SummaryEven in early times not only the growth of the crops but also the costs of their production played a certain role. Also the suitability of soils for various crops has always been changing according to economic circumstances (prices of products) and changes in technology.Land‐use is greatly influenced by historical developments. These reflect the various economic and technical circumstances of the past. A survey of present land‐use can never be a basis for predictions on optimum land‐use. The Soil Survey is the only basis for these predictions.Present thought on land‐use is also very strongly influenced by the chemical schools of soil science which played such a dominant role in the recent past. The soil surveyor should co‐operate with experts on soil chemistry and soil fertility to stimulate optimum agricultural productivity under present conditions.In this changing world, land‐use is going to change rapidly, because economic and technical circumstances alter from day to day. The soil surveyor must demonstrate the different repercussions which these changes will have on his different soil types. He is the only man who can predict which surface areas are going to be affected by various changes of prices and of agricultural techniques. In this he must co‐operate with farm economists and with agricultural engineers.The soil surveyor cannot leave this work to others, because he is the only man who fully understands the terminology of the soil map and because he is also the only man who can handle his soil units as natural units. Furthermore, he should do this because it gives him a better understanding of the units which he is mapping and therefore the quality of his soil maps will als