Traditional Agroforestry Systems Research Articles

Changes in soil physical and chemical properties in long term improved natural and traditional agroforestry management systems of cacao genotypes in Peruvian Amazon.

Growing cacao (Theobroma cacao L.) in an agroforestry system generates a productive use of the land, preserves the best conditions for physical, chemical and biological properties of tropical soils, and plays an important role in improving cacao production and fertility of degraded tropical soils. The aim of this study was to evaluate the impact of two long term agroforestry systems of cacao management on soil physical and chemical properties in an area originally inhabited by 30 years old native secondary forest (SF). The two agroforestry systems adapted were: improved natural agroforestry system (INAS) where trees without economic value were selectively removed to provide 50% shade and improved traditional agroforestry system (ITAS) where all native trees were cut and burnt in the location. For evaluation of the changes of soil physical and chemical properties with time due to the imposed cacao management systems, plots of 10 cacao genotypes (ICS95, UF613, CCN51, ICT1112, ICT1026, ICT2162, ICT2171, ICT2142, H35, U30) and one plot with a spontaneous hybrid were selected. Soil samples were taken at 0-20, 20-40 and 40-60 cm depths before the installation of the management systems (2004), and then followed at two years intervals. Bulk density, porosity, field capacity and wilting point varied significantly during the years of assessment in the different soil depths and under the systems assessed. Soil pH, CEC, exchangeable Mg and sum of the bases were higher in the INAS than the ITAS. In both systems, SOM, Ext. P, K and Fe, exch. K, Mg and Al+H decreased with years of cultivation; these changes were more evident in the 0-20 cm soil depth. Overall improvement of SOM and soil nutrient status was much higher in the ITAS than INAS. The levels of physical and chemical properties of soil under cacao genotypes showed a marked difference in both systems.

English

Agricultural production in northern Benin is characterized by smallholder traditional agroforestry systems, with on-farm remnant tree species. Among its numerous advantages, agroforestry is known for its valuable contribution to biodiversity conservation. This study quantifies the importance of Vitellaria paradoxa C.F. Gaertn agroforests in terms of woody species conservation in Atacora district in Benin. Forest inventories were performed within 50×50 m plots constructed on a net grid map of Atacora district. Diversity indices were computed for both adult and juvenile species in two land management regimes: fields and fallows. Overall 41 woody species were recorded; 28 in fields and 36 in fallows. Taking into account matured and juvenile individuals, the diversity of woody species increased: 86 species in total; 69 species in fields and 78 in fallows. The biodiversity of V. paradoxa’s agroforestry parklands increases from fields to fallows, and decreases from bulk species (considering mature and juvenile species) to adult ones. Leguminosae and Combretaceae were the most abundant families registered. From the Cover Value Index, V. paradoxa, Parkia biglobosa, Lannea microcarpa, Lannea acida and Diospiros mespiliformis were the most abundant species. Support for maintaining this kind of agricultural system is needed, as this exemplifies the synergy for providing, provisioning and supporting services and biodiversity conservation. Key words: Agroforestry, conservation, ecosystem services, farmland, shea tree.

