Draught Animal Power (DAP)
 
For millennia animals have been harnessed to pull carts, carry loads, transport people, haul water, trash harvests, plough, puddle and weed crop fields etc.
Donkey carrying water in Mauritania. Source FAO DAD, 1999 Despite motorization on all fronts the use of DAP is still often more economic than the use of machinery and vehicles, especially in small scale agriculture and in remote areas. Animals are produced and maintained locally and donít require the infrastructure needed for motorization. Where the value of machinery needs to be depreciated over time, that of animals can appreciate because of growth.
Livestock used as draught animals on a small mixed farm. Photo: Ian GrantThe principal environmental advantage of DAP compared with mechanisation is that DAP relies on bio-energy for its creation, maintenance and functioning instead of on fossil energy. Still, apart from these positive aspects, DAP can have negative impacts on the environment. Below are presented both the positive and negative impacts in general terms in the context of "Crop Residue" systems and that of "Cut and Carry" systems.

DAP in crop residue systems

The use of DAP in land preparation allows the preparation of more land at the onset of the growing season. This is most relevant in areas with a short growing season for annual cash crops. This expansion of land under cultivation may cause increased pressure on the land around settlements and may result in less land being available for other land use options - including livestock grazing.

In these circumstances, unless the pormotion of DAP is accompanied by appropriate levels of destocking, the resulting increased livestock densities on the remaining grazing land may lead to land degradation and erosion. In some cases, this could also lead to land-based social conflict, increased levels of poverty amongst the livestock sector.

The advantage of manure produced by draught animals is often over estimated. A general estimate shows that the manure produced can compensate only ¼ of the extra requirements for manure caused by the expansion that can be  realized.

Manure deficit due to Draught Animal Power
Assumptions:
  • DAP with two oxen (body weight about 250 kg)
  • Expansion of area under cultivation from 4 to 8 ha. (DAP: 32 plough days, 0.25 ha per day)
  • Manure requirements per ha. 1,000 kg 
  • Annual feed intake per animal 2,000 kg   (5.5 kg  / day) 
  • Average digestibility of feed 50% 
  • Annual faeces per animal produced 1,000 kg 
  • Manure available for crops 50% of faeces produced (50% loss: faeces not collected and storage losses)
 Note: (values are in Kg Dry Matter)
Result:
  • Manure requirements: increase by 4,000 kg 
  • Manure availability: increase by 1,000 kg 
  • Increase of Manure deficit by 3,000 kg per year.

DAP increases labor productivity. However, this also makes it still beneficial to cultivate marginal land and to prolong cultivation period even when expected yields per ha are low. Next, DAP is more easily employed in fields without roots of shrubs and trees. Consequently fallow periods will be shorter to prevent such "obstacles" appearing. Apart from lower yields per ha and higher risks of crop failure, the prolongation of cultivation and the shortening of fallow periods accelerates the process of soil mining and increases the risks of erosion and land degradation. When production levels decrease and new land is available elsewhere then farmers may move to there (i.e. as is the case in Northern Cameroon). When no alternatives are available then the production level will stagnate at a low level per ha and become more vulnerable for variations in weather conditions and for diseases (i.e. as is the case in the highlands of Ethiopia).

Crop cultivation is the primary factor responsible for soil mining and land degradation. However, Draught Animal Power also contributes to this process and can accelerate it. The longer term social, economic and environmental costs of the contribution by DAP to this process are often not considered in the calculations of cost Ė benefit and internal rate of return of development programs promoting DAP.

Some options to mitigate the negative impact of DAP on soil fertility and land degradation are: DAP in cut and carry systems

In areas with intensive crop cultivation the basic soil fertility in general is higher and more fertilisers are used to support permanent crop cultivation. Farm sizes are small and the livestock / cropland ratio can be high. DAP is used to intensify production and can also be employed for transport and/or water hauling. Sharing of DAP and renting DAP services are common. In irrigated rice cultivation buffaloes are used for land preparation, transport and threshing.

Replacement of DAP with mechanisation

There is a trend to promote motorization in agriculture through development programs and direct or indirect subsidies. Animal traction is therefore replaced by tractor mechanisation. However, the environmental cost of such a change is largely negative notably in respect of energy requirements. Tractor mechanisation requires fossil fuel for production, maintenance and running, while working animals are produced and run on organic energy sources.

The impact is more an increase of fossil fuel requirements than a decrease in the use of available feed resources. In Indonesia for instance tractor mechanisation in irrigated agriculture resulted in buffaloes (traction) being replaced by cattle (production of calves for fattening), making use of the same resources as buffaloes did earlier. (See also the discussion on Greenhouse Gases)

References and Further Reading

FAO. (1994). Draught Animal Power: A training manual for use by extension agents. FAO. Rome. http://www.fao.org/WAICENT/FAOINFO/AGRICULT/AGA/AGAP/FRG/Draught/draught.htm

FAO. (1999). Animal Production Service. Fact-File - Draught Power. http://www.fao.org/ag/aga/agap/factfile/draught.htm
 
 

Belorusskayas Stalion. Draught Animal. Belorus. Source: FAO DAD 1999 Tswana donkeys at water point. Botswana draught animal. Source FAO DAD, 1999 Sovetskii Tyazhelovoz mare. Russian draught animal. Source FAO DAD, 1999

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