Recently tropical agriculturalist have come to a new understanding of the mixed cropping system, especially from the points of view of ecology. But most of researchers have not realized peasants' value system concerning mixed cropping. This paper aims at analizing the mixed cropping system in the Bakumu people in Zaire in Tropical Africa from the points of view of their sense of value towards the mixed cropping comparing with the sole cropping and their own management system of mixed cropping. According to the result of the analysis we realized that their sense of value concerning mixed cropping is concentrated on “diversity”, associating with stability on three levels as follows: 1) diversity of crops, 2) diversity of nutrition, 3) diversity conservating and maintaining their own plants and seeds. In the context of their socio-economic process, their emphasis of diversity as sense of value towards mixed cropping is strongly linked with their life style on the following two dimensions. 1) The food habit of the Bakumu people having different food day by day, time by time, being maintained through the realization of the diversity by the cropping system, 2) the system of food storage of the Bakumu people, dispersing harvesting time of their crops and stocking their crops inside the cultivated land instead of having the food storage ystem as in the temperate region. On the other hand, “diversity” as their sense of value becomes realized accompanied with fallow system being longer, according to their model of management of mixed cropping, and then we can suppose that enriching of “diversity” is closely related to their own conception of “soil productivity”. Though these analysis, we can suppose that in the Bakumu society their sense of value on mixed cropping functions not only as the sense of value on the level of the cropping technique but also as a ‘value system’ of the society as a whole.
Man-plant relationships are tentatively categorized into four aspects. These are (1) men's cognition of plants, (2) men's utilization of plants, (3) plants' cognition of men and (4) plants' utilization of men, respectively. The first aspect has been mainly dealt with in the study of folk taxonomy and the second in the classical ethnobotany and economic botany. Last two viewpoints of anti-anthropo-centric nature may be difficult to understand for human being. Cultivated plants, however, can be a good example to explain. For instance, non-dehiscent wheat should recognize as well as utilize men as a sole agent of seed dispersal, and such recognition is directly concerned with the reproductive success of wheat. Mutually benefitial relationships which can be found typically between agriculturist and cultivated plants, is called man-plant symbiotic relationships, and domestication is defined as their diachronic process. In the present study, man-plant relationships in Acholiland are described in the viewpoints of (1) and (2). Hypothesis that the recognition of men by plants is most distinctively characterized by the weediness and/or colonizing ability of plants. This hypothesis may be indirectly evidenced by the recognition and utilization of plants by men. Five folk categories of vegetation are recognized among the Acholi. Of the five, only the luul (forest) is refered as a habitat of some vernacular species. In contrast with luul, two other folk categories, paaco and potho are mentioned to categorize folk plant species. Paaco literally means “man's place” and potho is a noun form of the verb pita (cultivate). The specimens of 320 folk vernacular species are identified. With each specimens, usage and habitat are inquired. The analysis of data revealed that; (1) relatively large number of plants from paaco are recognized. (2) Plants from paaco are used as food more commonly than those from other habitat. (3) Plants from luul are frequently utilized for material culture. And, (4) most of plants from potho are used for foods. In a total of eighty-seven Linnaean species which can be regarded as weedy or with high weediness in botanical description of the flora, seventy-five species are recognized as plants from paaco, but no plants of stable habitat as from paaco. Therefore, it is concluded that weeds which respond well to the man's distrubance of the habitat are likely to be recognized and utilized among the Acholi.