Enhancing Spinach (Spinacia oleracea L.) Growth and Soil Health Using Biochar-Coated Potassium Fertilizer

Abstract

This study was carried out in the wirehouse of the College of Agriculture, University of Sargodha, using potted plants to test how biochar-coated potassium fertilizer (BC-K) affects spinach (Spinacia oleracea L.) growth in cadmium (Cd)-contaminated soil. The goal was to improve soil health, reduce Cd availability, and increase spinach yield. The experiment followed a completely randomized design (CRD) with eight treatments and three replications, making a total of 24 pots. The treatments included a control (no fertilizer), recommended NPK, biochar alone, different doses of BC-K (1.5, 2.0, and 2.5 g per pot), and BC-K combined with micronutrients (Zn, Fe, B, Mn, Cu) and full fertilizer application. Results showed that BC-K improved soil fertility by increasing organic matter, making nutrients more available, and reducing Cd toxicity. Spinach plants treated with BC-K and full fertilizer had the best growth, with taller plants, more leaves, and higher fresh and dry weight. BC-K application also lowered Cd levels in spinach leaves, making it a safer food choice. This study suggests that biochar-coated potassium fertilizer is a useful and eco-friendly way to grow spinach in polluted soils. It helps increase crop yield, improves soil quality, and enhances food safety, making it a good option for sustainable farming.