Investigation of three traditional soil amendments for reviving soil health in petroleum-contaminated soils
摘要
This study investigates the potential of traditional organic amendments Panchagavya and livestock wastes for restoring germination capacity and soil fertility in engine oil–contaminated clay loam soil. The soil contamination was created by incorporating 1.5 kg of waste engine oil, corresponding to 5% of the soil volume. Panchagavya, prepared as per standard protocols, showed a mildly acidic pH (6.2) and contained abundant microorganisms, essential nutrients, and organic carbon. Treatment of oil-contaminated soil with 50 ml of Panchagavya resulted in 60% germination, whereas untreated contaminated soil showed no germination and normal soil had 90%. Subsequent treatment with chicken waste further enhanced germination to 80%. Soil analyses revealed that the combined treatments increased organic carbon (105.6 g kg⁻1), total nitrogen (72.6 kg ha⁻1), available nitrogen (from 5.664 to 8.712 kg ha⁻1), phosphorus (14.9 kg ha⁻1 total, 1.788 kg ha⁻1 available), and potassium, with values of 511.3, 403.63, and 388.6 kg ha⁻1 observed in the Panchagavya, chicken waste, fish waste, and Azolla treatments, respectively. Soils treated with Panchagavya and chicken waste showed the greatest hydrocarbon degradation, achieving 86–89%. Unlike previous studies that have examined either microbial inoculants or single organic wastes in petroleum remediation, this work demonstrates for the first time the effectiveness of integrating Panchagavya and livestock waste treatments. The findings highlight a low-cost, farmer-accessible approach that simultaneously promotes hydrocarbon degradation, restores soil nutrients, and recovers seed germination, thereby offering a sustainable strategy for managing petroleum-contaminated agricultural soils.