Ethnopedology and soil quality of bamboo (Bambusa sp.) based agroforestry system

It is widely recognized that farmers' hold important knowledge of folk soil classification for agricultural land for its uses, yet little has been studied for traditional agroforestry systems. This article explores the ethnopedology of bamboo (Bambusa sp.) based agroforestry system in North East India, and establishes the relationship of soil quality index (SQI) with bamboo productivity. The study revealed four basic folk soil (mati) types: kalo (black soil), lal (red soil), pathal (stony soil) and balu (sandy soil). Of these, lal mati soil was the most predominant soil type (~ 40%) in bamboo-based agroforestry system. Soil physio-chemical parameters were studied to validate the farmers' soil hierarchal classification and also to correlate with productivity of the bamboo stand. Farmers' hierarchal folk soil classification was consistent with the laboratory scientific analysis. Culm production (i.e. measure of productivity of bamboo) was the highest (27culmsclump−1) in kalo mati (black soil) and the lowest (19culmsclump−1) in balu mati (sandy soil). Linear correlation of individual soil quality parameter with bamboo productivity explained 16 to 49% of the variability. A multiple correlation of the best fitted linear soil quality parameter (soil organic carbon or SOC, water holding capacity or WHC, total nitrogen) with productivity improved explanatory power to 53%. Development of SQI from ten relevant soil quality parameters and its correlation with bamboo productivity explained the 64% of the variation and therefore, suggest SQI as the best determinant of bamboo yield. Data presented indicate that the kalo mati (black soil) is sustainable or sustainable with high input. However, the other three folk soil types (red, stony and sandy soil) are also sustainable but for other land uses. Therefore, ethnopedological studies may move beyond routine laboratory analysis and incorporate SQI for assessing the sustainability of land uses managed by the farmers'. Additional research is required to incorporate principal component analysis for improving the SQI and site potential assessment. It is also important to evaluate the minimum data set (MDS) required for SQI and productivity assessment in agroforestry systems.

Conservation of Plant Diversity in Rural Homegardens with Cultural and Geographical Variation in Three Districts of Barak Valley, Northeast India1

Homegardens are recognized worldwide as sustainable agroforestry systems that are repositories of species and genetic diversity. Species diversity and composition of homegardens are influenced by a number of environmental, socioeconomic, and cultural factors. The present study examines the tree species diversity in the homegardens of different cultural groups of Barak Valley, Assam, Northeast India. Complete enumeration was done for diversity analysis in 181 homegardens from 38 villages in the three districts of the Valley. Factors affecting plant diversity were analyzed, and the floristic composition of the homegardens was found to vary with garden size, ethnicity of the homegarden owners, and geographical parameters such as location and altitude. Results indicate high plant diversity, with a total of 161 tree species identified from 47 families. Tea garden labor communities were comparatively found to hold more diversity in their homegardens. Similarity and cluster analysis revealed the distinctness of the majority of the homegardens, and seven groups of homegardens with very low distance were revealed. Homegardens were also found to maintain considerable conservation value as repositories of many underutilized, wild, and rare plant species. Biodiversity conservation in the homegardens was found to be linked to the multiple values of the different plant species to the homegardeners and further highlight the concept of the “conservation through use” approach. For the preservation of such traditional agroforestry systems, which also have the potential to provide options for adaptation to climate change, proper documentation of traditional knowledge concerning the different plant species and the human-nature interaction in the homegardens is necessary before such systems are completely lost.

Agroforestry Systems In Poland A Preliminary Identification

Abstract This paper seeks to use state-of-the-art knowledge to depict the foundations and prospects for agroforestry systems in Poland to develop, in line with political, legal, historical and environmental conditions pertaining in the country. The main legal provisions concerning the presence of trees in agriculture are presented prior to a first-ever defining of key traditional agroforestry systems in Poland.

Diversity and uses of ethno-medicinal plants associated with traditional agroforestry systems in Kumaun Himalaya

Uttarakhand state is bestowed with great diversity of medicinally important plants which are used frequently by the local people/inhabitants to cure various ailments in their daily life. Traditional agroforestry is a common land use pattern in Uttarakhand which supports various indigenous medicinal plants. The present study provides comprehensive information on the diversity and utilization of medicinally important plants in existing traditional agroforestry systems. The information was gathered using semi-structured questionnaires about the types of ailments treated by the traditional use of medicinal plants, preparation of herbal medicine and formulations. A total of 68 plant species belonging to 38 families and 63 different genera, were reported from agroforestry systems of this region. The families; Rosaceae, Asteraceae, and Verbenaceae were represented by more than 3 species each and dominated the floral composition while remaining 35 families were represented by single species. Different plant parts such as roots/rhizomes/bulbs, leaves, bark, fruits, seeds, flowers, stem and whole plant were used for the treatment of various diseases.

