Presentations 2016

PHYSICAL AND CHEMICAL WATER FEATURES AS INDICATORS OF CHANGES FROM SOIL MANAGEMENT AND LAND USE

APTA

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Different land uses interferes on soil and water quality of hydrological resources. Water parameters evaluating can express the changes in a watershed over a period of time and its relationship with the management adopted as indicators of changes. With this aim the monitoring of the implementation of an Agroforestry System under different management in the water quality of four reservoirs of the Gully Watershed, Pindorama-SP, Brazil was done determining in situ four physico-chemical parameters (pH, electrical conductivity, dissolved oxygen and temperature) from July to October 2011. The water quality was monitoring in four dams under different management and water sampling was done every day when there was at least on-site activities as: fertilization, planting, hollow opening, irrigation, rotating or mowing and weekly when there was no activities. The water samples were taken before and after each activity. The revegetation after the dams construction was part of the recovery project to established a gully erosion process. The different managements resulted in 4 treatments: T1/Dam1: trees planted without tilling the soil, in hollows of 0.30 cm x 0.30 cm x 0.60 cm deep, spaced 3 x 2m, with control of weeds using lines coupled to the tractor and mower, without annual crops between rows; T2/Dam2: trees planted in hollows, spaced 3.5m x 2m, weed control with herbicide Roundup WG and annual crops (corn) between rows of tree in no-tillage system; T3/Dam 3: trees planted in furrows with soil tillage and furrow opening using soil disk and trencher, spaced 3.5 x 2m, annual corn crop under conventional tillage; T4/Dam4: trees planted in furrows with soil tillage using soil disk and trencher, spaced 3.5 x 2m with no annual crops between rows. The proposal of the plantation was to manage differently the plantation from a minimum interference on the soil (Treatment 1) to intensive tillage and no vegetation protection (Treatment 4). The means of each parameter were compared with completely randomized design and 5 % Tukey test. The means value of each parameter varied in each of the reservoirs, the pH ranged from 7.44 (T1) to 7.76 (T4), dissolved oxygen ranged from 6.09 mg L-1 (T1) to 6.43 mg L-1 (T2). Considering each reservoir separately, there was statistical difference between the parameters during the four months of evaluation suggesting that the evaluation of water resources can be a useful tool to evaluate the interference of different agricultural activities and their implications on the environment.