The objective of this study was to estimate direct methane and nitrous oxide emissions of South African dairy and beef cattle in total and per province using the Tier 2 methodology of the Intergovernmental Panel on Climate Change (IPCC), but adapted for tropical production systems. Dairy and beef cattle in 2010 contributed an estimated 964 Giga gram (Gg) or 72.6% of the total livestock methane emissions in South Africa. Beef cattle in extensive systems were the largest contributor (83.3%), followed by dairy cattle (13.5%), and feedlot cattle (3.2%). The enteric methane emission factors for dairy cattle of 76.4 kg CH 4 /head/year and 71.8 kg CH 4 /head/year for concentrate fed and pasture-based production systems, respectively, were higher than those reported by other developing countries, as well as the IPCC default value of 46 kg CH 4 /head/year for developing countries. The beef cattle methane emission factors of 78.9 kg CH 4 /head/year and 62.4 kg CH 4 /head/year for commercial and emerging/communal cattle, respectively, were similar to those reported by other developing countries, but higher than the IPCC default value of 31 kg/head/year. Primarily because of cattle numbers, Eastern Cape recorded the highest dairy and beef cattle methane emissions, whereas Gauteng showed the highest feedlot methane emissions. ________________________________________________________________________________Keywords: Greenhouse gas, production systems, commercial, communal, feedlot, rangeland # Corresponding author: dutoitcjl@tut.ac.za IntroductionRecently South African livestock producers have come under increasing pressure over the environmental impact of production systems. The FAO (2006) reported that livestock contributed an estimated 18% of global anthropogenic greenhouse gas (GHG) emissions. Livestock produce GHG's in the form of methane (CH 4 ) from enteric fermentation, and nitrous oxide (N 2 O) and methane from manure management and manure deposited on pastures and veld (rangeland) by grazing animals. Agriculture, forestry and land use (corrected for carbon sink values) emitted an estimated 4.9% of South African GHG gases in 2004, which makes it the third largest GHG contributor in South Africa after the energy industry and industrial processes with 78.9% and 14.1%, respectively (DEAT, 2009). Livestock produced approximately 27% of the national methane gas total, mainly through enteric methane emissions from ruminants. Otter (2010) reported that livestock contributed 98% of the agricultural sector's methane emissions. Methane is a potent GHG that remains in the atmosphere for approximately 9 to 15 years and is 25 times more effective in trapping heat in the atmosphere than CO 2 over a 100-year period (FAO, 2006; IPCC, 2006). Nitrous oxide has an atmospheric lifetime of 150 years and a global warming potential of 296 times that of CO 2 (IPCC, 2006). O'Mara (2011) stated that livestock GHG emissions relate closely with ruminant numbers, particularly cattle. In 2004, commercial beef cattle contributed 45% and ...

There are increasing concerns about the impact of agriculture and livestock production on the environment. As a result, it is important to have accurate estimations of greenhouse gas (GHG) emissions if reduction measures are to be established. In this study the direct GHG emissions from South African sheep and goats during 2010 were calculated. Calculations were done per province and in total. The Intergovernmental Panel on Climate Change (IPCC) methodology, adapted for tropical production systems, was used to calculate methane (CH 4 ) and nitrous oxide (N 2 O) emissions on a Tier 2 level. Small stock is a key methane emission source in the South African livestock sector, and is responsible for an estimated 15.6% of the total livestock emissions. Small stock contributed an estimated 207.7 Giga gram (Gg) to the total livestock methane emissions in South Africa in 2010, with sheep producing 167 Gg and goats producing 40.7 Gg. Calculated enteric methane emission factors for both commercial and communal sheep of 8.5 kg/head/year and 6.1 kg/head/year, respectively, were higher than the IPCC default value of 5 kg CH 4 /head/year for developing countries. A similar tendency was found with goat emission factors. The highest sheep and goat methane emissions were reported for the Eastern Cape province, primarily because of animal numbers. ________________________________________________________________________________

