PHOSPHORUS AVAILABILITY WITH ALKALINE/CALCAREOUS SOIL
PHOSPHORUS AVAILABILITY WITH ALKALINE/CALCAREOUS SOIL
复制标题
碱性/钙质土壤中磷的有效性
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
J. Ellsworth
中科院分区：
文献类型：
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作者：
B. Hopkins;J. Ellsworth
磷是植物正常生长发育所必需的营养元素。在碱性和石灰性土壤中，由于形成难溶的磷酸钙矿物，植物吸收和利用磷的有效性受到损害。在干旱和半干旱地区常见的这些土壤中，以“正常”比率和常规方法添加肥料磷可能不会导致最佳产量和作物质量。已经发现了几种肥料磷管理策略来改善碱性和石灰性土壤中生长的植物的磷营养。研究结果表明，在碱性土壤中生长的作物需要相对较高的磷肥用量，随着这些土壤中石灰含量的增加，所需的磷肥用量也增加。浓缩的磷肥带提高了磷的溶解度，从而提高了产量，即使施用于生长在土壤测试磷浓度相对较高的土壤中的作物。以生物固体或液体磷与腐殖物质的混合物形式施用有机络合磷也可以增强磷营养并导致产量增加。施用缓释和阳离子络合专用肥料磷材料也被证明可以有效地提高石灰性土壤的产量。当磷素缺乏时，通过灌溉水施用的磷素可以将磷素输送到植物根部，但效果和效果不如土壤中的磷素。最后，重要的是保持P与其他营养素的适当平衡，以确保植物的健康，并避免过量的营养素导致其他营养素的缺乏。在某些情况下，这些方法是相对较新的，需要进一步完善方面的利率，时间和技术，但都是潜在的方法，提高磷供应植物生长在碱性和石灰性土壤。磷（P）是一种必需的常量营养素，植物需要相对大量的磷（约0.2%至0.8%）（Mengel和柯克比，1987年;米尔斯和琼斯，1996年）。钾和氮是唯一需要比P量更大的矿物质营养素。为植物提供足够的P可能很困难，特别是在碱性和石灰性土壤中。碱性土壤被定义为pH大于中性的土壤，通常为7.5至8.5。石灰性土壤的定义是存在大量过量的游离石灰（碳酸钙或碳酸镁）。石灰在中性至酸性pH土壤中溶解，但在碱性土壤中不容易溶解，而是作为表面吸附磷酸钙沉淀的汇。磷的生物有效性与土壤pH值密切相关。铁和铝磷酸盐矿物的形成导致磷在强酸性土壤中的溶解度降低，随着pH值接近中性而提高。这种最大的溶解度和植物有效性的P在pH值为6.5下降再次作为pH值增加到碱性范围。碱性土壤中磷有效性降低的这种效应是由磷与钙的反应驱动的，这些磷酸钙矿物质在pH 8左右的溶解度最低。石灰在碱性土壤中的存在进一步
Phosphorus (P) is an essential nutrient required by plants for normal growth and development. The availability of P to plants for uptake and utilization is impaired in alkaline and calcareous soil due to the formation of poorly soluble calcium phosphate minerals. Adding fertilizer P at “normal” rates and with conventional methods may not result in optimal yield and crop quality in these soils common in arid and semi-arid regions. Several fertilizer P management strategies have been found to improve P nutrition for plants grown in alkaline and calcareous soil. Research results show that relatively high P fertilizer rates are required for crops grown in alkaline soil, with increasing rates needed as lime content in these soils increases. Concentrated P fertilizer bands improve P solubility with resulting yield increases, even when applied to crops grown in soil with relatively high soil test P concentrations. Applying organically complexed P in the form of biosolids or as a mixture of liquid P and humic substances can also enhance P nutrition and result in yield increases. Application of slow release and cation complexing specialty fertilizer P materials has also been shown to effectively increase yields in calcareous soil. In-season applied P through the irrigation water can deliver P to plant roots when deficiencies are observed, but the effectiveness and results are less than with P incorporated into the soil. Finally, it is important to maintain a proper balance of P with other nutrients for general plant health and to avoid excess nutrient induced deficiencies of other nutrients. In some cases, these methods are relatively new and need further refinement with regard to rates, timing, and technique; but all are potential methods for improving P supply to plants grown in alkaline and calcareous soil. PHOSPHORUS NUTRITION Phosphorus (P) is an essential macronutrient, being required by plants in relatively large quantities (~0.2 to 0.8%) (Mengel and Kirkby, 1987; Mills and Jones, 1996). Potassium and nitrogen are the only mineral nutrients required in larger quantities than P. Providing adequate P to plants can be difficult, especially in alkaline and calcareous soil. Alkaline soil is defined as soil with pH greater than neutral, typically 7.5 to 8.5. Calcareous soil is defined as having the presence of significant quantities of free excess lime (calcium or magnesium carbonate). Lime dissolves in neutral to acid pH soil, but does not readily dissolve in alkaline soil and, instead, serves as a sink for surface adsorbed calcium phosphate precipitation. The bioavailability of P is strongly tied to soil pH. The formation of iron and aluminum phosphate minerals results in the reduced solubility of P in strongly acidic soil, improving as pH approaches nearly neutral. This maximum solubility and plant availability of P at pH 6.5 declines again as the pH increases into the alkaline range. This effect of reduced P availability in alkaline soil is driven by the reaction of P with calcium, with the lowest solubility of these calcium phosphate minerals at about pH 8. The presence of lime in alkaline soil further