Integrative Management Of Cocoa Agroforestry Systems: Promoting Long-Term On-Farm Diversity

In cocoa (Theobroma cacao) agroforestry systems, upper canopy trees and food crops are frequently planted for shade, diversification of farm products, and improved soil fertility. As diversification remains a top priority for farm economic and environmental sustainability, systemmanagement plays a substantial role in farm diversity, requiring long-term analysis. We measured species richness dynamics in a chronosequence (N = 4) representing farms aged 2 to 25 years old in the western cocoa-growing region of Ghana, West Africa. Subsequently, we conducted farmer interviews to establish farming practices with regards to integration of non-cocoa species. After farm establishment, increases were recorded in non-cocoa and Simpson diversity index (for 2 years = 0.17 ± 0.167; for 15 years = 0.68 ± 0.026; for 25 years = 0.68 ± 0.036), but no changes were observed in crop richness. All participants interviewed managed supplementary species on their cocoa farms, with 92% of farmers purposefully establishing an upper canopy stratum. We discuss the use of principles from natural stand development for sustaining such diversity. Farmer managed crop re-initiation during farm maturation may promote higher diversity within an existing agroforestry framework

Addressing the resilience of tomato farmers in Ghana facing a double exposure from climate and market

Ghanaian tomato farmers are severely impacted by changing climate and related more frequent and extreme weather events such as drought and heavy rainfall. Furthermore, tomato production represents one of the main sources of income for these farmers, which leaves them highly exposed to market price variations. However, the full impact of changing climate and price variations for these farmers has not been assessed. Here, we examined how Ghanaian tomato farmers experience and respond to a double exposure from climate and market related shocks. The objectives were threefold: (i) to investigate how farmers in two different agroecological zones (savannah and semi-equatorial) experience climate and market shocks, (ii) to examine the major response strategies implemented in face of this double exposure, and (iii) to identify paths toward systemic changes to enhance resilience. A survey was conducted with 344 tomato smallholder farmers in the two agroecological zones. The results from the survey were complemented by semi-structured interviews and focus groups. We found that farmers are severely exposed to climate and market shocks, which causes a reduction in both production activities and revenues. A set of agricultural and water management practices, such as crop rotation, supplementary fertilization, and water tanks, have been adopted by farmers as response mechanisms to climate variations. However, no response mechanisms, other than agricultural diversification, are in place yet to face the economic shocks. Thus, enhancing systemic resilience becomes particularly important to face this double exposure and restructure and change feedback mechanisms within the current system. The reestablishment of tomato processing plants or formalizing the stakeholders’ network could both be ways to integrate value-chain stakeholders and support appropriate structures. Encompassing both climate and trading attributes through specific agro-food policies are much-needed for a sustainable and resilient transformation of the tomato production system.publishedVersio

Temporal changes in litterfall and potential nutrient return in cocoa agroforestry systems under organic and conventional management, Ghana

Litterfall is a critical link between vegetation and soils by which nutrients are returned to the soils, thus the amount and pattern of litterfall regulates nutrient cycling, soil fertility and primary productivity for most terrestrial ecosystems. We quantified, analyzed and compared macro and micro-nutrients return through litterfall in organic and conventional cocoa agroforestry systems in Suhum, Ghana. We further assessed the contribution of shade tree species to litterfall and nutrient dynamics. The annual pattern of litterfall was affected by seasonality, with a major peak in the dry season and minor peaks during the rainy season. In terms of annual fractional litterfall, mean leaf litter from shade tree species was significantly higher (50 %) in organic systems (5.0 ± 0.5 Mg ha-1 yr-1) compared to conventional systems (3.3 ± 0.6 Mg ha-1 yr-1). Whereas cocoa leaves (45.0 %) were the predominant fraction of annual litterfall from conventional farms, both shade leaves (40.0 %) and cocoa leaves (39.4 %) dominated litterfall from organic farms. The return of primary macro-nutrients (P and K), secondary macro-nutrients (Ca, Mg and S) and micro-nutrients (Mn, B, Cu, Zn and Mo) via litterfall varied significantly with season, and annual return of nutrients were similar in organic and conventional cocoa systems. Shade tree leaf litter accounted for 30–47 % of annual macro and micro-nutrient return (except Ni and Zn) in organic cocoa systems versus 20–35 % in conventional cocoa systems. The results emphasize the complementary role of the different shade tree species which compose organic and conventional cocoa systems in nutrient recycling. We conclude that organic management of cocoa agroforestry systems ensure nutrients return similar to those receiving synthetic fertilizer inputs, highlighting its potential to support cocoa productio

