Returning the Rice Residue Affects Accumulation and Physicochemical Properties of Wheat Starch

Removing rice (Oryza sativa) straw has the potential to impact nutrient cycling and wheat quality. The objective of this study was to determine the impact of rice straw removal on wheat production and quality. The experiment contained three rice residue rates: none, rice residue mixed into the surface 5-cm depth, and rice residue mixed into the 15-cm soil depth. Returning the rice residue increased the wheat production per plant, total starch content, and decreased amylose content. Incorporating rice straw into the surface 5 cm or the 15 cm of soil depth accelerated endosperm development and increased the amounts of B-type starch granules at 17 and 27 d after anthesis, and the proportion of small B-type starch granules. Incorporating rice straw into the surface 5 cm or the 15 cm soil depth decreased the relative degree of crystallinity and increased the ratio of amorphous structure to ordered carbohydrate structure in the external region of the granules. Pasting parameters including peak, breakdown, final, and setback viscosities increased, whereas pasting time and temperature decreased in the returning the rice residue group. Returning the rice residue at 5 and 15 cm exhibited similar effects on the granule development and physicochemical properties of wheat starch. The impact of returning the rice residues to the soil on wheat production and wheat kernel quality was attributed to enhanced soil fertility. This study may contribute to knowledge on crop cultivation, crop physiology, and food science.