农林复合系统固碳潜力研究进展

农林复合系统是解决当前资源枯竭、农林用地紧张和实现环境保护的一种可持续土壤管理模式。自《京都议定书》签订以来, 农林复合系统因其较高的固碳潜力引起了科学家的广泛关注。深入理解农林复合系统的固碳过程及其对气候变化、环境条件的改变和管理措施的响应, 是准确地预测农林复合系统在全球变化情景下固碳潜力的关键。该文综述了农林复合系统的概念和分类, 探讨了农林复合系统相比单一系统的固碳潜力及固碳机理, 分析了农林复合系统固碳潜力的测定方法和当前面临的挑战, 综述了气候因子、环境条件和人为管理措施对农林复合系统固碳潜力的影响。我国农林复合系统的固碳潜力相比全球其他区域还处于较低水平, 为提高我国农林复合系统的固碳潜力, 未来需要加强以下四个方面的工作: 扩大农林复合系统的分布面积、加强农林复合系统的合理配置和管理、选择适宜的物种组合和优化系统的群体结构。     

Modes of Communication and Effectiveness of Agroforestry Extension in Eastern India

Development of extension in agroforestry draws on the application of the innovation-diffusion process in agriculture. To be effective, agroforestry extension needs to fit the dynamics of the target farming system, the local socioeconomic and technological systems, and land use constraints. Failure of agroforestry extension has been blamed on inadequate and inappropriate methods, but there have been few studies to identify those factors that determine a farmer's awareness of, or attitude to, agroforestry. The present study focused on the modes of communication used in extension and how they affected adoption of agroforestry in a subsistence farming region of eastern India. The decision to adopt agroforestry was found to be determined by the farmers' attitude to agroforestry, which in turn was shaped by information received through farmer-to-farmer and farmer-to-extension contact. The mode of communication was important and, to be effective, needs to be customized for each target group.     

Possibilities for agroforestry development in Bulgaria: Outlooks and limitations

Current conditions in Bulgaria are favorable for the development of agroforestry due to socio-economic incentives and environmental necessities. As a scientific theory and practice, agroforestry is less familiar than other farming systems in Bulgaria. Hence, to ensure successful agroforestry development in Bulgaria, four necessary movements (or collective national ‘moments’) are described here: (1) wide-scale popularization of agroforesty's fundamental tenets, including its nature as a production system, types of agroforestry systems, structural components, methods for design, construction, maintenance and management, advantages and disadvantages and possible applications in Bulgaria; (2) a comprehensive research program on agroforestry, in areas such as high-tech selection of plant and animal species suitable for agroforestry technologies (including cultivation of lesser-known indigenous species that may be better suited to local conditions), studies of how to balance the biophysical interactions of agroforestry species to optimize and conserve natural recourses (e.g., sunlight, soil, water, microclimate), knowledge of best cultural practices (e.g., fertilization, irrigation, IPM) and economic analyses of various agroforestry systems; (3) education and preparation of interdisciplinary specialists for the development of this new economic direction; (4) realization of government policies to enhance and encourage the development of agroforestry in ways that are economically appropriate for the nation. These policies should include long-term development strategies, national and regional program plans and structures, financial incentives (loans, subsidies, tax reductions, ensuring production sales, awards, etc.) and establishment of agroforestry demonstration sites.     

西双版纳地区不同胶农(林)复合系统的植物水分利用效率比较

当前,西双版纳地区大面积橡胶单一种植林已引发了诸多的生态环境问题,为解决这些问题同时协调当地的经济发展,农林复合系统被生态学者们认为是最好的解决办法。然而目前关于不同间作模式下橡胶树水分利用效率研究还很少。因此,于2013－2014年的雨季中期(8月)和末期(11月)、雾凉季(1月)、干热季(3月),分别测定了中国科学院西双版纳热带植物园内四种不同胶农(林)复合系统(橡胶—叶茶、橡胶—咖啡、橡胶—大叶千斤拔、橡胶—可可复合系统)及单层橡胶林的土壤含水量、橡胶树及其林下间作植物的枝条凌晨水势和正午水势,以及它们植物叶片的δ13 C值,分析了各胶农(林)复合系统内橡胶树的水分利用效率,以期遴选出水分关系配置合理的复合橡胶林栽培模式,为环境友好型橡胶种植林的建设和推广提供相关的参考依据和理论支持。结果表明：除橡胶—可可复合系统以外,其余胶农(林)复合系统内的橡胶树水分利用效率值均高于单层橡胶林;橡胶—大叶千斤拔复合系统的土壤含水量显著高于其它复合系统;橡胶—叶茶复合系统的土壤含水量虽然低于橡胶—大叶千斤拔复合系统,但其最为稳定、季节变化小;橡胶—咖啡复合系统的水分利用效率最高最稳定,即使受到寒害也没有引起明显变化;而橡胶—可可复合系统的作用不明显,所有特征都与单层橡胶林相似。这表明除了橡胶—可可复合系统外,其他3种胶农(林)复合系统都显著地缓解了橡胶树在旱季所遭受的水分胁迫,同时也能有效地抵御突发性天气灾害。     

