Growth and production of physic nut irrigated with wastewater, under water stress conditions

The physic nut is a Brazilian native crop of the Euforbiaceae family. The objective of this study was to evaluate the effects of different levels of the evapotranspiration replacement on the growth and production variables of the crop irrigated with domestic sewage. The experiment was carried out in drainage lysimeters under controlled environment. A statistical scheme in randomized block was utilized with four repetitions and five water replacement levels (Nr(1) = 0.25; Nr(2) = 0.50; Nr(3) = 0.75, Nr(4) = 1.00 and Nr(5) = 1.25 of evapotranspiration). Plant height, stem diameter, number of leaves, leaf area and the number of fruit bunches were observed. The soil used as substrate was an Argisol, sandy loam non saline. The irrigation was realized at two days interval and the quantity of water applied in each treatment was determined from water balance in function of Nr(4) level. At the end of the study it was verified that the water stress caused significant effect in all studied variables, which indicates the sensibility of the crop to the low water content in the soil.