Towards an Exergy Methodology to Assess the Fertility of Topsoil

EasyChair Preprint 3450

Abstract

Feeding of global population is threatened by soil degradation, which affects around 38% of the world´s cropland. Soil fertility, defined by FAO as “the capacity of the soil to support the growth of plants on a sustained basis, yielding quantities of expected products that are close to the known potential”, is correlated with soil degradation and erosion. Soils are complex systems constituted by physical, chemical and biological properties. Due to the soil’s complexity, the measure of fertility or degradation represent an unsolved problem. Exergy is a tool with potential to be used in soil evaluation. A methodology to calculate the exergy value enclosed in a fertile soil due to its inorganic, organic and biological components is developed in this study and will be used to assess soil fertility, degradation and quality. As a starting point, the exergy of an ideal topsoil with optimal attributes called “OPT soil” is established in this study. The “OPT soil” is based on agronomic knowledge and will allow to establish a theoretical general line useful to perform exergy evaluation of the soil and compare the degradation degree of any soil with respect to the optimum. Chemical, concentration and/or comminution exergy is calculated for the defined values of the different inorganic, organic and biological components in the “OPT soil”. The exergy values of “OPT soil” are calculated using Thanatia as a reference. Thanatia represents the maximum state of degradation and it is the baseline to measure the exergy of substances on Earth through its abundances. Thus, the establishment of the values defining the “OPT soil” and the methodology to calculate its exergy will allow the quantification of the exergy level of any soil and its degradation.

Keyphrases: Exergy, Soil degradation, Thanatia, Topsoil, soil fertility

@booklet{EasyChair:3450,
  author    = {Antonio Valero and Bárbara Palacino and Sonia Ascaso and Alicia Valero},
  title     = {Towards an Exergy Methodology to Assess the Fertility of Topsoil},
  howpublished = {EasyChair Preprint 3450},
  year      = {EasyChair, 2020}}