不同磷水平下玉米-大豆间作对红壤无机磷组分及有效磷的影响

通过2年盆栽试验，探讨不同磷水平下玉米–大豆间作根际土壤无机磷组分、土壤有效磷含量及作物磷吸收的差异，明确土壤无机磷组分、土壤有效磷与作物磷吸收之间的相互关系。试验设置玉米单作、大豆单作、玉米–大豆间作3种种植方式以及3个P2O5施用水平(0、50、100 mg/kg，分别记作P0、P50、P100)，共9个处理。结果表明：与单作相比，2018年和2019年在P0、P50和P100水平下，间作显著提高玉米和大豆的籽粒产量，并显著提高玉米和大豆植株的磷素吸收量。与常规施磷水平(P100)下的单作处理相比，玉米–大豆间作在磷肥减少50%(P50)的条件下，并未降低玉米和大豆的磷吸收量与籽粒产量。3个磷水平下，间作提高了玉米和大豆根际土壤有效磷含量，而降低了根际土壤总无机磷以及Fe-P、Al-P、Ca-P、O-P的含量；同时适当增施磷肥显著提高了玉米和大豆根际土壤总无机磷及各无机磷组分的含量。本试验条件下，间作促进土壤中Fe-P、Al-P、Ca-P和O-P的活化(尤其是Fe-P)，是低磷胁迫下间作土壤有效磷含量与作物磷吸收量增加的重要原因。玉米–大豆间作具有节约磷肥、维持作物产量及根际土壤有...

Effects of Maize and Soybean Intercropping on Inorganic Phosphorus Forms and Available Phosphorus in Red Soil Under Different Phosphorus Levels

2-year pot experiments were conducted to investigate the effect of inorganic phosphorus forms in red soil in maize and soybean intercropping under different phosphorus levels, and studied the relationship between soil available phosphorus and various forms of inorganic phosphorus by path analysis and stepwise regression analysis. The results showed that compared with monocropping, intercropping increased soil available phosphorus content of maize and soybean under P0, P50 and P100 levels by 7.66%, 30.26%, 4.97% and 43.08%, 36.61%, 29.76% in 2018 and by 9.12%, 26.50%, 28.53% and 22.22%, 30.21%, 26.34% in 2019, respectively. Theavailable phosphorus contents of intercropped maize and soybean were not declined in the P50 level, compared to corresponding monocropping in P100 level. Intercropping decreased the contents of total inorganic phosphorus in rhizosphere soil of maize and soybean by 8.71%, 7.66% and 7.67%, 8.16% compared to monocropping, respectively, and mainly due to the decrease of Fe-P and o-P contents in soil inorganic phosphorus components. A significant positive correlation was observed between soil available phosphorus and each inorganic phosphorus form, and O-P exhibited the most significant effect on soil available phosphorus. Under this experimental condition, maize and soybean intercropping could increase the content of available phosphorus by promoting the activation of Fe-P and O-P in soil inorganic phosphorus. Maize-soybean intercropping has the potential to save phosphorus fertilizer while maintain soil available phosphorus.