Effect Of Different Fertilizer Rates And Fertilization Methods On Yield, Nutrients Accumulation And Tuber Quality Of Potato In Xiangyang

China is the biggest potato production country in the world, the planting area increased with years. Fertilization is one of the most important factors that affected the yield and quality of potato, The rational fertilization can increased potato yield, improved potato quality, and reduce the cost. In Xiangyang area, potato is one of the most fastest developed crops with its growing area increased year by year. However, over-fertilization was commonly found on potato planting in Xiangyang area, especially on nitrogenous fertilizer, such as partial application of ammonium bicarbonate. Based on potato planting habit of Xiangyang area, a field experiment with potato cultivar Zaodabai as experimental material was conducted to study the effects of fertilization amount and fertilization mode on potato growth, development and yield. The research was to discover the nutrient demand features on NPK of potato throughout of the whole growth period, as well as to obtain an optimal fertilization amount and fertilization mode that suitable for local potato production which would give a technical support on scientific potato planting in Xiangyang area. The results showed:1. During the whole potato growth period, the requirement for N, P2O5and K2O were130.62kg/hm2、47.46kg/hm2and104.28kg/hm2respectively. With a ratio of N:P2O5: K2O by1:0.37:0.80. Potato showed a highest demand on N input, then P2O5and K2O. The accumulation of N、P2O5and K2O throughout of the whole plant showed that:tuber> leaf> stem> root.2. N input amount significantly affected potato tuber quality. Compared to traditional planting habit, the contents of Vc, dissolubility sugar, protein and starch were significantly increased when N input was less than360kg/hm2, Vc from6.90mg/100g to24.87mg/100g, dissolubility sugar from1.07%to1.24%, protein from4.30mg/g to5.88mg/g, starch from58.40%to63.07%(dry weight). The contents of Vc, dissolubility sugar, protein and starch significantly decreased when N input was540kg/hm. Nitrate content in tuber increased with N input when N input was less than540kg/hm2.P input amount significantly affected potato tuber quality. Compared to control (without P input), the contents of dissolubility sugar increased from1.17%to1.32%, starch content increased from56.02%to61.70%(dry weight) when treated with P input of90kg/hm2. When P input over90kg/hm2, both Vc and protein content decreased. Nitrated content in tuber decreased by41.42%with180kg/hm2P input Compared to control (without P input). K input amount significantly affected potato tuber quality. When fertilized with210kg/hm2K, Vc and protein contents showed a highest value. Nitrated content in tuber decreased by33.90%with420kg/hm2K input, compared to the treatment without P input.3. Compared among different fertilization modes:farmer practices, ammonium bicarbonate+compound fertilizer, fully basal application of compound fertilizer, partial basal+partial dressing application of compound fertilizer. The best result was found in the treatment of partical basel+partial dressing application of compound fertilizer application, with a yield of20432.23kg/hm2which showed a yield of2412.67kg/hm2more than that of farmer practices, as well as higher contents in Vc, dissolubility sugar, protein, and starch. When compared to ammonium bicarbonate+compound fertilizer, the treatment of partial basal+partial dressing application of compound fertilizer showed an increasing rate of42.95%,56.54%,22.58%and4.12%for Vc, dissolubility sugar, protein, and starch, respectively. Ammonium bicarbonate application significantly decreased potato yield as well as Vc, dissolubility sugar, and protein contents, whereas enhanced nitrate content and lower potato quality.4. By comprehensive consideration of yield, quality, economic benefit and fertilizer utilization, the optimal fertilization amount of NPK was180-90-210kg/hm2(N2P1K2), and the best fertilization mode was by combined basal application with dressing application.