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Discipline: economics; Key words: sustainability, environmental impact, total factor productivity, pasture-based dairy.
As resources become limiting and environmental impacts are increasing, agriculture will have to introduce more sustainable practices to both stay viable and decrease its environmental footprint. However, the complexity of the biophysical system that needs to be considered is difficult which thus far has prevented meaningful measurement of progress. It is of course desirable to look at multiple dimensions of sustainability at the same time. For dairy farming, the sustainable production problem can be formulated either as minimising the environmental impact of a given level of milk production or maximising the output associated with a given level of environmental impact. The authors cited below took the second approach and used total factor productivity analysis as their main theoretical frame. In this approach, the technical (non-economic) efficiency with which all inputs are converted into all outputs was considered. The two main environmental impacts considered were nutrient and greenhouse gas emissions.
The dataset used in this analysis was obtained from Woodlands Dairy's Sustainability Project. The Sustainability Project runs the Trace & Save Programme which is aimed at cost effectiveness and limiting environmental impact. The program monitors milk, feed and fertilizer data as well as the soil and water data needed for carbon footprint and nutrient budget analyses and offers a field advisory service to producers. Woodlands Dairy draws milk from the southern portion of the Sarah Baartman District Municipality, the area between the Storms River in the west and the Great Fish River in the east. On the coast, forage production is mainly rain-fed with occasional irrigation from ground and surface water. Further inland, along the Great Fish River, it is fully irrigated. In both areas dairy production is pasture based, with purchased concentrates and some supplementary purchased roughage. The main dairy breeds are Holstein Friesians and Jerseys or cross breed herds of these two types. The typical farm is family owned and operated, with an average of 793 cows in milk and an annual milk turnover of R24.4 million. Feed costs account for 70% of farm expenses. The dataset contained 80 observations collected from 43 farms in the period 2012 and 2016. Three efficiency groups could be identified: upper (n = 27)(U), middle (n = 26)(M) and lower (n = 27)(L).
The main significant differences distinguishing the efficiency groups were: (1) stocking density (cows in milk/ha) 2.55 ± 1.32 (U), 2.47 ± 0.96 (M) and 1.66 ± 0.65 (L); (2) milk production (kg energy corrected milk [ECM]/ha) 17.2 ± 8.27 (U), 16.4 ± 5.62 (M) and 10.8 ± 4.83 (L); (3) purchased concentrates fed (MJ/kg ECM) 4.03 ±1.00 (U), 4.82 ± 0.68 (M) and 5.42 ± 0.98 (L); (4) fertilizer (R/kg ECM) 0.17 ±0.11 (U), 0.27 ± 0.16 (M) and 0.33 ± 0.13 (L); (5) kg K applied/ha 49 ± 71 (U), 98 ± 85 (M) and 75 ± 86 (L); (6) irrigated area (%) [ha irrigated /total ha] 55 ± 33 (U), 42 ± 31 (M) and 19 ± 21 (L); (7) soil carbon in sand (%) 3.17 ± 0.97 (U), 3.62 ± 2.03 (M) and 2.45 ± 1.60 (L); (8) GHG emissions (kg CO2e/kg ECM) 1.43 ± 0.20 (U), 1.42 ± 0.21 (M) and 1.61 ± 0.30 (L). Compared with the L efficiency group, the U efficiency group had higher stocking densities on pasture and therefore produced more milk per ha, produced more milk per kg purchased concentrates (implicating that L overfed concentrates which probable impaired pasture intake), spent less on fertilizer per kg ECM, in particular, applied less K/ha, and irrigated a larger percentage of pasture which would have been more beneficial to pasture quality and quantity. These favourable economic targets on U farms compared to L farms were not achieved at the expense of environmental sustainability indicators, as more soil carbon was measured in sandy soils on U farms than on L farms and their GHG emissions per kg ECM were less.
In conclusion, this study showed that the cost-drive influencing the efficiency on the farms, i.e. the efficient use of fertilizer and purchased feed, as well as the maximum utilisation of the available land, was beneficial to the environment. Thus sustainability and productivity goals can be met through the same practices on pasture-based dairy farms.
Reference:
C. Galloway, B. Conradie, H. Prozesky and K. Esler, 2018. Are private and social goals aligned in pasture-based dairy production? Journal of Cleaner Production 175, 402- 408.