The Food and Agriculture Organization of the United Nations’ Sustainability Assessment of Food and Agriculture Systems (SAFA) is a tool covering multiple fields, including the governance, the society, the economy, and the environment to assess the sustainability of agriculture. This system has an important feature, integrated evaluation with many indicators. In the present study, the evaluation of the sustainability of fields, Ibaraki University, with combined 3 types of tillage (plowing, rotary tillage, and no tillage) and 3 types of cover crop (fallow, rye, and hairy vetch) in the environmental dimension was performed using modified SAFA rating method. The objective numerical data in GHG (Greenhouse Gas) absorbance, soil properties and fuel consumption were used. Sustainability ranking was determined with SAFA method through data normalization. On comparison of the nine total combinations, no-tillage with rye as the cover crop had the highest rating and plowing with fallow had the lowest ranking. It revealed that no-tillage with use of cover crops would be the best management method to conserve the field environment.