Controlling the flow of pollutants on agricultural land

The control of pollutant flows requires correct identification of environme ntal factors where the pollution originates and the agricultural territorie s within that physical context. Even ii many diagnostic methods are now ava ilable for non point source nitrate pollution characterisation, the choice of a specific method depends on the objectives pursued. To be accepted, pro posed changes in practice must take into account the constraints of both th e farmers and the extension services in charge of the problem. Farmer recog nition of the importance of agricultural pollution and level of trust betwe en farmers and extension workers are determining factors. Research must pro duce new diagnostic methods making it possible to treat environmental risks within an agricultural territory on a hierarchical basis.