富钾土壤中氮、磷肥不同水平对甘薯生长及产量的影响

试验研究了氮肥、磷肥不同水平对甘薯生长发育动态、产量的影响。结果表明,在氮肥试验中,氮水平为75 kg/hm2处理的薯块鲜质量和茎叶鲜质量都达到最大,鲜薯产量达51 519.25 kg/hm2,单株结薯数达5.0个,商品薯率为89.43%,平均单株薯质量为1084.71g;氮水平小于等于75 kg/hm2处理的薯块鲜质量和茎叶鲜质量均随着施氮水平的提高而提高;氮水平大于等于75 kg/hm2处理薯块鲜质量和茎叶鲜质量随着施氮水平的升高急剧下降。在磷肥试验中,磷用量为135 kg/hm2时,鲜薯产量最大,为46 802.35 kg/hm2,单株结薯数为4.65个,商品薯率为91.0%,平均单株薯质量为978.0 g;磷水平低于135 kg/hm2时,随着磷用量的提高产量逐渐增大,磷水平高于135 kg/hm2时,随着磷用量的提高产量降低。合理施肥是甘薯增产增收栽培的有效措施。

Effect of Nitrogen and Phosphorus on Growth and Yield of Sweet Potato in Potassium-rich Soil

Field experiments were conducted to study the nitrogen and phosphorus fertilization on growth dynamics and tube production of sweet potato. The nitrogen test showed that fresh weight of tuber and aboveground parts reached the maximum in the plants treated with 75 kg/hm^2nitrogen, and the fresh potato yield was 51 519.25 kg/hm^2. In addition, the tuber number per plant was 5.0,commodity potato proportion was 89.43%, and the average weight of tuber per plant was 1 084.71 g. Further studies showed that the total biomass, increased as the nitrogen level rising under low fertilization rate（nitrogen≤75 kg/hm^2）, sharply decreased under high fertilization rate（nitrogen≥75 kg/hm^2）. The other fertilization experiment revealed that the maximum of potato production was 46 802.35 kg/hm^2 at the level of 135.0 kg/hm^2phosphate. And the number of tubers per plant was 4.65, commodity potato proportion was 91.0%, the weight of tubers per plant was 978.0 g. Under low phosphorus rate（≤135.0 kg/hm^2）, tuber yield increased as the application of phosphate.However, the production was significantly declined if the dosage of phosphorus was more than 135.0 kg/hm^2. This study suggested that, for optimum sweet potato yield and income, rational fertilization of nitrogen and phosphorus was very important.