Biochar effects on soil moisture and soybean yield in claypan soils

The role of biochar application in water storage and utilization in the soil has the potential to influence crop productivity and hydrological processes. These properties contribute to enhancing the resilience of agricultural systems against drought and have been the focus of numerous studies. However, biochar application is not well studied in claypan soils in the Midwestern United States. This research compared the effect of biochar application, at rates of 2.7 Mg ha -1 (B1) and 5.4 Mg ha -1 (B2), relative to a no biochar control (C) on soil moisture content in a soybean [ Glycine max (L.) Merr.] field in central Missouri, USA. Soil volumetric moisture content (VWC%) was monitored at depths of 5, 10, and 20 cm using water reflectometer sensors from June 2022 to December 2023 (57 weeks), at three replicate locations in a completely randomized plot design. The results indicated that in 2022, B1 significantly ( p < 0.02) increased VWC% at 5 cm depth compared to both C and B2. Throughout both years, B2 treatments consistently increased ( p < 0.001) soil moisture at 10 and 20 cm depths relative to control. However, these increases in surface moisture did not translate into improved soybean yield. These findings suggest that while biochar can modify soil moisture dynamics in claypan soils, increased VWC alone may not directly translate to yield benefits under current application rates and conditions. Future studies should incorporate additional soil and plant indicators beyond VWC and consider long-term monitoring and focus on optimizing biochar use in claypan soils to enhance agronomic performance. • Biochar increased soil water content in clay rich soils. • Different biochar application rates affect soil VWC% at specific soil depths. • Higher soil moisture does not result in increased soybean yield.