环境中磷化氢对水稻根际环境与土壤有效磷的影响研究

以稻田湿地中磷化氢为研究对象,采用室内模拟的方法,考察了不同浓度的磷化氢(0,1.4,4.2,7.0 mg·m-3)对水稻根际与非根际土壤的p H值、氧化还原电位、Fe2+、Mn2+、磷酸酶活性及有效磷的影响.结果表明:磷化氢导致根际土壤p H明显下降,非根际土壤中p H变化不明显.而氧化还原电位(Eh)则不同,磷化氢使水稻根际与非根际土壤的Eh均增大.磷化氢对Fe2+、Mn2+和碱性磷酸酶的影响具有相似性,磷化氢处理的前15 d,根际土壤中的Fe2+、Mn2+和碱性磷酸酶变化不明显,随着水稻的生长,根际土壤中的Fe2+和Mn2+随磷化氢浓度的增大而增加,随暴露时间的增加而减少;而根际土壤中的碱性磷酸酶随磷化氢浓度和暴露时间的增加而增加.非根际土壤中的Fe2+、Mn2+和碱性磷酸酶在磷化氢作用下变化不明显.水稻在磷化氢的环境影响下,根际与非根际土壤的有效磷含量都提高,表明一定浓度的磷化氢对土壤磷表现出活化效应.

Effect of phosphine in the environment on rice rhizosphere and available phosphorus in soil

The effects of phosphine (0, 1.4, 4.2, and 7.0 mg · m^-3) on pH, E_h, Fe²⁺, Mn²⁺, the alkaline phosphatase activity and available phosphorus content in the rhizosphere and non-rhizosphere soil of rice seedlings were investigated in laboratory tests. The results indicated that pH in the rhizosphere soil dropped obviously but kept nearly constant in the non-rhizosphere soil. E_h in the rhizosphere and non-rhizosphere soil both increased under the treatments of phosphine. The effects of phosphine on Fe²⁺, Mn²⁺ and alkaline phosphatase were similar. In the first two weeks, changes of these factors were not significant, with the growth of rice and the contents of Fe²⁺ and Mn²⁺ increasing with the increase of phosphine concentration and decreasing with the increment of exposure time; Alkaline phosphatase activity in the rhizosphere soil increased with the increase of phosphine concentration and exposure time. The changes of Fe²⁺, Mn²⁺ and alkaline phosphatase activity in the non-rhizosphere soil were not obvious. Moreover, the content of available phosphorus in the rhizosphere and non-rhizosphere soil of rice seedlings improved under phosphine exposure, indicating that a certain concentration of phosphine caused activation of soil phosphorus.