农林复合系统种间关系研究进展

种间相互作用在很大程度上决定了农林复合系统的生产力和可持续性,理解种间相互作用是经营和管理农林复合系统的关键。地上部分相互作用主要包括复合系统组分对光的竞争与互利、小气候的改变对系统生产力的影响;地下部分相互作用主要包括复合系统组分对水分和养分资源的竞争与互利、固氮树种对系统生产力的影响以及化感作用。今后需加强不同立地条件下的不同农林复合系统种间关系的比较、农林复合系统组分的空间分布格局、化感作用以及农林复合系统种间关系模型等研究。     

A renewed perspective on agroforestry concepts and classification

Agroforestry, the association of trees with farming practices, is progressively becoming a recognized land-use discipline. However, it is still perceived by some scientists, technicians and farmers as a sort of environmental fashion which does not deserve credit. The peculiar history of agroforestry and the complex relationships between agriculture and forestry explain some misunderstandings about the concepts and classification of agroforestry and reveal that, contrarily to common perception, agroforestry is closer to agriculture than to forestry. Based on field experience from several countries, a structural classification of agroforestry into six simple categories is proposed: crops under tree cover, agroforests, agroforestry in a linear arrangement, animal agroforestry, sequential agroforestry and minor agroforestry techniques. It is argued that this pragmatic classification encompasses all major agroforestry associations and allows simultaneous agroforestry to be clearly differentiated from sequential agroforestry, two categories showing contrasting ecological tree-crop interactions. It can also contribute to a betterment of the image of agroforestry and lead to a simplification of its definition.     

混农林生态系统服务研究进展

混农林产业是兼顾生态环境修复、土壤资源可持续利用与社会经济效益共赢的生态治理衍生产业,将生态系统服务与混农林实践相结合既是全球生态系统服务研究的主要前沿之一,也是推进石漠化治理向生态产业振兴与生态系统服务提升融合阶段转变的具体路径。研究系统回顾了混农林生态系统服务的研究进展与特征,揭示了混农林生态系统服务与喀斯特地区产业振兴的内在关系,从混农林生态系统服务认知、评估与决策三个层面探讨了喀斯特地区产业振兴的方向,强调未来喀斯特地区应围绕混农林生态系统服务的级联机理、供需关系、权衡协同及影响因素等层面为混农林产业振兴提供决策支撑,进而更好地服务于喀斯特地区以巩固石漠化治理成效,提升生态系统服务,助力乡村振兴。     

Seasonal contrasts in the response of coffee ants to agroforestry shade-tree management

In many tropical landscapes, agroforestry systems are the last forested ecosystems, providing shade, having higher humidity, mitigating potential droughts, and possessing more species than any other crop system. Here, we tested the hypothesis that higher levels of shade and associated humidity in agroforestry enhance coffee ant richness more during the dry than rainy season, comparing ant richness in 22 plots of three coffee agroforestry types in coastal Ecuador: simple-shade agroforests (intensively managed with low tree species diversity), complex-shade agroforests (extensively managed with intermediate tree species diversity) and abandoned coffee agroforests (abandoned for 10-15 yr and resembling secondary forests). Seasonality affected responses of ant richness but not composition to agroforestry management, in that most species were observed in abandoned coffee agroforests in the dry season. In the rainy season, however, most species were found in simple-shade agroforests, and complex agroforestry being intermediate. Foraging coffee ants species composition did not change differently according to agroforestry type and season. Results show that shade appears to be most important in the dry seasons, while a mosaic of different land-use types may provide adequate environmental conditions to ant species, maximizing landscape-wide richness throughout the year.     

