[Show abstract][Hide abstract] ABSTRACT: This study used data of a field experiment conducted at the Bebedouro experimental base of the Embrapa-Centro de Pesquisa Agropecuaria do Tropico Semi-Arido in Petrolina, PE, Brazil, from May to August, 1996, during the growing period of a five-year-old table grape (Vitis vinifera L.), Italy cultivar. The plants were conducted in a two-meter above soil surface trellis system, four meters between rows by two meters between plants, and daily irrigated by trickling system. The crop evapotranspiration was determined by the soil water balance method, and the reference evapotranspiration was estimated by the method of Penman, used to analyse the behaviour of the crop coefficient (K(c)) throughout the crop growing period. The maximum crop daily water use was 4.33 mm d(-1) and the total water consumption was 333.6 mm for the whole growing period. The crop coefficient values varied from 0.50 to 0.74. A characteristic curve of K(c) for the table grape vegetative cycle was obtained which allows to obtain daily values of K(c) as a function of days after pruning.
[Show abstract][Hide abstract] ABSTRACT: The field experiment was conducted at the Bebedouro experimental basis of the EMBRAPA/Semi-Árido in Petrolina-PE, during the growing period from may to august, 1996. This study had the objective of determining the seasonal behaviour of the crop coefficient of a five-years-old wine grape (Vitis vinifera L.) vinecrop, variety Italy, grown in a trellis system. The crop evapotranspiration (ETc), determined by the soil water balance method and the reference evapotranspiration (ETo), estimated by the method of Penman were used for analyzing the behaviour of the crop coefficient (Kc = ETc/ETo) throughout the crop growing cycle. The micrometeorological parameters were monitored continuously at 1m above canopy with sensors wired in Data Loggers. The tensiometry measures were made daily always before irrigations and the leaf area was obtained weekly. The crop coefficient (Kc) values showed to be comparable to those suggested by FAO with a small difference in the phenological phases of fruits formation and development when there was a greater contribution of the soil water table to the roots zone and a resulting underestimation of the Kc values to be applied in the irrigation calculus. It was obtained a characteristic curve of Kc for the wine grape vegetative cycle, which allows to obtain daily values of Kc as a function of days after pruning (DAP) by the adjustment equation : Kc = -8.10 -5 (DAP) 2 + 0.0091(DAP)+ 0.4886, with r 2 = 0.97.