Effects Of Different Potassium Application On Growth,Yield And Quality Of Potato

To study the effects of different potassium sources on potato growth and development,dry matter accumulation,yield,tuber quality,nitrogen,phosphorus and potassium uptake and accumulation in plants,potassium utilization rate,and screen suitable potassium application schemes for potato production increase and quality,in order to provide reference for field transformation to improve land utilization rate.Three potassium application levels were set with potato"Yanshu No.4"as the material:225kg/hm²（T₁）,375kg/hm²（T₂）and 525kg/hm²（T₃）.Four application schemes were as follows:Base fertilizer 1/2 potassium sulfate+topdressing 1/2 potassium sulfate（K₁）,base fertilizer 1/2 potassium sulfate+topdressing 1/2 potassium chloride（K₂）,base fertilizer 1/2 potassium chloride+topdressing 1/2 potassium sulfate（K₃）,base fertilizer 1/4 potassium sulfate-1/4 potassium chloride+topdressing 1/4 potassium sulfate-1/4 potassium chloride（K₄）,a total of 12 treatments,In seedling stage,potato tuber formation,tuber expansion period,starch accumulation period and mature period of potato fertility properties,physiological and biochemical indexes,yield and its composition,potato tuber quality,different periods of NPK plant accumulation and distribution and potassium accumulation rate change rule and potash fertilizer utilization ratio and analysis of relationship between above index and types and levels of potash.The results are as follows:（1）Under the same fertilization scheme,the growth and development,yield and quality of potato were different among different potassium levels.Among them,the plant height,stem diameter,leaf area,chlorophyll content,root activity,dry matter accumulation,soluble protein content,MDA content,SOD activity,yield,soluble protein,starch,soluble sugar and VC content in tubers under 375kg/hm²（T₂）potassium application level were better than other potassium application levels.However,too high or too low potassium application will increase the POD activity of leaves,and the nitrate content of tubers is the lowest under T₃ potassium application level.When the amount of potassium is the same,the combination of potassium sulfate and potassium chloride is more conducive to the growth and development of potato,and the application of potassium chloride or potassium sulfate is more conducive to the formation of soluble sugar in leaves.The application of potassium chloride can increase the activity of SOD and POD,improve the resistance of potato plants and delay aging.The increase of potassium fertilizer can increase the yield of tubers,and the basal application of potassium sulfate is more conducive to the formation of tubers.The combined application of two potassium fertilizers is beneficial to increase the tuber weight per plant and average tuber weight of potato,and the highest yield is K₄T₂ treatment.The application of potassium sulfate was beneficial to the synthesis and accumulation of starch,soluble sugar and soluble protein in potato tubers,and the application of potassium chloride in base fertilizer could reduce the nitrate content.Principal component analysis showed that K₄T₂treatment had the highest comprehensive score.（2）With the advancement of growth period,the potassium accumulation of plants peaked at 75 days after emergence and decreased to the lowest at 90 days after emergence,but the potassium accumulation in tubers gradually increased.In the early stage of growth,potassium was mainly distributed in leaves.At 45 days after emergence,the distribution ratio of potassium in leaves and other vegetative organs began to decrease,while the proportion of tubers gradually increased.The distribution ratio of potassium in tubers under 375kg/hm²（T₂）was higher than that under other potassium application levels.The combination of potassium sulfate and potassium chloride was more conducive to the transport of potassium to tubers,and the effect of potassium chloride was better.At the same time,it was found that the accumulation of potassium in potato conformed to the Logistic equation,and the potassium accumulation rate of each treatment showed a single peak curve.Increasing potassium fertilizer can delay the time of the maximum accumulation rate of potassium,but when the potassium level exceeds 375kg/hm²,the time will be advanced,and the maximum accumulation rate of each treatment occurs between 43d and 49d;the average maximum accumulation rate of each potassium application level increased and then decreased with the increase of potassium application rate.At the same time,it was found that low potassium or high potassium supply would reduce the accumulation rate of potassium in the late growth stage of potato.The accumulation and distribution of nitrogen and phosphorus in potato is similar to that of potassium,but the application of potassium sulfate is more conducive to the accumulation and distribution of phosphorus in tubers and whole plants than potassium chloride.（3）Excessive application of potassium fertilizer will lead to the decrease of agronomic efficiency and partial productivity of potassium fertilizer.Increasing potassium fertilizer application can improve the utilization rate and dry matter production efficiency,but the application level of potassium more than 375kg/hm²（T₂）will lead to a decrease in both;the agronomic efficiency of potassium fertilizer in single application of potassium sulfate treatment was higher than that in combined application treatment.The dry matter production efficiency of potassium fertilizer in combined application of two potassium fertilizers was better than that in single application of potassium sulfate,and the application of potassium chloride in base fertilizer was more conducive to improving the utilization rate of potassium fertilizer.