Mitigation of Boron Toxicity in Two Sorghum Cultivars Using a Novel Bio-Composite Derived from Waste Sheep Wool and Rice Husk

Excess boron (B) is a major stress factor limiting crop growth, particularly in semi-arid regions, creating an urgent need for environmentally friendly and cost-effective solutions to mitigate B toxicity. This study evaluated a newly synthesized bio-composite (WRHP), produced from waste sheep wool and rice husk, for its potential to reduce B toxicity in two sorghum cultivars and assessed its structural properties and effects on plant nutrient dynamics. Treatments included B-contaminated soil alone and soil amended with 0.5, 1.0 and 2.0 g kg − 1 WRHP. Fourier transform infrared spectroscopy (FTIR) analysis revealed a dominant peak at 1066 cm − 1 along with several weaker bands, while X-Ray Diffraction (XRD) showed characteristic reflections at 21°, 23°, and 31° 2θ, confirming keratin-derived components and silicon (Si), phosphorus (P), and potassium (K) bearing minerals. WRHP decreased tissue B concentrations, reducing levels in cv. Akdari from 189 to below 99.3 mg kg − 1 and in cv. Ogretmenoğlu from 115 to 75.7 mg kg − 1 . WRHP enhanced Si accumulation especially in cv. Ogretmenoglu and increased P concentration at the highest application rate. Oxidative stress indicators (Malondialdehyde (MDA) and H 2 O 2 ) decreased markedly following WRHP application. At the same time, WRHP enhanced non-enzymatic antioxidants and was accompanied by significant reductions in ascorbate peroxidase (APX) activity, along with dose-dependent decreases in superoxide dismutase (SOD) and catalase (CAT) activities. Post-harvest soil analyses showed lower plant-available B and increased P and Si levels with increasing WRHP doses. The WRHP effectively alleviates B toxicity by reducing B uptake, improving Si nutrition, and mitigating oxidative stress in sorghum.