Introduction of uncertainty into trade-offs between productivity and life cycle environmental impacts in rice production systems: assessing the effectiveness of nitrogen-concentrated organic fertilizers.

We compared three rice production systems, the system using a pelletized nitrogen concentrated organic fertilizer, the system using a conventional organic fertilizer, and the system using a chemical fertilizer, by calculating life cycle greenhouse gas (GHG) emissions. Two-dimensional uncertainty regions were introduced into the land-oriented expression, which was established to assess efficiency of agricultural production systems on the basis of constant returns to scale (CRS) and variable returns to scale (VRS), to analyze stability of the comparison. The results indicated that the rice production system using a high nitrogen organic fertilizer was recognized as a promising alternative and that this approach was useful in understanding the stability of the results through detecting overlaps among uncertainty regions.