An on-farm trial was conducted to determine dry matter production of four fodder tree species and their effect on soil water and maize production. The trees were planted in rows intercropped with maize. The four tree species selected were Acacia karroo Hayne (indigenous fodder tree), Leucaena leucocephala (Lam.) De Wit (nitrogen fixing), Morus alba L. (fodder and fruit), and Gleditsia triacanthos L. (fodder and fuel). Volumetric soil water was measured in the upper 0.3 m of soil in each row of the trial using the time domain reflectometry technique. The neutron probe technique was used for monitoring the water content deeper in the soil. Geostatistical methods were used to analyse treatment differences in the upper 0.3 m of soil. The soil water content did not differ significantly between the maize and tree rows indicating that competition for water in the upper horizon was not the reason for lower maize yields. However, at greater soil depths (75-125 cm) trees in the wide spacing used less water than those in the narrow spacing. Light interception was an important factor in reducing maize yields in the row nearest to the trees. High soil water values recorded during summer indicated that in the current cycle of good rainfall the plants in the agroforestry trial were not stressed. Thus the trees do not compete with the crops for soil moisture in good rainfall seasons. However, this study would need further evaluation for the competition for water for the low rainfall years. Since the trees have access to water at greater depths, they are likely to be more productive into the dry season than shallow rooted crops.

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Previous greenhouse gas (GHG) inventories did not include game as an emissions source. Recently game farming has become a recognized commercial enterprise in the agricultural sector in South Africa, contributing approximately R10 billion to the sectorial gross domestic product. The objective of this study was to estimate methane (CH 4 ) and nitrous oxide (N 2 O) emissions from privately owned game animals based on international recognized methodologies. The emissions were calculated on the basis of a large stock unit (LSU) selecting different quality diets. Daily enteric methane emissions were estimated as 0.28, 0.22, and 0.18 kg CH 4 /LSU/day consuming diets of 55%, 65% and 75% digestibility, respectively. The game industry contributed an estimated 131.9 Giga grams (Gg) of methane annually to agricultural emissions with the provinces of Limpopo, Eastern Cape and Northern Cape being the three largest contributors with 43.4, 37.3 and 21 Gg methane, respectively. The total privately owned game population was estimated at 299 1370 animals, utilizing 20.5 million hectares. IntroductionGame or wild ungulates have always inhabited southern Africa, although the population size has fluctuated greatly over the past 100 years. The establishment and growth of the private game industry is largely responsible for an increase in the number of game in recent years (Eloff, 2002; Bothma & Van Rooyen, 2005). Similarly, the industry has shown a steady growth in the number of game farms from 2 280 in 1980 to 9 000 in 1992 (Nell, 2003) and approximately 10 000 currently (G. Dry, 2013, Pers. Comm., Wildlife Ranching South Africa, P.O. Box 23073, Gezina, 0031, South Africa). The private game ranching industry occupies 16.8% (20 500 000 ha) of South Africa's total land area. This figure equates to 24% of South Africa's 84 million hectares of grazing land (Dry, 2011). This is more than double the area of officially declared conservation areas and approximately fivefold the area of the national parks (Carruthers, 2004).Game farming or ranching has become an organized and recognized enterprise in the agricultural industry (Eloff, 1996;Van Der Waal & Dekker, 2000). According to a recent article by Van Rooyen (2013) the wildlife industry ranked fifth largest in the agricultural sector, contributing R10 billion to the country's gross domestic product (GDP). Game farming is defined as an agricultural system in which wild animals are maintained in order to harvest by-products such as meat and skins in a domesticated or semi-domesticated manner by being enclosed in relatively small areas and provided with regular supplementary feeding and water (Carruthers, 2004;Du Toit, 2007). Part of the success of the industry is the ability of game to produce higher returns, compared to conventional livestock farming, under particular circumstances that may enhance the utilization of land with low agricultural potential (ABSA, 2003).Herbivorous game, with the exception of elephant, rhinoceros, hippopotamus, zebra, warthogs and bushpigs, are rum...