Francisco Lombardi Neto

Manejo da cobertura do solo e de práticas conservacionistas nas perdas de solo e água em Sumé, PB

The effect of the soil cover management and conservation practice on soil and water losses caused by the erosivity of rainfall in Haplargid soil have been analyzed in this paper. The field data corresponding to the years 1983-1990 were collected at the Experimental Basin of Sume, PB operated by the Federal University of Paraiba (UFPB). The experimental data resulting from one erosion plot cleared bare of vegetation and continuously ploughed in, two cleared bare runoff plots, one runoff plot with native semiarid vegetation, two mulched runoff plots, one plot with cactus planted down the slope and one plot with cactus planted along contour lines were used in the analysis. The bare ploughed plot contributed with annual soil and water losses of 23.1 t ha-1 and 201 mm respectively. In the cleared runoff plots, the soil losses were of 35.7 and 58.5 t ha-1 and the water losses of 224.2 and 241.0 mm, respectively. The runoff plot with native semiarid vegetation when compared with the bare runoff plots, showed a reduction in the soil losses of about 99% and the water losses of around 89%, while in mulched runoff plots there was a reduction of approximately 99% of soil losses and 74% of water losses when compared with the bare plots. The contour planted cactus plot reduced the soil losses by about 53.4% compared with the down the slope planted cactus plot.

Sistema de suporte à decisão para recomendação de uso e manejo da terra

The objective of this work was to develop a decision support system to recommend land use and practices for soil conservation and management, which integrates an Expert System, Geographic Information System (GIS), a database and an interface to monitor input and output data and the messages passed between the subsystems. Using soil and slope maps, the developed system determines land capability from information stored in the database and also supplied by SIG; it recommends adequate uses for land capability class as well as practices for soil conservation and management and identifies conflict areas comparing the maps of land use with the land capability. All results can be visualized by the user through windows of the program, recorded or printed in form of report. In order to test the system, the municipality of Santo Antonio do Jardim, in the State of Sao Paulo, Brazil, was selected. The system is a powerful and efficient tool, permitting the evaluation of a region and thereby offering support for adequate decision making.

Ajuste dos simuladores de dados meteorológicos do modelo EPIC para diferentes locais do Estado de São Paulo

EPIC (Erosion Productivity Impact Calculator) model has been developed to simulate the effect of agricultural management strategies of water resources and soil productivity. In this study, the performance of meteorological data simulators were evaluated for six (Campinas, Jau, Manduri, Mococa, Pindorama and Ubatuba) localities in the State of Sao Paulo, Brazil, which include the Markov chain probabilities for the sequences of wet and dry days; the maximum air temperature model adjusted for wet days; and the solar radiation model also adjusted for wet days. From tests and adjustments of the models using the historical data for each locality, the best performance for the model of probabilities for dry days sequence has been found, taking into account the last wet day - P(W|D) in relation to the model of probabilities of two consecutive wet days sequence - P(W|W). The maximum air temperature and solar radiation models have presented good performance in tests after the adjustment for each locality. For all models, the best results have been obtained from the local adjustments, when compared to the original model conceived for EPIC. Model results for Ubatuba data were distinct from the other sites.

Tentative Hydrologic Soil Classification for Tropical Soils

The Runoff Curve Number (CN) method is applied for estimating direct runoff from rainstorms. Its application is based on the selection of input “CN” from handbook tables of USA origin. The use of these tables is by default, insofar as CN determinations for various land use and soils have not been done for the local conditions. Soils are classified in four groups (A, B, C and D); from the lowest to the highest runoff potential. At this point, the most difficult task is classifying a soil because the general characteristics of the hydrologic soil groups (HSGs) do not provide objective criteria for applying the method outside the USA, mainly for regions or countries where there are highly weathered soils, such as Brazil. This happens because the criteria are mainly based on soil texture, once the steady infiltration rate data or saturated hydraulic conductivity data are not always available or obtained. Thus, after reviewing the current HSGs criteria, new ones were developed based on Brazilian soils to improve accuracy and consistency in allocating tropical soils to the appropriate group.