CSA News, the magazine of three related societies: the Agronomy Society of America, Crop Science Society of America, and Soil Science Society of America, published an article in its January 2021 issue describing research led by research scientist Robinson Negrón Juárez, on behalf of the NGEE-Tropics project. The article highlights a paper published recently in the Vadose Zone Journal, which evaluates soil moisture dynamics in Amazon tropical forest.
Soil moisture plays an important role in the hydrological, biogeochemical, and energy budgets of terrestrial ecosystems. Logistical constraints can make it difficult to obtain accurate soil moisture measurements in remote ecosystems such as the Amazon. The paper described the work of researchers, including Juárez, Jeff Chambers, and Boris Faybishenko, to develop a field‐based calibration of time domain reflectometry (TDR) sensors in a central Amazonian old‐growth upland forest. The team set out to evaluate how well the calibrated sensors work to determine changes in soil moisture at various depths extending 14.2 meters below ground, and across different time intervals in wet and dry seasons. They found soil moisture varied significantly by depth and over time due to soil-texture differentiation, root uptake depths, and event and seasonal precipitation. Results of this study help to enhance our understanding of eco-hydrological processes within tropical forests, and to improve model representation of these systems in the context of changing environmental conditions.