A part of biomass resources are used for agricultural production and are recycled for materials of other activities, such as compost made from livestock excrement or rice plant straw used for litter. However, these activities are not revealed in economic statistics because of bartering and trading without any charge. It is necessary to understand transactions of biomass resources in agricultural sector properly. The purpose of this soudy is to propose an accounting system for evaluating biomass resources used in the agricultural sector, as well as to understand the status of wastes and environmental pressure arising from agricultural production. The waste acounting system can be adapted to the case of the agricultural sector to grasp the status of transactions of organic resources. It can also show the amount of environmental pressure arising from agricultural production in addition to the amount of biomass resources and their disposal and recycling. Finally, as an example of the use of information obtained from the accounting system, reducing environmental pressure is estimated if imported rice plant straw is substituted for domestic supplies. The results of the analysis are 1) Environmental pressure reduction due to reduction of burnt straw is 2, 089 ton-SPM, 1, 572 ton-CH₄ and 25 ton-N₂O in the case without regional constraint of straw supply, 2) When considering the regional constraint of the straw supply, the effect is reduced to 71% of the total. 3) Chubu area shows the largest effect of environmental pressure reduction.