| NPK are essential nutrient element and related to growth of sweet potato closely and they play a key regulatory role on tuber differentiation and yield formation of sweet potato. The research is from 2009 to 2011, choosing areas of sweet potato of the middle and lower reaches of Yangtze river including of Jiangsu Province, Anhui province and Hubei province, to study the nutrient absorption and optimization fertilizer of the seleced local sweet potato cultivals, the results show that: ? The nutrient absorption law and optimization fertilization dosage of Ningzi 1The stimulation effect of NK was significantly of Ningzi 1, and compared with the treatment with no NK application, the average yield of 40.82%,37.95%?respectively, The increasing effect of N was higher than K; The absorption of potassium of the part on the ground and nitrogen were increased firstly and then decreased with the increase of NK application, with the nitrogen rate of 180kg/hm~2and potassium of 337.5 kg/hm~2 treatment got the highest yield, respectively and potassium uptake of the root increased as K application rate increasing. The nitrogen utilization efficiency is from 15.80?40.09%, while increasing of nitrogen fertilizer yield of sweet potato was decreased, the potassium utilization efficiency is in the range of 12.72?22.06%, the potassium utilization efficiency of Ningzi 1 was without obvious regularity with Potassium application.Under different NK application levels, the demand relations of the three elements of NPK is K>N>P; Nutrient uptake for Ningzi 1 to yield 100 kg tubers under different soil fertility conditions is 5.86-7.12kg, N:P2O5:K2O= 1:0.71-0.81:2.50-2.73; the recommended N application amount was 100?180kg/hm~2, and the recommended K application amount was 200-300kg/hm~2. ?The nutrient absorption law and optimization fertilization dosage of SushuNo.8The yield of SushuNo.8 increased firstly then decreased with the increament of NPK application, compared with the treatment with no NPK, the treatment with NPK's average increasing effect were 32.19%,4.70% and 16.19%, the stimulation effect was N>K>P; N and K nutrient uptake of sushuNo.8 was effected significantly by NK application levels, the N and K nutrient absorption was increased with the increament of N and K application of sushuNo.8, but the P nutrient absorption decreased with the increament of P application; The N and P and K utilization efficiency of sushuNo.8 is negatively correlated with N and P and K application amount.Under different NPK application levels, the treatment of the maximum yield's nutrient uptake of Sushu No.8 to yield 100 kg tubers of NPK in a total is 3.81-7.09 kg, N:P2O5: K2O=1:0.44?1.08:1.03?1.98; The recommended N application amount of SushuNo.8 was 100-200 kg/hm~2, the recommended P application amount was 75-100kg/hm~2, recommended K application amount was 150-210kg/hm~2. ?The nutrient absorption law and optimization fertilization dosage of Eshu No.6 and Eshu No.7Under the different of NK application levels, the yield of Eshu No.6 was increased firstly and then decreased with the increament of NK application, the yield of Eshu No.6 was increased gradually with the increament of P application. Compared with the treatment of with no NPK, the treatment of with NPK of eshu No.6 average increasing effect was 106.06%,11.63% and 17.95%. NPK was significant influence on the yield of Eshu No.7, the yield of Eshu No.7 increased with the increament of NP application, while the yield of Eshu No.7 increased firstly and then decreased gradually with the increament of K application. The stimulation effect of NPK of eshu No.7 was 94.57%,26.19% and 20.60%. Under different NPK application levels, the root of Eshu N0.6 and Eshu No.7's NPK nutrient absorption were increased with growth period of development, and Eshu No.6 reached the absorption peak at day after planted 120, Eshu No.7 reached the absorption peak at day after plant 90.Nutrient uptake for EshuNo.6 to yield 100 kg tubers under different soil fertility conditions is 1.86~2.59 kg, N:P2O5:K2O= 1:0.13-0.22:1.14-1.82, Eshu No.6's optimized N application amount was 100-200kg/hm~2, optimized P2O5 application amount was 50?100 kg/hm~2, optimized K2O application amount was 200?250 kg/hm~2, and Eshu No.7 optimized N application amount was 200?280 kg/hm~2, optimized P2O5 application amount was 50?100 kg/hm~2, optimized K2O application amount was 250-350 kg/hm~2.Therefore, in the area of Middle and lower reaches of Yangtze River, Nutrient uptake for sweet potatoe to yield 100 kg tubers under different soil fertility conditions is aboutl.86?7.12kg, average is 4.11kg, N:P2O5:K2O= 1:0.13?1.08:1.03?2.73; optimized N application amount was 100?200 kg/hm, optimized P2O5 application amount was 50-100kg/hm~2, optimized K2O application amount was 200?250 kg/hm~2. In addition, when apply fertilizer on sweet potato, should according to the local soil conditions, formula fertilization by soil testing, achieve apply the fertilizer because it required, not only meet the nutrient requirements of sweet potato, and but also saving resources and reducing waste. |
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