农林系统研究进展

综述了国内外农林系统的研究进展 ,介绍了农林系统的概念、产生背景和过程及主要的研究方向。从农林系统的结构和分类、农林系统小气候及系统效益评价等 3个方面对当前农林系统的研究现状进行了评述。重点从水分、温度、辐射、光照及人体舒适度等方面分析了农林系统小气候的研究状况 ;从化感作用和地下部分相互作用两个方面介绍了系统组分间的相互作用关系。同时指出农林系统类型较为单一、理论研究落后于实践、基础理论研究相对薄弱等研究中存在的问题。提出农林系统的研究应进一步加强多学科深层次、实质性的交流与合作 ,注重科研机构与生产基层的有机联系 ,加强理论基础研究 ,因地制宜地发展农林系统 ,更好地为生产实践服务。     

Dung Beetle and Terrestrial Mammal Diversity in Forests, Indigenous Agroforestry Systems and Plantain Monocultures in Talamanca, Costa Rica

In order to explore the importance of indigenous agroforestry systems for biodiversity conservation, we compared the abundance, species richness and diversity of dung beetles and terrestrial mammals across a gradient of different land use types from agricultural monocultures (plantains) to agroforestry systems (cocoa and banana) and forests in the BriBri and Cabécar indigenous reserves in Talamanca, Costa Rica. A total of 132,460 dung beetles of 52 species and 913 tracks of 27 terrestrial mammal species were registered. Dung beetle species richness and diversity were greatest in the forests, intermediate in the agroforestry systems and lowest in the plantain monocultures, while dung beetle abundance was greatest in the plantain monocultures. The number of mammal tracks per plot was significantly higher in forests than in plantain monocultures, whereas mammal species richness was higher in forests than in either cocoa agroforestry systems or plantain monocultures. Species composition of both terrestrial mammals and dung beetles also varied across the different land use types. Our study indicates that indigenous cocoa and banana agroforestry systems maintain an intermediate level of biodiversity (which is less than that of the original forest but significantly greater than that of plantain monocultures) and provide suitable habitat for a number of forest-dependent species. Although the agroforestry systems appear to serve as favorable habitats for many terrestrial mammal species, their potential positive contribution to mammal conservation is being offset by heavy hunting pressure in the reserves. As in other agricultural landscapes, the conservation of biodiversity in Talamanca will depend not only on maintaining the existing forest patches and reducing the conversion of traditional agroforestry systems to monocultures, but also on reducing hunting pressure.     

Is soil degradation unrelated to deforestation? Examining soil parameters of land use systems in upland Central Sulawesi, Indonesia

It is generally assumed that declining soil fertility during cultivation forces farmers to clear forest. We wanted to test this for a rainforest margin area in Central Sulawesi, Indonesia. We compared soil characteristics in different land-use systems and after different length of cultivation. 66 sites with four major land-use systems (maize, agroforestry, forest fallow and natural forest) were sampled. Soils were generally fertile, with high base cation saturation, high cation exchange capacity, moderate pH-values and moderate to high stocks of total nitrogen. Organic matter stocks were highest in natural forest, intermediate in forest fallow and lowest in maize and agroforestry sites. In maize fields soil organic matter decreased during continuous cultivation, whereas in agroforestry it was stable or had the tendency to increase in time. The effective cation exchange capacity (ECEC) was highest in natural forest and lowest in maize fields. Base cations saturation of ECEC did not change significantly during cultivation both maize and agroforestry, whereas the contribution of K cations decreased in maize and showed no changes in agroforestry sites. Our results indicate that maize cultivation tends to reduce soil fertility but agroforestry systems are able to stop this decline of soil fertility or even improve it. As most areas in this rain forest margin are converted into agroforestry systems it is unlikely that soil degradation causes deforestation in this case. On the contrary, the relatively high soil fertility may actually attract new immigrants who contribute to deforestation and start agriculture as smallholders.     

气候变化背景下农林复合系统碳汇功能研究进展

农林复合系统作为一种土地综合利用体系,可以有效吸收和固定CO₂、增加碳储量,在达到收获目的的同时,可有力减轻温室效应.农林复合系统对CO₂的调控作用,使人们认识到农林复合系统较单一作物系统有着明显优势,因此,深入了解不同农林复合系统的碳汇功能及其影响因素,对全球碳循环研究及碳收支准确评估具有重要意义.本文综述了农林复合系统的概念与分类,探讨了农林复合系统不同组分的碳固存潜力及其影响因子,得出不同区域、不同类型农林复合系统内植被的固碳速率相差很大(0.59～11.08 t C·hm^-2·a^-1),其主要受到气候因子和农林复合系统自身特性(物种组成、林木密度和林龄)的影响.农林复合系统内土壤的固碳潜力受到系统内树木和非树木成分输入的生物量多少和质量、土壤质地、土壤结构的影响.不同地区的任何一个农林复合系统的碳储量多少主要依赖于复合系统中各组分的结构和功能.针对目前的研究现状,指出应重点加强农林复合系统优化结构的碳汇功能研究,以及加强农林复合系统碳储量的时空分布格局及其固碳机制的长期研究.     

