Effects of phosphate sludge-enriched compost on tomato growth and physiology, Meloidogyne javanica reproduction, soil pH and electrical conductivity

Summary The management of waste and execution of sustainable pest control pose considerable challenges in modern agriculture. This study introduces an innovative approach using phosphate sludge-enriched compost (PSEC) and demonstrates its significant dual function of improving crop yield and controlling nematodes. PSEC, made up of 20% phosphate sludge, 70% food waste, and 10% green waste, was tested at concentrations ranging from 0% (serving as infected, non-treated control) to 100% for their impact on the physio-morphological development of tomato plants, management of Meloidogyne javanica , and improvement of soil quality, especially pH and electrical conductivity (EC). The results revealed a significant improvement in plant growth at 20% PSEC, which led to substantial increases in fresh weight (873.43%), dry weight (549%), and root weight (359%), followed by a decline at higher concentrations. Examination of biochemical variables demonstrated increased levels of chlorophyll a and b at lower concentrations (1-3%), whereas heightened PSEC concentrations initiated a strategic compromise between phenolic compounds and flavonoid contents, signifying enhanced physiological response. The 100% PSEC treatment achieved remarkable nematode control, reducing the gall index by 40% and decreasing the reproduction of M. javanica by 92%. PSEC had the ability to modify soil properties, elevating pH from 6.65 to 8.30 and EC from 83.4 to 762.67 μ S cm −1 . These results indicate that PSEC is an effective strategy for sustainable agriculture, offering simultaneous benefits in yield enhancement, pest management and soil quality improvement, while presenting a novel method for the circular economy in agriculture by transforming industrial and agricultural waste into a valuable resource for enhanced crop protection, nematode management and soil health.