“Several of the gardening practices that were observed seem to have conservation value. The Tsembaga practice selective weeding, for instance. From the time that weeding begins, five to eight weeks after planting, second-growth tree seedlings are allowed to remain, while herbaceous forms are uprooted. Not only does this avoid a definite grassy phase in the post-gardening succession, thereby minimizing the danger of a deflection toward a grassy disclimax, but it also provides during the cropping period deep tree roots that penetrate farther into the substrate than the roots of most crops. These roots are able to recover nutrients that otherwise might be lost through leaching. The development of trees over the garden also provides some protection for the exposed soil against tropical downpours and, furthermore, induces the gardeners to abandon the garden before the structure or content of the soil is severely damaged. People abandon gardens not because the crops are completely exhausted, but because the developing trees make the harvesting of the remaining root crops difficult” (Rapport 1968: 53)
In this quote, famous ecological anthropologist Roy A. Rappaport describes the sustainable gardening practices of the Tsembaga, a tribe living in Papua New Guinea. Rappaport lived with the Tsembaga from October 1962 to December 1964, The Tsembaga, who live between enemy groups in the highlands of New Guinea, understand that their territory is limited and thus conserving it for future plantings is paramount. They are a ‘slash and burn’ people, which means that after growing gardens for a prescribed number of years, they then burn them and let them rest for a fallow period before planting them again. This is also referred to as ‘shifting agriculture’ as the physical location of gardens shift over time. These small multi-crop gardens must fit into the mountainous and forested landscape in which the Tsembaga live. Practices such as growing trees within the gardens make sure that nutrients are not wasted, and that these areas will remain viable for planting well into the future. Other practices such as allowing pigs to browse in fallow gardens, or pollarding trees (cutting the top branches off of trees) also help to keep these gardens stable.
The Tsembaga, at this time (Rappaport performed his fieldwork in October 1962-December 1963, so we must keep in mind that there could be drastic changes that have taken place within the last 80 years) would not have used any chemical fertilizers, and so they relied on relationships with other species like pigs and trees to keep their gardens healthy. Definitely an interesting contrast to the many mono-cropped fields of the U.S. in which humans, their machines, tools and chemicals are the only ones allowed to enter (then again, we must also remember that the Tsembaga are small and rely on subsistence agriculture, whereas U.S. agriculture is big and must feed a population of over 327 million people, if not more)
References:
Rappaport, R.A. 1977 [1968]. Pigs for the Ancestors: Ritual in the Ecology of a New Guinea People. New Haven, CT: Yale University Press.
The Edited Jottings of an Amateur Anthropologist 