A note on ringed fields

Stocks (1983) suggested four reasons which motivate the planting of South American tropical forest swidden crops in concentric rings. His third proposal, that of protection from insect pests, is examined in the light of recent fieldwork with the Bari, and reformulated to suggest that protection from mammalian pests may be a more accurate explanation of the value of this type of field architecture.     

Maintenance of agriculture and human habitats within the tropical forest ecosystem

The tactics of shifting cultivation are reviewed with particular reference given to techniques of forest regeneration. The desirability of a forest-fallow system of agriculture is explained. Also discussed are the causes, indicators, and consequences of a breakdown of forest-fallow cultivation. In conclusion, the future of tropical forests for agriculture and habitats for man is considered.This article is a modified version of one originally prepared for a Man and the Biosphere Symposium entitled The Ecological Effects of Increasing Human Activities on Tropical Forest Ecosystems. The Symposium met in Port Moresby, Papua New Guinea, April 28–30, 1975. Proceedings are scheduled for publication in late 1976 and will include another version of the present article.     

The role of biomass in shifting cultivation

Shifting cultivation has traditionally been characterized as a highly productive system in terms of the ratio of energy outputs to inputs. This characterization, however, does not take into account the energy contribution of the natural vegetation cleared in preparing the field for cultivation. As a result, the central feature of shifting cultivation, the exploitation of the natural vegetationsoil complex as a substitute for human labor, has been ignored. The omission of the biomass contribution can be attributed to both a focus on the practices involved rather than the underlying strategy of the shifting cultivator, and an excessive preoccupation with the renewability of the energy sources involved in different agricultural systems. A definition of shifting cultivation is proposed that focuses attention on the relationship between the natural vegetationsoil complex and the shifting cultivator. Two methods of including the energy contribution of forest biomass in calculating the productivity of shifting cultivation systems are compared. When the biomass contribution is included, shifting cultivation appears to be an extremely unproductive system of agriculture.I would like to thank Bill Denevan, Chris Uhl, Christine Padoch, Tom Klak, Bob Buschbacher, and Mimi Kranichfeld for their comments on earlier versions of this paper.     

Swidden cultivation in forest and savanna in lowland southwest Papua New Guinea

Ecological aspects of traditional swidden cultivation by Bine- speaking groups in wetland areas of lowland southwest Papua New Guinea are examined. A notable feature of the area is the coexistence of extensive, polycultural forest cultivation and more intensive, specialized savanna cultivation. Both agrosystems occur on soils of inherently similar properties. The savanna vegetation is secondary in character and, once established, is better suited to more intensive swidden cultivation based on taro (Colocasia esculenta). The agrosystems in question represent stages in the local development of agriculture, and, although multiple causes of intensification may be involved, the study confirms that lowland, as well as highland, areas of New Guinea have provided development opportunities for traditional cultivators.     

Consequences of Swidden Transitions for Crop and Fallow Biodiversity in Southeast Asia

Swidden agriculture, once the dominant form of land use throughout the uplands and much of the lowlands of Southeast Asia, is being replaced by other land uses. While change and adaptation are inherent to swiddening, the current rapid and widespread transitions are unprecedented. In this paper we review some recent findings on changes in biodiversity, especially plant diversity at various scales, as swidden farming is replaced by other land uses. We focus particularly on two areas of Southeast Asia: northern Thailand and West Kalimantan. We examine actual and potential changes in the diversity of crops that characterize regional swidden systems, as well as that of the spontaneously occurring plants that appear in swidden fields and fallows. Severe declines in plant diversity have been observed in most areas and at most spatial scales when swidden is replaced by permanent land use systems. However, shifts away from swidden agriculture do not invariably result in drastic declines or losses of biological diversity, but may maintain or even enhance it, particularly at finer spatial scales. We suggest that further research is necessary to understand the effects of swidden transitions on biodiversity.     

