Enhancing maize productivity by mitigating alkaline soil challenges through acidified biochar and wastewater irrigation

In alkaline soil conditions, the availability of essential nutrients for plant growth becomes limited, posing a significant challenge for achieving optimal maize growth and yield. Exploring the impact of biochar and waste irrigation on soil alkalinity and maize production in arid regions has received limited attention. This study aimed to evaluate the effects of three levels of acidified biochar (0, 5, and 10 Mg ha(−1)) in two growing seasons of maize—spring and autumn. The treatments were applied following a randomized complete block design with three replications. Biochar was applied only in the autumn season, and its residual effects were evaluated in the spring season. The study found that using acidifying biochar at a rate of 10 Mg ha(−1) significantly increased maize yield by 35.8% compared to no application and by 16.4% compared to a rate of 5 Mg ha(−1). In the autumn, applying acidified biochar at 10 Mg ha(−1) reduced soil pH by 3.65% and 6.41% compared to 0 and 5 Mg ha(−1). In the spring, the same application led to a decrease in soil pH by 5.84% and 7.37% compared to the lower rates. Additionally, using 10 Mg ha(−1) of acidifying biochar increased soil phosphorus concentration by 87.6% and soil potassium concentration by 38.0% compared to not using biochar, and by 46.2% and 35.0% compared to the 5 Mg ha(−1) application. These findings suggest that the reduction of soil pH by applying biochar at a rate of 10 Mg ha(−1) facilitated an increase in nutrient availability in the soil, consequently leading to higher maize yield. Notably, no significant differences were observed in maize productivity and soil properties between the spring and autumn seasons. Therefore, this study paves the way for further exploration into the long-term effects of acidifying biochar on maize productivity and soil properties in similar agroecological contexts.