For decades there have been controversies related to the changes generated by oil palm plantations in the physicochemical properties of the soil, soil biota, and ecological interactions. Therefore, the present investigation evaluated root diameter and biomass at three ages of oil palm cultivation. Besides, we evaluated the effect of the ages on the physicochemical parameters of the soil in comparison with pasture plots. To know the diameter, fresh, and dry biomass of roots, soil sampling was carried out around the oil palm (3-, 5-, and 15-years-old) at distances of 1, 2, and 3 m from the trunk plant. Also, to know the changes in the properties of the soil, the sampling was carried out randomly in the same plots and the pasture plot (control). The results showed that both the diameter and the fresh and dry root biomass increased in 15-year-old plantations compared with 3- and 5-year-old. In addition, correlation analysis and principal component analysis indicated that the parameters evaluated are associated with the adult age of the oil palm. Also, the results of soil physicochemical showed that low soil fertility was associated with an increase in the age of the palm.

Currently, some concerns regarding the potential toxicity of nanoparticles (NP) on the environment have emerged. The effect of ZnO, TiO2, and Fe2O3 NP on corn (Zea mays L.), common beans (Phaseolus vulgaris L.), nanobioremediation of polycyclic aromatic hydrocarbons (PAH), and soil organisms from agricultural or forest soils was studied at laboratory, greenhouse, and land level. The samples were analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy with X-ray energy dispersion spectrometry (FESEM-EDS), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) gas chromatography (GC), ultra-performance liquid chromatography coupled to mass spectrometry (UPLC-MS) and Fourier transform infrared spectrometry with attenuated total reflectance (FTIR-ATR). ZnO-NP did not harm the mycorrhizal root colonization but, the presence of ZnO-NP decreased the degradation of PAH. The synthesis of metabolites from corn was more affected by the PAH than by ZnO-NP. FTIR spectra showed that NP affected the synthesis of compounds from specific functional groups in common bean plants. Fe2O3-NP were attached to the body of forest-soil organisms and significantly increased the concentration of Fe in their body, while TiO2-NP changed the morphological tissue of roots and stems of common bean as witnessed by micrographs of longitudinal and cross-sections. The NP used in this research significantly changed some response variables on the experiments carried-out at laboratory, greenhouse, and land level.