Leytem A B, Sims J T, Coale F J
USDA-ARS, North West Irrigation and Soils Research Lab, Kimberly, ID 83341-5076, USA.
J Environ Qual. 2004 Jan-Feb;33(1):380-8. doi: 10.2134/jeq2004.3800.
Phosphorus losses in runoff from application of manures and biosolids to agricultural land are implicated in the degradation of water quality in the Chesapeake and Delaware Inland Bays. We conducted an incubation study to determine the relative P solubility and bioavailability, referred to as P source coefficients (PSCs), for organic P sources, which are typically land-applied in the Mid-Atlantic USA. Nine organic and one inorganic (KH2PO4) P amendments were applied to an Evesboro loamy sand (mesic, coated Typic Quartzipsamments) at a rate of 60 mg P kg(-1) and incubated for 8 wk with subsamples analyzed at 2 and 8 wk. There was an increase in Mehlich-3 P (M3-P), water-soluble P (WS-P), iron-oxide strip extractable P (FeO-P), and Mehlich-3 P saturation ratio (M3-PSR) with P additions, which varied by P source. The trend of relative extractable WS-P, FeO-P, and M3-P generally followed the pattern: inorganic P > liquid and deep pit manures > manures and biosolids treated with metal salts or composted. We found significant differences in the availability of P from varying organic P sources. The use of PSCs may be beneficial when determining the risk of P losses from land application of manures and other organic P sources and could be used in risk assessments such as a P site index. These PSCs may also be useful for determining P application rates when organic P sources are applied to P deficient soils for use as a fertilizer source.
将粪肥和生物固体施用于农田后，径流中的磷流失与切萨皮克湾和特拉华内陆湾的水质退化有关。我们进行了一项培养研究，以确定美国中大西洋地区通常用于土地施用的有机磷源的相对磷溶解度和生物有效性，即磷源系数（PSC）。以60 mg P kg⁻¹的速率向埃夫斯伯勒壤质砂土（潮湿，典型的石英质新成土）施用九种有机磷和一种无机磷（KH₂PO₄）改良剂，并培养8周，在第2周和第8周对亚样本进行分析。随着磷添加量的增加， Mehlich-3磷（M3-P）、水溶性磷（WS-P）、氧化铁条带可提取磷（FeO-P）和Mehlich-3磷饱和度（M3-PSR）均有所增加，且因磷源而异。相对可提取的WS-P、FeO-P和M3-P的趋势通常遵循以下模式：无机磷>液体和深坑粪肥>经金属盐处理或堆肥的粪肥和生物固体。我们发现不同有机磷源的磷有效性存在显著差异。在确定粪肥和其他有机磷源土地施用磷流失风险时，使用磷源系数可能有益，并且可用于诸如磷位点指数等风险评估。当将有机磷源施用于缺磷土壤作为肥料来源时，这些磷源系数也可用于确定磷的施用量。
