New approach for drought assessment: A case study in the northern region of Minas Gerais

Abstract

Drought poses a major threat to food security and maintenance of rural populations in dry lands, because it leads to losses in agriculture and other productive sectors. Given the intensification and recurrence of drought events and their impacts, it is necessary to deepen our knowledge as a key to subsidize mechanisms for drought preparation and mitigation plans. Therefore, this study aimed to develop and apply methodologies for drought characterization and impact assessment, considering different agro-ecosystems and the impact on smallholder farmers. The new approach developed included as dataset LULC maps, the limits of rural properties, and the Vegetation Supply Water Index (VSWI) time series. The z-score was used in order to identify areas affected by droughts and a zonal statistic was used to compare the results of VSWI in a municipal and rural property scale. Afterwards, the areas identified as significant statistics were used to determine the LCLU and rural property most affected. The results of the analysis showed that Agricultural Lands were the most affected LULC during the study period (about 50%), whereas Micro and Small Properties were the most affected by droughts, over than 65% and 15% respectively. Besides, an important finding is that the analysis at the municipality or rural property levels can affect the drought assessment. This can result in an underestimated or overestimated of drought intensity and in the expansion of impacts. Thus, these results contribute to the local drought mitigation actions and help determine the threshold to better spatialize drought impacts on smallholder farming.