Effects Of Different Techniques Of Reducing Fertilizer On Potato Yield,Nutirent Accumulation And Quality

Potato is the fourth major grain after rice,wheat and corn.Hubei Province is one of the important potato producing areas in China.Potato cultivation has developed from Enshi to Xiangyang and Xiaogan,and the planting area extended as well.However,the characteristics of potato’s fertilizer demand and soil nutrient status were not fully considered when high content of N,P,and K balanced compound fertilizer was widely applied to increase the yield of potato.Therefore,the high application of nitrogen and phosphorus caused the accumulation of nitrogen and phosphorus in the soil,and the aerial parts of the potato grew excessively,which led to poor ventilation,more disease,less output and waste of fertilizer resources.In addition,focusing on macroelement but neglecting medium and trace elements and focusing on chemical fertilizer but neglecting organic fertilizer is common in potato planting,which would cause nutrient imbalance and soil acidification,and directly restricted the efficiency of potato planting.In aim to achieve the goal of fertilizer reducing and efficiency increasing of potato,and to provide technical support for potato effiency planting,a two-year field experiment was conducted.The study is based on the experiment of multi-point formula fertilizer in early years.Huashu 1 and Zhongshu 5 were used as the research objects,and the special formula fertilizer for potato was applied,while medium and trace element fertilizer,water-soluble humic acid fertilizer and organic fertilizer were applied as well.The main conclusions are as follows:1. Different fertilizer reduction techniques can effectively increase the yield of potato tubers under the condition of reducing fertilizer nutrient by 20%-50%,and achieve the goal of fertilizer reducing and efficiency increase of potato.Compared with conventional fertilization,the total nutrients of N,P and K of potato special formula fertilizer were reduced by 165 kg/hm²,and under the condition which the total nutrients were reduced by20%,the average increase of potato tuber yield was 6 923 kg/hm²with a growth rate of16.3%.Compared with the single formula fertilizer,the total nutrients of N,P and K of the special formula fertilizer combined with water-soluble humic acid fertilizer and medium trace element fertilizer were reduced by 90 kg/hm²,and under the condition which the total nutrients were reduced by 15%,the average yield of potato tubers increased by 953 kg/hm²and 566 kg/hm²,with the increase rates of 1.9%and 1.1%respectively.Compared with the single formula fertilizer,the total nutrients of N,P and K of the special formula fertilizers combined with organic fertilizer were reduced by 180kg/hm²,and under the condition which the total nutrients were reduced by 30%,the yield of potato tubers increased by 1 605 kg/hm²with the increase rate of 3.2%.Compared with the single formula fertilizer,the total nutrients of N,P and K of integrated special fertilizer,water-soluble humic acid fertilizer,medium and trace element fertilizer and organic fertilizer application technology were reduced by 180 kg/hm²,and under the condition which the total nutrients were reduced by 30%,the yield of potato tubers increased by2 025 kg/hm²with the increase rate of 4.3%.Therefore,applying potato specific formula fertilizer combined with water-soluble humic acid fertilizer,medium and trace element fertilizer and organic fertilizer can reduce the nutrients by 20%-50%,while maintaining a stable increase in potato output.2. Compared with conventional fertilization,the fertilizer nutrients of different fertilizer reduction techniques decreased by 20%-50%,but the nutrient absorption of potato did not decrease.Moreover,the fertilizer reduction techniques promoted the nutrients transfer from the shoot to the tuber,and increased the nutrient distribution proportion of the tuber.Compared with conventional fertilization,applying special formula fertilizers increased the total accumulation of N,P and K in potato by an average of 15.72,2.43 and 25.06 kg/hm²respectively.And the cumulative distribution rate of N,P and K in tuber increased by 4.08%,2.79%and 3.55%.The cumulative distribution rate of N in potato tuber with special formula fertilizer combined with water-soluble humic acid fertilizer,medium and trace element fertilizers,and organic fertilizer increased by 5.17%,5.26%and 5.51%,respectively,and the cumulative distribution rate of P increased by4.28%,3.88%and 3.97%,the cumulative distribution rate of K increased by 6.05%,5.77%and 6.07%respectively.Integrated special fertilizer,water-soluble humic acid fertilizer,medium and trace element fertilizer and organic fertilizer application technology,the total accumulation of N,P and K in potato was increased by 16.94,4.67 and 22.47kg/hm²,and the cumulative distribution rate of N,P and K in tuber was increased by7.35%,5.67%and 3.34%,respectively.3. Different fertilizer reduction techniques can effectively improve the utilization rate of NPK fertilizer in potato.Compared with conventional fertilization,the N,P and K utilization rates of the special formula fertilizer increased from 24.16%to 36.33%,8.37%to 22.04%and 44.82%to 52.18%respectively.Compared with single application of special formula fertilizers,the N utilization rates of special formula fertilizers combined with water-soluble humic acid fertilizer,medium and trace element fertilizers,and organic fertilizers increased from 36.33%to 40.35%,39.54%and 43.86%,the P utilization rates increased from 22.04%to 24.80%,25.95%and 30.62%,the K utilization rates increased from 52.18%to 58.23%,60.02%and 67.78%.Integrated special fertilizer,water-soluble humic acid fertilizer,medium and trace element fertilizer and organic fertilizer application technology,the N,P and K utilization rates increased from 36.33%to 44.98%,22.04%to 35.53%and 52.18%to 67.24%.Therefore,the key to achieve the goal of fertilizer reduction is to improve the fertilizer utilization rate.4. Different fertilizer reduction techniques can effectively regulate the growth of the shoot of potatoes and promote the growth of tubers.Compared with conventional fertilization,the plant height,stem diameter,and dry weight of each part of the potato by the different techniques of reducing fertilizer did not increase significantly in each growth period,while the tuber yield increased significantly.5. The characteristics of potato’s fertilizer requirement are clarified.The amount of N,P₂O₅and K₂O absorbed per 1 000 kg were 2.26 kg,0.49 kg and 4.78 kg,respectively,with a ratio of 1:0.22:2.11.Different fertilizer reduction techniques had no significant effect on the content of N,P and K in different parts of potato in three periods.During the whole growth period,the nitrogen and phosphorus contents of each part of the potato were leaf>stem>root,and the potassium content was stem>leaf>root.The content of N,P and K in tubers of different grades in maturity stage basically showed as small tuber>large and medium tuber.6. The fertilizer reduction techniques have no significant influence on the quality of tubers of different grades.The dry matter,vitamin C,and starch content of tubers of different grades showed as large and medium tubers>small tubers,while the contents of nitrate,reducing sugar and soluble sugar were small tubers>medium tubers>large tubers.Compared with conventional fertilization,different fertilizer reduction techniques reduced the content of nitrate and increased the content of vitamin C in tubers.It showed that these fertilizer reduction techniques can guarantee the quality of potatoes.