Why farmers rotate fields in maize-cassava-plantain bush fallow agriculture in the wet Peruvian Amazon

The maize (Zea mays) -cassava (Manihot esculenta)-Musarelay-cropped sequence as practiced among 28 Yanesha families in the Palcazu Valley in Central Amazonian Peru was surveyed to determine why farmers rotate fields into bush fallow. Typically, this sequence is planted on alluvial Inceptisols after the clearing of 2–5 year tree and shrub growth. During the 18–30 months of cropping, fields showed a buildup of weeds and an increase in banana stem borer and nutrient deficiency symptoms. Farmers attributed the decline in Musayields from the first to third harvests to stem borer, weeds, or soil infertility but were not unanimous. Any or all of these factors facilitate the decision to abandon a field. A 3-year record of fields cleared by each farm family indicated that field rotation stems from two independent decisions: selection of a fallowed field to clear for maize and vegetables, important for family nutrition, which are planted right after field clearing, and discontinuation of weeding in old fields as labor is used primarily on new fields, a decision leading to bush fallow recovery. Work with these families during 4 years suggests that the distribution of land and labor is based on a sense of relative labor productivity, on diverse dietary needs and preferences, and on the maintenance of a balance between areas in cropping and under fallow.     

Cassava (Manihot esculenta Crantz), Cyanogenic Potential, and Predation in Northwestern Amazonia: The Tukanoan Perspective

The Tukanoans of northwestern Amazonia cultivate high-cyanogenic potential cassava, which provides 80% of their dietary energy. In an effort to understand why the Tukanoans cultivate primarily high-rather than low-cyanogenic potential cassava, which requires far less processing before consumption, this paper seeks to determine whether the Tukanoans discern a difference in levels of predation on high-and low-cyanogenic potential cassava. Given the potential protection afforded by high-cyanogenic potential, it was hypothesized that the Tukanoans would report higher predation upon low-cyanogenic potential cassava in comparison to high-cyanogenic potential cassava. Both unstructured interviews and pile-sort exercises were conducted to address this question. The unstructured interviews provide some support for the hypothesis, while the pile-sort interviews did not support the hypothesis. These data demonstrate that while the Tukanoans are cognizant of differences in predation on different cassava cultivars, resistance to predation may not be a characteristic of paramount concern in cultivar selection.     

Ecological Praxis and Blackwater Ecosystems: A Case Study From the Brazilian Amazon

This article explores how anthropogenic modifications of soil condition human adaptive processes on the Amazonian uplands. The occurrence of black earth (a nutrient-rich anthrosol) in nutrient-poor blackwater environments and its cultivation by contemporary residents provide a unique opportunity for understanding the ecological praxis of Amazonian groups. Two years of ethnographic, ethnoscientific, and agronomic research among caboclo residents of the Lower Rio Negro and Rio Urubú confirm that unique cognitive and behavioral orientations characterize black earth and adjacent environments. When compared with cognitive and behavioral orientations to these two environments in distant blackwater regions, data suggest that political-economic, technological, cultural, and ecological factors have had~a strong influence on the trajectory of human-environmental interactions. Data in large part illustrate the utility of historical ecological models, yet point to an interactive role of diverse histories in shaping the range of human responses.     

Development of a nature value index for pastoral farmland—A rapid farm-level assessment

Sustainable agriculture is important for the safeguarding of natural resources (e.g. semi-natural habitats, clean water and energy), food production and for the survival of rural communities. As part of the EU strategy towards sustainability Member States are committed to identifying and protecting areas of agrobiodiversity. Identification of the extent and support of High Nature Value (HNV) farmland across the EU was an important policy requirement of Member States Rural Development Programmes (RDP) (2007–2013) but problems defining the extent of HNV farmland have delayed progress to date. Following a five step statistical process, we developed a simple 10 point nature value index based on percentage improved agricultural grassland, stocking density (LU/ha Utilisable Agricultural Area) and length of linear habitats per hectare on a farm. We propose an index that can be used to highlight farms with low biodiversity allowing targeting of sustainability measures such as increasing field boundary area or reducing inorganic Nitrogen inputs, farms that are already sustainable from a biodiversity perspective, and could be labelled as such through national programs or even farms that are High Nature Value (HNV) and should be targeted through results-based agri-environment schemes. This nature value index has potential to be applied to a range of farmed pastoral landscapes in North West Europe's Atlantic biogeographic region. The methodology used in the development of the index has the potential to be used in other biogeographic zones to develop similar indices of nature value at farm level. This index is a simple to use, easily accessible identification tool based on farm-level data which can be utilised in sustainability indices and HNV farmland identification.     

