Risco de estresse térmico para o feijoeiro em Santa Maria, RS

Quantifying thermal conditions for crops is important for planning agribusiness activities. The purpose of this study was to determine sowing dates with smaller risk of high air temperatures during flowering of common bean and to verify if there are differences among maturation groups considering the occurrence frequency of elevated temperatures, in the Central Region of Rio Grande do Sul State. The occurrence frequency of daily maximum air temperatures greater than or equal to 28, 30 and 32°C was determined for the period from bud emission to beginning of grain formation for three maturation groups and for each sowing date. The crop cycle was simulated with data collected in a climatological station at Santa Maria, from August 1968 to July 2004. There was not significant difference among the maturation groups for frequency of occurrence of elevated temperatures. There is lower risk of damages caused by elevated air temperatures when sowing is performed early in the spring growing season and late in the autumn growing season.