In modern industrial countries, intensive agriculture is one of the causes of environmental pollution and a contributing factor to global change, for instance:

• soil erosion and soil degradation;
• decreasing biological diversity;
• eutrophication of water;
• disturbance of biogeochemical and energy cycles.

It is, therefore, necessary to specify agroecological concepts — as a part of concepts for a whole landscape — which can be integrated into national and international programmes to protect the environment as well as to permit environmentally compatible production, and safeguard sustainable development in agricultural landscapes.

The basis for further investigation in the economic and social spheres seems to be the natural sphere. Before connecting different types of ecosystems it is important to know the fluxes of material end energy within a special ecosystem like an agroecosystem. Profound knowledge of the dynamics of a system is a prerequisite for ecologically sound management.

This paper gives a short survey on the development of a physiologically based detailed plant model, developed in the group “Agro-ecosystem research Quedlinburg” , and the soil model “Candy” of the section “Soil Sciences” at the Centre for Environmental Research Leipzig-Halle. The paper shows possible connections between these tasks and the issues of Potsdam Institute for Climate Impact Research (Pik).