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Mechanical soil conservation with contour ridges: Cure for, or cause of, rill erosion?
Author(s) -
Hagmann Jürgen
Publication year - 1996
Publication title -
land degradation and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.403
H-Index - 81
eISSN - 1099-145X
pISSN - 1085-3278
DOI - 10.1002/(sici)1099-145x(199606)7:2<145::aid-ldr224>3.0.co;2-z
Subject(s) - rill , erosion , siltation , soil conservation , tillage , environmental science , erosion control , surface runoff , hydrology (agriculture) , land degradation , geology , agroforestry , land use , geotechnical engineering , geography , agriculture , geomorphology , sediment , civil engineering , engineering , ecology , archaeology , biology
Based on the results of an erosion damage assessment in Southern Zimbabwe, where mechanical conservation work has been carried out since the 1940s, this paper describes the impact of mechanical conservation systems on processes leading to rill erosion. In a study of a catchment area, it was found that influxes of water from roads and waterways as well as contour ridges that were originally designed to control rill erosion had a major role in the formation of rills. Existing rills and depressions which cause water concentration, siltation of contour drains and overflowing of contour ridges were the main factors leading to excessive rill erosion. The study showed that particularly during a highly erosive year like 1992/93, the damage due to rill erosion can be excessive, causing an abrupt degradation. It is concluded that the present conservation system is insufficient to control rill erosion effectively and is often the cause of this erosion. Effective control of rill erosion is a pre‐condition for optimal implementation of land management systems such as conservation tillage. Therefore, an integrated approach to land husbandry must be developed jointly with farmers and promoted in order to improve crop production and sustainable management of natural resources. This should consider improved mechanical conservation as well as agronomic and biological soil and water conservation techniques.