肥料运筹对砂姜黑土甘薯生长和产量的影响

氮肥氮肥易引起甘薯徒长而使产量下降，生产上农民一般采用较低施氮量确保甘薯稳产，但也影响了甘薯产量潜力的发挥。笔者通过田间试验研究了施肥量和钾肥品种运筹对砂姜黑土甘薯生长和产量的影响，为甘薯高产创建提供施肥依据。试验表明：施肥促进甘薯地上部生长大于促进块根的生长，且施肥量越大，根冠比下降越多。全部用硫酸钾高量施肥1导致甘薯地上部徒长，与习惯施肥相比，甘薯减产3.7%；钾肥一半用氯化钾的高量施肥2处理能使甘薯地上部和地下部协调生长，甘薯比习惯施肥增产6.2%，比高量施肥1增产10.4%，达显著差异水平。将习惯施肥氮肥用量124.5 kg/hm2提高到225 kg/hm2时，氯化钾是“忌氯”作物甘薯产量进一步提高关键，与单施硫酸钾相比，氯化钾与硫酸钾配施显著提高了甘薯N、P、K养分利用效率。试验表明砂姜黑土区甘薯不施含氯钾肥的习惯施肥不利于甘薯的高产，甘薯钾肥品种运筹值得进一步深入研究。

Influences of Fertilizing Management on Sweet Potato Production Cultivated on Lime Concretion Black Soil

Nitrogen fertilization tends to cause over-growth of sweet potatoes and leads to the yield decrease. Pragmatically, farmers apply relatively low quantity of nitrogen fertilizers to guarantee their sweet potato yield. In doing so, the insufficient application of nitrogen limits their yield potential. In this study, field experiments were designed to understand the relationships between fertilizing management (i.e. different amount of nitrogen and different potassium formulas) and yield and growth of sweet potatoes cultivated on lime concretion black soil. The results could be used to establish an optimal fertilization strategy for high yield sweet potato production. Results showed that fertilization promoted the growth of above-ground organs more than the underground tubers. More fertilizers applied, greater the differences were. In Treatment 1, which was applied with high amount of potassium sulfate (K2SO4) as the only potassium source, the over-growth of above-ground organs was observed. Yield was 3.7% decreased compared with the local fertilizing tradition. In Treatment 2, where half of the potassium was applied as potassium chloride (KCl), could realize a balanced growth promotion in both the underground and above-ground organs. Such fertilization gained 6.2% of yield increase compared with the traditional fertilization, and 10.4% yield increase compared with Treatment 1. Once the nitrogen was increased from 124.5 kg/hm2 in the traditional fertilization to 225 kg/hm2, potassium chloride was proved to be the key nutrition element of yield increase. Compared with solo potassium sulfate application, integration of potassium chloride and potassium sulfate significantly increased the absorption of various nutrients, such as nitrogen, phosphorus and potassium. Results suggested that the traditional fertilization for sweet potatoes cultivated on lime concretion black soil, which applied non-chloride potassium fertilizers, limited the yield increase of the crop. Further studies were thus needed to establish an optimal strategy of potassium fertilization for high yield sweet potato production.