Avaliação de genótipos de mandioca baseada em processos físico-hídricos no solo

Abstract

Climate change has altered the rainfall regime, promoting prolonged droughts in various parts of the world, which, added to the growing demand for food, makes the rational use of water an urgent need for the sustainability of agricultural enterprises, especially for cassava, a crop of high livelihood potential for developing countries. Thus, the objective of this study was to characterize the flow of water in the soil and determine the efficiency of water use in 10 genotypes and 2 varieties of cassava (Manihot esculenta Crantz) from the germplasm bank of Embrapa Mandioca e Fruticultura, in Cruz das Souls, BA. For this purpose, an instantaneous profile was installed to monitor the saturated and unsaturated hydraulic conductivity of the soil and, in each cultivation plot of the 10 genotypes and 2 varieties of cassava, access tubes were inserted to determine - through the FDR technique - the balance of water in the soil and from this, the survey of the real evapotranspiration and the efficiency of water use of the genotypes and varieties under study. The experiment was carried out at the Experimental Farm on the Campus of the Federal University of Recôncavo da Bahia in Cruz das Almas, Bahia, 12°40'19” South latitude, 39°06'23” West of Greenwich in a Distrocohesive Yellow Latosol of Coastal Tablelands. The lowest values of hydraulic conductivity obtained were between the depths of 0.30 to 0.80 m, cohesive range, indicating a limitation of water flow due to subsurface consolidation, characteristic of these soils. The highest efficiency in water use was achieved by BRS Formosa. Considering that this variety of cassava is widely accepted by producers and has expanded in the North-Northeast regions of Brazil, it is therefore promising in the face of climate variations, aiming at saving water with maintenance of productivity.