Nitisol

As Nitisol (formerly Nitosol) after World Reference Base for Soil Resources referred to a reference floor pan (WRB), which mainly in the tropics occurs. The soil profile has (according to the FAO Guidelines for Soil Description) either a horizon sequence A-Bo-C or A- (E-) Bto-C. The ground is deeply weathered . The source rocks are neutral to basic rocks rich in silicate .

Nitisols are found worldwide on an area of ​​200 million hectares, mainly under tropical rainforest and wet savannah , with about half of them occurring in tropical East Africa .

properties

The horizon borders are only weakly defined due to strong bioturbation , the color change is fluid. Overall, weathering has not progressed as much as with the ferralsoles , so that mostly weatherable (primary) minerals are still present.

The diagnostic horizon is the nitic horizon . This is a clay-rich (at least 30%), at least 30 cm thick subsoil horizon with partly shiny aggregate surfaces in a characteristic polyhedral (nutty) structure. The humus contents are relatively high. The soil profile is characterized by strong aggregation and high porosity (50–60%), and thus by good water conductivity (approx. 50 mm h ⁻¹ ). Due to the type of soil and the depth, a large amount of water can be stored.

These properties result in relatively high fertility as long as the problems associated with erosion and P fixation are controlled.

Web links

• uni-bayreuth about Nitisole (PDF file; 3.08 MB)
• Profile photos (with classification) WRB homepage
• Profile photos (with classification) IUSS World of Soils

literature

• IUSS Working Group WRB: World Reference Base for Soil Resources 2014, Update 2015. World Soil Resources Reports 106, FAO, Rome 2015. ISBN 978-92-5-108369-7 ( PDF 2.3 MB).
• W. Zech, P. Schad, G. Hintermaier-Erhard: Soils of the world. 2nd Edition. Springer Spectrum, Heidelberg 2014. ISBN 978-3-642-36574-4 .
• W. Amelung, H.-P. Blume , H. Fleige, R. Horn, E. Kandeler , I. Kögel-Knabner , R. Kretschmar, K. Stahr , B.-M. Wilke: Scheffer / Schachtschabel textbook of soil science. 17th edition. Heidelberg 2018. ISBN 978-3-662-55870-6 .
• FAO: Guidelines for Soil Description. Prepared by R. Jahn, V. Asio, H.-P. Blume , O. Spaargaren and P. Schad. Rome 2006. ISBN 92-5-105521-1 .