Cost-efficient choice of measures in agriculture to reduce the nitrogen load flowing from the Danube River into the Black Sea: An analysis for Austria, Bulgaria, Hungary and Romania

Selected measures in agricultural production are presented which reduce the national nitrogen soil surface balances and the nitrogen loads in the waters of Austria, Bulgaria, Hungary and Romania entering the Danube River. The measures are appraised empirically by calculating the ratio between their costs to the farmers and their effects on the respective balances and the load of the water entering the Black Sea. The ratios are used to rank the measures accordingly, either separately for each country, or jointly. The measures consist in implementing the best available techniques of agricultural production. The costs of the measures are defined as the net effect of changes of production costs and revenues of the agricultural producers involved. There are even measures characterised by costs being outbalanced by the increase of gross output induced, resulting in negative costs and, hence, negative ratios. This indicates that these measures are profitable to the producers, provided obstacles to their implementation are overcome. Furthermore, a linear optimisation model is developed which is used to ascertain the measure combinations which accomplish a politically demanded amount of reduction of the nitrogen load at minimum total costs ('cost-efficient solutions'), either at the national or international level. Optimisation at the international level turns out to be superior. Cost savings by an international choice of measures can be induced, and shared, by international compensation payments to be financed from these savings.