Emergy assessment of integrated production systems of grains, pig and fish in small farms in the South Brazil

摘要

The present study uses emergy methodology to evaluate environmental aspects of integrated production systems of grains, pig and fish in small farms in the South region of Brazil. New emergy parameters that use partial renewability factor of each input were used to improve emergy accounting. These parameters were already applied to different case studies and are very appropriate for use in emergy assessment of integrated agricultural systems. The following indicators were calculated for the integrated production system of grains, pig and fish: transformity: 948,000 sej/J; renewability: 24%; emergy yield ratio: 1.44; emergy investment ratio: 2.28; environmental loading ratio: 3.13 and emergy exchange ratio: 6.8. These values were compared with results calculated for grains, pig and fish production subsystems working in a separated way. The results obtained signalize that an integrated system has better emergy efficiency, is more sustainable and is less stressful on the environment in comparison with separated production subsystems. The emergy indicators presented are discussed in the text and they will be useful in further work to assist the formulation of public policy, and also to recommend better management practices to farmers.