Hidrodinâmica tridimensional na zona radicular do meloeiro em condições semiáridas

Abstract

The knowledge on evapotranspiration and water uptake by agricultural crops brings great contribution to solving problems related to the soil-water-plant-atmosphere system and irrigation management. The basic components of this system can be determined with the water balance obtained using TDR. This study aimed to observe the dynamic flow of evapotranspiration, percolation and uptake of water by the melon crop, using TDR to improve the calculation of water balance and the irrigation management of the melon crop cultivated in the semi-arid region. The experiment was carried out at the field and in the laboratory, at the Federal Institute of Education, Science and Technology of Bahia - IFBAIANO, Campus of Senhor do Bonfim-BA. An area of melon cultivation was installed on May 3, 2015, using the variety ‘Redondo Gaúcho’. In the cultivation area, 21 drainage lysimeters were installed, with volume of 1.12 m3, length of 1.4 m, width of 1 m and depth of 0.8 m. Forty TDR probes were distributed inside one lysimeter in four monitoring profiles to determine the variations of water storage in the soil. The temporal variability of water uptake is greater than its spatial variability. The region indicated as the one with highest uptake activity in the root zone of melon under drip irrigation is delimited, in relation to the stem, at 0.36 m of radial distance and 0.3 m of depth, for all crop development stages. There are no differences in the estimate of melon evapotranspiration through water balance as the number and position of soil moisture monitoring sensors varied.