Agricultural drought monitoring based on soil moisture derived from the optical trapezoid model in Mozambique

Soil moisture (SM) at three depths (15, 25, and 30 cm), derived from the optical trapezoidal model (OPTRAM), was used for multiyear, multisite monitoring of agricultural droughts over two agricultural crops (Maize and Soybean) in southern Mozambique. The OPTRAM was implemented using satellite data from Sentinel-2 and was validated against field SM assessed by gravimetric methods and by Watermark Sensors in sandy-soils with very low water holding capacity (0.13 cm(3)/cm(3)). The OPTRAM model estimated the SM at 15 and 25 cm yielding a R-2 >= 0.79 and RMSE <= 0.030 cm(3)/cm(3). The OPTRAM-derived SM was successfully used as input to compute and map the soil water deficit index, an indicator of agricultural drought. The results indicate that OPTRAM can provide useful information to improve water productivity in cropland under the specific conditions of Mozambique agricultural systems and for early warning systems development. (C) 2019 Society of Photo-Optical Instrumentation Engineers (SPIE)