Sources and Pathways of Formation of Recalcitrant and Residual Phosphorus in an Agricultural Soil
Sources and Pathways of Formation of Recalcitrant and Residual Phosphorus in an Agricultural Soil
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DOI：
10.3390/soilsystems2030045
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发表时间：
2018-09-01
期刊：
影响因子：
3.5
通讯作者：
Jaisi, Deb P.
中科院分区：
文献类型：
--
作者：
Joshi, Sunendra R.;Li, Wei;Jaisi, Deb P.
磷是维持生命和农业生产所必需的营养物质。将易于获得的磷转化为植物无法获得的形式，增加了补磷的成本，最终导致农艺效益降低，土壤磷进入径流的潜在损失可能会降低水质。因此，了解土壤中残余磷库的来源和形成途径是开发任何技术或管理工作所需的有用信息，以尽量减少或抑制这种磷库的形成，从而最大限度地提高植物的可利用性。在这项研究中，我们将磷酸盐氧同位素比率（δ (18)Op）与固态P-31核磁共振和定量XRD技术以及一般土壤化学方法配对，以确定酸提取的无机P （Pi）池在农业土壤中的沉淀途径。通过对0.5 mol L-1 NaOH-P-i、1 mol L-1 HCl-P-i和10 mol L-1 HNO3-P-i池同位素值的比较以及这些池中伴生元素（Ca、Fe和Al）的相关性分析，认为HNO3-P-i池最有可能由NaOH-P-i池转化而来。在浅层（耕作深度）和以下（没有物理混合的地方），酸性磷-i池的同位素值范围很窄，这很有趣，但可能表明在较深的土壤中，颗粒结合的磷被浸出。总的来说，这些发现提供了对农业土壤中酸性磷-i库的来源、运输和转化的更好理解，并进一步了解土壤中遗留磷的积累。
Phosphorus (P) is an essential nutrient for sustaining life and agricultural production. Transformation of readily available P into forms that are unavailable to plants adds costs to P replenishment, which eventually translates into lower agronomic benefits and potential loss of soil P into runoff may degrade water quality. Therefore, understanding the sources and pathways of the formation of residual P pools in soils is useful information needed for the development of any technological or management efforts to minimize or inhibit the formation of such P pool and thus maximize availability to plants. In this research, we paired phosphate oxygen isotope ratios (delta(18)Op) with solid-state P-31 NMR and quantitative XRD techniques along with general soil chemistry methods to identify the precipitation pathways of acid-extracted inorganic P (Pi) pools in an agricultural soil. Based on the comparison of isotope values of 0.5 mol L-1 NaOH-P-i, 1 mol L-1 HCl-P-i, and 10 mol L-1 HNO3-P-i pools and correlations of associated elements (Ca, Fe, and Al) in these pools, the HNO3-P-i pool appears most likely to be transformed from the NaOH-P-i pool. A narrow range of isotope values of acid-P-i pools in shallow (tilling depth) and below (where physical mixing is absent) is intriguing but likely suggests leaching of particle-bound P in deeper soils. Overall, these findings provide an improved understanding of the sources, transport, and transformation of acid-P-i pools in agricultural soils and further insights into the buildup of legacy P in soils.