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Potchefstroom University for Christian Higher Education (2002)

The evaluation of two biological restoration techniques in the semi-arid rangelands of Southern Africa

Buys Louisa Elizabeth Johanna

Titre : The evaluation of two biological restoration techniques in the semi-arid rangelands of Southern Africa

Auteur : Louisa Elizabeth Johanna Buys

Université de soutenance : Potchefstroom University for Christian Higher Education,

Grade : Master of Science (MS) 2002

Résumé
Due to the worldwide impact of land degradation on agricultural dryland, proper management of the utilisation of natural resources has become extremely important. Some areas, however, have become degraded to such an extent that proper management, on its own, would not be enough for maintaining a stable system. Active intervention, such as rangeland restoration, is then required. Rangeland restoration is a process by which a damaged or degraded portion of land is returned to its original state, in other words back to a fully functioning self-sustaining ecosystem. The organic block and supplement feed block were evaluated as two new biological restoration methods in selected degraded conservation and agricultural areas. The economic implications as well as the feasibility of these methods were evaluated. The evaluation of these methods was mainly aimed toward the subsistence farmers in communal areas where land degradation mostly is a problem. Consequently, the involvement of community members was also important in the study. The organic block is a mixture of organic material (cattle dung), milled grass (mulch), super phosphate, water and a seed mixture, molded into small 10x10x3cm or 10x10x2cm blocks. The seed mixture consists of Anthephora pubescens, Cenchrus ciliaris, Chloris gayana, Digitaria eriantha and Panicum maximum. The blocks were placed out under natural conditions in communal rangelands in the North West Province as well as on conservation land in the Loskop Dam Nature Reserve. It was also placed out under natural conditions on an experimental natural site and covered with silica sand. The experimental natural site was protected from animal access and served as a control. Organic blocks were placed out under controlled conditions in the greenhouse, which also served as a control. The supplement feed block, manufactured at Blokmolasses Feeds (Pty) Ltd in Queenstown, contained seeds of Cenchrus ciliaris, Chloris gayana, Digitaria eriantha and Panicum maximum. The supplement feed block was fed to cattle on various farms in the North West Province as well as to buffalo in the Loskop Dam Nature Reserve. Dung was collected after a week and placed in the greenhouse under controlled conditions to evaluate the germination of grass seed after having passed through the rumen of an animal. The viability of grass seed used in the trial was also evaluated in the laboratory according to the prescriptions of the International Seed Testing Association (ISTA) Results obtained in the greenhouse and on the experimental natural site showed the remarkable potential of the organic block as well as supplement feed block. However, results obtained in rangeland under natural conditions were less successful and could possibly be attributed amongst other factors, to various soil factors and a lack of proper community participation The conclusion drawn is that, although rangeland restoration is a time consuming and expensive process, it is a necessity in highly degraded areas. With the current knowledge obtained through this study, the organic block and supplement feed block can, therefore, be further evaluated as cost-effective and feasible biological restoration methods.

Présentation (NRF)

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