Mechanistic Insights into Pressmud-Mediated Improvement in Wheat Growth, Quality and Productivity under Lead Contaminated Salt-Affected Soil
摘要
Soil contamination with lead (Pb) adversely affects wheat production and consumer health. Applying organic amendments like pressmud (PM) may reduce Pb uptake and boost crop yield. This study aims to evaluate the effect of PM application to Pb-contaminated salt-affected soil on the growth, quality and productivity of wheat, and elucidate the underlying mechanisms. The salt-affected soil was spiked with Pb at 0, 50 and 100 mg kg− 1. After two weeks, soil was amended with PM at 0, 10 and 20 g kg− 1, and seeds of wheat (cv. Faisalabad-2008) were sown. One set of experiments was harvested at seedling stage, another at maturity. Soil contamination with 100 mg Pb kg⁻¹ reduced seedling biomass by 42% than control. Pb stress at 100 mg kg⁻¹ increased superoxide dismutase, peroxidase and catalase production by 144%, 49% and 41%, respectively. Moreover, phosphatase, dehydrogenase and urease activities of soil decreased by 18%, 26% and 28%, respectively. Applying PM mitigated the adverse effects of Pb on seedling growth, antioxidant production and microbial activities. At maturity, Pb contamination decreased yield and nutrient uptake in grains in a dose-dependent manner. In un-amended soil having 100 mg Pb kg⁻¹, grain yield decreased by 30% than control. This treatment decreased uptake of nitrogen, phosphorus and potassium in grains by 26%, 28% and 32%, respectively. PM amendment increased nitrogen, phosphorus and potassium uptake by 2.6-, 2.22- and 1.86-fold, respectively. Pb contamination of soil produced grains having 8.48- to 13.66-fold higher Pb contents than control, while PM application reduced Pb concentrations in grains by 59–62%. Pressmud improves growth, yield and quality of wheat grains through regulating antioxidant production, restoring microbial activities, improving nutrient uptake and decreasing Pb absorption from contaminated soil.