Decomposition and nutrient mineralisation of leaf litter in smallholder cocoa agroforests: a comparison of organic and conventional farms in Ghana

© 2020, The Author(s). Purpose: Although litter decomposition and nutrient release patterns have been studied in cocoa agroforestry systems in general, studies focusing on organic and conventional cocoa systems are lacking which is critical as organic farms are particularly dependent on nutrient returns from decomposing litter. Materials and methods: Dynamics in leaf litter decomposition and the mineralisation of macro- and micro-nutrients in organic and conventional cocoa agroforestry systems were studied using the litterbag technique for 12months. Results: The average monthly mass loss was more than two times higher on organic farms (9.2–14.4gmonth−1) compared to conventional farms (4.2–7.3gmonth−1) in the first five months. The annual rate of decomposition (k) was higher on organic farms (1.9) compared to conventional systems (1.4). The time required for 50% (t50) and 99% (t99) decomposition of leaf litter was both lower on organic farms (t50 = 0.4years, t99 = 2.6years) than conventional farms (t50 = 0.5years, t99 = 3.5years). The estimated k values for macro- and micro-nutrients on organic cocoa systems ranged from 2.3 for calcium to 4.5 for potassium compared to 1.6 (Ca) to 2.8 (K) on conventional farms. The k values of all nutrients (except nitrogen and phosphorus) were significantly greater on organic farms than conventional systems. The estimated k values for both litter decomposition and nutrient mineralisation correlated with soil pH and moisture content, but not initial litter chemistry. Conclusions: Organic management of smallholder cocoa agroforestry systems enhanced leaf litter decomposition and nutrient mineralisation through improved soil conditions. Thus, organic management of cocoa agroforestry systems may contribute to sustainable cocoa production in smallholder systems through enhanced nutrient return from litter decomposition

Can sustainability certification enhance the climate resilience of smallholder farmers? The case of Ghanaian cocoa

Sustainability certification has been posited as a key governance mechanism to enhance the climate resilience of smallholder farmers. Whilst many certifications now include climate resilience in their standards, their ability to deliver this for smallholders remains untested. We take the case of the 2015–16 drought-shock to cocoa production in Ghana to examine whether certification can enhance smallholder climate resilience. We used a novel transdisciplinary methodology combining participatory outcome definition with household surveys, biophysical measurements, satellite data and counterfactual analysis. Utilising our climate resilience framework, we find that certification has a strong effect on the adoption of basic management, e.g. fertilization, but a weak influence on more complex resilience strategies, e.g. agroforest diversification. Beyond certification, we identify strong regional patterns in resilience. These findings suggest that certification has some potential to enhance climate resilience but greater focus on facilitating diversification and adapting to sub-national contexts is required for improved effectiveness.publishedVersio

Rubber and plantain intercropping: Effects of different planting densities on soil characteristics

Two field experiments were conducted at Ellembelle and Jomoro districts in the Western region of Ghana where rubber cultivation is a predominant farming activity. The objective of the study was to assess the effect of rubber and plantain intercropping systems on selected soil properties. The experiment was arranged in a randomized complete block design (RCBD) with 3 replications. The treatments were the sole crop rubber (R), sole crop plantain (P) and three intercrop systems comprising an additive series of plantain: one row of plantain to one row of rubber (PR), two rows of plantain to one row of rubber (PPR) and three rows of plantain to one row of rubber (PPPR). Generally, agroforestry systems improved the soil hydraulic properties considerably, with the highest cumulative infiltration rates of 5.16 and 8.68 cm/min observed under the PPPR systems at the Ellembelle and Jomoro sites, respectively. Microbial biomass C (Cmic), N (Nmic) and P (Pmic) was significantly improved (P < 0.05) under the agroforestry than the monocrop systems. The Cmic, Nmic and Pmic values were highest under the PPPR system at both Ellembelle (Cmic, = 139.9 mg/kg; Nmic = 36.26 mg/kg and Pmic = 87.6 mg/kg) and Jomoro (Cmic = 78.7 mg/kg; Nmic = 80.3 mg/kg and Pmic = 3.45 mg/kg) sites

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

A Comparative Study of Carbon Storage in Two Cocoa (Theobroma cacao) Shade-Types and a Teak Plantation in the Moist Semi-deciduous Forest Zone of Ghana.

