水稻旱作下土壤水分状况和施用磷肥对红壤有效磷含量的影响

通过盆栽和模拟实验探讨了水分状况和施磷量对红壤有效磷的影响。结果表明,水分状况和施磷量均显著地影响红壤有效磷含量,二者的交互作用达极显著水平;同时也均显著地影响水稻生物量和对磷的吸收量,二者的交互作用达显著和极显著水平。红壤有效磷含量基本上随红壤水分含量和施磷量的增加而提高,随水稻生长时间的延长而降低;水稻的生物量和对磷的吸收量均随施磷量的增加和水稻生长时间的延长而增加,但以中水条件下最高。在保证80%的饱和持水量和常规氮、钾等养分投入条件下,施磷量为67.5 kg hm-2就可以满足水稻旱作的生长需求。

Effect of soil moisture and phosphorus application on concentration of available phosphorus in red soil under aerobic rice cultivation

Pot and incubation experiments were carried out to study effects of soil moisture and phosphorus (P) application on soil available P concentration in a new rice cultivation system, i.e. aerobic cultivation of rice crop. In the experiments, significant effects were observed of both soil moisture and P fertilization, and more of the interaction between the two, on soil available P concentration, and on biomass and P uptake by rice, as well. The concentration of soil available P in the tested soil increased with increasing soil moisture and P application rate, but decreased with growth of rice. Biomass and P uptake of rice increased with increasing P application rate and growth period of the crop, and peaked when soil moisture was moderate in content. Therefore, when the rice field is ensured soil moisture being 80% of the soil saturation moisture capacity and conventional N and K input, P application at 67.5 kg hm-2 is adequate to meet the P requirement of rice for growth in aerobic soil.