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Master
Afrique du Sud
2018
Investigating the impact of cattle path erosion on soil organic carbon and nitrogen, Okhombe Valley, KwaZulu-Natal, Drakensberg, South Africa
Titre : Investigating the impact of cattle path erosion on soil organic carbon and nitrogen, Okhombe Valley, KwaZulu-Natal, Drakensberg, South Africa
Auteur : Blicq, Ashleigh Justine.
Université de soutenance : University of KwaZulu-Natal
Grade : Master of Science, in the School of Agricultural, Earth and Environmental Sciences 2018
Résumé partiel
While soil erosion is a natural geologic phenomenon, its exacerbation as a consequence of socioeconomic and political factors, threatens rural sustainability and livelihoods. Smallholder rural
farmers within the KwaZulu-Natal Drakensberg region of South Africa are reliant on the
surrounding grasslands for livestock grazing. Mismanagement of land through overgrazing,
overstocking and livestock trampling have led to excessive cattle path formation and resultant soil
erosion, which negatively affects these montane grasslands. Community members have identified
cattle path formation, as a grave concern, as the loss of land through increase erosion leads to gully
formation and presents a safety hazard to residents and livestock. This study investigated the impact
of cattle path erosion on soil properties, in particular soil organic carbon (SOC) and nitrogen (N)
along a degraded slope profile. For this purpose four positions (reference site, top-slope, mid-slope
and lower-slope) were identified and sampled at three soil depths (0-5 cm, 5-15 cm and 15-30 cm)
along a degraded slope at Okhombe, Drakensberg region South Africa. Soil properties, soil
nutrients, SOC and N were measured (over a two day period) and physical soil fractionation were
completed to determine carbon (C) and N protection within soil aggregates. To understand SOC
and N distribution, areas of erosion and deposition were determined by measuring fallout
radionuclides caesium-137 (137Cs) and excess lead-210 (210Pbex). Soil property measurements
revealed that the undisturbed reference site contained higher nutrient content and greater C and N
protection within soil aggregates compared to the degraded slope profile. This suggests that nutrient
loss has occurred on the degraded slope, possibly as a result of cattle path erosion.
Page publiée le 17 janvier 2021