Traditional Agroforestry Systems: One Type of Globally Important Agricultural Heritage Systems

Abstract: As one kind of land use practice, traditional agroforestry systems already have a long history of hundreds of years in practice and still play a significant role in the world today, especially in tropical and subtropical areas. In this era of globalization and food in security, more and more governments and non-governmental organizations are paying attention to traditional agroforestry systems because of their economic, ecological and socio-culture benefits. These benefits are also in accord with the characteristics of Globally Important Agricultural Heritage Systems (GIAHS). So far, four typical traditional agroforestry systems from five countries have been designated as GIAHS. These traditional agroforestry systems have rich agricultural and associated biodiversity, multiple ecosystem services and precious socio-culture values at a regional and global level. Although traditional agroforestry systems are confronted with many threats and challenges, such as population growth, migration, market i...

Productivity of Wheat (<i>Triticum Aestivum</i>) as Intercrop in <i>Grewia Optiva</i> Based Traditional Agroforestry System along Altitudinal Gradient and Aspect in Mid Hills of Garhwal Himalaya, India

Grewia optiva, wonder tree of western Himalaya locally known as Bhimal is the most common multipurpose tree is a boon for the inhabitants of Garhwal Himalayan region. About 2/3rd of the cultivated area of Garhwal is rainfed and Wheat (Triticum aestivum) is the predominant food grain crop cultivated on the sloppy terraces in combination of G. optiva trees on terrace bunds. In Present study the productivity of wheat (Triticum aestivum) as intercrop in Grewia optiva based traditional agroforestry system along altitudinal gradient and aspect in mid hills of Garhwal Himalaya, India revels that G. optiva occupied average highest frequency (85%), stem density (145 trees/ha), TBC (7.68 m<SUP>2</SUP>/ha), IVI (86.51), tree height (7.38 m), Crown spread (5.34 m) in the elevation 1000-1500 m of Northern aspect (E1/N site). In the elevation 1000-1500 m, it was observed that there is a reduction in grain, straw and biological yield of wheat as 17.59%, 17.77% and 17.71% respectively on the southern aspect compared to northern aspect. Further elevation 1500-2000 m, the reduction in the average grain yield was recorded 37.31% under G. optiva based traditional agroforestry system in E2/S site. The phenophases of the wheat crop is sown in the month of December which emerges to crown root initiation (CRI) in January followed by tillering, milking, maturity and final harvest during May while G. optiva remain dormant from December to February, leafless in March and new flush of shoots in May. This reversal phenopases of two components are complimentary in tree crop interaction to enhance productivity.

Marginal effects on biodiversity, carbon sequestration and nutrient cycling of transitions from tropical forests to cacao farming systems

Cacao (Theobroma cacao), a perennial crop predominantly cultivated as a multi-product and multi-strata agroforestry system, has been identified as one of an array of factors behind land use changes in the tropics. Concerns have also been raised about the gradual shift from traditional cacao growing systems under diverse and dense tree canopy to lower or no-shade cover, leading to further loss of direct and functional forest ecosystem values such as protective and regulatory environmental services. This paper surveys existing literature and focuses on changes to biodiversity, carbon sequestration and nutrient cycling conditions due to a transition from natural forests to traditional lower-density agroforestry and high-density hybrid monoculture cacao systems. We derive marginal effects on selected ecosystem functions expressed as a percentage unit change in corresponding ecosystem values from a natural forest baseline scenario. Data from 16 studies conducted in Africa and the Americas show a negative trend in marginal changes in above-and below-ground carbon sequestration potential for the two cacao farming systems. The extent of marginal losses in carbon storage was comparatively higher for the monoculture than cacao agroforestry system. A general trend denoting positive marginal changes has been reported for mean species richness in soil and litter and some essential chemical and physical soil properties (Calcium, Magnesium, sand and silt) of cacao agroforestry systems compared with a natural forest baseline. The balance between negative and positive changes show that traditional cacao agroforestry systems have greater potential for conservation of ecosystem services closer to a natural forest state than monocultures.

