通过大田和盆栽试验,探讨了在水稻种植过程中土壤水分含量和施磷量对简育水耕人为土中磷素形态的影响。结果表明:土壤中不同形态无机磷含量占无机磷总量的顺序为O-P〉Fe-P〉Al-P〉Ca—P;随着水稻栽种时间的延长、土壤含水量和施磷量的降低,土壤Al—P、Fe-P和Ca-P含量下降,O-P含量则上升。大田试验中,土壤水分含量仅对水稻生长初期和后期的Ca-P以及中期的O-P影响显著,而对其他水稻生长期下土壤Al-P、Fe—P影响不显著;施磷量与红壤无机磷组分存在显著的相关。盆栽试验中土壤水分含量对无机磷形态的影响均不显著;施磷量与Al-P、Fe-P和水稻生长初期、中期的Ca—P含量有显著的正相关作用,而对后期的Ca—P和O-P的影响不显著。水分含量和施磷量对土壤四种形态的无机磷存在显著的交互作用。
Effects of soil moisture contents and phosphorus (P) application rate on form of soil inorganic P in red paddy soil were investigated through pot and field experiments. Results show in terms of percentage against the total P, inorganic P of different forms were lined in a decreasing order of O-P 〉 Fe-P 〉 Al-P 〉 Ca-P. In the pot experiment, with increasing days of rice growth or increasing soil moisture and P application rate, contents of Al-P, Fe-P and Ca-P decreased, but content of O-P increased, whereas, in the field experiment, the effect of soil moisture content was markedly observed only on Ca-P in the early and late rice growth periods and on O-P in the mid grwoth period, and nothing was on Al-P and Fe-P. Compostion of soil inorganic P was closed related with P application rate. In the pot experiment, the effect of soil moisture on soil inorganic P, regardless of form, was not as significant, while the effect of P application rate was significantly positive on Al-P and Fe-P in the early rice growth periods, and on Ca-P in the mid growth period, but little on O-P and Ca-P in the late growth period. Furthermore, the effect of interaction between soil moisture and P application rate was distinct on the four forms of inorganic P.