Most soils in Easthern Africa present a low inherent fertility, both from the chemical and from the physical viewpoints This fact hinders the agricultural production, and without proper management it is easy to push the soils beyond their capacity to sustain use This research describes the effect of cultivation on soil degradation levels as reflected by changes in the chemical, physical and mineralogical properties, and their bearing on loss Of Overall fertility with special emphasis on the associated soil organic matter (SOM) characteristics The soil formations selected for study were representatives of one of the most important agricultural areas in Tanzania: Mkindo site in Mvomero district and Mafiga site in Morogoro district These areas are devoted to the cultivation of maize and rice crops Our results have shown the extent to which cultivation has lead to important changes in most physico-chemical properties of the soils studied. These changes were related to the concentration and distribution patterns of plant nutrients and to the total amount and characteristics of the SOM The most significant effects of cultivation on the soil chemical properties coincided with those considered to favour clay dispersion and crusting phenomena, including desaturation of the exchange complex and losses of divalent ions with a potential bridging effect between soil particles In face in Mkindo, increasing surface crusting as well as development of hydrophobic characteristics have been observed. The SOM in all the soils studied consists mainly of colloidal humus fractions with negligible amounts of not-yet-decomposed organic residues The overall SOM composition in both soil formations, suggests high-performance humification processes in tropical environments and in the presence of a mineral substratum suitable for the stabilisation of the humic substances. In Mkindo, cultivation has produced significant changes in SOM composition, related to a noteworthy increase in the degree of association between the organic and the mineral fractions in the more resilient Mafiga soil, the changes after cultivation were of lower extent than in Mkindo, and reflected by higher stability in the soli organic mineral complex.
Monitoring cultivation effects on soil fertility status and organic matter accumulation patterns in Eastern African Soils
DAcqui LP
2004
Abstract
Most soils in Easthern Africa present a low inherent fertility, both from the chemical and from the physical viewpoints This fact hinders the agricultural production, and without proper management it is easy to push the soils beyond their capacity to sustain use This research describes the effect of cultivation on soil degradation levels as reflected by changes in the chemical, physical and mineralogical properties, and their bearing on loss Of Overall fertility with special emphasis on the associated soil organic matter (SOM) characteristics The soil formations selected for study were representatives of one of the most important agricultural areas in Tanzania: Mkindo site in Mvomero district and Mafiga site in Morogoro district These areas are devoted to the cultivation of maize and rice crops Our results have shown the extent to which cultivation has lead to important changes in most physico-chemical properties of the soils studied. These changes were related to the concentration and distribution patterns of plant nutrients and to the total amount and characteristics of the SOM The most significant effects of cultivation on the soil chemical properties coincided with those considered to favour clay dispersion and crusting phenomena, including desaturation of the exchange complex and losses of divalent ions with a potential bridging effect between soil particles In face in Mkindo, increasing surface crusting as well as development of hydrophobic characteristics have been observed. The SOM in all the soils studied consists mainly of colloidal humus fractions with negligible amounts of not-yet-decomposed organic residues The overall SOM composition in both soil formations, suggests high-performance humification processes in tropical environments and in the presence of a mineral substratum suitable for the stabilisation of the humic substances. In Mkindo, cultivation has produced significant changes in SOM composition, related to a noteworthy increase in the degree of association between the organic and the mineral fractions in the more resilient Mafiga soil, the changes after cultivation were of lower extent than in Mkindo, and reflected by higher stability in the soli organic mineral complex.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
