Application of hydrological model HidroBacia in Jaqueira stream watershed, Espirito Santo

Hydrologic simulation of watersheds is an useful tool for the water resources management and to reduce environmental degradation in watersheds. This work evaluated the applicability of the hydrologic modeling in a small watershed using the HidroBacia model at Alegre-ES and compare the results of flow maximum (Q(max)) and surface runoff flow (LES) in watershed "outlet" with rational methods (MR) and Curve Number (MNC). The soil water infiltration process is represented by means of the Green-Ampt equation, modified by Mein and Larson (GAML) in this model. This equation needs the parameters: matric potential in the wetting front, hydraulic conductivity and soil moisture in the "field saturation". This work assessed seventy two input combinations of parameters for equation GAML. Compared to real data (obtained at the watershed "outlet") the Q(max) and LES with the simulated by HidroBacia and by the MR and MNC. Verify in this work seven best combinations estimated Q(max) and LES in simulations with HidroBacia. The simulated data by the MR and MNC overestimated Q(max) and LES, respectively. Therefore, for experimental condition, recommend the use of hydrological model HidroBacia to estimate both parameters the Q(max) and the LES.3452103211

Water Storage In The Soil Profile Under Subsurface Drip Irrigation: Evaluating Two Installation Depths Of Emitters And Two Water Qualities

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Knowledge about soil moisture is essential to maximize irrigation efficiency because it allows the application of water in the proper quantity and at the proper time, thus improving water management. The objective of this study was to evaluate water storage in the soil profile when using a subsurface drip irrigation system at two emitter installation depths (0.20 or 0.40 m) and two water qualities (treated sewage effluent (TSE) and freshwater) in two crop cycles of sugarcane (Saccharum officinarum L.) in Campinas SP (Brazil). The experiment was conducted in the experimental area of FEAGRI-UNICAMP, Campinas-SP, Brazil, adopting a randomized block design (RBD) in a factorial 2 x 2 + 1 with 3 replications. The factors studied included the installation of dripper tube at two depths (0.2 and 0.4 m) and two qualities of water (TSE and freshwater) plus a non-irrigation control. The TDR (time domain reflectometry) technique was used to evaluate the moisture in the soil profile by installing five probes with rods at 0.2 m up to 1.0 m depth. Replacement of the calibration equation provided by the TDR reduced the water depth between the first ratoon and the sugarcane plant and reduced the excess humidity from 0.029 and 0.045 cm(3) to 0.002 and 0.007 cm(3) when the drippers were installed at 0.2 m depth (T2 and T4). The installation of a 0.2 m drip tube proved to be an ideal solution for both environmental management and water use efficiency when using treated sewage effluent. No effect on the water distribution in the soil was observed when comparing the water qualities. For management of subsurface drip irrigation by the water balance in the soil, different layers in the soil profile should be considered to calculate the water depth, using the depth of the drip tube installation as a reference. (C) 2015 Elsevier B.V. All rights reserved.1709198FAPESP [2010/15382-8, 2011/07301-0]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

EVALUATION OF SOME PHYSICAL ATTRIBUTES OF AN OXISOL UNDER DIFFERENT CROP COVER

Soil attributes are dynamic and are subject to change according to the use and management adopted, is important for determining its best use agricultural soil. Thus, it was aimed to evaluate some physical attributes (particle size, water dispersible clay and flocculation) of an Oxisol on different uses, namely: cultivated with two species of legumes and natural vegetation, in an area previously cultivated with vegetables, for about 10 years, under intense agricultural mechanization and application of lime and fertilizer. The experiment was conducted in a randomized block design, being conducted in factorial 2 x 3, two depths (0 to 20 and 20 to 40 cm) and three cover crops, with four replications. Data were submitted to analysis of variance and averages compared by Tukey test at 5% probability. It was observed that the slow agitation provides better physical dispersion when compared with the fast agitation, showing greater accuracy and precision. The values of clay dispersed in water are larger at a depth of 20-40 cm. The soil under Mucuna pruriens L., in depth of 20-40 cm, has a higher value of water dispersible clay in water compared with to other cover crops and the soil under natural vegetation greater degree of flocculation this depth.26694094