ABSTRACT
CHAPTER 6 This chapter discusses thermodynamics on agricultural systems (man-made and controlled ecosystems). It is the so-called eco-energetic approach which looks into all the inputs and outputs of energy to an agroecosystem, but most often not including the solar radiation. The energetic efficiency is found as the ratio energy outputs to energy inputs. Two additional concepts are used in the thermodynamic analysis and comparison ofagroecosystems: (1) energy flow density, defined as the energy flows per unit of area and (2) redundancy index which can be calculated as 1-H/ln N, where H is Shannon's index (also sometimes called information entropy) and N is the total number of flows. The redundancy index is smaller the more homogeneous the energy allocation is among the flows and the more aligned the hierarchy of the flow.
