Abstract：
Historical applications of manures and fertilizers at rates exceeding crop P removal in the Mid-Atlantic region (United States) have resulted in decades of increased water quality degradation from P losses in agricultural runoff. As such, many growers in this region face restrictions on future P applications. An improved understanding of the fate, transformations, and availability of P is needed to manage P-enriched soils. We paired chemical extractions (i.e., Mehlich-3, water extractable P, and chemical fractionation) with nondestructive methods (i.e., x-ray absorption near edge structure [XANES] spectroscopy and x-ray fluorescence [XRF]) to investigate P dynamics in eight P-enriched Mid-Atlantic soils with various management histories. Chemical fractionation and XRF data were used to support XANES linear combination fits, allowing for identification of various Al, Ca, and Fe phosphates and P sorbed phases in soils amended with fertilizer, poultry litter, or dairy manure. Management history and P speciation were used to make qualitative comparisons between the eight legacy P soils; we also speculate about how P speciation may affect future management of these soils with and without additional P applications. With continued P applications, we expect an increase in semicrystalline Al and Fe-P, P sorbed to Al (hydro)oxides, and insoluble Ca-P species in these soils for all P sources. Under drawdown scenarios, we expect plant P uptake first from semicrystalline Al and Fe phosphates followed by P sorbed phases. Our results can help guide management decisions on coastal plain soils with a history of P application.
摘要：
在大西洋中部地区（美国），肥料和肥料的历史应用速度超过了作物P的去除速度，导致数十年来农业径流中P的损失导致水质恶化。因此，该地区的许多种植者面临着未来P应用的限制。对命运的更好理解，转换，管理富磷土壤需要磷的可用性。我们配对化学萃取(即，Mehlich-3，水萃取P，和化学分馏)使用非破坏性方法(即，边缘结构附近的X射线吸收[XANES]光谱学和X射线荧光[XRF]），以研究具有各种管理历史的八种富含P的中大西洋土壤中的P动力学。化学分馏和XRF数据用于支持XANES线性组合拟合，允许识别各种铝，Ca,以及用肥料改良的土壤中的磷酸铁和磷吸附相，家禽垫料,或乳肥。管理历史和磷形态被用来对八种遗留磷土壤进行定性比较；我们还推测了磷形态如何在有或没有额外施用磷的情况下影响这些土壤的未来管理。随着P的持续应用，我们预计半晶Al和Fe-P会增加，P吸附到Al（氢）氧化物中，以及所有P源在这些土壤中不溶性Ca-P物种。在缩编情况下，我们预计植物首先从半结晶磷酸铝和磷酸铁吸收磷，然后是磷吸附相。我们的结果可以帮助指导具有施用P历史的沿海平原土壤的管理决策。
