Energy Status of Soil Agro-ecosystems

Abstract

The activity and resilience of agro-ecosystems depend on soil – as a reservoir and biochemical reactor transforming substances and energy. But under cultivation, energy reserves have been much depleted. Protection of soil functions and solar gain in the form of soil organic matter is a priority for environmental protection.

Energy stocks under the plough with addition of green manure and mineral fertilizer, and with addition of farmyard manure, are compared with stocks under the same treatments under conservation tillage. In chernozem, there is no evidence of stabilization of the humus content at a new equilibrium value under arable farming; the energy balance of conventional crop rotations is profoundly negative. Over 38 years, a six-field rotation with application of 60 tonnes/ha farmyard manure every cycle lost 19–29 % of its initial organic matter; under mineral fertilizer with one catch crop of green manure, losses were 30–33 %.