黄土高原刺槐人工林根际和非根际土壤磷酸酶活性对模拟降水变化的响应

Responses of Phosphatase Activity in Rhizosphere and Non-rhizosphere Soils to Simulated Precipitation Changes in Planted Robinia pseudoacacia Forest on the Loess Plateau

利用野外控制穿透雨试验,分析了7个降水梯度处理(增水20%,60%,80%,减水20%,60%,80%和对照)对黄土高原刺槐人工林根际和非根际土碱性磷酸酶活性的影响。结果表明:0—20 cm和20—40 cm土层增水处理的根际土磷酸酶活性分别比对照处理高55.9%和88.3%,非根际土磷酸酶活性分别高109%和121%。减水处理的土壤磷酸酶活性没有明显低于对照,但是显著低于增水处理。0—20 cm的土壤磷酸酶活性在3个增水梯度上根际间差异不显著,但在3个减水梯度上差异显著。磷酸酶活性与土壤含水量和土壤有机磷含量均呈显著正相关关系。上述结果说明在半干旱地区短期降水增加对土壤磷酸酶活性的影响比短期干旱的影响大,降水变化可以通过影响土壤含水量、土壤有机磷和生物量改变土壤磷酸酶活性。研究降水对土壤酶活性的影响对气候变化下黄土高原植被恢复具有重要意义。

This study investigated the responses of phosphatase in rhizosphere and non-rhizosphere soils in a planted Robinia pseudoacacia forest on the Loess Plateau via a manipulative throughfall experiment.Increased precipitation enhanced the phosphatase activities in rhizosphere soils by 55.9%and 88.3%in 0—20 and 20—40 cm layers,respectively.Increased precipitation also enhanced the phosphatase activities in non-rhizosphere soils by 109%and 121%,respectively.In contrast,deceased precipitation was not significantly lower than the control but obviously lower than increased precipitation.The difference of soil phosphatase activity between rhizosphere and non-rhizosphere in 0—20 cm layer was not significant across the precipitation gradients,but significant across the drought gradients.Soil phosphatase activity was positively correlated with both soil water content and soil organic phosphorus content.These results indicated that precipitation increase more affected the soil phosphatase activities than drought in a short time in semi-arid region.Changing precipitation affected soil phosphatase activity through impact on soil moisture,soil organic phosphorus and biomass.It was important for vegetation restoration in planted forest on the loess under global climate change to study the influence of precipitation on soil phosphatase activity.