Effects of soil drying and rate of re-wetting on concentrations and forms of phosphorus in leachate
Effects of soil drying and rate of re-wetting on concentrations and forms of phosphorus in leachate
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DOI：
10.1007/s00374-009-0375-x
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发表时间：
2009-07-01
影响因子：
6.5
通讯作者：
Haygarth, P. M.
中科院分区：
文献类型：
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作者：
Blackwell, M. S. A.;Brookes, P. C.;Haygarth, P. M.
土壤的干燥和再润湿会导致养分的数量和形式发生变化，这些养分可以通过渗滤液从土壤转移到地表水。我们在实验室条件下测试了以下假设：干燥土壤的再润湿率会影响渗滤液中不同形式磷 (P) 的溶解度和浓度。将草原 pelostagnogley 土壤的一部分（筛分的湿度 < 2 mm）在 35°C 下干燥，另一部分保持约 40% 的持水能力。在 0、2、4、24 和 48 小时内，以 10 个规则间隔的时间间隔以 2.5 毫升等分试样向两种土壤的表面添加水（25 毫升），从而产生不同的施用率。收集渗滤液并分析溶解的（< 0.45μm）和颗粒总磷以及钼酸盐反应性和非反应性磷。再润湿率显着改变了渗滤液中磷的浓度，尤其是溶解形式。 2 小时处理渗滤液中溶解磷浓度最高，而 0 小时处理渗滤液中颗粒磷浓度最高。在所有情况下，大多数磷都是不反应的，因此很可能是有机形式。土壤干燥减少了微生物生物量，但这与渗滤液中磷的增加没有直接关系。这些结果表明，气候变化情景预测的降雨频率和强度模式的变化可能会显着影响土壤中磷的浸出量。
The drying and re-wetting of soils can result in the modification of the amounts and forms of nutrients which can transfer, via leachate, from the soil to surface waters. We tested, under laboratory conditions, the hypothesis that the rate of re-wetting of a dried soil affects the solubilisation and concentrations of different forms of phosphorus (P) in leachate. A portion of grassland pelostagnogley soil (sieved moist < 2 mm) was dried at 35A degrees C and another portion maintained at approximately 40% water-holding capacity. Water (25 ml) was added at ten regularly spaced time intervals in 2.5-ml aliquots to the surfaces of both soils over periods of 0, 2, 4, 24 and 48 h, resulting in different rates of application. The leachate was collected and analysed for dissolved (< 0.45 mu m) and particulate total P and molybdate reactive and unreactive P. The rate of re-wetting significantly changed the concentrations of P, especially dissolved forms, in the leachate. Dissolved P concentrations were highest in leachate from the 2-h treatment, while particulate P concentrations were highest in the 0-h treatment leachate. In all cases, most P was unreactive and, therefore, likely to be in an organic form. Soil drying decreased microbial biomass, but this could not be directly linked to an increase of P in leachate. These results suggest that changes in patterns of rainfall frequency and intensity predicted by climate change scenarios could significantly affect the quantities of P leached from soils.