Avaliação de indicadores de impactos ambientais no perímetro irrigado Cruzeta-Região semi-árida do RN

Environmental impacts are defined as the processes of social and ecological changes caused by nuisance ambient. In agriculture are diverse, and the intensive use of land and inappropriate agricultural practices causes negative effect on the environment besides affecting crop productivity and quality of life of man. So this study was objective to analyze parameters indicators of environmental impacts in the Cruzeta the Discrict Irrigation. During the period July 2007 to March 2008 samples were collected in lot 01 and 02 of the irrigation district. The monitoring was conducted in four sampling points, three (3) located in the irrigation channels and 1 (one) located in a cacimbão. Were monitored pH, CE, STD, SS, NO3-, OD, DT, PST, RAS, CT, Ca+2, Mg+2, Na+ and K+ and heavy metals. Analysis was performed, soil fertility, determining the infiltration rate, moisture content of soil and flow measurement. The results showed that the parameters considered most effective in evaluating the indicators of environmental impacts were: Suspended solid, turbidity, dissolved oxygen and Coliform termotelerantes. The concentrations of nitrate were below the limit established by CONAMA (2005). High levels of STD were found in the point P4. The risk of salinity in cacimbão Lot 02, the water was classified as Class II, or medium risk of salinity in the remaining points was classified as Class I. The iron and aluminum were found high concentrations in four sampling points independent of the dry or rainy. On the ground, found high levels of phosphorus in both samples collected in the batch 01, as the lot 02. The pH levels found in samples of soil, the soil can be classified as neutral and moderate alkalinity. The high infiltration rate obtained in the tests performed in lots 01 and 02 indicated the high permeability of soil at these points

Evolução da paisagem do baixo curso do rio de Piranhas-Assu (1988-2024): uso de autômatos celulares em modelo dinâmico espacial para simulação de cenários futuros

The lower course of Piranhas-Assu river, located in the north coast of Rio Grande do Norte, Brazil, arouses a keen interest as a study field, once it concentrates, besides petroleum and gas exploration, activities related to shrimp culture, salt and horticulture, factors that also deserve special attention. Thus, the awareness of the study field environmental stage demands studies from researchers and discernment from society, as a way of understanding the inter-relation between environment and men. Therefore, this work attempts at understanding and studying the dynamics of land use in the lower course of Piranhas-Assu river, through a multitemporal analysis of present and past, accomplishing future projections through simulation models. The work is divided in stages that include the research, analysis, interpretation of results, and the generation of simulation models, to analyze the landscape tendencies, making possible to identify indicators which cause such changes in the lower course of the river. From Geographical Database, the necessary exploratory analyses were accomplished to the following items: land use evolution, natural and environmental vulnerability, multiple geodiversity indexes, and preparation of the data to be used in the simulation model. Later, the construction of the landscape simulation model was conducted. Sequentially, simulations of future sceneries were accomplished through the execution of the model in a specific software environment. Last, the analyses of landscape tendencies in the study field were carried out. The lower course of Piranhas-Assu River didn't show any intense dynamics in landscape changing, once in the period taken into account (from 1988 to 2004) class stability proved to be superior to its transformations. Activities related to agriculture and livestock are the ones that influence, mostly, the landscape dynamics. The production of sea shrimp and petroleum also infers in the landscape, although in smaller proportion. INCRA s public policies excessively determined the dynamics of the landscape in the lower course of Piranhas-Assu River, RN. In respect to its natural vulnerability, the lower course of Piranhas-Assu River, RN, features more vulnerable than stable areas. The landscape simulation, in the first taken period (2004-2009), indicated considerable increases and decreases of antropic activities, if compared to its sequent periods (2009-2014, 2014-2019 and 2019-2024). The simulation, in a wider analysis, showed that the determining factors for the space mobility of antropic activities, in the focused area, are related to the pre-existence of communities with agricultural capability and to the existence of access routes and drainage. Considering the area that features fixed and mobile dunes, located in Porto do Mangue district, we recommend its conversion into a conservation area