characteristics of the above-ground dry matter accumulation and the yield of maize under different retention methods of straws of the preceding spring wheat. The treatments were: no-tillage with long spring wheat straw mulched in the field (NTM), no-tillage with spring wheat straw standing in the field (NTS), conventional tillage with long spring wheat straw incorporated into the soil (CTS), and conventional tillage without straw retention (CT). The results showed that the NTM and NTS treatments increased the maximum and the mean dry matter accumulation rate and delayed the emergence time of the maximum dry matter accumulation rate of maize. The NTM treatment had the most obvious effect. Compared to CT, the NTM treatment significantly increased the maximum and mean dry matter accumulation rate of maize by 5.7% and 11.2%, respectively. The emergence time of the maximum dry matter accumulation rate underh NTM was delayed by 3.4 days (P < 0.05). The NTM and NTS treatments maintained a high dry matter accumulation rate, effectively delaying the decline of dry matter accumulation rate for maize from the silking to filling stage. This prolonged the duration of dry matter accumulation and increased the amount of dry matter accumulation at the maturing stage. Compared to CT, NTM and NTS treatments significantly increased the dry matter accumulation of maize at the harvest stage by 11.3% and 9.9% (P < 0.05), respectively. The grain yield of maize was 15.6%, 13.0%, and 7.8% higher in NTM, NTS, and CTS treatments than in CT treatment (P < 0.05). The most significant effect on improved yield was from NTM treatment, which was 7.3% higher than that of CTS (P < 0.05). The main reason for the increased yield was the combined increase in spike numbers, grain numbers per spike, and 1000-grain weight. Correlation matrix analysis showed that the population size of following maize could be regulated by optimizing the previous spring wheat straw returning methods, which affected the growth and yield characteristics. Our results showed that the NTM (no-tillage with spring wheat straw mulch) is the most appropriate cultivation method to optimize dry matter accumulation and obtain high yields of maize in an arid inland irrigation region.