秸秆全量还田下磷钾配施对晚粳稻产量及品质的影响

Effects of Combined Application of Phosphorus and Potassium on Japonica Rice Yield and Quality Under Total Crop Residue Incorporated During the Late-rice Cropping Seasons

作物秸秆含有丰富的磷、钾等营养元素,但秸秆还田下晚粳稻最佳磷钾配施目前尚不明确。采用磷钾两因素完全随机试验设计,设磷(P2O5)0,63.75,127.50,191.25 kg/hm^2(记P0、P1、P2、P3)和钾(K2O)0,102,204,306 kg/hm^2(记K0、K1、K2、K3)各4个水平。在水稻成熟期取样测定产量、品质及精米氮素累积量。结果表明:磷肥和钾肥均显著提高了晚粳稻产量、干物质量和收获指数,且二者具有显著互作效应;磷钾合理配施可协同促进晚粳稻产量,当磷、钾肥用量分别62.45 kg/hm^2和206.08 kg/hm^2时实现较高产。同时,适宜磷钾配施也显著协同提高精米氮素累积量。磷钾合理配施能够提高稻米出糙率、精米率、整精米率及胶稠度,但增加了垩白粒率、垩白度、直链淀粉及粗蛋白含量。除峰值黏度、热浆黏度及冷胶黏度在钾肥用量上存在显著性差异外,各RVA谱特征值在钾肥、磷肥及二者互作上均无显著性差异;其中增施钾肥峰值黏度、热浆黏度及冷胶黏度均先增后降。南方晚粳稻实际生产中应重视优化磷钾配施比例,在土壤地力中上等及秸秆全量还田条件下,采用P1K2的施肥方案可充分发挥磷钾的协同促进效应,同步实现晚粳稻高产、高效并兼顾优质生产。

Crop straw is rich in phosphorus(P),potassium(K)and other nutrient elements,but the optimal combined application of phosphorus and potassium on late japonica rice under crop residue incorporation is still unclear.A two-factor(P and K)experimental design was adopted in the field experiments,four levels of P and K fertilizer application rates were set up,which P2O5 were 0,63.75,127.50,191.25 kg/hm^2(denoted by P0,P1,P2,P3)and K2O were 0,102,204,306 kg/hm^2(denoted by K0,K1,K2,K3),respectively.The yield,quality,and milled rice nitrogen accumulation of japonica rice were investigated and analyzed at rice harvest stage.Both P and K fertilizer could significantly enhance the yield,dry matter weight and harvest index of late japonica rice,and the significant interaction effect between them was found in our study.The reasonable combined application of P and K fertilizers had synergetic effect on the yield of late japonica rice,the high yield was achieved when the application rates of P and K fertilizer were 62.45 kg/hm^2 and 206.08 kg/hm^2,respectively.At the same time,the milled rice nitrogen accumulation was significantly increased by the reasonable combined application of P and K fertilizers.The brown rice rate,milled rice rate,head milled rice and gel consistency were improved by the reasonable combined application of P and K fertilizers,but the chalkiness rate,chalkiness degree,amylose content and protein content were also increased.Except that the peak viscosity,hot viscosity and cool viscosity had significant differences among the amount of K fertilizer,there were no significant differences in the rice RVA profile characteristics in P,K fertilizer and interaction of both.And the peak viscosity,hot viscosity and cool viscosity were first increased and then decreased with the increased amount of K fertilizer applied.In practices,optimizing the combined application of P and K fertilizers on japonica rice should be concerned during the late-rice cropping seasons in Southern China.The synergy effect of K and P was best under P1K2,which simultaneously achieved the high yield,high efficiency and high quality production of late japonica rice under upper-middle soil fertility and total rice straw incorporation.