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close this bookBoiling Point No. 12 - April 1987 (ITDG, 1987, 36 p.)
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View the documentI.T. PUBLICATIONS

Agricultural Residues in Farming Systems

By Geoffrey Barnard, Panos lnstitute,
London


Many people in the energy field refer to agricultural residues as an "unused resource " and point to residues as being a potential solution to many countries' energy problems. While agricultural residues can offer a useful additional source of energy, it is dangerous to make assumptions without examining the role that those residues play within the relevant farming and social systems.

One of the biggest mistakes that can be mace is that of aggregation. A number of studies nave identified large amounts of residue at the national level and Projects have been designed accordingly. Once on the ground, however, it often turns out that the residues a-e highly decentralized and the cost of collection cannot be economically justified.

The availability of residues for fuel use is difficult to measure at the national level. . only becomes slightly clearer where good quality village studies are available. For example, modern high input systems with everal cross per year can give far more esidues than traditional rain-fed systems. In the other hand, many HYV (nigh-yield ariety) crops grow on much smaller 'stalks than traditional varieties. High-input farming, relying on chemical fertilisers, will tend to regard residues as a waste, whereas traditional farming methods may use much more of the residues as mulch, compost or fodder. In certain regions, farmers pay pastoralists to graze their cattle on their land to process their residues into high quality manure.

Residue production alone is not enough. The question of access to those residues is equally important. In India, people will weed wealthier landowners' land simply to obtain fodder for their cattle: they receive no payment. While a prosperous farmer with several hectares of farmland and a suitable herd of cattle may produce a large surplus of residues, a landless labourer may have automatic access to very little. What his family is able to obtain in practice may be determined more by the generosity of his employer than by the level of production in the village.

The other major danger in identifying unused resources, is actually in recognising how unused the resource really is. Agricultural residues provide three major - often conflicting - inputs to farming and social systems: fodder for livestock, compost/manure for soil fertility and energy for cooking and crop processing. Residues also provide roofing material, raw materials for a range of handcraft, and - as ash additives to ceramics, soap and other products.

These conflicts can sometimes be overplayed

It is often regarded, for example, that any dung burnt is to the immediate detriment of soil fertility, and stability. While this is, in theory, true, there are a variety of practical and economic considerations which prevent farmers from doing -what in strict soil science terms would be best. Organic farming is much more labour-intensive than using concentrated chemical fertilizer. Animal dung can be quite difficult and time consuming to collect unless the animals are penned in. Some crop residues decompose so slowly as to be of little nutritional or structural benefit to the soil. Again, -arming systems have to be examined on a local basis: only if residues are currently being used for fodder or fertiliser can one measure a conflict with energy use.

A more important conflict can be between different users of the same residues. Many briquetting projects fail to recognise this problem. Briquetting is an excellent way of upgrading many residues: it also raises its price. Residues that were a waste to afarmer become something of value. That is fine for the farm: but what about the poor landless labourer who is currently using that residue to cook with. However inferior that material is as a fuel, it is all they can afford. Briquetting in those circumstances is actually depriving the poorest people of one of their very few sources of energy.