In 2005, 30% of the Flemish farms faced
a manure excess, while at aggregated level still 9.7% of
the emission rights were unused. This means that,
despite the various possibilities, Flemish farmers do not
succeed in an effective exchange of manure between
farms. In current paper is shown how inorganic
fertilizer use influences the use and exchange of organic
nitrogen. Because of the mutual interdependency
between organic and inorganic nitrogen emission rights
(or quota), inorganic nitrogen use limits the emission
rights for organic nitrogen. Utilisation of these emission
rights are analysed as a trade-offs choice between plant
productivity (use of inorganic nitrogen) and manure
disposal, as the major abatement alternative of manure
production. Farmers still prefer inorganic fertilizers
because of their effect on plant productivity and
income. However, by changing the quota rent of
organic nitrogen, the fertilization behaviour can be
influenced. A higher quota rent of organic nitrogen
would increase the use of manure. This trade-off
behaviour seriously influences effectiveness of policies.
When the objective is to lower the total nitrogen use, a
mere reduction of organic quota can partially be
counteracted by a higher inorganic nitrogen use. When
the objective is to better spread the manure, increasing
the quota rent for deficit farms will increase their
acceptance of manure