SOCIOECONOMIC EVALUATION OF TRADICIONAL AGROFORESTY SYSTEM OF COFFEE-BANANA-CITRUS IN THE COUNTY TLAPACOYAN, VERACRUZ, MEXICO

&lt;p&gt;Agroforestry system Coffee-Banana-Citrus Tlapacoyan, Veracruz, is a dynamic and complex system; with cultural and social wealth; less risk to weather and economic events; and implies greater labor need a polyculture. This work aims a socioeconomic assessment for family production units of Traditional Agroforestry System Coffee-Banana-Citrus in the county Tlapacoyan, Veracruz , based on the methodology of the INA / PG , France; and construction of a typology of producers. Agroforestry system is characterized agronomically, producer categories defined by the surface, available manpower and technological level, through surveys, field observations, developing a database and to define the job categories MODE were constructed. Each category (I, II and III) was defined costs and income with the help of the development of technical itineraries; later to determine indicators to 30 years, where Category II expressed best results. We conclude that building typologies to understand the complexity of agroforestry production systems and socio-economic indicators (PMO and PT) show a higher income than wages in the region and a higher return is obtained when the area is a small.&lt;/p&gt;

Contribution à l'inventaire et à la domestication des espèces alimentaires sauvages de Côte d'Ivoire: Cas des Départements d'Agboville et d’Oumé

Objective: The current study aims at identifying the wild edible species still present in the department of Agboville and save in collections the endangered ones that have a high communitary importance. Methodology and Results: An ethnobotanical survey was conducted. Seeds and wildlings collected were used to produce plants (in nursery) and create a collection. The survey revealed 18 species distributed in 18 genera and 15 families. Trees represent 81.8 % of the surveyed flora and species producing edible seeds or kernels were 50%. In nursery, the emergence rate of species ranged between 60 and 100%, except for Garcinia kola and Xylopia aethiopica. In collections, at 7 years, the 4 main species assessed showed survival rates of 40.71 to 86 % and heights of 4.86 to 12.68 m. Conclusion and Application: With only 18 species recorded in a forest area, the study revealed the high level of vegetation degradation in the surveyed sites. This shows the need for an urgent domestication program of residual species before total extinction. The high survival rates observed in nursery showed that the studied species can be propagated by seeds and by wildlings as well. Propagation by wildlings can help solve the problems of seeds seasonal scarcity. The satisfactory skills of the studied species in nursery and plantation indicate that they are suited to grow in traditional agroforestry systems, in association with cash crops (coffee and cocoa) and food crops. Nevertheless, it is important to practice seed pretreatments to remove dormancy faster. Also, vegetative propagation of priority species should be undertaken to shorten unproductive period in order to raise up a greater interest from rural populations.Keywords: wild edible species; ethnobotanical survey; domestication.

Ecosystem services of native trees: experiences from two traditional agroforestry systems in Karnataka, Southern India

Agroforestry systems with native trees provide an interesting instance wherein provisional, regulatory, habitat, and ancillary ecosystem services are simultaneously exploited, but are least recognized. In the present study, the potential of native trees to optimize different ecosystem services is compared, versus introduced species in two traditional agroforestry systems in Karnataka state, Southern India: (a) coffee-based shaded perennial systems in Kodagu district of the tropical humid zone; and (b) dryland agro-ecosystems with Ficus trees in Mandya district of the semi-arid zone. Ecosystem services were assessed based on collected field data and farmers’ perceptions. Compared with exotic species, native trees provide more direct and indirect benefits, irrespective of differences in type, location, scope, and management of these systems. The role of native trees in supporting the overall sustainability of agroforestry systems is highlighted in the study. Moreover, it is emphasized that the long-term sustenance of traditional agroforestry systems depends on appreciation of the indirect and intangible benefits that are provided.

