Desenvolvimento do pimentão irrigado com água residuária tratada.

Abstract

This work aims the evaluation of: the productivity of the pepper when irrigated with treated wastewater; the physical, chemical and microbiological qualities of the irrigation water, before and after the percolation of the soil; the physical, chemical and microbiological characteristics of the soil, before and after the application of the irrigation water; and the microbiological quality of the pepper's fruit irrigated with treated wastewater. The experiment was carried out in the time period beginning at July 19th to December 31th, in 2001. Two different varieties of pepper were cultivated, Yollo-Wonder and Rubi- Giant, which were drop irrigated individually by four different water types: Campina Grande's water supply system (Tl); polishing pond effluent with sand filter (T2); polishing pond effluent with cloth filter (T3); and UASB reactor effluent with sand filter (T4). The following physical, chemical and microbiological parameters were analyzed for the different irrigation waters: pH, electrical conductivity, ammoniacal nitrogen, nitrate, soluble orthophosphate, calcium, magnesium, potassium, total solids and fractions, fecal coliforms and Helminths. For the soil, the following parameters were analyzed: macronutrients, micronutrients, organic matter, Salmonella spp. and fecal coliforms. The analyzed nutritional parameters for the plants were the macronutrients and the micronutrients of the tissue of the plant's leaf, while for the pepper's fruits the microbiological parameters were analyzed, such as Salmonella spp.. and fecal coliforms. The production components and length and surface measurements were also analyzed. The electrical conductivity and pH values for the different irrigation waters varied from slightly to moderate and from neutral to slightly basic, respectively. The concentration of calcium was considered adequate for the irrigation waters, while the concentration of potassium and magnesium was above the recommended values. The wastewater used for irrigation presented elevated values of ammoniacal nitrogen and soluble orthophosphate, varying from 38,7mg/l to 48,7mg/l and from 4,53mg/l to 5,18mg/l, respectively. For the microbiological analyses, the concentration of fecal coliforms in the wastewater remained above the limit recommended by WHO (World Health Organization) (200 UFC/lOOml). The percolated waters presented high levels of nitrate, which required special attention. Before the irrigation process, the soil had lack of micronutrients, organic matter and macronutrients, except phosphorus, and after the irrigation process, the wastewater based treatments supplied the soil with the required macronutrients. The tissue of the plant's leaf presented adequate values of macronutrients, which did not happen for the case of micronutrients. The concentration of fecal coliforms and Salmonella spp. was bellow the limits recommended, which consequently does not represent health risk for consumers. The productivity of the plants irrigated with treated wastewater remained within the expected productivity range, which is from 20 to 40 t/ha, while the productivity of the plants using T2 and T4 treatments remained above the expected productivity for the Yollo-Wonder variety and presented values equals to 62,5 t/ha and 45,7 t/ha, respectively.