Theme 2-3: Forage Production and Utilization--Poster Sessions

Description

The debate on appropriate stocking rates (SR) increasingly recognizes the importance of variable, targeted and adaptive stocking in response to a temporally variable and spatially heterogeneous resource distribution, particularly in challenging environments such as the Namibian savannah. In common extensive ranching systems, a farmer’s scope of action is often limited to flexibly adjusting the number and concentration of livestock to the available forage in space and time. SRs are commonly set according to carrying capacity recommendations which usually have a low spatio-temporal resolution. This may lead to punctual under- and overutilization. The Namibian Rangeland Management Strategy advocates adjusting SR in response to the fodder reserve at the end of the rainy season in May. Based on records of the 9,500 ha commercial cattle and sheep farm Springbockvley (avg. annual rainfall 272 mm, Jun-May) in central Namibia we calculated effectively applied annual (Jun-May) SRs from 2006 to 2017 for 50 paddocks. We then looked at spatial and temporal variation indicated by the coefficient of variation (CV in %). Overall average SR was 35 kg ha-1 with an average annual spatial CV of 35 % and an average temporal CV of 37 % within a paddock. The mean farm SR increased following a linear trendline to above the regional average but not all paddocks supported this increase alike. Until 2013 the farm was grazed with four mixed herds of cattle and sheep, each rotating in a separate farm section. Three farm sections showed linearly increasing SR trendlines, while one section’s SR remained static with some paddocks showing falling trendlines. Since 2014, three large herds (cows, sheep, mixed) grazed all farm paddocks in a predefined sequence (each herd grazed each paddock once per year). We discuss environmental and management influences on SR variation at different scales.

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Spatial and Temporal Variation of Stocking Rate in a Rotational Grazing System on a Namibian Cattle and Sheep Farm from 2006 to 2017

The debate on appropriate stocking rates (SR) increasingly recognizes the importance of variable, targeted and adaptive stocking in response to a temporally variable and spatially heterogeneous resource distribution, particularly in challenging environments such as the Namibian savannah. In common extensive ranching systems, a farmer’s scope of action is often limited to flexibly adjusting the number and concentration of livestock to the available forage in space and time. SRs are commonly set according to carrying capacity recommendations which usually have a low spatio-temporal resolution. This may lead to punctual under- and overutilization. The Namibian Rangeland Management Strategy advocates adjusting SR in response to the fodder reserve at the end of the rainy season in May. Based on records of the 9,500 ha commercial cattle and sheep farm Springbockvley (avg. annual rainfall 272 mm, Jun-May) in central Namibia we calculated effectively applied annual (Jun-May) SRs from 2006 to 2017 for 50 paddocks. We then looked at spatial and temporal variation indicated by the coefficient of variation (CV in %). Overall average SR was 35 kg ha-1 with an average annual spatial CV of 35 % and an average temporal CV of 37 % within a paddock. The mean farm SR increased following a linear trendline to above the regional average but not all paddocks supported this increase alike. Until 2013 the farm was grazed with four mixed herds of cattle and sheep, each rotating in a separate farm section. Three farm sections showed linearly increasing SR trendlines, while one section’s SR remained static with some paddocks showing falling trendlines. Since 2014, three large herds (cows, sheep, mixed) grazed all farm paddocks in a predefined sequence (each herd grazed each paddock once per year). We discuss environmental and management influences on SR variation at different scales.