福建甘薯氮磷钾施肥指标研究

Study on Fertilization Index of Nitrogen,Phosphorus and Potassium for Sweet Potato in Fujian

根据近年来在甘薯主产区完成的118个氮磷钾肥效田间试验结果,建立甘薯氮磷钾施肥指标体系,包括甘薯施肥效应和土壤肥力分级、土壤速效氮磷钾丰缺指标、不同产量水平的氮磷钾最佳用量和比例、土测值与最佳施肥量关系式以及施肥时期和施肥方法等5个方面内容。结果表明,土壤对甘薯产量的平均贡献率为62.5%,氮磷钾平均增产效果是N>K>P,均达显著水平;土壤碱解氮、Olsen-P和速效钾的高产临界指标分别为176 mg kg-1、17 mg kg-1和106 mg kg-1;平均经济施肥量是N165kg hm-2、P2O5 63 kg hm-2、K2O 204 kg hm-2,比例为1∶0.38∶1.24,但不同土壤肥力等级的推荐施肥量存在较大差异;土壤速效氮磷钾土测值与最佳施肥量之间满足指数模型,该式实现了根据土测值预测具体地块推荐施肥量的目的。研究结果为福建甘薯高效施肥提供了科学依据。

This paper established a fertilization index of N, P and K for sweet potato production based on 118 field experiments on the fertilizer efficieneies of N, P and K in main production areas of Fujian in recent years. The index included 5 items, such as fertilization effects and soil fertility grading, soil available N, P and K critical indexes, NPK optimum application rate and their proportions in different yield levels, relationship between testing value of soil available NPK and their optimum application rate, and fertilization time and method. Results showed that soil average contribution rate for yield of sweet potato was 62.5%. Applied NPK fertilizers may get significant increasing yield and their average effects ordered as N 〉 K 〉 P. High yield critical value of soil alkali-hydrolyzable N, Olsen-P and available K were 176 mg kg, 17 mg kg and 106 mg kg, respectively. Economic application rates on sweet potato were N 165 kg hm2, P205 63 kg hm2 and K20 204 kg hm2 on average, respectively, and their proportion was 1：0.38：1.24. However, the optimum application rates in different soil fertility grades were different. Relationship between soil available NPK testing value and optimum application rate fitted exponential model, and the model realized intention that the fertilization recommendation for plot according to soil testing. The results provided a scientific foundation for highly effective fertilization on sweet potato production in Fujian.