On-farm sugarcane water productivity influenced by environmental and management practices in Brazil

Quantifying the impact of driving factors on crop water productivity (WP) is essential for efficient agricultural water use. To date, few studies have investigated the influence of management and environmental factors on sugarcane WP at the mill scale. This study aimed to assess the contributions of management practice factors, weather variables, and soil management zones (SMZs) on on-farm sugarcane WP in a single mill in the southern region of Brazil. An extensive on-farm database of commercial sugarcane field plots was used with a weather database to estimate evapotranspiration and water-limited potential yield (Yw). This was achieved by employing a crop sugarcane model to calculate actual water productivity (WPa) and attainable water productivity (WPw). The results demonstrated an inverse relationship between management practices and WPa, while harvest date and vinasse positively impacted on WPa. The Yw, actual yield (Ya), actual evapotranspiration (ETa) or crop evapotranspiration (ETc), and WPa varied according to the SMZ. The lowest WPa values were observed in the worst soils. The analysis revealed that weather variables collectively accounted for 46.2 % of WPa variability, management practice factors accounted for 40.5 %, and SMZs contributed 13.3 % of WPa variability. Despite weather variables being the primary source of WPa variability, management practice factors still played a key role in WPa variability.