Studies of phosphorus (P) behaviour in soils receiving sugar cane filter cake are important for determining doses, its contribution to P nutrition and maximizing fertilizer efficiency, especially in soils with low P availability. This study aimed to assess organic and inorganic forms of P in soils treated with sugar cane filter cake, and the relationship between these and plant available P. Soil inorganic (P_i) and organic (P_o) phosphorus forms, organic carbon, pH and resin P were measured in two soils; a Typic Hapludox with clay texture and an Arenic Hapludult with loamy sand texture, subject to three fertilizer treatments (nil P control and 100 mg P dm⁻³ as filter cake and triple superphosphate). Inorganic P was fractionated to soluble/loosely bound, Al-bound, Fe-bound, occluded and Ca-bound P forms. Organic P was fractionated into labile, fulvic, humic and residual P_o forms. Plant dry matter yield and P uptake were also determined. Both fertilizers increased the Al- and Fe-bound P fractions, with the increases caused by triple superphosphate 14.7 and 7.2 mg kg⁻¹ higher than filter cake, respectively. Filter cake increased the fulvic P_o by 40.9 mg kg⁻¹, while triple superphosphate increased it by 28.5 mg kg⁻¹, in the fine-textured soil. Al-, Fe-bound and labile P_o fractions in both soils had significant correlations (p <. 01) with plant absorbed P (r = .75, .84 and .54, respectively). Filter cake resulted in lower P_i fractions and availability, and it has potential to partially replace mineral P fertilizer in fine-textured soils and, entirely, in coarse-textured soils.

中文翻译：

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甘蔗滤饼改良土壤中磷的有机和无机形态

研究接受甘蔗滤饼的土壤中的磷 (P) 行为对于确定剂量、其对 P 营养的贡献和最大限度地提高肥料效率非常重要，尤其是在 P 可用性低的土壤中。本研究旨在评估用甘蔗滤饼处理的土壤中磷的有机和无机形式，以及它们与植物有效磷之间的关系。土壤无机 (P _i ) 和有机 (P _o ) 磷形式、有机碳、pH 值和在两种土壤中测量树脂 P；a 具有粘土质地的典型 Hapludox 和具有壤土质地的 Arenic Hapludult，经过三种肥料处理（无 P 控制和 100 mg P dm ^-3作为滤饼和三重过磷酸钙）。无机 P 被分成可溶/松散结合、Al 结合、Fe 结合、封闭和 Ca 结合的 P 形式。有机磷被分馏成不稳定，灰黄霉，腐殖酸和残余P _Ò形式。还测定了植物干物质产量和磷吸收量。两种肥料都增加了铝和铁结合的 P 部分，三重过磷酸钙分别比滤饼高14.7 和 7.2 mg kg ^-1引起的增加。在质地细腻的土壤中，滤饼使富里酸 P _o增加了40.9 mg kg ^-1，而三重过磷酸钙增加了 28.5 mg kg ^-1。AL-，铁结合的和不稳定的P _ö在两种土壤馏分有显著相关（p < . 01) 植物吸收的 P（分别为r  = .75、0.84 和 0.54）。滤饼导致较低的 P _i分数和可用性，它有可能在细质地土壤中部分替代矿物磷肥，在粗质地土壤中完全替代。