Mineralogical Characterization of Pozuzo District's Soils through Physical Techniques

We introduce a study on soils in three different fields of plantations in Pozuzo District, Oxapampa province, Peru. Two of the fields are cultivated and the third one has a degradation problem. In situ, in all, we collected 29 samples in the three plantations. We utilized analytical and physical techniques, namely, energy dispersive X-ray fluorescence, X-ray diffractometry, and transmission Mossbauer spectroscopy; we complemented our research with a physical-chemical analysis to determine texture, pH, content of organic matter and cation interchange capacity. For all analyzed samples, the results of the analysis by energy dispersive X-ray fluorescence show the presence of the following elements: Si, Cl, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Rb, Sr and Zr. By X-ray diffractometry, we observe the structural phases associated with quartz, montmorillonite, illite, microcline, kaolinite, muscovite, and iron oxides such as goethite and hematite. By using transmission Mossbauer spectroscopy, we observe the presence of magnetic sextets assigned to Fe3+ from hematite (Fe23+O3) ; doublets associated with Fe3+ and Fe2+, respectively, localized in illite and/or interstratified montmorillonite; similarly, we observe other states attributed to a Fe3+ site. The results of the physical-chemical analyses of the plantations are of great importance to determine the soil conditions. Furthermore, a low level of organic matter is observed with a pH ranging from 4.6 to 6.0, what limits the nutrient absorption by the plants.