A pilot study into biomass yield and composition under increased stocking rates and increased stocking densities on a Namibian organic beef cattle and sheep farm

Sustainable rangeland management is crucial for conservation and improvement of global grassland ecosystems, livestock performance and grassland-linked livelihoods. This applies in particular for Sub-Saharan African countries like Namibia with its rangeland-based low external input livestock husbandry. In the local savannas, productivity and resource distribution is spatially heterogeneous and temporally variable, which calls for adaptive and responsive grazing strategies to meet the needs of livestock and vegetation. The adjustment of stocking rate (SR; kilogramme livestock per hectare per year) and stocking density (SD; kilogramme livestock per hectare during a specific grazing event) is considered as a key success factor but very different rates and densities have been recommended in the past by practitioners, scientific evidence is lacking. On an Organic Namibian beef cattle and sheep farm were these recommendations assessed in order to investigate the responses of savanna rangelands to varying grazing intensities. Since 2014, forage biomass production and composition under three different grazing regimes have been assessed: (1) the routine management (here Holistic Management) as control and in comparison to this (2) an increased SR or (3) increased SD. Destructive biomass sampling was done each May in 2014, 2015, 2016 and 2017, respectively. The results showed that the increased SR or SD can be beneficial for average fodder production, but not significantly. However, the negative standing dead biomass accumulation was significantly reduced.