Land or plants: Agricultural tenure in agroforestry systems

The distinction between the rights to land and rights to plants is often overlooked when viewing agricultural tenure in developing countries. This distinction is crucial to understanding traditional agricultural systems, especially where agroforestry is practiced or its introduction has been proposed. Rights to land versus rights to plants are viewed in two Asia-Pacific agroforestry systems: one in Indonesian Borneo and the other in Papua New Guinea. Conflicts are discussed between the traditional dichotomy of land and plant rights and government policy. The success of an indigenous agroforestry system based on plant rights is contrasted to the failure of a proposed agroforestry system for similar reasons. It is concluded that the perceptual separation of land and plant rights needs to be explored if agroforestry practices are not only to be ecologically and economically feasible but also culturally acceptable.     

Incorporating livelihoods in biodiversity conservation: a case study of cacao agroforestry systems in Talamanca,Costa Rica

Over the past two decades, various organizations have promoted cacao agroforestry systems as a tool for biodiversity conservation in the Bribri-Cabécar indigenous territories of Talamanca, Costa Rica. Despite these efforts, cacao production is declining and is being replaced by less diverse systems that have lower biodiversity value. Understanding the factors that influence household land use is essential in order to promote cacao agroforestry systems as a viable livelihood strategy. We incorporate elements of livelihoods analyses and socioeconomic data to examine cacao agroforestry systems as a livelihood strategy compared with other crops in Talamanca. Several factors help to explain the abandonment of cacao agroforestry systems and their conversion to other land uses. These factors include shocks and trends beyond the control of households such as crop disease and population growth and concentration, as well as structures and processes such as the shift from a subsistence to a cash-based economy, relative prices of cacao and other cash crops, and the availability of market and government support for agriculture. We argue that a livelihoods approach provides a useful framework to examine the decline of cacao agroforestry systems and generates insights on how to stem the rate of their conversion to less diverse land uses.     

Agroforestry and Biodiversity Conservation – Traditional Practices, Present Dynamics, and Lessons for the Future

The environmental services that agroforestry practices can provide, and especially their potential contribution to the conservation of biodiversity, have only recently attracted wider attention among agroforestry and conservation scientists. This new view is consistent with the ecosystem approach to natural resource management advocated by the Convention on Biological Diversity. This collection of six papers, which is based on a Workshop held in June–July 2004, brings together studies of biodiversity impacts of traditional agroforestry practices from Central and South America, Africa and Asia. The contributions highlight the considerable potential of traditional agroforestry practices to support biodiversity conservation, but also show their limits. These include the importance of sufficient areas of natural habitat and of appropriate hunting regulations for maintaining high levels of biodiversity in agroforestry land use mosaics, as well as the critical role of markets for tree products and of a favourable policy environment for agroforestry land uses. In combination the case studies suggest that maintaining diversity in approaches to management of agroforestry systems, along with a pragmatic, undogmatic view on natural resource management, will provide the widest range of options for adapting to changing land use conditions.     

西双版纳地区不同胶农复合林对土壤理化性质的影响

对云南西双版纳地区橡胶-大叶千斤拔、橡胶-可可、橡胶-茶叶、橡胶-龙血树4种较典型的胶农复合林和单层橡胶林的土壤理化性状进行研究,并利用主成分分析法评价,揭示不同胶农复合林的土壤特性差异,为单层橡胶林的胶农复合林改造提供理论依据。结果表明,单层橡胶林的土壤有机质含量、土壤容重、土壤含水量、土壤总孔隙度及土壤导水率与橡胶-大叶千斤拔、橡胶-可可、橡胶-茶叶、橡胶-龙血树等4种胶农复合林土壤的相应指标均具有显著性差异(P<0.05);单层橡胶林改造为胶农复合林后,土壤有机质含量和全氮含量增加幅度分别为21.3%～50.1%和26.2%～39.9%,同时土壤容重降低,土壤孔隙度增加,土壤含水量与导水率显著增加。在西双版纳地区,将单层橡胶林改造为胶农复合林可提高土壤肥力、保持水土,是较理想的生态农业模式。     

