Some Psamosoils of the Mio-Plio-Pleistocenic of Southern Portugal: 1. Soil properties. Total and extractable micronutrients
1980
Teixeira, A.J.S. | Sequeira, E.M. | Lucas, M.D. | Santos, M.J. (Estacao Agronomica Nacional, Oeiras (Portugal))
The soils studied are normally deep soils (lm); with 92=7% of sand, very poor in silt, clay and organic carbon, and acid (pH 5,4=0,6). These soils, with 2,27 me/100 g exchange capacity and very low levels of K, P and N, are very poor. As to micronutrient levels these soils show strong molybdenum deficiency (0,016 ppm mean extractable Mo), cobalt deficiency (0,05 ppm mean extractable Co), high copper deficiency (0,16 ppm mean extractable Cu), high manganese deficiency (5,8 ppm mean extractable Mn), high zinc deficiency (0,2 ppm mean extractable Zn), and, occasionally, boron deficiency (0,3 ppm mean extractable B). These soils behave practically as a mechanical support for plant growth. They need a well thought-out fertilization and management, since leaching is extremely high as a result of very low exchange capacity, very low percentages of clay, organic matter and moisture retention, and high permeability. Increasing organic matter content is emphasized as a method to improve fertility, by raising exchange capacity, moisture retention and levels of extractable micronutrients
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