Water Availability and Soybean Productivity in Western Paraná

The present dissertation aimed to evaluate the influence of climate variability and water availability on soybean productivity in western Paraná. Historical series of precipitation from the Water Institute of Paraná of ten municipalities in the region were studied, with daily data from 1977 to 2015. The effects of the ENOS phenomenon during its El Niño and La Niña phases on the interannual variation of rainfall, and the LTO on the decadal cycles of precipitation in the region were analyzed. The analysis of microclimate and soybean productivity was performed in the municipality of Guaíra, using data from a soybean field experiment conducted from 2010 to 2014 and an automatic weather station installed in the center of the 1 ha experimental area. It was found that the risks of veranicos can reach up to 20% in the month of November, while October and December presented lower risks. Through regression analysis it was verified a high correlation between rainfall in the reproductive phase and soybean productivity, as shown in the sequential water balances and variation of water storage in the cycles of the soybean crops under study.