EFFECTS OF PROCESSING COFFEE WASTEWATER ON FIRST YEAR COFFEE PLANTS GROWTH

Using the soil as a form of treatment and final disposal for coffee wastewater (CW), considering its water and nutrient content to the coffee, solves environmental problems and reduces production costs for coffee growers. This research had the objective to evaluate the influence of different potassium levels from WC on the growth of (Coffea arabica L.), 'Catuai' and 'Catucai' coffee varieties, in their fist year, as well the potassium increase and electrical conductivity in the soil solution. The experiment was carried out in a greenhouse of the Engineering Department, of Universidade Federal de Lavras, in Lavras - MG, Brazil. The treatment levels were defined as: 30 mg L-1; 65 mg L-1; 100 mg L-1; 135 mg L-1 of potassium (K+), applied through CW and the control (irrigation water and conventional fertilization). Coffee processing wastewater with concentration up to 135 mg L-1 of potassium contributes to coffee growth, specifically, plant height and shoot diameter, showing to be equal or even better than irrigation water and potassium via conventional fertilizers. In addition, during the period evaluated the increase in soil potassium concentration was not enough to increase electrical conductivity to levels that could affect plant growth.