Yield gap of cassava crop as a measure of food security - an example for the main Brazilian producing regions

Cassava is a crop of major importance for family agriculture in Brazil and around the world, with its yield varying considerably among different producing regions. The aim of the present study was to assess the yields of cassava roots and the yield gaps in the main Brazilian producing regions, to propose strategies for reducing such gaps and thereby to improve food security. For this, potential and attainable cassava yields were evaluated in 13 major producing regions of the country over the last 24 years. Yield gaps caused by water deficit (YG) and crop management (YG) were determined, using potential and attainable yields obtained by means of a calibrated and validated Agroecological Zone crop simulation model along with actual yield data. The locations in the Northern region of the country had the lowest climatic risk for cassava production, but the lowest agronomic efficiency (44.1%). Sites located in the Northeast region had a YG of 34.1 t ha, with the highest climatic risk. The South-Central region showed good climatic and agronomic efficiencies. Based on our assessment, the main strategies for reducing cassava yield gaps are: setting up the planting dates based on a zoning approach to climatic risk; use of fertilizers, pesticides and green manures; use of drought tolerant genotypes; improvement of soil profiles; and, where possible, irrigation. All of these tools may be employed to reduce yield gaps in order to make the cassava crop more resilient to climate variability in Brazil.