Short-term changes in the soil carbon stocks of young oil palm-based agroforestry systems in the eastern Amazon

The current expansion of the oil palm (Elaeis guineensis Jacq.) in the Brazilian Amazon has mainly occurred within smallholder agricultural and degraded areas. Under the social and environmental scenarios associated with these areas, oil palm-based agroforestry systems represent a potentially sustainable method of expanding the crop. The capacity of such systems to store carbon (C) in the soil is an important ecosystem service that is currently not well understood. Here, we quantified the spatial variation of soil C stocks in young (2.5-year-old) oil palm-based agroforestry systems with contrasting species diversity (high vs. low); both systems were compared with a ~10-year-old forest regrowth site and a 9-year-old traditional agroforestry system. The oil palm-based agroforestry system consisted of series of double rows of oil palm and strips of various herbaceous, shrub, and tree species. The mean (±standard error) soil C stocks at 0–50 cm depth were significantly higher in the low (91.8 ± 3.1 Mg C ha−1) and high (87.6 ± 3.3 Mg C ha−1) species diversity oil palm-based agroforestry systems than in the forest regrowth (71.0 ± 2.4 Mg C ha−1) and traditional agroforestry (68.4 ± 4.9 Mg C ha−1) sites. In general, no clear spatial pattern of soil C stocks could be identified in the oil palm-based agroforestry systems. The significant difference in soil carbon between the oil palm area (under oil palm: 12.7 ± 2.3 Mg C ha−1 and between oil palm: 10.6 ± 0.5 Mg C ha−1) and the strip area (17.0 ± 1.4 Mg C ha−1) at 0–5 cm depth very likely reflects the high input of organic fertilizer in the strip area of the high species diversity oil palm-based agroforestry system treatment. Overall, our results indicate a high level of early net accumulation of soil C in the oil palm-based agroforestry systems (6.6–8.3 Mg C ha−1 year−1) that likely reflects the combination of fire-free land preparation, organic fertilization, and the input of plant residues from pruning and weeding.

Efeitos do sombreamento na anatomia foliar de Gallesia integrifolia (Spreng) Harms e Schinnus terebinthifolius Raddi

Realizou-se estudo com o objetivo de analisar as alterações na anatomia foliar de Gallesia integrifolia (Spreng) Harms e Schinnus terebinthifolius Raddi quando cultivadas em ambientes de sombra moderada ou densa, simulando as condições naturais encontradas em sistemas agroflorestais tradicionais do sul da Bahia, Brasil. Plantas das duas espécies, com aproximadamente um ano de idade, foram cultivadas em casa de vegetação sob quatro níveis de sombreamento (25%, 17%, 10% e 5%). Estudos anatômicos do limbo foliar foram realizados a partir de material incluído em parafina e seccionado em micrótomo rotativo. Os diferentes níveis de sombreamento ocasionaram alterações na estrutura do mesofilo de ambas as espécies, com diferenças significativas na espessura do parênquima paliçádico, limbo foliar, e densidade estomática. Nas condições em que o experimento foi realizado os resultados obtidos indicaram que G. integrifolia apresenta maior capacidade de aclimatação a ambientes de sombra moderada e densa do que S. terebinthifolius, sendo mais indicada para o cultivo em sistemas agroflorestais pré-estabelecidos.

Retraction Note: Patterns of bee diversity in mosaic agricultural landscapes of central Uganda: implication of pollination services conservation for food security

