LIMA, A. S.; Antônio Suassuna de Lima.; LIMA, ANTÔNIO SUASSUNA DE.; http://lattes.cnpq.br/1629414012209201; LIMA, Antônio Suassuna de.
Resumo:
For a better agricultural performance in the Northeast of Brazil, an adequate
management of irrigation water is necessary. This has stimulated the cultivation of
crops with high water use efficiency, for example, the fodder palm, which although it is
adapted to regions of semi-arid climate, presents changes in production according to
water availability. The objective of this study was to determine the water requirement,
the thermal demand and the coefficient of cultivation of fodder palm varieties in the
semi-arid region of Brazil. Three varieties of fodder palm were used (elephant ear
Opuntia fícus-indica L.; baiana and chick Nopalea cochenillifera Salm) in a field
experiment in Santa Luzia-PB, fertirrigated with 150 kg ha-1 of N. The soil water
balance was performed to determine the actual crop evapotranspiration (ETr) under
hydric restriction. For the determination of crop evapotranspiration (ETc) and thermal
requirement, three lysimeters of drainage located in the center of the experimental area
were used. Each lysimeters contained four plants with similar characteristics and under
the same management system of the external plants. A fourth lysimeters was planted to
determine reference evapotranspiration (ET0). Based on the emission of cladodes and
the sum of degrees days, four phenophases were determined for the forage palm. The
mean reference evapotranspiration values determined by Penman-Monteith (ET0PM) and
by lysimetry (gram) (ET0G) were 6,2 and 7,2 mm d-¹ respectively. The daily mean
values of actual crop evapotranspiration (ETr) and crop coefficient (Kc) under water
restriction were: 1,4 mm d-1 and 0,31; 0,27; 0,27 for the elephant ear varieties; baiana
and chick respectively. The daily average values of crop evapotranspiration and crop
coefficient determined by means of lysimeters of drainage were: 4,8; 4,8 and 4,6 mm
day-1 and 0,72; 0,70 and 0,70 for the elephant ear, baiana and chick varieties
respectively. The basal temperature of the palm was equal to 18 °C for the three
varieties and the accumulated thermal sum in the period was over 4000 °C.