Effects Of Both Nitrogen And Potassium Fertilizers On Yield And Quality Of Potato In Rainfed Area

Potato has become the dominant grain crop in Ningxia rainfed area,but unreasonable fertilizer not only can affect potato yield and quality,but also causes soil pollution.Therefore,this experiment adopted "3414" partial fertilizer design to study the effects of dry matter accumulation as well as nutrient absorption about applying different nitrogen and potassium fertilizer ration in potato growth stages,and to research the effects of different nitrogen and potassium fertilizer on yield and quality of potato.It had an important significance to guide local fertilization as well as increase crop yield and economic benefits.The main conclusions are as follows:1.The dry matter accumulation of potato was "S" type curve,which conformed the Logistic growth equation.Fertilization was beneficial to increase dry matter accumulation,but excessive nitrogen and potassium reduce dry matter accumulation,the application rate of nitrogen,phosphorus and potassium fertilizer was 225-120-45kg/hm2(N2P2K1)and 225-120-90kg/hm2(N2P2K2)that ware most beneficial to dry matter accumulation.2.In potato growth period,nitrogen and potassium fertilizer could improve mass fraction of N,P,K about potato organs,the application rate of nitrogen,phosphorus and potassium fertilizer was 225-120-90kg/hm2(N2P2K2 treatment)that was the highest,and it was significantly higher than the treatment with no using N fertilizer(NOP2K2);the application rate of nitrogen,phosphorus and potassium fertilizer was 225-120-45kg/hm2(N2P2K1 treatment)that was the highest,and it was significantly higher than the treatment with no using K fertilizer(N2P2K0).In the tuber formation stage,N,P,K nutrient uptake was the largest at 3g/plant;in the starch accumulation stage,N uptake accumulated up to 0.937g/plant;in the tuber expansion stage,P uptake accumulated up to 0.623g/plant;in the tuber formation stage,K uptake accumulated up to 1.598g/plant.3.Potato tuber required the N,P,K nutrient was K>N>P.Producing each 1000kg tuber need N 5.66～9.19kg,P 0.99～1.71kg,K 9.44～16.84kg,the average ratio of the three elements(N:P:K)was 1.00:0.18:1.76.4.Reasonable rate of nitrogen and potassium fertilizer can significantly improve the potato yield,big tuber number and commodity rate.The application rate of nitrogen,phosphorus and potassium fertilizer was 225-120-45kg/hm2(N2P2K1 treatment)that was the highest,and it was significantly higher than the treatment with no using fertilizer(N0POK0).With nitrogen fertilizer applied rates increasing,the income,nitrogen fertilizer agronomic efficiency,nitrogen fertilizer contribution rate were increased firstly and then decreased,but the partial factor productivity of nitrogen was significantly decreased,N2P2K2 treatment(225-120-90kg/hm2)was the best.With potassium fertilizer applied rates increasing,the income,potassium fertilizer agronomic efficiency,potassium fertilizer contribution rate and the partial factor productivity of potassium was gradually decreased,the application rate of nitrogen,phosphorus and potassium fertilizer was 225-120-45kg/hm2(N2P2K1 treatment)that was the best.5.The amount of nitrogen fertilizer significantly affected the quality of potato,with nitrogen fertilizer applied rates increasing,the content of VC was increased firstly and then decreased;the content of reducing sugar was gradually decreased;while the contents of nitrate,nitrite and protein were gradually increased.The amount of potassium fertilizer significantly affected the quality of potato,with potassium fertilizer applied rates increasing,the content of VC was increased firstly and then decreased;the content of reducing sugar was gradually decreased;while the content of starch was gradually increased,while the contents of nitrate,nitrite and protein were increased firstly and then decreased.Considering the point of view about quality,the application rate of nitrogen,phosphorus and potassium fertilizer was 112.5-120-45kg/hm2(N1P2K1 treatment)that was the best.6.By comprehensive consideration of yield,quality,economic benefit and fertilizer utilization,the best nitrogen,phosphorus,potassium was 225-120-45kg/hm2(N2P2K1 treatment)in Ning xia rainfed area.