Energy analysis of wetland rice systems in Thailand

Abstract

An energy analysis of wetland rice systems in Thailand indicates that the traditional practices were largely dependent on deposits of organic silt from flooding, which accounted for 49% of the total energy input for the transplanting and 48% for the direct seeding systems. The ratio of total grain output to total input was 4.5 for the transplanting system and 2.7 for the direct seeding system. In the quest for yield, profit and ease, wetland rice cultivation practices have been changed. Today, the industrially based inputs account for 69% of the total input for the direct seeding system, and for 23% in the transplanting system. The number of persons fed by the transplanting system has increased from 8.7 to 20 ha −1, and by the direct seeding system from 5.3 to 12.5 ha −1 year −1. Increasing energy yields per unit area have been accompanied by a greater input intensity, resulting in decreasing energy efficiency. The ratio of total grain output to total input has decreased to 1.2 for the transplanting system and 0.3 for the direct seeding system—a clear case of diminishing returns.