三峡库区移民安置区生态农业发展模式的研究

就三峡库区农用土地的分布、开发方式、存在问题、生态农业发展模式等方面进行了初步的探讨．在分析三峡库区现已开发的农用土地存在着地力衰退、生产力低、自然灾害频繁及生态环境恶化等问题的基础上,从人与自然相协调的角度,提出了建立农林复合生态系统、木本粮油型、农林牧复合型、农林牧渔复合型的发展模式的思路和建议．     

Allelopathic Interactions in Agroforestry Systems

Agroforestry is a modern tool to develop sustainable land use and to increase food production by growing woody species (trees, shrubs, palms, bamboos, etc.) with agricultural crops and/or animals in some form of spatial arrangement or temporal sequence. Because these species co-exist with the agricultural crops, their allelopathic compatibility may be crucial to determine the success of an agroforestry system. A survey of the available information reveals that most of the agroforestry species (AF species) have negative allelopathic effects on food and fodder crops. Therefore, it is desirable to do further research in this direction so that AF species with no or positive allelopathic effects on the companion crops may be promoted for agroforestry programs. As AF species remain a part of the agroecosystem for a longer period, and most of them produce a large amount of leaves and litter, their allelochemicals may play an important role in developing an eco-friendly pest management strategy. Besides these generally studied aspects of allelopathy, some comparatively newer aspects of research have been identified, such as evaluation of qualitative yield of agroforestry systems, selective behavior of the allelochemicals, effect on soil quality, and the role of tree allelochemicals in animal and human nutrition. If given due consideration, allelopathy could play a pivotal role in conservation of the highly threatened environment, biodiversity, natural resource base, and making agriculture more sustainable through broadening the scope of agroforestry.     

Agroforestry Systems as Habitat for Avian Species: Assessing Its Role in Conservation

In the current scenario of rapid conversion of tropical forests into human-dominated activities landscape, the present study was undertaken to understand the role of existing agroforestry systems in conservation of avian species. Three types of agroforestry systems namely tea gardens, homegardens and agrisilviculture were selected in the Brahmaputra North Bank Landscape of Assam, northeast India for the study. A total of 468 point counts revealed 164 bird species belonging to 51 families and 18 orders across all the three different types of agroforestry systems. Tea gardens showed significantly higher bird species richness followed by homegardens and agrisilviculture systems. As per IUCN, four species were categorized as Near Threatened and one species was categorized as Vulnerable. Out of 164 species recorded, 68.3% species were residents, 30.5% species were winter visitors and remaining were summer visitors (1.2%). Majority of the species (45.7%) were common to all the three types of selected agroforestry systems. The feeding guilds revealed that most of the species were insectivorous (50.0%) in habit. A total of 167 tree species belonging to 54 families and 24 orders was recorded across all the three different types of agroforestry systems. The highest tree species richness was recorded in the homegardens (160), followed by agrisilviculture systems (19) and least in tea gardens (11). No statistically significant correlation was found among bird species richness and patch size, tree species richness and number of bird species individuals. The selected agroforestry systems have provided shelter, nesting space, feeding and foraging grounds for birds during the winter season. This data can be useful for the policy makers, tea garden managers, homegarden owners for framing conservation policies of avian species in an era of natural wildlife habitat loss and degradation.     

Impacts of monoculture cropland to alley cropping agroforestry conversion on soil N2O emissions

Monoculture croplands are a major source of global anthropogenic emissions of nitrous oxide (N₂O), a potent greenhouse gas that contributes to ozone depletion. Agroforestry has the potential to reduce N₂O emissions. Presently, there is no systematic comparison of soil N₂O emissions between cropland agroforestry and monoculture systems in Central Europe. We investigated the effects of converting the monoculture cropland system into the alley cropping agroforestry system on soil N₂O fluxes at three sites (each site has paired agroforestry and monoculture) in Germany, where agroforestry combined crop rows and poplar short-rotation coppice (SRC). We measured soil N₂O fluxes monthly over 2 years (March 2018–January 2020) using static vented chambers. Annual soil N₂O emissions from agroforestry ranged from 0.21 to 2.73 kg N ha⁻¹ year⁻¹, whereas monoculture N₂O emissions ranged from 0.34 to 3.00 kg N ha⁻¹ year⁻¹. During the rotation of corn crop, with high fertilization rates, agroforestry reduced soil N₂O emissions by 9% to 56% compared to monocultures. This was mainly caused by low soil N₂O emissions from the unfertilized agroforestry tree rows. Soil N₂O fluxes were predominantly controlled by soil mineral N in both agroforestry and monoculture systems. Our findings suggest that optimized fertilizer input will further enhance the potential of agroforestry for mitigating N₂O emissions.