Effect of Optimal Reduction of Chemical Fertilizer on Eating and Nutritional Quality of Superior and Inferior Grains of Dry Direct-Sowing Rice in Wheat-Rice Rotation Cropping District
The effect of optimal reduction of chemical fertilizer[F1(N 280 kg/ha,P2O5 108 kg/ha,K2O 135 kg/ha),F2(N 210 kg/ha,P2O5 81 kg/ha,K2O 135 kg/ha),F3(N 140 kg/ha,P2O5 54 kg/ha,K2O 135 kg/ha)]on eating and nutritional quality of superior and inferior grains of dry direct-sowing rice was studied in wheat-rice rotation cropping district,with conventional fertilization(F0:N 350 kg/ha,P2O5 135 kg/ha,K2O 135 kg/ha)as control,so as to provide reference for high quality and high yield fertilization management of direct-sowing rice.The results showed that optimal reduction of chemical fertilizer generally significantly enhanced the breakdown and peak viscosity of superior and inferior grains of dry direct-sowing rice,improving eating quality.Compared with F0 treatment,the breakdown of superior grains of F1,F2 and F3 treatments significantly increased by 8.35%,7.65%and 9.78%,respectively,the value of breakdown of inferior grains of F1 and F3 treatments significantly enhanced by 13.25%and 11.13%,respectively.Generally,optimal reduction of chemical fertilizer significantly decreased the contents of histidine(His),proline(Pro)and Mn in superior and inferior grains,but enhanced the tyrosine(Tyr),arginine(Arg)and lysine(Lys)contents in superior and inferior grains and contents of Cu and Zn in inferior grains.In addition,the Fe content in inferior grains was significantly increased by F1 treatment,and the Fe and Cu contents in superior grains and Ca content in superior and inferior grains were significantly increased by F2 treatment.Compared with F0 treatment,the Tyr content in superior grains of F1,F2 and F3 treatments significantly enhanced by 100.28%,44.76%and 41.08%,respectively,and that in inferior grains of F1,F2 and F3 treatments significantly increased by 85.21%,61.64%and 22.47%,respectively;the Lys content in superior grains of F1,F2 and F3 treatments significantly enhanced by 28.87%,27.32%and 70.62%,respectively,and that in inferior grains of F1 and F3 treatments significantly increased by 27.23%and 39.44%,respectively;the Arg content in superior and inferior grains of F1,F2 and F3 treatments significantly increased by 6.54%,11.84%,2.18%and 32.83%,33.59%,23.02%,respectively.Compared with F0 treatment,the Fe content in inferior grains of F1 treatment significantly increased by 27.16%,Zn content in inferior grains of F1,F2 and F3 treatments significantly enhanced by 18.86%,6.56%and 3.39%,respectively,Cu content in inferior grains of F1,F2 and F3 treatments significantly increased by 2.49%,2.95%and 3.11%,respectively.In summary,optimal reduction of chemical fertilizer enhances eating quality,improves nutritional quality of superior and inferior grains of dry direct-sowing rice,and F1 treatment is the best.