Effects Of Water And Fertilization Coupling On Reowth And Nutrient Use On Potatoes In Sandy Area Of Yulin

Considering the low water and fertilizer use efficiency with the flood irrigation in sandy soil of YuLin,Northern Shaanxi,the effects of different water and fertilization supply on potato growth,yield and water and fertilizer use efficiency were investigated through the field experiments.There were three water levels W₁?60%ET_c?,W₂?80%ET_c?,W₃?100%ET_c?and three fertilizer levels N1P1K1?100-40-150kg/hm2?,N₂P₂K₂?175-60-225 kg/hm2?,N₃P₃K₃?250-80-300 kg/hm2?,resulting in a total of nine treatments.Based on those,key indicators?e.g.,growth,yield,etc.?of potato in response to different irrigation water and NPK amounts were further analyzed.The main results are as follows:?1?Different water and fertilizer amounts significantly influenced the plant height,leaf area index,dry weight,yield,water use efficiency?WUE?,partial factor productivity of fertilizer?PFP?,different tuber quality,yield related relations and economic benefits.The growth,yield and PFP increased with the increase in irrigation amount,and W₃ was more beneficial to the growth of potato.However,the water use efficiency of W₃ was significantly lower than that of W₁ and W₂.The average water use efficiency of W₁ was 5.83% and 13.05% higher than that of W₂ and W₃.The impact of fertilizer on growth and yield showed an increasing but then decreasing trend,with the yield reaching the maximum 59394.98 kg/hm2 at W₃N₂P₂K₂ level.The water use efficiency of N₂P₂K₂ was significantly greater than that of N1P1K1 and N₃P₃K₃.Linear fitting revealed a positive relationship between the plant height,leaf area index,dry weight and the yield of potato within a certain range.Comprehensive analysis indicated that the appropriate irrigation and NPK amounts can not only maintain the good growth of potato,but also obtain greater yield and economic benefits.From the point of view of obtaining high yield and saving water and fertilizer,W₃N₂P₂K₂?100%ET_c,175-60-225 kg/hm2?can be used as an appropriate combination under the present experimental conditions.?2?Nutrient uptake and utilization of potatoes in response to different irrigation water and NPK amounts were further analyzed.Results showed that the nutrient contents in the whole plant of potatoes at different growing stages performed as: K>N >P.The nitrogen,phosphorus and potassium uptake and accumulation of potatoes showed an "S" type growth curve,with the peak absorption and accumulation close to the tuber enlargement stage,and a gradually decreasing trend afterwards.The cumulative uptake of N,P and K in potatoes was significantly affected by the amounts of irrigation and fertilization,and the uptake of N,P and K increased with the increase in irrigation amount.However,the uptake of N,P and K showed an increasing but then decreasing trend with the increasing fertilization amount.The coupling of water and fertilizer under drip fertigation conditions significantly increased the efficiency of nutrient absorption of potatoes,with the maximum absorption rate of nitrogen,phosphorus and potassium in the W₃N₂P₂K₂ treatment.The distribution of N,P and K in soil profiles performed as: K>N>P,and showed surface accumulation characteristics with increasing soil depths.The contents of N,P and K in each soil layer increased with increasing fertilizer amount,which was directly proportional to the amount of supplied fertilizer.