The Effects Of Mineral Nutrition On Submergence Tolerance Of Rice At Tillering Stage And Post-Submergence Remediation

In the middle and lower reaches of the Yangtze River,plum rain season causes long and heavy rainfall,which often results in floods.This period is the tillering stage of rice.How to improve waterlogging tolerance of rice at tillering stage and how to provide timely and effective relief after waterlogging disaster is a common concern of research and production.The experiments were conducted in the deep pool,setting basal silicon fertilizer trial,water,nitrogen fertilizer,silicon fertilizer and nitrogen + silicon fertilizer foliar spray trial after de-submergence,as well as nitrogen trial at booting stage.Improving waterlogging tolerance of rice,rapid repair after waterlogging and remedial measures according to the growth of the seedlings in the later stage can be analyzed.The results are as follows:1.Basal silicon fertilizer significantly increased the submergence tolerance of rice at tillering stage,and could also reduce the losses caused by flood effectively.In 2015,the yield of basal silicon fertilizer after dister was 9.71t,which increased 21.8%than the control;in 2016,the yield of basal silicon fertilizer was 7.97t,which increased 5.3%than the control.The treatment of basal Si keeped higher tillers number,green leaves and dry matter accumulation.The content of soluble protein increased high antioxidant activity,which could eliminate active oxygen more quickly.The higher content of chlorophyll is beneficial for photosynthesis,and the soluble sugar can be used to providing energy for growing development.Basal Si was beneficial to absorb N and significantly increased the N content at maturity stage.2.On the base of basal silicon,foliar spraying nitrogen and silicon significantly increased the speed of recovey,reducing the loss caused by waterlogging,and foliar sprayed nitrogen and silicon simultaneously resulting in best effects.Foliar spraying fertilizer significantly increased the tillers number,green leaves,aboveground dry mass and belowground dry mass.The higher panicles contributed to the improvement of yield.After de-submergence,treatments of foliar spraying fertilizer maintained higher content of chlorophyll and also had a large increase in the amount of chlorophyll.Foliar spraying significantly increased the N content and accumulation at heading stage and N accumulation also increased at maturity stage.Foliar spraying N along with Si had the best effects,and the spraying N followed.After foliar spraying,activities of SOD,POD,CAT and another antioxidant enzymes were increased rapidly and the content of MDA,H2O2 and O2-· production rate were seen a commensurate fall.Foliar spraying increased the content of soluble and protein,which was beneficial for sustaining the development of the plant.From the point of the effects of spraying fertilizer,spraying N with Si had the highest activities of antioxidant enzymes,followed by spraying Si,and the N was the last.In general,under conditions of basal Si,spraying N with Si was propitious to reduce damage caused by reactive oxygen,also increased the content of soluble sugar and soluble protein,improving the rice recovery ability after the flooding,and showed that the basal Si and spraying N with Si can improve the physiological characteristics effectively at tillering stage of rice after de-submergence,eventually,the loss of yield was reduced.3.The remediation effects of supplemental nitrogen fertilizer on rice at booting stage varied with seedlings.The rice yields of S1?S3 and S4 were increased after the application of panicle fertilizer,and the S3 rice with nitrogen(urea)75kg/ha and 150kg/ha panicle fertilizer reached significant level due to the increase of panicles.Panicle fertilizer had significantly increased the tillers of S3 and S4;the rice of S1 and S4 had larger leaf length at the mature stage;the value of SPAD after fertilizing had some advantages.The day mass and nitrogen accumulation of S3 and S4 had significantly increased at maturity stage,especially,the phosphor and potassium accumulation also increased for the submerged rice for S3 after fertilizing with nitrogen 75kg/ha.