ABSTRACT The aims of this study were to see the effect of variability of crop residues viz., rice straw, wheat straw, mustard stover, chickpea stover and tree leaves on solubilization and availability of phosphorus (P) fractions during composting of rock phosphate enriched composting (RPEC) vis-a-vis ordinary compost; to propose suitable bioavailable index for RPEC; and to recommend the maturity time of RPEC for its field application to maximize P availability. Results revealed that the rice straw-RPEC had higher total N and lower C/N ratio than composts prepared with other crop residues. Total and available P fractions were higher in RPEC than ordinary compost. The concentration of bioavailable P increased significantly in RP-enriched composts of rice straw, wheat straw, chickpea stover and mustard stover during composting. The distribution indicated that citrate-soluble P (CSP) was the major component of the bioavailable P during composting. The efficiency of crop residues in enhancing P solubilization from RP followed the order: rice straw > chickpea stover > wheat straw > mustard stover > tree leaves. Solubilization trend indicated that 90-days-old compost would maximize P availability in RPEC and could be applied in field to maximize P availability. The bioavailable indices as obtained from the ratios of total organic C (TOC) to total P (TOC/TP), water-soluble C (WSC) to total P (WSC/TP) and total organic C to citrate soluble P (TOC/CSP) correlated well with Olsen-P (NaHCO3-P) and water-soluble P (WSP) of RPEC. Thus, we recommend these ratios as the bioavailable indices of P.

中文翻译：

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与普通堆肥相比，在富含岩石磷酸盐的堆肥堆肥过程中，作物残留物的变化决定了磷组分的溶解性和可用性

摘要 本研究的目的是观察作物残留物的变异性，即稻草、小麦秸秆、芥菜秸秆、鹰嘴豆秸秆和树叶对富磷岩堆肥堆肥过程中磷 (P) 组分的溶解性和可用性的影响。 (RPEC) 与普通堆肥的对比；为RPEC提出合适的生物利用度指数；并推荐 RPEC 在其现场应用中的成熟时间，以最大限度地提高磷的可用性。结果表明，水稻秸秆-RPEC 比用其他作物残留物制备的堆肥具有更高的总氮和更低的 C/N 比。RPEC 中的总磷和有效磷含量高于普通堆肥。在堆肥过程中，水稻秸秆、小麦秸秆、鹰嘴豆秸秆和芥菜秸秆的富含 RP 的堆肥中生物可利用 P 的浓度显着增加。分布表明柠檬酸盐可溶性磷（CSP）是堆肥过程中生物可利用磷的主要成分。作物残留物对RP增溶磷的作用大小顺序为：稻草>鹰嘴豆秸秆>麦秸秆>芥菜秸秆>树叶。溶解趋势表明，90 天龄的堆肥将最大限度地提高 RPEC 中磷的可用性，并且可以在田间应用以最大限度地提高磷的可用性。从总有机碳 (TOC) 与总磷 (TOC/TP)、水溶性碳 (WSC) 与总磷 (WSC/TP) 和总有机碳与柠檬酸可溶性磷 (TOC/TP) 的比率获得的生物利用度指数CSP) 与 RPEC 的 Olsen-P (NaHCO3-P) 和水溶性 P (WSP) 相关性很好。因此，我们推荐这些比率作为 P 的生物可利用指数。