Proton induced X-ray emission analysis of soils with various length of fallow: The effect on soil total elemental composition

Abstract

Fallowing of whatever kind is beneficial to elemental (nutrients) recovery. To what length (years) should a land be left fallowed for optimum elemental recovery is of serious concern to stakeholders owing to the limited availability of land. This work aimed at accessing the effect of fallow duration on soil total elemental composition. Proton induced X-ray emission (PIXE) technique has been used to assess the effect of relative longer length of fallowed land on soil total elemental composition using a 5SDH Tandem Pelletron accelerator available at Centre for Energy Research and Development, Obafemi Awolowo University Ile-Ife. The results at a 2.5 MeV energy revealed the presence of elements: Si, P, Ca, Ti, Mn, Fe, Zn, Rb and Zr with the only sharp difference being the fact that elements Zn and Rb were only detected in the soil of continuous cropping probably due to the agrochemical applications prevalent in the study area. The inter-elemental correlation trend revealed a significant positive correlation of P to Ti and Cr (.916 and .937) at P < 0.05 level of significance. A similar trend was obtained for Ca to Mn and Zr (.955 and .925). There was a very strong positive significant inter elemental correlation between Ti and Cr (.994) at P < 0.01 level of significance. On the whole, leaving a land fallow for a relative longer period of time is beneficial in nutrients replenishment.