ENVIRONMENTAL FRAGILITY HIDROGRAPHIC BASIN OF RIBEIRÃO DA PICADA, JATAÍ, GOIÁS/BRAZIL

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1 ENVIRONMENTAL FRAGILITY HIDROGRAPHIC BASIN OF RIBEIRÃO DA PICADA, JATAÍ, GOIÁS/BRAZIL Régia Estevam Alves MS in Geography from the Federal University of Goiás / Brazil (regiaestevam@gmail.com) Helder Barbosa Paulino Dr. in Agronomy / Department of Agronomy, Federal University of Goiás/Brazil Alécio Perini Martins MS in Geography / Department of from the Federal University of Goiás / Brazil PROJECTO REPORT Brazil presented in the 80's a characterization of Brazilian soils (scale 1:250,000 ), which presents the methodology used, low accuracy with respect to refinements of soil, which can vary in scales less than those used by RADAMBRASIL. So in many regions, the political actions for land use, and consequently of the different watersheds, based on the work environment has imposed an environmental pressure, which often has not been supported, thereby causing problems of environment degradation in different levels depending on the fragility of the environment. In that sense the present study aimed to evaluate the environmental fragility Basin Ribeirão da Picada, in a scale 1:85.000, located in the municipal district of Jatai, Goias / Brazil, as an aid in the management of the basin with emphasis on soil conservation and water. The watershed has approximately km ² in extent, comprising several farms, a process for use and occupation occurred at different times for the use of intensive grazing, which inferred the landscape (Figure 01). To conduct this study was carried out mapping of environmental fragility from the use of GIS (Geographic Information System), and physical and chemical analysis of soils. We used satellite images, which were treated in the Spring software and ArcGIS 10.

2 Figure 01: Location map of the basin of the Ribeirão da Picada, city of Jataí Goiás/Brazil. From the mapping of land use over a period of twenty years, it was observed that large areas were cleared of vegetation of the Cerrado biome, including the banks of the river drainages, in violation of the law (4.771/65). Another important aspect observed was the conversion of native vegetation in areas with ecological function, which imposes the biome changes in ecological relationships between species. Thus the increase of forest areas and reduction of the Cerrado areas endangers the flora and fauna of this region. Moreover, there is an increase in areas with bare soil, reflecting the inclusion of these areas for agricultural production and especially to the advanced stage of degradation and failure to provide the development of vegetation cover (Figure 02).

3 Figure 02: Maps of land use Basin Ribeirão da Picada, city of Jatai, Goias/Brazil. Thus, for over twenty years, the soils in this basin have been intensively used for grazing without proper management, especially downstream of the basin, where there are sandy soils, Órticos not initially identified by RADAMBRASIL (1982). The soils of the basin are predominantly weak, inadequate physical and chemical conditions to promote the production of biomass suitable for the protection of these. So once in stage of degradation of soil and environment, the recovery of these becomes slow and costly, given the increasing importance of organic matter in these soils, which is formed from the remains of plants and animals, which have not found environmental conditions are produced in amounts suitable for return to their function ecological environment. This is due, as shown in Table 01, the values of ph, CEC, Base saturation and soil sand, silt and clay. The values found indicate that the soils of the study area and presents a high fragility, do not have adequate levels of nutrients to be revegetated, conventional crops, without using fertilization techniques, soil amendment and irrigation.

4 Table 01: Analysis of soil texture Basin in the city of Jataí - Goiás / Brazil in the year Soil classes / Sample under Cerradão under Cerradão under Cerradão Red Oxisols under Red Oxisols under Red Oxisols under Red-Yellow Oxisols Depth Texture Chemistry Clay Silt Sand Organic material ( g.dm -3 ) ph Cmolc.dm - (meq.100c m -3 ) Cation exchange capacity (Cmolc.dm -3 ) Saturation for bases 0-20 cm 0, 015 0,025 96,0 8,5 4,1 3,23 7, cm 0,015 0,025 96,0 5,8 4,0 2,66 2, cm 0,015 0,025 96,0 3,1 4,1 2,33 1, cm 0,02 0,025 95,5 10,3 3,9 3,40 3, cm 0,045 0,025 93,0 8,4 3,9 2,65 2, cm 0,045 0,025 93,0 5,3 4,0 2,75 1, cm 0,045 0,075 47,5 27,0 4,2 10,4 9, cm 0,03 0,05 65,0 18,4 4,0 8,1 3, cm 0,025 0,025 75,0 14,4 4,0 5,4 3, cm 0,17 0,044 79,4 10,8 4,5 4,89 4,89 Red-Yellow Oxisols cm 0,19 0, ,9 8,2 4,6 3,66 3,66 Red-Yellow Oxisols cm 0,17 0,079 4 Ultisols 0-20 cm 0,24 0, ,5 6,9 5,5 3,56 3,56 68,4 27,2 5,4 8,94 8,94 Ultisols under Ultisols under cm 26,29 0, cm 0,27 0, ,7 27,3 5, ,68 67,5 20,2 5,2 8,81 8,81 The results (Figure 03) indicate that in general, the soils of the watershed Ribeirão da Picada have fragile natural, but is enhanced with the types of abuse / exploitation that has been submitted. Thus, this basin presents emergent fragility considered very strong, considering anthropogenic actions on the ecosystem. So you can see, across the Basin Ribeirão da Picada, various types of degradation, for example, in various advanced stages of erosion, siltation of rivers and sandy desertification / desertification (Figure 04).

5 Figure 03: Mapping of the fragility of the Enviromental River Basin Ribeirão da Picada, city of Jataí - Goiás / Brazil. Figure 04: fades as intense, erosions, arenization / desertification and silting of rivers in the basin of the Ribeirão da Picada, city of Jataí - Goiás / Brazil, 2011.

6 Thus it is concluded that it was important actions in order to find management alternatives for the disturbed areas, as well as recovery policies of the native flora, to not only preserve the soil, but above the plant species and water, responsible for maintaining fauna. In addition, there should be more detailed studies in Brazil basins, in order to try to assess the occupation of Brazilian ecosystems. BIBLIOGRAPHY PROJECT RADAMBRASIL. National Integration Program. Survey of natural resources, vol. 31, Sheet SE. 22, Goiânia: geology, geomorphology, pedology, vegetation and land use potential. Rio de Janeiro, 1982.