Little is known about bee communities and pollination services conservation strategies in sub-Sahara Africa. A study was conducted at 26 different sites with varying local landscape characteristics in farmlands of central Uganda in 2006. Bees were sampled using coloured pantraps, handnet and line transect counts. Overall 80,883 bee individuals from 6 families and 652 species were encountered. The bee fauna was characterized by a lower diversity of Melittidae and Andrenidae and a high diversity of Apidae, Megachilidae and Halictidae. Megachile and Lasioglossum were the two most species-rich genera. The most abundant species was Apis mellifera adansonii Linnaeus (23 % of total individuals) followed by Hypotrigona gribodoi Magretti (19 %), Meliponula ferruginea Lepeletier (13 %), Lasioglossum ugandicum Cockerell (7 %), Apis mellifera scutellata Latreille (6 %), Allodapula acutigera Cockerell (6 %), Ceratina rufigastra Cockerell (5 %), Ceratina tanganyicensis Strand (5 %), Braunsapis angolensis Cockerell (5 %), Megachile rufipes Fabricius (5 %), Meliponula bocandei Spinola (5 %) and Seladonia jucundus Smith (5 %). The mean number of species recorded per study site per day ranged between 14 and 49, whereas the abundance ranged between 188 and 1,859 individuals. Study sites in areas with intense land-use had species-poor bee communities compared to sites with medium to low land-use intensities. Study sites with riparian forest fragments and wetlands, or with forest fallows in their vicinity had significantly (P < 0.05) higher species richness and diversity than sites dominated by small-scale monoculture/polyculture fields or sites dominated by either simple or complex traditional agroforestry systems. An ordination analysis also revealed that bee communities were significantly (P < 0.01) influenced by the presence of semi-natural habitats (woodlands, fallows) and forest fragments in the surrounding of fields. Thus, natural and semi-natural habitats are of great value for afrotropical farmland bee communities. There is a need to put in place strategies and policies for semi-natural and forest fragments preservation for spatio-temporal stability of pollination services in rural landscapes. Farmers are recommended to increase on-farm trees cover to safeguard and enhance pollination function and services in fields. Mimicking natural vegetation through promoting establishment of forest plantations and village community forestry in rural landscapes is also critical for conserving pollination services.

Agricultural Land-Use Changes and Soil Quality: Evaluating Long-Term Trends in a Rural Mediterranean Region

Land-Use Changes (LUCs) are the result of interacting environmental and socioeconomic factors. Although in southern Europe traditional agroforestry systems are an important component of the Mediterranean landscape, intensification and simplification of the rural space coupled with the increasing sensitivity to soil degradation are potentially harmful for the integrity of natural resources and biodiversity stock. The present study introduced a quantitative assessment of rural LUCs that occurred in a region devoted to agriculture and experiencing a progressively higher human impact from both urbanization and land abandonment. The assessment was carried out at the municipality scale along forty years (1970–2010) using data collected every ten years in the framework of the National Census of Agriculture. The Maximum potential Water Capacity (MWC) in the soil, taken as a proxy for agricultural soil quality, and an index of crop intensity have been introduced in the analysis as supplementary variables. A Multiway Factor Analysis (MFA) was developed to evaluate stability or dynamics in the investigated land-use classes. Results illustrate relevant changes in the rural landscape by identifying the classes “moving” towards better soils. An integrated evaluation of rural LUCs and soil resources based on long-time inventories available at an adequate spatial scale is a tool informing policies against soil degradation.

Soil quality, resistance and resilience in traditional agricultural and agroforestry ecosystems in Brazil's semiarid region

Agroforestry represents an alternative to traditional agricultural systems in semiarid regions, since it effectively provides soil coverage and improves the amount and quality of soil organic matter. The sustainability of agricultural systems can be assessed by evaluating soil quality, resistance and resilience. Therefore, this work evaluated soil quality, resistance and resilience under traditional cropping and agroforestry systems. The study took place at an experimental station in Brazil’s semiarid northeast region. Studied land use systems include agrosilvopastoral, silvopastoral and traditional cropping, as well as areas under traditional fallow for six and nine years and unaltered ecosystem. Small trenches were dug randomly to collect soil from three depth increments. Soil Quality (SQ) was assessed using chemical, physical and biological indicators. Based on these indicators, resistance, resilience and soil quality indices were calculated. The index quality of the soil was generated using soil water retention, nutrient supply and biological activity promotion functions. Comparisons of index means indicate that agroforests maintained SQ, while traditional fallow systems resulted in improved SQ up to levels similar to the unaltered ecosystem. Traditional cropping lead to a reduction in SQ, resistance and resilience. Agroforestry systems are sustainable. Fallow can improve soil quality, soil resistance and resilience. Key words: Agrosilvopastoral, silvopastoral, slash-and-burn agriculture, agricultural sustainability, soil management, conservation.