Effects of length of forest fallow on fertility dynamics in a Mexican ultisol

Changes with time in the fertility of a Mexican ultisol were evaluated from analyses of soil samples from fields representing 50 years of pineapple slash-and-burn agriculture. Sixteen fields with similar soil profile charactersitics representing eight ages of forest fallow were sampled. The fields, within an area of 5 km² of nearly level tropical forest, had been cleared by hand, initially intercropped with corn and manioc, followed with 3 to 4 y of pineapple, and then abandoned. The surface soils contained relatively high levels of C and N (5% and 0.3% respectively), were strongly acid (pH 5 to 5.5), and supplied very low levels of available P and K. Soil contents of both C and N declined rapidly after clearing to levels approximately 20% lower at 10y, then increased steadily during the fallow period to values not different from their initial levels. Since little of the N released was utilized by the low-yielding, P-deficient crops, this loss of C, N and accompanying cations is a most serious consequence of this rotation. Both the exchangeable and reserve K levels of these ultisols are low. Thus, K is identified as second to P as a growth limiting factor and the most difficult fertility management problem.     

Adaptive strategies in the breakdown of shifting cultivation: The case of Mambwe,Lamha, and Lala of northern Zambia

Many researchers have commented on the remarkable ability of African shifting cultivators to adjust their agricultural methods to available resources. In northern Zambia, where the shifting cultivators depend on woodlands as an agricultural fallow crop, deforestation is prevalent under the increasing population pressure. Adaptations to the less vigorous forest cover have taken various forms, but all of them can be described as succession to a common system of shifting cultivation. In many respects, these can be regarded as part of a process of agricultural adaptive radiation as the affected populations were pushed into new environments as a result of warfare and/or population pressure.     

Folk taxonomy and evolutionary dynamics of cassava: A case study in Ubatuba, Brazil

A survey was conducted of Caicara farmers from Ubatuba in the Brazilian coastland between São Paulo and Rio de Janeiro States regarding the folk-taxonomy for cassava (Manihot esculenta Crantz) landraces they cultivate and cassava evolutionary dynamics in swidden cultivation. The accuracy of their folk taxonomy was assessed. Cluster analysis was used to make comparisons between names given by the farmers to sampled individuals and their isozyme phenotypes obtained with four isozyme systems. Interviews with farmers were done and ethnobiological data collected. These farmers possess a loose taxonomic system and tend to underestimate cassava genetic diversity in their gardens. However, classification skills vary considerably among them. The accuracy of their taxonomy along with the results of interviews with farmers and ethnobiological data are discussed in light of a proposed evolutionary dynamics model for cultivated cassava and its ecology in tropical swidden cultivation.     

Piaroa Manioc Varietals: Hyperdiversity or Social Currency?

The maintenance of exceptionally high numbers of folk varieties by the Piaroa people of the Venezuelan Amazon is considered. We cataloged 113 manioc folk varieties, their nomenclature, use and relevant characters, revealing significant insights into the role of manioc in Piaroa social life. Through a qualitative investigation of the cultivation, processing and symbolic significance of manioc (Manihot esculenta) in two Piaroa regions over a period of 18 years, we have found that such agrobiodiversity can only be fully explained by a combination of multiple factors, including pragmatic and ecological considerations, the subtle and complex diversity of Piaroa manioc preparations and a variety of sociocultural factors, such as manioc’s role as a mediator of social relationships and as a marker of cultural and social heritage.

