Effect Of Irrigation Threshold And Fertilization On The Growth, Water And Fertilizer Use Efficiency Of Potato In Yulin Sandy Land

Understanding the effects of soil moisture threshold and fertilizer regulation on growth,the amount of dry matter accumulation,yield,tuber quality,water and fertilizer use,plant nutrient absorption and soil nutrient residual distribution of potatoes under drip irrigation at the growing stages in YuLin areas,Northern Shaanxi and in order to explore the water and fertilizer regulation mode of high quality and high yield of potato with the potato species of ZiHuaBai,there were total of 12treatments combining three lower limits of soil moisture regulation,i.e.W1?55%?60%?65%?55%?55%?,W2?65%?70%?75%?65%?65%??W3?75%?80%?85%?75%?75%?and four N-P₂O₅-K₂O?kg/hm²?fertilization rates,i.e.F1?100-40-150kg/hm²??F2?150-60-225 kg/hm²??F3?200-80-300 kg/hm²??F4?250-100-375 kg/hm²?at different growing stages?seedling stage?tuber formation stage?tuber swelling stage?starch accumulation stage?maturity stage?.The plant height,stem diameter,leaf area index and SPAD were measured during the growing season,the amount of dry matter accumulation,yield and yield components,the content of starch,vitamin C and reductive sugar in Tuber,accumulation of nitrogen,phosphorus and potassium in plant organs and residual nitrogen,phosphorus and potassium in soil during the whole growth period of potato,exploring the responses mechanism of each index of potato to irrigation and fertilizer.The test results are as follows:?1?At the same fertilizer rate,the growth,yield,quality and water and fertilizer use efficiency of potato of W2 were significantly higher than W1 and W3.The yield of W2 was 43187.15 kg/hm²,24.59%and 5.26%higher than W1 and W3.The starch content and vitamin C content of W2 was respectively increased by 15.32%and8.04%,6.37%and 4.66%.Water use efficiency?WUE?of W2 increased by 15.53%and 7.54%.The partial fertilizer productivity?PFP?of W2 increased by 21.65%and4.41%.At the same irrigation level,the growth,yield and water use efficiency of potato of F3 were higher than those of F1,F2 and F4.The starch content and vitamin C content of F2 were the highest.The average yield of F3 was 44691.32 kg/hm²,which was 41.79%,10.98%and 6.34%higher than F1,F2 and F4.The water use efficiency showed a parabolic trend with the increase of fertilization amount.The PFP gradually decreased with the increase of fertilizer application.The PFP of F1 was108.69kg/kg,which was 17.41%,41.06%and 87.50%higher than F2,F3 and F4.?2?The lower limit of irrigation and the amount of fertilizer had significant effects on the nutrient accumulation and soil nutrient residue of each organ in the whole growth period of the plant.During the whole growing period,the accumulation of nitrogen,potassium and phosphorus in the plant was expressed as potassium>nitrogen>phosphorus.At the same fertilizer rate,the total amount of nitrogen and potassium and phosphorus in mature stage was the highest under W2,compared with W1 and W3,nitrogen increased by 10.55%and 5.42%,phosphorus increased by24.59%and 12.77%,and potassium increased by 14.21%and 9.40%.W2 lower limit was more suitable for the accumulation of plant nutrients.At the same irrigation level,the total accumulation of nitrogen,potassium and phosphorus in mature stage increased first and then decreased with the increase of fertilizer application.The highest treatment was F3.Under F3,nitrogen increased by 116.55%,26.98%and20.72%,phosphorus increased by 73.31%,35.55%and 27.07%,and potassium increased by 62.05%,19.12%and 11.57%,respectively,compared with F1,F2 and F4.Excessive application of fertilizer could not increase plant nutrient absorption.At the same irrigation level,the use efficiency nitrogen and potassium and phosphorus with utilization efficiency decreases with the amount of fertilizer increased and reached the maximum under F1 treatment.At the same fertilization level,the NPK absorption efficiency of plants first increased and then decreased with the increase of the lower limit of irrigation,and reached the maximum under W2 treatment.In the mature stage,the contents of nitrate nitrogen,available phosphorus and available potassium in the soil profile under drip irrigation increased with the increase of the amount of fertilizer,but decreased with the increase of the lower limit of irrigation water.Nutrients were concentrated in the soil surface layer,and the proportion of soil nutrients in 0-20 cm to 0-100 cm was the largest in each soil layer.In conclusion,under F3W2 treatment,plant nutrient accumulation reached the maximum,and soil residual nutrient was less.?3?The evaluation of potato quality by principal component analysis showed that F3W2 treatment ranked first.Comprehensively considering growth,quality,yield,water and fertilizer use efficiency,nutrient uptake by plants and soil nutrient residues,F3W2 treatment was the best water and fertilizer combination for high quality and yield of potato in Yulin area.