Analyses of Socioeconomic Factors influencing on-farm Conservation of Remnant Forest Tree Species: Evidence from Ghana

The contribution of remnant trees in traditional agro forestry systems in recent times has attracted significant attention from policy makers, stakeholders, and academicians due to their important role in conserving biodiversity within agricultural systems, reserves of genetic resources and provision of other important environmental services. The study seeks to determine socioeconomic factors influencing farmers’ decision to maintain remnant trees in agricultural landscape. Data was solicited from 220 households in three rural communities through structured interviews and on farm visitations. We employed Poison and Negative Binomial Regressions to determine factors influencing rural farm households’ decision to retain remnants forest tree species in agro ecosystem. The regression results indicated that the key factors strongly affecting farmers’ on-farm conservation decision to retain remnant forest trees in agricultural landscape were age, gender, years of schooling, religion, land tenure, farmers’ perceptions to current environmental problems, distance to farm land, erosion and the size of the landholdings. The study recommends that forest governance with focus on collaborative forest resource management and equitable distribution of benefits generated from extraction of forest resources should be given high impetus in policy formulation. The needs and concerns of forest fringe communities should feature paramount in this regard.

Low carbon emission development strategies for Jambi, Indonesia: simulation and trade-off analysis using the FALLOW model

Economic growth in rural areas has to align with preservation of land uses that optimise environmental services. This means that trade-offs between economic and ecological priorities need to be understood, quantified and managed. We aimed to estimate the trade-off in the Tanjung Jabung Barat district of Jambi province Indonesia, where traditional agroforestry systems on both peat and mineral soils and logged-over forests give way to monocultural plantations of pulpwood and oil palm (Elaeis guineensis). Simulations of a 30-year time period of four scenarios using the FALLOW (Forests, Agroforests, Low-value-Landscape, Or, Wastelands) model show that a business-as-usual scenario of economic growth unhindered by the application of conservation scenarios will lead to high carbon dioxide CO2 emissions. The forest and agroforest protection scenario, with moderate assumptions for peat-based emissions, had opportunity costs of 3–100 USD/t CO2e. This occurred especially when the establishment of oil palm plantations, which are currently the most profitable land use option in the area, is directed solely to under utilized mineral soils. The high trade-off values are difficult to reconcile when relying only on C trading mechanism to offset economic opportunity costs of not converting forests and/or agroforests to plantations. We conclude that law-based protection of existing forests, investment in intermediate intensity agroforestry options that utilize locally adapted trees and do not require drainage of peatlands, and re-introduction of tapping Jelutung (Dyera sp) latex as non-timber peat forest product, are needed in the Tanjabar district to provide options that are sustainable from both ecological and economic perspectives.

Soil carbon and nitrogen stocks in traditional agricultural and agroforestry systems in the semiarid region of Brazil

In the semiarid region of Brazil, inadequate management of cropping systems and low plant biomass production can contribute to reduce soil carbon (C) and nitrogen (N) stocks; therefore, management systems that preserve C and N must be adopted. This study aimed to evaluate the changes in soil C and N stocks that were promoted by agroforestry (agrosilvopastoral and silvopastoral) and traditional agricultural systems (slash-and-burn clearing and cultivation for two and three years) and to compare these systems with the natural Caatinga vegetation after 13 years of cultivation. The experiment was carried out on a typical Ortic Chromic Luvisol in the municipality of Sobral, Ceará, Brazil. Soil samples were collected (layers 0-6, 6-12, 12-20, 20-40 and 40-60 cm) with four replications. The plain, convex and concave landforms in each study situation were analyzed, and the total organic C, total N and densities of the soil samples were assessed. The silvopastoral system promoted the greatest long-term reductions in C and N stocks, while the agrosilvopastoral system promoted the smallest losses and therefore represents a sustainable alternative for soil C and N sequestration in these semiarid conditions. The traditional agricultural system produced reductions of 58.87 and 9.57 Mg ha-1 in the organic C and total N stocks, respectively, which suggests that this system is inadequate for these semiarid conditions. The organic C stocks were largest in the concave landform in the agrosilvopastoral system and in the plain landform in the silvopastoral system, while the total N values were highest in the concave landform in the native, agrosilvopastoral and silvopastoral systems.