COELHO, D. K.; http://lattes.cnpq.br/0167224406405533; COELHO, Daniel Kühner.
Resumo:
This study was carried out aiming to evaluate the effects of irrigation with saline waters,
reproducing ion ratios found in produced water from Petrobras in Rio Grande do Norte, and
incorporation of castor cake, as organic matter, on growth, development and production of
castor bean, besides water and ionic balance in the soil-water-plant system, in greenhouse of
UFCG. The experiment was installed in randomized block design, in 5 x 2 factorial, with five
levels of water salinity (0.2, 0.8, 1.6, 2.4 and 3.2 dS.m"1, at 25 °C) and without and with
addition of castor cake (100 g) in substrates, resulting in ten treatments with three
replications. The pots were filled with soil material from Carnaubais - RN, and fertilized with
nitrogen, phosphorus and potassium. The percentage of germination and velocity of
emergence decreased 5.72 and 7.71% per unit increment of electric conductivity of irrigation
water (ECw), due to irrigation waters salinity, and were 40.8 and 26.6% higher in treatments
without castor cake. During growth and development phase, a negative effect in plants by
addition of cake was observed in the initial phase, with decrease of 22.8% in plant height,
9.3% in stem diameter and 23.8% in leaf area, 40 days after sowing (DAS); and for the
salinity increases, possibly associated to the fermentation of castor cake in soil, after 80 DAS
the decreases per unit increment in ECw were 6.56% in plant height, 5.69% in stem diameter
and 18.15% in leaf area. As propagation of the effect of growth and development phase, unit
increment in ECw promoted decrease of 14.58% in number of fruits, while addition of castor
cake reduced the value of inflorence emission by 6.5%. The volume of water consumed was
reduced by salinity of irrigation water, with decrease of 9.54% per unit increment in ECw. It
was concluded that the increase of the salinity in irrigation water promoted significant
negative effects in germination, growth and development of castor bean and raised the ECse
and soil pH, reflecting in water consumption and yield of the crop. While the castor addition
of cake caused damage to the crop in its initial phase.