A new report published in December 2017 by the Namibian University of Science and Technology, Cheetah Conservation Fund and Columbian University reveal that there was no evidence of restoration of soil fertility 13 years after bush clearing. The research was undertaken on four commercial farms in the Waterberg Conservancy to assess the overall soil fertility on uncleared, partially cleared and totally cleared land. Nutritious grass is unlikely to grow well after de-bushing, and more bushes are likely to grow in attempt of restoring fertility over the long term.
Thus, the study strongly recommends that if bush encroachment is addressed through bush thinning, the minerals removed in harvested wood should be returned to the land. This should be done in conjunction with aftercare practices and rangeland management techniques such as rotational grazing to allow enough grace period of cleared land to rest and animals to deposit dung and urine on the cleared land while grazing elsewhere. The pattern of partial de-bushing also play a role on the impact of fertility. For example, if bush are cleared in strips, the stripes of uncleared bushes could serve as windbreaks and fertility generators. While elsewhere such as in very sand soils where rainwater infiltrates straight to the soil, the alignment of strips could be at right angles to the prevailing or most destructive, wind to reduce evaporation and erosion.
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