Effects of grazing and cultivation on soil patterns and processes in the Paulshoek area of Namaqualand

摘要: Soils were sampled at three different sites within the Paulshoek area of Leliefontein District in Namaqualand, South Africa. At one site effect heavy grazing on soil characteristics under shrubs and from open positions was compared to a more lightly grazed area. this diverse shrub community mostly replaced by single species, Galenia africana, when overgrazed. In another effects cultivation properties investigated. third size measured. Namaqualand are generally infertile very low arbuscular mycorrhizal propagules. Patterns nitrogen distribution landscape level result nutrient enrichment associated with perennial shrubs. Arbuscular infectivity, moisture pH also affected Only species capable forming mycorrhizas support populations propagules their rhizosphere. Differences plant available phosphorus some indicate that processes cycling tended deplete increase than other Small stock production results depletion nutrients scale since larger areas develop density decreases following grazing. Heavy affects indirectly through change composition. Cultivation resulted decrease organic matter, loss which still detectable after 20 years fallow. Zones higher found where established old field. When positive correlation between diameter nitrogen, indicating establishing patches rather selecting such for establishment. Thus, is able maintain patterns typical Succulent Karoo although it establishes conditions probably ensure its success. Individual affect differently respect components as mycorrhizas.