Effect of Biochar-Coated Potassium Fertilizer on Spinach (Spinacia oleracea L.) Growth and Soil Health

Abstract

This research was conducted in the wirehouse of the College of Agriculture, University of Sargodha as a pot experiment to study the effect of biochar-coated potassium fertilizer (BC-K) on spinach (Spinacia oleracea L.) growth in cadmium (Cd)-contaminated soil. The study aimed to improve soil health, reduce Cd bioavailability, and enhance spinach yield. A completely randomized design (CRD) was used with eight treatments and three replications, making a total of 24 pots. The treatments included 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 with micronutrients (Zn, Fe, B, Mn, Cu) and full fertilizer application. The results showed that biochar-coated potassium fertilizer improved soil fertility by increasing organic matter, enhancing nutrient availability, and reducing cadmium toxicity. Spinach plants treated with BC-K + full fertilizer package showed the best growth, including higher plant height, more leaves, and increased fresh and dry biomass. The application of BC-K also reduced Cd uptake in spinach leaves, making it a safer food option. This study suggests that biochar-coated potassium fertilizer can be an effective and sustainable amendment for growing spinach in heavy metal-contaminated soils. It helps improve crop yield, soil quality, and food safety, making it a useful strategy for sustainable agriculture.