Improving soil health through manure and biochar amendments under climate-smart agriculture

Enhancing crop productivity and soil sustainability under climate-smart agriculture involves strategically using soil amendments to improve soil health and resilience. A field experiment at Prairie View A&M University, Texas, studied the effects of soil amendments (chicken and dairy manures and biochar) on some soil health indicators. The experiment used two biochar rates (2268 and 4536 kg ha⁻¹) and two types of manure (chicken and dairy) at three rates (0, 224, and 448 kg total N ha⁻¹ for sweet corn [Zea mays (L.)] and 0, 180, and 360 kg N ha⁻¹ for sorghum [Sorghum bicolor (L.) Moench]) in a factorial design with three replications. Soil macronutrients and micronutrients were measured as chemical soil health indicators, and bulk density, porosity, and saturated hydraulic conductivity were measured as physical soil health indicators. Dairy manure significantly increased soil calcium (Ca) and potassium (K) concentrations. Higher manure application rates improved soil nutrient concentration, with the highest phosphorus (P), Ca, magnesium (Mg), and manganese (Mn) concentration levels at the double recommended rate. Biochar did not affect nutrient concentration but improved soil physical properties by increasing porosity, hydraulic conductivity, and reducing bulk density, especially at higher rates in sweet corn. Correlation analysis showed bulk density was negatively correlated with key nutrients like potassium (K), Ca, and Mg, while porosity and hydraulic conductivity positively influenced nutrient availability. The principal component analysis highlighted that sweet corn and sorghum respond positively to selected soil amendments, while their specific impacts vary based on crop type. The findings emphasize balancing manure and biochar application rates to optimize soil fertility and minimize environmental risks, supporting sustainable soil management strategies.