Terry Leahy 2015
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Acknowledgements to Ezra Mbendera for cropping calculations from Malawi. Acknowledgements to Unathi Sihlahla for helpful suggestions where wood lots are concerned.
How much land is required for cropping?
The following calculations are based on quantities made use of by the Malawi agriculture department. The calculation is for a family of six – with three adults and three children. It assumes a rainfall of at least 500 mm per annum. For more desert like conditions, you would need more land and would make use of topographic features in the landscape to gather water – for example a rocky slope leading to a small gully which could be dammed to provide enough water for a small cropping field.
The Malawi department of agriculture estimates that to feed one adult for a year you will need to harvest 6 x 50 kg bags of maize kernels. In other words, 300 kg of maize kernels.
For a family of 6:
3 Adults = 3 x 300 = 900 kg
3 Children = 3 x 150 = 450 kg
Total = 1,350 kg of maize kernels is needed for the full year for the whole family.
Smallholder farmers are typically getting about one tonne per hectare in the villages. They are unable to afford synthetic fertiliser and are not using any of the variety of techniques available to boost production without fertilisers. However it would be reasonable for a project to aim at a much higher yield, using some fairly simple low cost techniques. For example, Erenstein et al. (2012) report trials of “conservation agriculture” with smallholder farmers in Zimbabwe. Yields were 2.7 tonnes per hectare. With other techniques such as legume intercrops or cover crop this could be boosted to 4 tonnes per hectare (Gitari et al 2000: Gitari et al 2003; Japan Association 2008). But to be on the safe side let us estimate a yield of two tonnes per hectare.
If the yield is 2 tonnes per hectare (40 bags per hectare), how many hectares do you need to get 1,350 kg (1.35 tonnes)?
0.675 hectares is required for the cropping field.
How much land is required for the vegetables and chickens?
We also need a garden for vegetables and a place for chickens or other small livestock (for example a fish pond, pigeons, rabbits, guinea pigs) and for the house itself. Let us assume that we have 1,000 square metres (that is one tenth of a hectare, a hectare is 10,000 square metres) for this purpose. A big housing block in suburban Australia. This is probably generous. We could likely do it on less land.
0.1 hectares is required for the house and garden and small livestock.
How much land is required for the orchard?
We also need an orchard of fruit and nut trees and legume trees, shrubs, vines and the like. We will also use this area for free range for the poultry (probably in rotation – not all at once). Let us assume that this is also 0.1 ha. There would be plenty of produce from this area and an excess to swap with neighbours or sell to a local market.
0.1 hectares is required for the orchard.
How much land is required for the wood lot?
We also need a woodlot which will provide fodder and mulch, fuel wood and timber, as well as habitat for pest eating species and bees. Dovie, Witkowski and Shackleton (2004, p. 127; see also Shackleton 1993, p252) estimate utilisation of firewood at 692 kg/capita of wood per annum for rural communities in South Africa. A family of six would need 4,152 kilograms of firewood per annum. Shackleton (1993, p. 248) estimates the total amount of wood available in community forests that have not been harvested as 18,907 kg/hectare. He argues that the sustainable yield is 3 per cent per annum from this total. This would be 567 kilograms of wood per hectare, which would be close to being enough for one person. So a family of six would need six hectares.
6 hectares is required for the woodlot.
Total area required
So the total area required would be 0.675 (cropping field) + 0.1 (vegetables, house and small livestock) + 0.1 (orchard) + 6 (woodlot) = 6.875 ha for a family of six, where rainfall is more than 500 mm per year.
The implication of these figures for the countries in Africa where I have worked is as follows.
For the most part, holdings for cropping fields are close to adequate, but only if sustainable agriculture techniques are being used to boost and maintain production.
The land required for orchards, vegetables and small livestock is larger than some residential stands but many residential areas are adequate for this purpose. In planning for rural villages housing blocks should always be set at 0.2 ha to allow for these purposes.
Fuel wood supplies are very variable. The use of grazing land to grow wood supply is a problem in many communities, as cattle and goats impair the productivity of this resource where fuel is concerned. Other communities have adequate wooded land, but this is under pressure as wealthier villages expand their cattle herds. In many cases, all current grazing land should really be turned over to grow wood for cooking! This is a very difficult proposition to implement, given the local political power of wealthier village cattle owners.
References
Dovie, DBK, Witkowski, ETF & Shackleton, CM (2004) ‘The fuelwood crisis in southern Africa – relating fuelwood use to livelihoods in a rural village’, GeoJournal, vol. 60, no. 2, pp. 123-133.
Erenstein, O, Sayre, K, Wall, P, Hellin, J & Dixon, J (2012) ‘Conservation agriculture in maize and wheat-based systems in the (sub) tropics: lessons from adaptation initiatives in South Asia, Mexico, and Southern Africa’, Journal of Sustainable Agriculture, vol. 32, no. 2, pp. 180-206.
Gitari, N., Karumba, S., Gichovi, M., & Mwaniki, K. (2000) ‘Farmer evaluation of green manure legumes in Embu and Mbere districts’, Legume Research Network Project Newsletter, Kenya Agricultural Research Institute, Issue No 2, February 2000, p. 7-8
Gitari, N., Karumba, S., Mugendi, D.N. & Kung’u, J. (2003) ‘Effect of intercropping different densities of green manure legumes on maize performance in the central highlands of Kenya’, Legume Research Network Project Newsletter, Kenya Agricultural Research Institute, Issue No. 10, p. 7-10
Japan Association. (2008) The Maize in Zambia and Malawi. Tokyo: Japan Association for International Collaboration of Agriculture and Forestry.
Shackleton, CM (1993) ‘Fuelwood haversting and sustainable utilisation in a communal grazing land and protected area of the eastern Transvaal lowveld’, Biological Conservation, vol. 63, pp. 247-254.