on life, it is important that steps are taken to mitigate its effects. With the intensification of cocoa production, there has been a shift in traditional cocoa farming over the years leading to the removal of shade trees, hence, removal of carbon sinks. This study was carried out to compare the amount of carbon stored in cocoa ecosystems to that of a 20 years teak plantation and to calculate the trade-off of carbon between the two systems. Cocoa farms of similar ages (20 years) were selected in which three-subplots were demarcated on each farm at Piase in the Bosomtwe District. Tree Diameter at Breast Height (DBH) was measured and soils samples were collected and analyzed for organic carbon percentage and bulk density. One-way Analysis of Variance was used to analyze above and belowground tree carbon and two-way analysis of variance was used to analyze soil organic carbon stored. Teak plantation recorded higher carbon stock (739.33±2.24 Mg C.ha-1) compared to full sun cocoa (9.36±2.24 Mg C.ha-1). Soil organic carbon across the three farms showed significant (p = 0.0010) variations with depths. The 0-20 cm soil depth stored significantly more (p = 0.0000) organic carbon compared to 20-40 cm soil depth. Total soil carbon stored revealed significant differences amongst the various farms with the full sun (40.857±0.52 Mg C.ha-1) being the least whilst the teak plantation stored the highest (72.42±0.52 Mg C.ha-1). Total carbon (above-ground tree carbon + below-ground tree carbon + soil organic carbon) showed significant difference (p= 0.0000) between land use types with shaded cocoa farm (74.3±0.89 Mg C.ha-1), full sun cocoa farm (32.02±0.89Mg C.ha-1) and that of the teak plantation (950.91±0.89 Mg C.ha-1) respectively. Traditional cocoa ecosystem (shaded cocoa farms) has the potential to store carbon significantly higher than that of the full sun systems

Development Interventions and Agriculture Adaptation: A Social Network Analysis of Farmer Knowledge Transfer in Ghana

Social ties play an important role in agricultural knowledge exchange, particularly in developing countries with high exposure to agriculture development interventions. Institutions often facilitate agricultural training projects, with a focus on agroecological practices, such as agroforestry and agrobiodiversity. The structural characteristics of social networks amongst land managers influences decision-making to adopt such adaptive agroecoloigcal practice; however, the extent of knowledge transfer beyond direct project participants is often unknown. Using a social network approach, we chart the structure of agrarian knowledge networks (n = 131) in six communities, which have been differentially exposed to agriculture development interventions in Ghana. Farmer network size, density and composition were distinctly variable; development project-affiliated farmers were embedded in larger networks, had non-affiliated farmers within their networks, were engaged in more diverse agricultural production and reported adopting and adapting agroecological practice more frequently. Such bridging ties that link across distinctive groups in a network can expose network members to new and innovative agroecological practices, such as increasing agrobiodiversity, thus, contributing to livelihood strategies that mitigate environmental and market risk. Furthermore, we show that these knowledge networks were crop-specific where network size varied given the type of crop produced. Such factors, which may influence the rate and extent of agroecological knowledge diffusion, are critical for the effectiveness of land management practices as well as the persistence of agriculture development interventions

Shade tree diversity and aboveground carbon stocks in Theobroma cacao agroforestry systems: implications for REDD+ implementation in a West African cacao landscape

Abstract Background The promotion of cacao agroforestry is one of the ways of diversifying farmer income and creating incentives through their inclusion in REDD+ interventions. We estimated the aboveground carbon stocks in cacao and shade trees, determined the floristic diversity of shade trees and explored the possibility of implementing REDD+ interventions in cacao landscapes. Using replicated multi-site transect approach, data were collected from nine 1-ha plots established on 5 km long transects in ten cacao growing districts in Ghana West Africa. Biomass of cacao and shade trees was determined using allometric equations. Results One thousand four hundred and one (1401) shade trees comprising 109 species from 33 families were recorded. Total number of species ranged from 34 to 49. Newbouldia laevis (Bignoniacea) was the most frequently occurring specie and constituted 43.2 % of all shade trees. The most predominant families were Sterculiaceae and Moraceae (10 species each), followed by Meliaceae and Mimosaceae (8 species each) and Caesalpiniacaea (6 species). Shannon diversity indices (H’, Hmax and J’) and species richness were low compared to other similar studies. Shade tree densities ranged from 16.2 ± 3.0 to 22.8 ± 1.7 stems ha−1 and differed significantly between sites. Carbon stocks of shade trees differed between sites but were similar in cacao trees. The average C stock in cacao trees was 7.45 ± 0.41 Mg C ha−1 compared with 8.32 ± 1.15 Mg C ha−1 in the shade trees. Conclusions Cacao landscapes in Ghana have the potential of contributing to forest carbon stocks enhancement by increasing the stocking density of shade trees to recommended levels