Phosphorus dynamics in soils irrigated with reclaimed waste water or fresh water — A study using oxygen isotopic composition of phosphate
Phosphorus dynamics in soils irrigated with reclaimed waste water or fresh water — A study using oxygen isotopic composition of phosphate
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DOI：
10.1016/j.geoderma.2010.07.002
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发表时间：
2010-10
期刊：
影响因子：
6.1
通讯作者：
I. Zohar;A. Shaviv;M. Young;C. Kendall;S. Silva;A. Paytan
中科院分区：
文献类型：
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作者：
I. Zohar;A. Shaviv;M. Young;C. Kendall;S. Silva;A. Paytan
利用磷中氧稳定同位素组成（δ18Op）和磷（Pi）浓度，追踪了不同土壤组分中磷（Pi）的转化。来自以色列的粘土用回收的废水（二级，低级）或用已知同位素特征的化学肥料修正的淡水处理。在一个月的培养过程中，不同土壤组分中的δ 18Op和Pi的变化阐明了土壤中的地球化学过程，揭示了影响各种P库的生物和化学转化。土壤溶液中的磷主要受酶活性的影响，酶活性与土壤溶液中的水分子产生同位素平衡。溶解的P与松散结合的P（由碳酸氢盐提取）迅速相互作用。被认为是相对稳定的磷池的氧化物和矿物磷组分（分别用NaOH和HCl提取）在施磷后的前两周也表现出同位素变化，这可能与土壤表面微生物种群的活性有关。具体而言，同位素贫化，这可能导致有机磷矿化，其次是同位素富集，这可能导致从优先生物吸收贫化P从矿化池。在两种土壤中观察到类似的转化，虽然与生物活性相关的转化在用再生废水处理的土壤中比用肥料处理的土壤中更明显。
Transformations of phosphate (Pi) in different soil fractions were tracked using the stable isotopic composition of oxygen in phosphate (δ18Op) and Pi concentrations. Clay soil from Israel was treated with either reclaimed waste water (secondary, low grade) or with fresh water amended with a chemical fertilizer of a known isotopic signature. Changes of δ18Opand Pi within different soil fractions, during a month of incubation, elucidate biogeochemical processes in the soil, revealing the biological and the chemical transformation impacting the various P pools. P in the soil solution is affected primarily by enzymatic activity that yields isotopic equilibrium with the water molecules in the soil solution. The dissolved P interacts rapidly with the loosely bound P (extracted by bicarbonate). The oxides and mineral P fractions (extracted by NaOH and HCl, respectively), which are considered as relatively stable pools of P, also exhibited isotopic alterations in the first two weeks after P application, likely related to the activity of microbial populations associated with soil surfaces. Specifically, isotopic depletion which could result from organic P mineralization was followed by isotopic enrichment which could result from preferential biological uptake of depleted P from the mineralized pool. Similar transformations were observed in both soils although transformations related to biological activity were more pronounced in the soil treated with reclaimed waste water compared to the fertilizer treated soil.