有机肥施用对珠三角菜地土壤磷污染风险的初步研究

通过田间小区试验研究有机肥施用量对菜心产量、土壤磷形态的影响,分析土壤磷形态之间的相关性,评估菜地红壤磷污染风险。结果表明,有机肥施用并未提高菜心的产量和生物量,而超过一定使用量之后,反而降低菜心产量和生物量;土壤无机磷形态以Fe-P和Al-P为主,占土壤无机磷质量分数的90%以上。有机肥施用提高土壤各形态无机磷的质量分数,且有机肥用量越高,土壤Fe-P、Al-P、Ca-P和O-P质量分数越高。有机肥过量施用显著提高土壤速效磷和水溶性磷质量分数;分别对Olsen-P和CaCl2-P与各形态磷进行逐步回归分析,只有Olsen-P和CaCl2-P与Ca-P具有线性关系（p〈0.05）,方程为Y1=36.95＋0.622 1X,Y2=-0.102 5＋0.048 6X。表明施用有机肥下,Ca-P是菜地土壤有效磷的最直接来源,可以作为红壤磷污染风险评价指标。

Pollution risks of phosphorus in vegetable field soil by application of organic fertilizer

Effect of organic fertilizer application on yield of flowering Chinese cabbage and phosphorus forms were studied in field plot experiment, and contamination risks of vegetable soil phosphorus were evaluated. The results showed that the yield and biomass did not increase while both decreased significantly by excessive application of organic fertilizer. The Fe-P and A1-P were main available phosphorus forms and accounted for more than 90% in vegetable soils. The contents of inorganic phosphorus fractions of vegetable soil were increased using of organic manure, and the larger the amount of application, the greater change of Fe-P, A1-P, Ca-P and O-P. The excessive organic fertilization will lead to the significantly increasing of Olsen-P and CaC12-P, which will increase pollution risk of soil phosphorus. By using progressive regression analysis, it showed that there was the linear relationship between Ca-P and Olsen-P, also wise Ca-P was significantly correlated with CaC12-P（p〈0.05）. The regression equation is Y1=36.95＋0.622 1X and Y2= -0.102 5＋0.048 6X. Ca-P was main source of soil available phosphorus in vegetable soil