Effects Of Potassium Fertilizer On Tuber Yield And Quality For Potato From Rain-fed Areas In Ningxia

Based on 2013-2014 fertilization effect, this trial aim at potash fertilizer unreasonable question in rain-fed agriculture of Ningxia, through fertilizer field trials, using a single factor potassium fertilizer randomized block design to study the influence of different amount of potassium to dry matter accumulation, nutrient absorption and yield and quality of potato’s each organ. Thereby determine further the amount of potash fertilizer and high yield, high quality and optimization technology, thus provide a scientific basis for large scale optimal fertilization technology to improve the yield and quality. The results show that:1 Throughout the growth period of potato dry matter accumulation with slow-fast-slow the law, which was similar to the "S" trend, the regression analysis and curve fitting, in accordance with the Logistic growth function. The amount of dry matter accumulation is 169.72 g/plant and fresh tuber yield reached 26.86 t/hm2; Dry matter accumulation in each period were:tuber expansion stage> starch accumulation stage> tuber formation stage> seedling stage.2 From different potassium fertilizer on potato nutrient content of various organs and its allocation pattern it can be seen that vivo nitrogen, phosphorus, potassium content inside potato vary with the growth of organs varies. In different potassium fertilization treatment, potato leaves, roots, stems nitrogen content and potassium content is with the advance of the growth process and showed a gradual downward trend, phosphorus content showed a sharp decline in first and then the stable development trend of the last rise again. And different amount of potassium, potato accumulation of NPK vary with organs. Leaves is the mainly absorbing center of nitrogen, phosphorus and potassium accumulation during seedling stage; from tuber formation stage to starch accumulation stage, since needs of tubers’ growth, potato leaves, roots and stems nutrient accumulation began to decrease; In the stage of starch accumulation of nitrogen, phosphorus and potassium reach the highest cumulative amount of tubers. As can be seen in the study, if potassium controlled within a certain range, the various organs of the potato are a positive impact on the nitrogen, phosphorus and potassium nutrient absorption. If the amount of potassium is too high, it will caused nutrient imbalances affect plant absorption of other nutrients.3 Producing each 1000kg tubers needs 4.07-7.77 kg N,0.84-2.09 kg P2O5,7.54-11.99 kg K20, three elements (N, P2O5, K2O) an average of 6.42 kg,1.45 kg,10.03 kg, ratio of average nutrition (N: P2O5:K2O) is 1:0.23:1.56.4 In the view of different K rates change on potato yield, with different amounts of potassium, potato production also are different. Different potassium potato had some effect on the increase, with increasing amounts of potassium, yield increases. But to a certain amount of potassium, yield declined. When K application rate increased to 6.21 kg/667m2, potato yield reached, the maximum value for 1344.15 kg/667m2, with potassium fertilizer application increased yield decreased slowly. The top economic yields reached 1332.49 kg/667m, under 3.23 kg/667m of potash fertilizer. (Pure K20 was 7.84 yuan/kg, potato was 1.00 yuan/kg).5 In the view of effect of different dosage of potash to potato quality, applying potassium fertilizer can promote the absorption of potato starch, vitamin C, crude protein, and increases the amount of potassium, starch, vitamin C and crude protein content shows the trend of increasing first and declining later. This shows that moderate potash can improve potato quality, excess potassium decreases the chlorophyll content in potato leaves, influence the photosynthesis and starch accumulation. Meantime it will also causes an imbalance to other plant nutrient uptake and nitrogen Su assimilation, bad for the accumulation of potato tuber starch, vitamin C and crude protein content. Nitrate content lowest is no-fertilizer treatment, the highest is no-potassium fertilizer treatment, within a certain range of the content within the potato tuber nitrate and reducing sugar was increased with the application of potash constantly decreased, indicating that the using potassium can effectively reduce the tubers nitrate and reducing sugar content.