12. Achieving sustainability in cropping systems: the labour requirements of a mulch rotation system in Kalimantan, Indonesia.
Trop. Agric. (Trinidad), 68, 3, 1991, pp. 249-254
The present paper demonstrates that the Mulch Rotation System has another major advantage over more traditional systems since its labour requirements more closely match labour availability on the settlement units. It thus demonstrates the importance of including a systematic assessment of labour requirements and labour availability in the field trials of any new farming system.
In order to overcome the considerable problems of replacing rainforest with sustainable agricultural systems, IITA has developed a 'Living Mulch' system. The results have shown that in contrast to a conventional till system, in which yields decline rapidly after six seasons, sustainable yields of food crops can be achieved under a live mulch which tends to take over most of the functions of the natural vegetation.
A somewhat different approach described as a 'Mulch Rotation" System has attracted considerable interest in Indonesia.
The system starts with a one-year fallow when a legume cover crop - Pueraria javanica Benth. - is grown on the land cleared of rain forest.
After one year the cover crop is cut by hand and food crops are sown into the decomposing mulch. This continues for three seasons (one year) and the cover crop is again planted (as cuttings) into the last food crop - upland rice - after which the land is left under the legume cover crop fallow for a further year.
In addition to plant nutrients, however, the sustainability of a farming system depends on the availability of a whole range of other inputs.
Labour is a major constraint. However, both the Living Mulch and the Mulch Rotation Systems use no-till methods; and because the mulch, whether living or dead, tends to suppress weed growth, two of the most labour-intensive operations, soil tillage and weeding, are markedly reduced.
This paper shows how labour profile techniques can be used to evaluate this aspect of the Mulch Rotation System.
The introduction of the Mulch Rotation System can reduce the labour peaks dramatically. All the data for this system show a profile with less severe peaks and some extended troughs giving time for social activities and leisure. It should be noted that the Mulch Rotation System does include a one-year fallow. This implies the need for some additional land though the actual amount required depends on the yield improvement of food crops grown after a legume cover crop. Trials' work to date suggests that this yield improvement may be substantial but further work needs to be done to establish whether the introduction of the Mulch Rotation System would in fact need to be accompanied by a change in the standard size of settlement farm (from 2 to,say 2.5 ha).
Labour requirement data of the type used in this study must be validated under different climatic and soil conditions and further data gathered on other food crops. On the labour supply side, more reliable information is needed on the relative contribution of different family members in order to include appropriate weighting factors in the analysis.
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Asia, Philippines, IRRI, green manure, legumes, biomass, nitrogen accumulation, nitrogen substitution, rice yield, residual effects
MEELU, O.P. et al.
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