Climatic Risk Zoning Methodologies For Soybean Cultivation In The Cerrado Biome

Agriculture is an activity of risk and uncertainty. Agricultural Climate Risk Zoning (ZARC) indicates what, where and when to plant to escape climate events. The objective of this work was to compare two methodologies for agricultural climate risk zoning of soybean (Glycine max (L) Merrill) in the Cerrado Biome. The Water Requirement Satisfaction Index (WRSI) was used considering the phenological phases critical to water deficit: Phase I (germination and emergence) and Phase III (flowering and grain filling). In the first approach, phase III was considered. In the second approach, phases I and III were considered. The SARRAZON program was used to simulate water balance. The low climate risk zone corresponded to WRSI > 0.50 in phase I; and WRSI > 0.65 in phase III. For comparison purposes, the sowing time, percentage of risk areas and number of recommended municipalities were considered. In the second methodology, the low risk zones were smaller. Soybean has been recommended in soils with the highest available water capacity. The high-risk areas were in the transition between the Caatinga and Pantanal biomes. This study guides soy agroclimatic risk and subsidizes public policies in the Cerrado.