[目的]通过比较不同施肥水平下木薯氮磷钾养分积累、分配和产量的差异,探讨粤北坡岗地优质高产木薯氮磷钾养分的最佳用量.[方法]以木薯品种南美119为材料,采用"3414"方案,在粤北翁源进行大田试验.试验共设14个处理.[结果]施肥处理的氮素主要分配到地上部,不施肥处理的氮素则主要分配到根部;不同施肥处理的磷素均主要分配到地上部;不施肥处理和不施钾处理的钾素主要分配到根部,不施氮处理的钾素在根、冠间分配较均衡.在木薯不同生长阶段,植株氮磷钾含量均呈下降趋势,但施氮、磷、钾化学肥料处理植株氮磷钾含量的下降速度小于不施氮、磷、钾化学肥料的处理.处理NPK的氮、磷、钾含量和积累量在各生育期均为最大,不施肥处理(NPK)的氮、磷、钾含量和积累量在各生育期均为最小(PPK处理,为22 694.06 kg·hm,其次是NPK处理,为21 417.87 kg·hm.[结论]木薯产量、氮磷钾养分积累及其在根冠间的分配,对施肥水平高度敏感,适当比例的氮磷钾肥配合施用既可以显著增加木薯植株的氮磷钾含量和积累量,又可以提高产量.在粤北坡岗地木薯生产中,氮素最重要,在氮素得到满足的条件下,磷素较钾素更重要.在本试验条件下,氮磷钾养分最佳用量为358.80 kgN·hm、89.10 kg PO·hm和187.50 kg KO·hm.%[Objective] The present study was carried out to analyze the differences in cassava (Manihot esculenta Crantz) N,P, K accumulation, allocation and yields. The best N, P, K application rates were studied at sloping lands of Wengyuan of North Guangdong. [Method] Cassava genotype South America 119 was used as materials in a field experiment of "3414" conducted in Wengyuan of North Guangdong. The experiment have 14 treatments. [Result] Nitrogen in cassava with fertilizer treatment was mainly treatments allocated to the shoot, and nitrogen in cassava with out fertilizers treatment was mainly allocated to the root.Phosphorus in cassava with N, P, K treatment at different levels was all mainly allocated to the shoot, potassium in treatments of N0P0K0 and N2P2K0 was mainly allocated to root, and potassium in treatment of N0P2K2 was equilibrium in root and shoot. During different growth periods, N, P and K content of cassava all showed a dropping trend, but the falling rate of cassava with N, P and K fertilizer application was less than cassava with no N, P and K fertilizer. Content and accumulation of N, P,K in treatment N2P2K2 were the maximal, and that of treatment N0P0K0 were the lowest among all treatments at each growth stage of cassava (P＜0.05).Among all 14 treatments, yields of N2P3K2 (22 694.06 kg·hm-2) was the highest, followed by N2P2K2 (21 417.87 kg·hm-2).[Conclusion] Cassava yield, N, P, K accumulation, and allocation between root and shoot were highly responsive to N, P, and K fertilization. Applications of combinations of N, P2O5, and K2O in a proper ratio significantly increased cassava concentrations of N,P, K, and yield. For cassava yield in sloping lands of North Guangdong, N is the foremost factor, P2O5 is more important thasn K2O under the conditions of N sufficient. In the present study, the best N P K application rates were 358.80 kgN·hm-2、 89.10 kg P2O5·hm-2 和 187.50 kg K2O·hm-2.
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