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Household level problems
- terrace farms
- compound farms
- Near fields close to the compound but with fewer crops, than compound farms;
- Outlying & distant fields.
These are problems that occur within the farming system experienced at the level of the farm household; for example, insufficient food production to feed the family
These are problems beyond the boundaries of a single farm system operating at a larger scale; for example, sedimentation of a reservoir.
A group of farms (individual farm systems or households) that are sufficiently similar to be considered together for a particular purpose (such as description or the formulation of extension recommendations). This implies that a general model can be used as representative of the individual farms involved. In this case study there appears to be two separate farming systems: the older generation farmers on the plateau engaged more in arable practices, and the younger generation farmers in the valleys engaged more in pastoralism. Information in the case study indicates that these two generations operate and manage their farms discretely at the household level, and as such, can be assumed to constitute separate farming systems.
This is a particular methodology for diagnosing problems in land use systems and designing agroforestry interventions to address them. It was developed by the International Council for Research in Agroforestry (ICRAF) during the 1980s (Raintree, 1990)
A feedback is where the effects of a causal influence also have a causal influence acting on causal factors earlier in the causal chain or network.
Household level farming (or land use) systems
At the household level the land use system comprises the entire activity of the farm household and may involve several agricultural (and often non-agricultural) enterprises on various types of land (for example, monocultural paddy rice cultivation on alluvial soils in valley bottoms and multilayered tree gardens on less fertile soils on mid-slopes, as is common in the Kandy district of Sri Lanka. The household allocates resources such as labour and capital amongst these activities and thus, even if they are on different land they interact via resource allocation decisions, and possibly some material transfers (such as dung from livestock kept in the garden being applied to the rice fields).
See also Chitemene farming system
The Chitemene system of shifting cultivation in the "miombo" woodland of N.E. Zambia involves a six year crop rotation, including several years of woody fallow. The majority of households maintain a minimum of four fields in different stages of the cycle to enable production of the full range of major crops.
Agroforestry practices are discrete groups of tree and agricultural components that are managed together to perform one or more functions, and in which there are significant ecological interactions between the tree and agricultural components. If we take as our example a multilayered tree garden with a live fence surrounding it, clearly the live fence in this case is identifiable as a discrete practice because it is managed differently than the rest of the garden it protects, for the purpose of protecting it. By-products of fodder and/or fuelwood may also be obtained from the fence. It is useful, therefore, to view the garden- live fence complex as a spatial group of two practices because of their discrete functionality. It is also common for agroforestry practices to be functionally grouped in time. As, for example, in the case of chena shifting cultivation in the dry zone of Sri Lanka where a fallow phase (comprising natural vegetation) is temporally linked with a cultivation phase (comprising planted crops and some retained natural vegetation).
In the example of a multilayered tree garden with a live fence surrounding it, the live fence was identified as a discrete practice, and the garden-live fence complex, a spatial group of two practices. It is clearly necessary to identify the spatial linkage in this example, since the performance and prospects of a garden surrounded by a live fence may be quite different from that of a garden that is not so protected. By contrast, hedgerow intercropping where crop alleys (several rows of crops) are interspersed with hedges of fast growing, usually nitrogen fixing, shrubs that are coppiced every few weeks to provide a nitrogen-rich mulch for the crop, is clearly a single integrated agroforestry practice, because the hedgerow-crop complex is managed together for a common purpose and there are very significant ecological interactions between the shrub and agricultural crop components.
In the example of chena shifting cultivation, the fallow phase was identified as being temporally linked with the cultivation phase. The fallow and cultivation phases are clearly two discrete practices, in that different components are involved in each and they are managed at very different levels of intensity. However, they are also clearly linked in time, since the fertility generated in the fallow phase is exploited in the cultivation phase. Sequential linkages are common in agroforestry because the tree component may be long lived and there may be different opportunities for agricultural activity associated with trees at different points in the tree rotation. This is evident in the coconut production systems of Sri Lanka where it is common to intercrop coconut in the first five years when the palms are young and then again when the palms are mature (20 years old) but there is less scope for intercropping when the palms are 5 to 20 years old.
Viewing the phases of an agroforestry rotation as a set of temporally linked practices (each with common components) is more useful than primarily characterising the entire rotation. This is well illustrated by the fact that it is common to intercrop trees with arable crops until the shade from the trees inhibits ripening of grain crops at which point the agricultural activity is switched to grazed pasture. There is thus a silvoarable phase followed by a silvopastoral phase. At no time are there livestock, arable crops and trees all interacting on the same land at the same time.
Although the prevailing definition now in use does not distinguish between agroforestry as an interdisciplinary approach to land use and as a set of integrated land use practices (Lundgren, 1987), it is appropriate and useful to do so. The approach combines the study of woody perennials, herbaceous plants, livestock and people, and their interactions with one another in farming and forest systems. It embraces an ecosystem focus considering the stability, sustainability and equitability of land-use systems, in addition to their productivity (see Conway, 1985 & 1987; Marten, 1988). Consideration of social as well as ecological and economic aspects is implied. The set of land-use practices involve the deliberate combination of woody perennials and herbaceous crops and/or animals on the same land management unit in some form of spatial arrangement or temporal sequence such that there are significant ecological and economic interactions between woody and non-woody components (Adapted from Lundgren, 1987). Agroforestry is a relatively new subject for scientific study but a traditional practice with a long history in many parts of the tropics (King, 1968; Nair, 1989). Consequently analysis of the vegetation structure and dynamics of natural ecosystems (Oldeman, 1983), and the indigenous knowledge of local practitioners (Walker, Sinclair and Muetzelfeldt, 1991) might be expected to be principal sources of information about tree species and how they might be utilized in agroforestry.
Compound farms are found within the vicinity of the homesteads and comprise numerous multipurpose woody species in intimate multistoried associations with annual crops (usually staple food crops) and small livestock. The multistoried structure and species diversity allow almost complete coverage of the soil by plant canopies, thereby promoting soil conservation. Soil fertility is maintained by the use of household refuse, crop residues and animal manure. The system has been recognised as a potentially sustainable form of land use (Lagemann 1977) with possible application for the entire humid tropics.
In Imo, Cross River and Rivers States, timber is exploited from natural forests within forest reserves. The species extracted include Entandrophragma spp., Khaya ivorensis A. Chev., Mitragyna ciliata Aubrev. & Pellegr., Nauclea diderrichii, Chlorophora excelsa (Welw.) Benth., Gossweillerodendron balsamiferum (verm.) Harms. and Cylicodiscus gabunensis Harms.
Major plantation species include Gmelina arborea L., Tectonia grandis L.f., Nauclea diderrichii (De Wild. Th. Dur.) Merril., Terminalia ivorensis A. Chev. and Pinus caribaea Morelet. These are planted for fuelwood, poles and pulpwood. To a lesser extent, Cassia siamea Lam. and Eucalyptus spp. are planted on poorer sites.
The periodic movement of both cropland and settlement
The periodic shifting of farmland only
Rudimentary sedentary cultivation
This generally involves one- or two- year fallow rotations
Intensive sedentary cultivation
There are two types of intensive sedentary cultivation in south-eastern Nigeria:
Associated fields are a common feature of the homegarden type of system (Fernandes and Nair 1986; Jacob and Alles 1986; McConnel and Dharmajala 1973; Michon et al. 1986; Nair and Sreedharan, 1986; Soemarwoto et al. 1976). These fields are often used to produce food or cash crops that are not suitable for growing within the multistoried homegardens, e.g., maize (intolerant of shade), rice or millet simply to supplement homegarden production.
Associated fields can be categorized as: