Effects Of Soil Health And Different Fertilization Ratios On The Growth And Quality Of Jujube

In recent years,with the continuous improvement of winter jujube technology in Dali facilities,the output of winter jujube has been relatively stable,and the winter jujube industry has developed rapidly,thus promoting the steady growth of Dali’s economy.In order to make the Dali winter jujube industry develop more efficiently,we need to carry out accurate soil health evaluation of jujube orchards to clarify the current soil health status of jujube orchards.Therefore,this study took 13 towns and towns in Dali County as the research area,based on the fuzzy mathematics evaluation method and principal component analysis method to comprehensively evaluate the soil health of jujube orchards with 12 indicators such as soil texture,organic matter,PH,etc.Database of comprehensive soil scores and health grades of jujube orchards.At the same time,combined with the nitrogen,phosphorus and potassium fertilizer effect experiments in jujube orchards,the effects of different fertilizer ratios on the yield,quality,mineral nutrients and fertilizer utilization rate of winter jujube were analyzed,and the optimal fertilization mode of jujube orchards was explored.The purpose is to provide theoretical support for the sustainable development of Dali jujube orchard with healthy soil and excellent jujube fruit.The main conclusions of this study are as follows:（1）Based on fuzzy mathematics evaluation method and principal component analysis method,the soil health status of winter jujube orchards in 13 townships in Dali County was comprehensively evaluated.The results of principal component analysis were as follows:Fengcun,Shuangquan,Nianqiao,Xuzhuang,Chengguan,Xiazhai,Chaoyi,Anren and other towns were healthy in soil health,while Weilin,Fanjia,Liangyi,Qiangbai,Zhaodu were healthy.The soil health status of other towns is sub-healthy.The results of the fuzzy mathematics evaluation method are:Fengcun,Nianqiao and Shuangquan three towns’soil health status is at a relatively high level II,and other towns are at a moderate III level.There is consistency between the two evaluation methods.The scores of Fengcun,Shuangquan and Nianqiao are in the top three in the county,while the soil scores of Liangyi,Qiangbai and Zhaodu are the lowest in the county.Soil alkaline-hydrolyzed nitrogen,available iron,organic matter,available potassium,sand content and available copper were the main limiting factors for soil health in Dali jujube orchards.（2）The field trials of NPK15（N:0.244,P2O5:0.422,K2O:0.165 kg/plant）for two consecutive years in 2020 and 2021 showed that the yield and quality of NPK15were significantly better than other treatments.The principal component analysis method was used.It was found that the top three fertilization treatments were NPK15（0.244,0.422,0.165 kg/plant）,NPK1（0.390,0.672,0.264 kg/plant）,NPK4（0.390,0.171,0.067 kg/plant）,with a score of 1.12,0.71 and 0.66 points,NPK15 fertilization treatment was the most beneficial to improve the yield and quality of winter jujube,and it was the optimal treatment.（3）The daily changes of net photosynthetic rate,transpiration rate,and stomatal conductance at different fertilizer levels all showed a"single-peak"curve that first increased and then decreased,and the peak value of net photosynthetic rate of NPK15was the largest,and stomatal conductance reached at 11:00.The maximum value,the transpiration rate of winter jujube is the lowest at 17:00.Therefore,nitrogen application in jujube orchards can increase the area of jujube leaves,and the appropriate level of nitrogen,phosphorus and potassium fertilizers can improve various photosynthetic indexes of jujube leaves to a certain extent,promote the accumulation of photosynthetic products,and then improve the quality of jujube fruit.（4）The seasonal utilization rate of nitrogen fertilizer under different fertilizer ratios ranged from 13.78%to 40.87%,the seasonal utilization rate of phosphate fertilizer was between 6.29%and 18.27%,and the seasonal utilization rate of potassium fertilizer was between 30.61%and 68.27%.Among them,the N,P and K fertilizer utilization rates of NPK15 were significantly higher than those of other treatments,which were 40.87%,18.27%and 68.27%,respectively.Therefore,the appropriate level of nitrogen,phosphorus and potassium fertilizer ratio can significantly improve the fertilizer utilization rate of jujube orchards.（5）Based on the multiple linear regression model to explore the fertilizer effect of different fertilization levels,it was found that the positive effect of nitrogen,phosphorus and potassium fertilizers on the yield of winter jujube was:nitrogen fertilizer>phosphorus fertilizer>potassium fertilizer.Taking the yield of 35300 kg·hm²as the target,the fitting optimal fertilizer ratio is:N:0.348,P₂O₅:0.520,K₂O:0.175kg/plant（equivalent to N:427,P₂O₅:221,K₂O:238 kg/ha）,It is close to the fertilization amount of NPK15（N:0.244,P₂O₅:0.422,K₂O:0.165 kg/plant）in the fertilization plan（N:300,P₂O₅:180,K₂O:225 kg/ha）,so the fertilization ratio is N:427,P₂O₅:221,K₂O:238 kg/ha were the recommended fertilization rates for jujube orchards in this area.To sum up,the soil health status of jujube orchards in Zhaodu,Liangyi,Qiangbai and other towns in Dali County is sub-healthy,the soil productivity is not high,and the nutrient structure is unbalanced.Chemical fertilizers and organic fertilizers should be applied reasonably to improve soil fertility..From the results of the fertilizer effect test in jujube orchards,it can be seen that the ratio of nitrogen,phosphorus and potassium fertilizers is N:0.244,P₂O₅:0.422,K₂O:0.165 kg/plant,which can significantly improve the yield,quality,photosynthetic characteristics and fertilizer utilization rate of winter jujube.That is,the optimal fertilizer ratio of N:427,P₂O₅:221,K₂O:238 kg/ha can be used as the recommended amount of fertilizer for winter jujube orchards in this area.