Effects Of Different Potassium Fertilizers On Yield,Quality And Lodging Of Rice

In order to explore the effects of different potassium application on yield formation,stress resistance and lodging resistance of rice,three experimental sites were set up in Longtan Village of Conghua City,Xincun village and Dongwan village of Zhuhai City respectively.Guangfengxiang 8 was used as the material.Under the condition that the application amount of nitrogen fertilizer and phosphorus fertilizer were kept the same,four different potassium fertilizer levels were set,including no potassium fertilizer treatment（T1）,K₂O 64.2kg·hm^-2 treatment（T2）,K₂O 128.2 kg·hm^-2treatment（T3）,K₂O 153.9kg·hm^-2 treatment（T4）,the effects of different potassium application on yield,quality,stress resistance and lodging resistance of rice were analyzed.The main results were as follows:1.Suitable application of potassium fertilizer can significantly increase the grain number per panicle,seed setting rate of rice and number of effective panicles,thus significantly improving the rice yield.With the increase of potassium application,the rice yield increased first and then decreased.The yield was the highest at 128.25 kg·hm^-2.The quality of rice could be significantly improved with the suitable application of potassium.The brown rice rate,milled rice rate and head rice rate were all increased first and then decreased with the increase of potassium application,and reached the highest at 128.25kg·hm^-2;the amylose content were decreased with the increase of potassium application,and reached the lowest at 153.9 kg·hm^-2.The protein content were increased first and then decreased with the increase of potassium application,and reached the highest at 153.9kg·hm^-2.In terms of comprehensive yield and quality,a better yield and quality could be obtained by applying potassium at 128.25 kg·hm^-2.2.Suitable application of potassium could improve the photosynthetic capacity and material accumulation of rice.Both the photosynthetic enzyme activity and chlorophyll content increased first and then decreased with the increase of potassium application,and the net photosynthetic rate of leaves also increased and then decreased with the increase of potassium application.The chlorophyll content,photosynthetic enzyme activity and net photosynthetic rate were optimal when potassium was applied at 128.25 kg·hm^-2.The dry matter accumulation of rice increased at first and then decreased with the increase of potassium application in each experimental site,and it was larger when potassium application at 128.25 kg·hm^-2.3.The application of potassium can improve the stress resistance of rice.The activity of SOD,POD and CAT were increased first and then decreased with the increase of potassium application,and the activity of antioxidant enzyme reached the highest at 128.25kg·hm^-2,while the content of MDA decreased first and then increased with the increase of potassium application,4.Suitable application of potassium fertilizer was conducive to improving the lodging resistance of rice.The lodging index of rice decreased with the increase of potassium application.The activities of lignin synthase PAL and TAL increased with the increase of potassium fertilizer application,which resulted in the increase of lignin content.The change trend of cellulose content was consistent with lignin.The lodging index of rice decreased with the increase of potassium fertilizer application.The content of lignin and cellulose were the highest when potassium was applied at 153.9 kg·hm^-2,and the lodging index was the smallest,but it was not significantly different from that at 128.25 kg·hm^-2.According to the comprehensive analysis,128.25 kg·hm^-2was the optimal application amount of potassium fertilizer.Under this potassium application,rice can obtain excellent lodging resistance,stress resistance,photosynthetic characteristics and material accumulation,thus ensuring the high and stable rice yield.