合成磷源在石灰性潮土中的有效性及氮肥形态对其的影响

采用盆栽试验的方法研究了几种人工合成磷源在两种质地土壤中的有效性及不同氮肥形态对它们有效性影响的机理。研究结果表明 :几种合成磷酸盐在轻壤质和轻粘质潮土中的生物有效性的大小顺序分别为 :磷酸二钙 (DCP) >磷酸八钙 (OCP) >磷酸铝 (Al P) >磷酸铁 (Fe P) >氟磷灰石 (FA)和DCP >Al P >OCP >Fe P >FA。几种人工合成磷源在两种质地土壤中的有效性与土壤中相应形态无机磷的有效性相一致。它们在轻粘质潮土中的生物有效性明显受氮肥形态的影响。配施NH 4 N和CO(NH2 ) 2 时 ,Al P和FA的有效性比配施NO-3 N明显提高。配施NO-3 N可以明显提高Fe P的有效性。它们在配施不同氮肥形态下的生物有效性与不同氮肥形态处理下的根际pH变化密切相关。

AVAILABILITY OF PHOSPHATES AND EFFECT OF DIFFERENT FORMS OF NITROGENOUS FERTIL IZER

Pot trials were conducted to study on availability of several forms of a rtificial mineral phosphate in light loam and light clay calcareous Chao soils, and mechanisms of effects of NH 4 N, CO(NH 2) 2,and NO - 3 N on their availability. The results showed that the order of the five phosphates in avail ability in light loam and light clayed calcareous Chao soils was as follows re spectively: DCP>OCP>Al P>Fe P>FA and DCP>Al P>OCP>Fe P>FA,consisten t with those of the corresponding forms of inorganic in soils. Their availabilit y was markedly affected by forms of nitrogen applied. The availability of Al P and FA coupled with NH 4 N and CO(NH 2) 2 in light clayed soil was obvio usly higher than that with NO - 3 N, while application of NO - 3 N could s ignificantly raised the availability of Fe P. Their availability varies with ni trogenous form and pH in rhizosphere.