Agronomic dry line

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The agronomic dry line is one of the agro- geographical cultivation borders and separates areas in which it is sensible to cultivate rain or the special form of dry cultivation from areas where this is no longer possible and where irrigated cultivation can be carried out or only pasture farming is possible. It roughly coincides with the 400 mm isohyete . The agronomic dry line should not be confused with the climatic dry line .

The agronomic dry line can be roughly defined by the annual precipitation N (measured in mm) and the annual average temperature T (measured in ° C): N = 15 (mm / ° C) × T For rain- fed agriculture, the amount of precipitation must therefore be at least fifteen times the average temperature . This formula is only a guideline, as the agronomic drought limits vary due to the variability of rainfall over the course of the year, the shape of the terrain, the type of soil and the humus and nutrient content of the soil. With details of the agronomic management limits, u. a. Reiner Keller , Hans-Hartwig Ruthenberg and Peter Frankenberg . Examples of the agronomic dry line can be found in the Syrian Desert and the Dahomey Gap in West Africa.

Further cultivation limits are the agronomic polar limits and the agronomic height limits .

See also


  • Peter Frankenberg: On the problem of the dry line in Geographischer Rundschau Volume 37 (1985).
  • Reiner Keller: Waters and water balance of the mainland: an introduction to hydrography , Teubner, 1962, p. 432.
  • Hans-Hartwig Ruthenberg: Farming Systems in the Tropics, Göttingen 1971.

Web links

Individual evidence

  1. Fritz Jaeger, O. Lütschig-Loetscher: The climatic limits of agriculture in Google Books
  2. Reiner Keller: Gewässer und Wasserhaushallt, definition of agronomic dry limit on Google Books
  3. Hans Ruthenberg on the agronomic dry areas in Google Books
  4. ↑ School book center: Nature sets limits to agriculture ( Memento of the original from April 23, 2017 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. pdf accessed April 22, 2017 @1@ 2Template: Webachiv / IABot /