Alleviating soil salinity stress in castor (Ricinus communis L.): Synergistic effects of organic amendments and arbuscular mycorrhizal fungi on growth, yield, and antioxidant improvement under effluent contaminated ecosystem

Textile and dye industrial effluents, overloaded with salts and contaminants, significantly endangers soil quality and agricultural production. This study assesses the efficacy of organic amendments and arbuscular mycorrhizal fungi (AMF) in mitigating salinity stress and promoting the growth of castor ( Ricinus communis L.) in effluent-contaminated soils. A field experiment was conducted with recommended dose of fertilizers (RDF) with AM fungi and organic amendments, including farmyard manure (FYM), vermicompost (VC), composted press mud (CPM), and composted poultry litter manure (CPLM). The treatment utilizing the recommended dose of N & K combined with 50 % P + CPLM @ 5 t ha −1 + AMF demonstrated the most significant enhancements across several parameters. Post-harvest soil study indicated a decrease in electrical conductivity to 3.49 dS m −1 (from 3.56 dS m −1 ) and an increase in organic carbon to 0.39 %. The quantities of available nitrogen, phosphorus, and potassium rose to 185 kg ha −1 , 23.97 kg ha −1 , and 362 kg ha −1 , respectively. Castor plants subjected to the treatment RD of N & K + 50 % P + CPLM @ 5 t ha −1 + AMF exhibited improved growth and production, with a seed yield of 2168 kg ha −1 . The quality indicators shown substantial enhancement, with oil content at 48.9 % and crude protein at 32.4 %. Antioxidant markers, including proline, malondialdehyde (MDA), and catalase, were lowered to 0.5 µmol g −1 , 0.4 µmol g −1 , and 32.7 ml min −1 , respectively which signifies diminished oxidative stress. Arbuscular mycorrhizal fungal root colonization reached a maximum of 65 %, with spore densities attaining 120 per 100 g of soil. This study introduces a novel, sustainable strategy for biologically remediating saline, effluent-contaminated soils through the combined use of composted poultry litter manure and arbuscular mycorrhizal fungi. The integrated approach not only enhanced castor growth and yield but also reduced soil salinity and improved key soil fertility indicators, offering a viable solution for eco-friendly desalination and agricultural sustainability in salt-affected ecosystems. Alleviating Soil Salinity Stress in Castor ( Ricinus Communis L.)