ABSTRACT
Denmark is well suited for agriculture. Solar radiation energy is about half of that in Sahara and with strong seasonality, but the days are longer during the growing season, thus as a whole providing a perfect incidence of light for photosynthesis without scorching the plants. Water supply is ample, generally without the flood-causing torrents or the long dry periods common in Southern Europe, and finally, the nutrient availability is excellent. Danish soils are deep glacial clay and sand layers, which after millennia of plant growing provides a thick humus layer, not prone to being washed away during rain or eroded and carried away by wind in dry periods. The initial felling of natural vegetation followed by burning tree stubs in most cases did not lead to significant nutrient loss, because cultivated plants and animals were introduced at about the same time, so that the animals could return manure and its nutrients in at least a partial recycling process (cf. Chapter 4). In coastal areas, further fertilization was achieved by people spreading seaweed or kelp (ashes from combusted seaweeds). The introduction of shifts, working the land-plots in rotation for cereals, cattle grazing and fallow, ensured continuing productivity.
