Re-analysis of engineering the stabilization and restoration of supercritical hardpans in the Umfolozi catchment, South Africa

1Clifford Tafangenyasha, 2Amos T. Mthembu, 3Blessing Kavhu, 3Knowledge Vingi, 2Hector Chikoore, 2Nothile Ndimande, 2Sifiso Xulu and 2Nonkululeko Gwensa

Abstract

 

Accepted 16^TH May, 2016

 

The hypothesis that lack of vegetation establishment exacerbated degradation of landscapes in the Umfolozi catchment, South Africa was investigated by germinating seed bank in the University of Zululand Greenhouse. Soil samples from 10 degraded plots and ten un-degraded plots were collected. In each 20x20 m plot, three 1x1 m quadrats were randomly located within a plot. Soil core samples were collected on the outer edge of quadrats within the plots. A volume of 400g soil was placed in each pot.  Each pot measured 13 cm diameter and a depth of 7 cm. A soil depth of 4 cm and diameter of 13 cm in each pot was used for germination tests. Seedling density was 18 seedlings per 52 cm³ in soil samples collected on degraded sites and 10 seedlings per pot on un-degraded sites. Spearman rank correlation showed strong negative correlation between seedling density and soil compaction (r = -0.481, P<0.05). Plant species germinating in nursery pots in the university greenhouse showed a mix of species including woody plants, grasses and weeds in soil samples from both degraded and un-degraded sites. The study leaves gaps on the bearing of soil nutrient supply during the pre-germination and post germination stages of woody plants and a de-novo approach is required. The study provides critical understanding relevant to stabilization and restoration of the supercritical degraded Umfolozi catchment soils and other similarly affected areas elsewhere.

 

Keywords: Soil seed bank, Soil bulk density, Soil stabilization and restoration

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