Alteração química no solo irrigado por gotejamento e microaspersão com água residuária no cultivo da bananeira

Abstract

The reuse water for non-potable purposes has been driven around the world due to increasing difficulty in meeting a growing demand of water for public supply. Moreover, the use of wastewater in agriculture has been presenting itself as an alternative to reduce their environmental impact by generating economic benefits and increased crop yields. The objective of this study was to evaluate the effect on the irrigation system and soil chemical properties by application of treated effluent of domestic sewage, water and semi-artesian well conventional fertigation, applied by drip irrigation and micro irrigation culture Banana (Musa spp. (AAA)) cv. Grande Naine. The experiment was conducted during October 2009 to November 2010, the State University of Goiás - UEG, located in the city of Anapolis-GO. The experimental design was randomized blocks in factorial 3 x 2 with four replications, with treatments consisting of the combination of the three water quality (Ap: water semi-artesian well, air, wastewater, Af: fertigation) and two types of irrigation (Ig: surface drip irrigation, Im: micro sprinkler irrigation). We evaluated the physical and chemical wastewater and well water, the uniformity of water distribution systems for irrigation and chemical characteristics in the soil profile in layers of from 0.00 to 0.20 m and 0.20-0 , 40m at the beginning and end of the experiment. The results show that the quality of wastewater presented for use in irrigation restrictions related to hardness, iron and manganese, with average values of 435 mg L-1, 1.79 and 1.34 mg.L-1 mg.L -1, respectively, considered medium to high risk for clogging of drippers. However, after a period of 140.85 hours of operation of drip irrigation and 82.20 h of operation of the sprayer, there was no obstruction of the transmitters and emitters, presented the results of good excellent uniformity of the distribution system. A reduction in CUD compared to the beginning of the cultivation of 13.67% and 1.93% in drip and micro sprinkler, respectively. The EC assessment of wastewater and RAS showed moderate risk and severe, respectively, soil salinization, may cause medium-term reduction in soil infiltration rate. With respect to the parameters analyzed in the soil pH was a limiting factor in the development of culture, remaining below the recommended for the cultivation of banana, coming to have a pH 3.93 In order to treat and is very acid to the culture. Calcium, phosphorus, magnesium and zinc showed increases compared to baseline both in profile and in the 0.00 to 0.20 m from 0.20 to 0.40 m. Highlighting the match that had an increase of 2775% in the treatment APIM layer 40m from 0.20 to 0. Even with that showing nutrient additions, are still below the rates indicated for the cultivation of banana. The values of copper, manganese and sodium, in general, showed reduced levels in the soil as compared to initial, probably due to absorption by plants. The results show that the use of treated effluent of domestic sewage can be a viable alternative to the irrigation of banana using both the micro and drip irrigation.