Effects Of Combined Application Of Polyaspartic Acid And Fertilizer On Growth And Yield Of Potato

Potato has different fertilizer requirements in different growth stages,and production efficiency can be effectively improved by adjusting soil fertilizer supply in different stages.Polyaspartic acid(PASP),as a water-soluble and environmentally friendly material,can be used as a slow/controlled release agent with fertilizers.Due to its excellent effect on slow release of fertilizer and soil structure regulation,there have been some studies on various crops,however,whether it can regulate potato production by regulating fertilizer release rate is rarely studied.This experiment aimed to study the effects of PASP as functional fertilizer combined with fertilizer on potato growth and development,and to observe its physiological effects on potato yield through biomass,plant morphology,root structure,leaf physiological indexes,dry matter accumulation and mineral content in the early and late growth stages.This study contains two parts of experiments as below,which were conducted with the experimental base of Sichuan Agricultural University in Wenjiang from 2018 to 2019.(1)Low(750 kg/hm~2),Medium(1500 kg/hm~2),High(1800 kg/hm~2)compound fertilizer(17-17-17)application level combined with Low(120 kg/hm~2),Medium(240 kg/hm~2),High(360 kg/hm~2)functional fertilizer consumption,apply with randomized block experiment to observe the growth of potato.(2)According to the results of experiment(1),combined inorganic and organic fertilizer with 375 kg/hm~2PASP fertilizer under normal fertilization using,and the effects were observed.The main results of this study are as follows:1.When the application rate of compound fertilizer was 1500 kg/hm~2,it had the most favorable effect on the growth and development of potato,which could improve fresh weight,leaf area and dry matter accumulation of roots,stems and leaves,increase plant height and root length,and improve the yield of potato.However,there may be a critical value of potato nitrogen tolerance between the fertilizer levels of1500～1800 kg/hm~2compound fertilizer(with 255～306 kg/hm~2pure nitrogen).When the application rate of compound fertilizer reached 1800 kg/hm~2,plant fresh and dry weight accumulation decreased.When 750～1500 kg/hm~2compound fertilizer was applied,the combined application of 120～360 kg/hm~2functional fertilizer promoted plant height,root length,biomass,dry matter accumulation,leaf area and yield.When the fertilizer amount reached 1800 kg/hm~2,the combined application of functional fertilizer could increase yield.However,it could not offset the negative effect of high fertilizer level on yield.2.The proper application of organic fertilizer was beneficial to the morphological construction of potato.At the seedling stage,the leaf area,leaf fresh weight,chlorophyll content of the shoot and the average root length-surface area-diameter-volume of the underground shoot under the organic fertilizer treatment were greater than those under the inorganic fertilizer treatment.Functional fertilizer had an effect on both organic and inorganic fertilizer,but had a greater effect with fertilizer efficiency of inorganic fertilizer,which generally inhibited plant growth in the early stage,promoted growth and delayed senescence in the later stage.In the tuber expansion stage,the application of functional fertilizer could significantly increase plant height,fresh weight,dry matter content,root length and root volume.3.Functional fertilizer can improve the efficiency of substance accumulation and transport in potato plants.The main source of N,P and K in the plant is the soil,and the mineral elements in the soil come from the applied fertilizer.It was found that the contents of total nitrogen,total phosphorus and total potassium of plants increased significantly with the increase of the amount of functional fertilizer.The contents of N,P and K of plants were the highest when the fertilization levels of 750 kg/hm~2and1500 kg/hm~2combined with the high functional fertilizer level of 360 kg/hm~2.The N,P and K contents of 240 kg/hm~2functional fertilizer were the highest in the combination of 1800 kg/hm~2fertilization level.The content of N,P and K in soil was positively correlated with that in plants,and functional fertilizer significantly affected soil N,P and K.4.Appropriate fertilization can increase potato yield,with the highest yield of1500 kg/hm~2compound fertilizer application,and the highest yield of 240 kg/hm~2compound fertilizer application when 750～1500 kg/hm~2compound fertilizer application,high fertilizer level(1500～1800 kg/hm~2)is not conducive to the formation of yield,adding functional fertilizer can alleviate fertilizer stress.Proper application of organic fertilizer was beneficial to increase potato yield.Functional fertilizer had little effect on the percentage of commercial potato,but the combination of 1500kg/hm~2compound fertilizer(25-7-8),375 kg/hm~2urea(46%)and potassium sulfate(51%)with 375 kg/hm2 functional fertilizer was unfavorable to potato production.As mentioned above,the principle of high fertilizer low PASP and low fertilizer high PASP should be followed in production.