Effects of wheat straw returning patterns on characteristics of dry matter accumulation, distribution and yield of rotation maize

Abstract

Research on the response of dry matter accumulation, distribution and yield of crops to previous straw returning usually plays an important role for optimizing cropping systems. In this investigation, a field experiment was carried out in typical oasis irrigation region, to determine the characteristics of dry matter distribution and yield of rotated maize with four previous wheat straw treatments, including 25 cm no tillage with straw standing (NTSS); 25 cm no tillage with straw covering (NTS); 25 cm tillage with straw incorporation (TIS); and conventional tillage (CT). The results showed that, compraed with CT, NTSS, NTS, TIS significantly increased dry matter accumulation by an average of 4.8% to 12.7% after maize heading stage in two years; and improved contribution rate to grain yield (i.e. GCR) of maize by an average of 12.8% to 25.0% from leaf, 6.3% to 11.3% from stem, and 18.3% to 78.4% from sheath, respectively. Especially, NTS had more improvement than NTSS, TIS. The grain yield of maize was 11.3% to 17.5% higher in the three straw returning treatments than in CT check. NTS exhibited the most significant effect of improving yield, reaching 13 470 and 13 274 kg ha-1 in two study years, which was 5.6% to 9.0% higher than that of TIS due to the increase of kernel number per spike. Meanwhile, NTS had the best effect on increasing harvest index, which was increased by 6.4% to 8.4% during the two study years, and resulted in a high grain yield. Our results showed that NTS treatment is recommended as the best feasible cultural method to optimize dry matter accumulation, distribution and obtain high yield for rotated maize in the oasis irrigation region.