Balanço hídrico para épocas precoce, média e tardia da cana-de-açucar nos tabuleiros costeiros de Alagoas

Abstract

The objective of this research was to carry out a mobile water balance for sugarcane planting periods in the region of Rio Largo, AL, in order to identify the planting period where the crop will have less water stress in this region. The research simulations were carried out between 2015 and 2019 and three planting times normally used in the region were considered: early – planting in March and harvesting in February; middle- planting in September and harvesting in November; and late planting in June and harvesting in December. The variables analyzed were Precipitation (P), Crop Evapotranspiration (ETc), Actual Evapotranspiration (ETr), Water Deficit (DEF) and Water Excess (EXC). The values of precipitation, evapotranspiration of the crop, real evapotranspiration, water excess and water deficiency were different between the same varieties, being the same place and the same period, because the farming time is different. The late cycle presents the highest values for the variables: precipitation (P), crop evapotranspiration (ETc), real evapotranspiration (ETr) than the other cycles, and water surplus (EXC) were the same in all cycles. Late-cycle sugarcane has the highest water demand, followed by mid- and early-cycle sugarcane. The water deficit gap in the early cycle occurs from September to December in the period from 2015 to 2019. The excess occurs in the first ten-day period from March to the first ten- day period from June for all years. The intermediate cycle is penalized by a water deficit during the first ten-day period in October extending to the third ten-day period in March. The water surplus occurs from the second ten-day period of May to the second ten-day period of July. The water deficit is most pronounced between September and March in the late cycle for any observed year. The excess is greater between the months of April to August.

Keywords: Evapotranspiration, water requirement, soil water storage