【摘要】 通过室内培养试验,发现不同氮肥处理对污染红壤中铜有效性有显著影响。在培养前期(0~15 d),施用尿素显著降低了红壤水溶态铜和有效态铜含量,而施用硫酸铵和硝酸钙则显著提高了水溶态铜含量,且硝酸钙的作用显著大于硫酸铵,但这两种氮肥对红壤有效态铜含量影响较小;培养60 d后,尿素对该红壤两种形态铜的抑制效应逐渐转为正效应,且硫酸铵的促进作用更为显著;硝酸钙对红壤两种形态铜的促进作用不如尿素。氮肥的施用量对两种形态铜也具有显著影响。同一施氮水平下,水溶态铜含量和有效态铜含量在不同氮肥处理间均达显著差异(硫酸铵>尿素>硝酸钙)。不同氮肥影响红壤铜有效性的主要机制是土壤pH的变化,红壤水溶态铜和有效态铜含量均与pH呈极显著负相关。更多还原

【Abstract】 Effect of forms of N fertilizers on Cu bioavailablity in a contaminated red soil was investigated.Results show that contents of water-soluble and available Cu varied with the forms of N fertilizer.At the first days of cultivation,the application of CO(NH2)2 significantly decreased the two fractions of soil Cu,while the addition of(NH4)2SO4 and Ca(NO3)2 increased water-soluble Cu,and the effect of the latter was much higher than the former.But the two forms of N did not have as much effect on available Cu.After 60 days’ cultivation,the negative effect of CO(NH2)2 on the two fractions of Cu turned to be positive,and the positive effect of(NH4)2SO4 was further more enhanced.The positive effect of Ca(NO3)2 on the two fractions of Cu was,however,less than that of CO(NH2)2.The two fractions of Cu also varied sharply with the application rates of nitrogen fertilizer.When N levels were kept the same,the effect of N fertilizer on both water-soluble and available Cu differed significantly,showing an order of(NH4)2SO4 > CO(NH2)2 > Ca(NO3)2.The change in soil pH led to different effect of different N on Cu bioavailability.Significant negative correlation was observed between pH and two fractions of Cu.更多还原