Agricultural intensification in a Philippine frontier community: Impact on labor efficiency and farm diversity

There continues to be much debate in anthropology concerning the mechanism by which agricultural intensification takes place and its impact on labor efficiency, farm diversity, and quality of diet. A major reason for this lack of consensus is the paucity of data from case studies that focus on specific agricultural systems at the point of transition from extensive to intensive methods of cultivation. Research in a frontier community in the Philippines, where farmers are making the shift from swidden cultivation to small-scale irrigated rice production, indicates that intensification does not necessarily result in lower efficiency or a decline in dietary standards. Rather, farmers faced with growing population pressure and an unproductive short fallow swidden system have been motivated to adopt irrigation because it increases the efficiency of their labor while maintaining a reliable and diverse farming system.     

Shifting Cultivation and Conservation of Biological Diversity in Tripura, Northeast India

Shifting cultivation (jhooming) has been identified as one of the main human impacts influencing biodiversity in Tripura, Northeast India. Over the last few years a new class of shifting cultivators has emerged that has adopted non-traditional forms of jhooming, which have been responsible for the loss of biological diversity in the state. This paper describes the successes achieved by the state government in providing the jhumias (tribes practicing jhooming) with various non-jhooming options. Recommendations include the need for short and long term control measures, improvement of existing jhooming methods, and integration of traditional knowledge with new practices.     

西双版纳热带雨林不同土地利用方式对土壤动物个体数量的影响

以自然林为对照,研究了云南省西双版纳热带地区耕火种农业（旱稻）和林下种植砂仁（Amomum villosum）2种不同土地利用方式对土壤弹尾、螨和线虫3类土壤动物个体数量的影响。通过24个月的取样分离,获得土壤动物个体49.912个。结果表明：不同土地利用方式导致了土壤理化性质不同程度的改变,例如土壤容重的增加、肥力下降、土壤水分蒸发加快等,这些土壤指标的变化是影响土壤动物个体数量的决定性因素。动物的个体数量在3个样地中以自然林最多,砂仁地次之,刀耕火种地最少;在季节分布上以雾冷季最多,干热季最少。各样地的动物个体数量以刀耕火种与自然林之间的差异最显著,刀耕火种样地与砂仁样地或砂仁样地与自然林样地之间的差异有时达到显著水平,但在不同季节中各类型样地间的差异有所不同。土壤动物的季节变化不但受气候条件变化的影响,同时受到人类土地利用活动的影响,在人为干扰样地中高峰与低谷之间的变化幅度较大。某些土地利用的行为不但杀死了动物本身,而且破坏了动物的营养源,因此土壤动物个体数量随着土地利用强度的增加而下降。     

Palms,Pastures, and Swidden Fields: The Grounded Political Ecology of “Agro-Extractive/Shifting-cultivator Peasants” in Maranhão,Brazil

This article examines transformations associated with changes in resource use and land cover dynamics in the community of São Manoel, Maranhão state, in the eastern Brazilian Amazon. The shifting cultivator peasants in São Manoel integrate swidden fields for annual cropping, the extraction of babassu palm products, and pastures for cattle ranching. Since the early twentieth century, predominant vegetative cover patterns have been altered from species-rich mature forests to secondary succession with babassu dominant to pasture or swidden fields containing palm stands of various densities. A grounded political ecology of resource use in the area suggests that management strategies and the resulting land cover dynamics integrate site-specific decisions of peasant producers. I discuss the trajectory of production strategies in São Manoel since the establishment of the community in the 1920s, and identify the multiple dimensions affecting resource use and environmental outcomes, with an emphasis on the period following land struggles and the recovery of peasant tenure rights in the mid-1980s. The analysis indicates that socionatural trajectories that optimize resource use and address the socioeconomic needs of the community include the maintenance of palm/pastures associations.