Biochar-enhanced soil pH and nutrient retention in Sudan Savanna agricultural soils of Nigeria

This in-depth study explores the transformative effects of biochar incubation on key soil properties, emphasizing sulphate, phosphate, and chloride retention; soil pH alteration; and dissolved organic matter dynamics. Initial analyses of the soil used revealed a fertile soil environment with a slightly alkaline pH, moderate phosphorus availability, and a loam texture conducive to robust plant growth. Different biochar types (rice husk and corn cob) were accurately applied at four levels (0 t ha−1, 5 t ha−1, 10 t ha−1, and 20 t ha−1). The investigation into the soil pH alterations post-biochar incubation highlighted a dose-dependent relationship, revealing variations in acidity and alkalinity. There was an emphasis on sulphate, phosphate, and chloride retention, elucidating the intricate interplay between biochar feedstock, application rates, and soil conditions. The sulphate retention exhibited notable variations influenced by biochar type, with the corn cob biochar (0.16 mg kg−1) demonstrating distinct advantages over the rice husk biochar (0.11 mg kg−1). The phosphate retention showed a dose–response relationship, correlating with increased biochar application levels. Surprisingly, the chloride retention demonstrated a complex trend, with the highest retention observed at control levels (0 t ha−1 = 1.82 mg kg−1), challenging conventional expectations. The dissolved organic matter dynamics revealed consistent responses to biochar application levels, indicating its potential to influence nutrient cycling and microbial activity. This study contributes valuable insights into biochar’s role as a sustainable soil amendment, providing a foundation for tailored soil management practices that enhance nutrient availability and overall soil health.