Identification and diagnosis of salt-affected soils in the baixo-açu irrigated perimeter, RN, Brazil

Abstract

Soil salinization is one of the main environmental problems in arid and semi-arid regions. Thus, the objective of this study was to evaluate the problems of soil salinity in an area of the Baixo-Açu Irrigated Perimeter, RN, Brazil, through joint analysis using remote sensing, pedology and geostatistics techniques. The study was conducted in the Baixo-Açu Irrigated Perimeter (1500 ha), with soil salinity sampling at 42 points, used to correlate with the Salinity Index 1 (SI1) spectral index. After spectral analysis, one of the lots identified with salinity problems was selected and subjected to pedological analysis to classify the problems of soil salinity in surface and in subsurface. Subsequently, 45 points were sampled in the same lot to assess the spatial distribution of soil salinity and diagnosis of the problem of salinity using geostatistical analysis. The SI1 index in areas with Normalized Difference Vegetation Index (NDVI) < 0.33 showed the highest correlation with soil electrical conductivity. The soil in the evaluated area showed saline horizon in surface and saline-sodic horizon in subsurface. The areas most affected by salinity are concave areas, with deficiency of natural drainage.