Study Of Physical And Chemical Soil Properties And Potential Of Post-Mining Substrates As A Habitat For Plants During Restoration At Sendelingsdrif Mine

Abstract

Soils influence the growth and performance of plants. Sendelingsdrif is a new area in Sperrgebiet National Park that had been identified by NAMDEB for diamond mining. Little is known about soil properties in this area yet after mining, it will be important to have good knowledge of soil properties and post-mining substrate to facilitate restoration of the mined and surrounding sites. The main aim of the study was to determine how the physical and chemical properties of post-mining substrates differ from that of natural soils and how these properties among substrates relate to plant performance. Field and greenhouse studies of soil properties and post-mining substrates was carried out at Sendelingsdrif mine in the Tsau //khaeb (Sperrgebiet National Park) from September 2012 to June 2013. In the greenhouse, ten substrates (including two natural soils and potting soil as reference) were prepared and plants (Radish (Raphanus sativus), Juttadinteria albata (L. Bolus) L. Bolus and Cephalophyllum herrei L. Bolus) performances were tested across them. Lucerne was added to some of the prepared mixes of post-mining substrates to act as nutrients and the plants performances were assessed. During fieldwork, environmental data such as infiltration rate, soil texture and rock cover were recorded. Seventy soil samples were collected from seven habitats in the study area. The analysis of soil properties revealed that water infiltration rate and soil texture differed significantly (H = 48.15, df = 9, P < 0.05) between natural soils and post-mining substrates in the study area. Soil chemical properties such as pH, total nitrogen, organic matter, phosphorus, calcium and iron were not significantly different (F = 1.82, F = 2.05, H = 7.51, F = 0.35, H = 12.41, H = 17.89, df = 6, P > 0.05) across the landscape in the study area. Soil chemical properties such as calcium carbonate, potassium, copper and electrical conductivity differed significantly (H = 21.13, F = 2.56, F = 3.02, H = 16.59, df = 6, P > 0.05) between habitats across the landscape. Chemical properties of natural soils such as nitrogen, organic matter, phosphorus, calcium, potassium and conductivity was

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significantly different from that of post-mining substrates. The post-mining substrates lacked essential nutrients such as nitrogen, organic matter and phosphorus that are needed by plants for growth. Post-mining soils had significantly high content of salt; this salt was significantly high in content in comparison to that of natural soils (H = 31.21, df = 9, P < 0.05). The experiment revealed that the germination of the Juttadinteria albata and Cephalophyllum herrei differed significantly between natural soils and post-mining substrates (F = 6.55, H = 35.56, df = 9, P < 0.05). Plants used in the greenhouse showed improved growth in substrates where Lucerne (Medicago sativa L.) was added. The study concluded that there are major differences in the physical and chemical properties between natural soils and post-mining substrates. The study also concluded that the addition of Lucerne to post-mining substrate improves the performance of plants.

Key words: Soil, Sendelingsdrif, restoration, post-mining substrate, natural soil, Sperrgebiet, mining, radish, Juttadinteria albata and Cephalophyllum herrei