Phosphogypsum and biosynthesized selenium nanoparticles synergistically mitigate cadmium contamination and promote maize growth in wastewater-irrigated alkaline soil

Abstract

Aims

Maize (Zea mays L.), a critical crop for global food security, is indispensable for livestock feed and human consumption. However, the prolonged use of cadmium-contaminated wastewater for irrigation, particularly in alkaline soil, can cause soil degradation and poses a significant threat to crop production.

Methods

The study tested the combined application of 10 t ha^-1 PG and 25 mg L^-1 BioSeNPs on maize plants cultivated in Cd-contaminated alkaline soils. Comprehensive assessments were conducted on soil chemical properties, enzymatic activities, plant physiological responses, and nutrient content in leaves.

Results

The co-application of PG and BioSeNPs significantly reduced Cd bioavailability in the soil and its accumulation in maize roots, shoots, and grains. Soil Cd levels decreased by 33.01%, accompanied by enhanced soil enzymatic activities and improved soil respiration. Physiological stress markers, including malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), were reduced by 34.61%. Additionally, chlorophyll content, stomatal conductance, and net photosynthetic rate increased by 54.23%, 54.28%, and 93.80%, respectively. The nutritional content of essential elements—nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), and selenium (Se)—in maize leaves also showed substantial improvements.

Conclusions

The combined application of PG and BioSeNPs effectively mitigated Cd contamination and enhanced soil health and maize growth. This innovative approach offers a sustainable solution for managing alkaline soils irrigated with Cd-contaminated wastewater.