CENTENO, C. R. M.; http://lattes.cnpq.br/4929183533136683; CENTENO, Cruz Ramón Marenco.
Resumo:
The castor-oil plant (Ricinus communis L.) is an oleaginous species which belongs to the
Euphorbiaceae family. It is originated from Ethiopia and is normally cultivated under rain-fed
conditions, which is relevant to the diversification of family agriculture and it is an important
alternative to the progress of Brazil's northeast region. The experiment was conducted at
Bahia's Federal Institute, inside the area for experiments on irrigation and drainage at the
Senhor do Bonfim Campus. The objective of this work was to evaluate the water use in the
castor-oil seed crop, BRS energy, irrigated with water containing different levels of salinity.
The average crop cycle used was of 120 days, and the experiment began in September 2008
and ended in January 2009. The experimental design was composed of three repetitions, with
a total of 21 experimental units. The reference evapotranspiration (ETo) was determined
through the grass lysimeter method and the collected data were compared with the estimated
data, through the Hargreaves-Samani empirical method. The crop evapotranspiration (ETc)
was measured through the water balance method. It was also obtained to the BRS energy the
crop coefficient (Kc), the production and the water efficient use. It was used the statistical
software (STAT) for the data analysis and the treatment average were compared to the Turkey
test with 5% of probability. The daily average values of the ETo which were measured during
the cycle by means of the grass lysimeter, and estimated through the Hargreaves-Samani
method, was 5.5 mm and 4.4 mm respectively. The average value of Kc, from the moment of
sowing until the 79 DAE, was 1.11. It was observed that the total crop water consumption
was gradually lowered according to the salinity levels used, and the largest reduction was
identified in the water with a CEa of 4.8 dS m~'. The efficient use of water in the crop cycle
was not altered on account of the fact that the amount of water used in the treatment was
directly related to the crop efficiency itself. In other words, for the treatment in which a water
supply (the witness) was used, the crop utilized a larger amount of water in order to yield
more, since the plant showed a better growth and development when compared with the ones
which were irrigated with water containing different levels of salinity, that is, they showed
lesser growth and development, indicating low use of water.