Amending Two Different Soil Types with Biochar: Do Row Crops Benefit from Biochar?

The National Center for Environmental Information reported a loss of $236.6 billion from droughts in the United States between 1980 and 2018. In different areas of the U.S. drought and floods have increased and resulted in significant economic impacts. Biochar has the potential to improve the water holding capacity of soils and be a useful tool for improving soil productivity. Understanding the controls on water movement through biochar-amended soils is critical to improve row crop productivity under poor soils, during drought events or following the deposition of sand in flooded fields. Therefore, the addition of biochar to soils to improve soil water holding capacity and crop productivity under water deficit was studied in a series of greenhouse experiments, at the University of Tennessee during 2018 and 2019. The transpiration rates of 4-week old cotton, soybean, and corn were measured under progressive soil drying for 28 days with application of 0%, 10%, and 25% biochar incorporated with potting mix and sand in two sets of experiment. The greenhouse studies showed that 10% biochar improved corn and soybean water saving potential in both potting mix and sand. But adding biochar amount at any rates to both soil types had negative impact on water saving potential in cotton. The results suggest that biochar may improve water holding through stomatal closure in corn and soybean productivity in a sandy soil. But increasing the amount of biochar at the rates applied in the current study may reduce cotton plants water saving potential, negatively. These controlled environment experiments have pointed out the direction for the next series of biochar trials in cotton.