Resposta espectral de sedimentos de reservatórios do semiárido brasileiro

Assuming that physico-chemical attributes affect the spectral curve of sediments, the objective of this work is to study the relationships of organic matter, phosphorus, nitrogen and granulometry with the laboratory spectral reflectance (350 to 2500 nm) of Brazilian semiarid sediments from the bottom of reservoirs. The study was carried out in the reservoirs Pereira de Miranda and General Sampaio, belonging to the watershed of the Curu river, in the state of Ceará. The results showed that sand and silt produced positive and negative correlation with reflectance, respectively. The best correlation for them was obtained in the band positioned at 662 nm. The clay had negative correlation with reflectance, especially at 2290 nm. The mostly correlated chemical attribute with reflectance was organic matter with negative coefficients from 567 to 761 nm, and a correlation peak at 662 nm. For phosphorus, the correlations were positive and from 0.37 to 0.63 with a maximum value at 511 nm. On the other hand, nitrogen behaved differently, with much lower correlation coefficients (0.19 to -0.17). We concluded that the spectral reflectance of sediments from the bottom of reservoirs can be used to estimate their physical and chemical attributes, confirming that the reflectance spectroscopy is a valuable tool for this purpose.