Abstract
Past studies showed a gradual expansion of forest over savannah in forest-savannah transition zones in Central Africa. While the natural encroachment of savannah by forest is more and more impeded by human activities, farmers in Cameroon have proven that afforestation of savannah is achievable using cocoa and specific technics to build up an associated tree canopy. Furthermore, mature cocoa agroforestry systems created on savannah (S-cAFS) or in forest (F-cAFS) exhibit comparable multi-strata structures. By combining measurements of cocoa yield, litterfall, soil quality, carbon storage and tree species diversity along an age gradient (1 to 70 years), we showed that those variables in S- and F-cAFS tended to comparable levels after several decades. Results also emphasized the ability of S-cAFS to increase most of the ecosystem services (including soil fertility and plant diversity) although the time needed to reach levels found in F-cAFS varied strongly amongst variables. In addition to the previous study, we compared in a second time the impacts of the presence of shade trees on soil functions and cocoa yield in cocoa farms set up after savannah. To do so, we sampled 5 cocoa monocultures and 8 cAFS. Cocoa yield did not vary between these systems. Nonetheless, the soil P availability was improved in cAFS compared to monocultures. Within cAFS, unshaded cocoa conditions showed the lowest soil functions associated with the low leaf litter quality of cocoa plants. Tree species had contrasting effects on soil functions. Cocoa association with the fruit trees Canarium schweinfurthii and Dacryodes edulis did not improve soil fertility compared with unshaded cocoa, while associations with the legume tree Albizia adianthifolia, or the timber trees Milicia excelsa and Ceiba pentandra significantly improved soil N and P availability. These differences could be explained by the quality of the recycled litter, since low litter recalcitrance was strongly associated with increases in soil N and P availability, while soil pH and soil C contents increased with litter Ca restitution from C. pentandra. Our results highlighted the positive impacts of cAFS establishment in savannah on soil fertility, species diversity and carbon storage in biomass and soil over time. Furthermore, we showed that using specific trees for soil quality and compatible with cocoa, and other trees for the provision of goods, can ensure cocoa AFS multifunctionality and sustainability. Future research will need to understand how plant diversity in these cocoa systems, can help to adapt to climate change. Keywords: Cocoa agroforestry; ecosystem services; forest-savannah transition, litter traits, soil fertility
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 13
Claim · model-written summary
Measured cocoa agroforestry variables in savannah and forest systems tended toward comparable levels after several decades.
- Taxon
- cocoa
Theobroma cacaoe0 - Outcome
- cocoa yield, litterfall, soil quality, carbon storage and tree species diversitye0
- Direction
- comparablee0
- Comparator
- F-cAFSe0
- Setting
- S- and F-cAFSe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“By combining measurements of cocoa yield, litterfall, soil quality, carbon storage and tree species diversity along an age gradient (1 to 70 years), we showed that those variables in S- and F-cAFS tended to comparable levels after several decades.”
Claim · model-written summary
Savannah cocoa agroforestry increased most ecosystem services, including soil fertility and plant diversity.
- Taxon
- cocoaTheobroma cacaot0
- Outcome
- soil fertility and plant diversitye0
- Direction
- increasee0
- Qualifier
- time needed to reach levels found in F-cAFS varied strongly amongst variablese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Results also emphasized the ability of S-cAFS to increase most of the ecosystem services (including soil fertility and plant diversity) although the time needed to reach levels found in F-cAFS varied strongly amongst variables.”
t0“cocoa agroforestry”
Claim · model-written summary
Cocoa yield did not vary between monoculture and agroforestry systems.
- Taxon
- CocoaTheobroma cacaoe0
- Outcome
- Cocoa yielde0
- Direction
- did not varye0
- Comparator
- 5 cocoa monocultures and 8 cAFSe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cocoa yield did not vary between these systems.”
e1“we sampled 5 cocoa monocultures and 8 cAFS.”
Claim · model-written summary
Soil phosphorus availability improved in cocoa agroforestry relative to monoculture.
- Taxon
- cocoaTheobroma cacaot0
- Outcome
- soil P availabilitye0
- Direction
- improvede0
- Comparator
- monoculturese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nonetheless, the soil P availability was improved in cAFS compared to monocultures.”
t0“cocoa agroforestry”
Claim · model-written summary
Unshaded cocoa had the lowest soil functions within agroforestry systems.
- Taxon
- cocoaTheobroma cacaoe0
- Outcome
- soil functionse0
- Direction
- loweste0
- Setting
- unshaded cocoa conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Within cAFS, unshaded cocoa conditions showed the lowest soil functions associated with the low leaf litter quality of cocoa plants.”
Claim · model-written summary
Canarium schweinfurthii association did not improve cocoa soil fertility compared with unshaded cocoa.
- Taxon
- CocoaTheobroma cacaoe0
- Treatment
- Canarium schweinfurthiie0
- Interactor
- Canarium schweinfurthii
Canarium schweinfurthiie0other - Outcome
- soil fertilitye0
- Direction
- did not improvee0
- Comparator
- unshaded cocoae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cocoa association with the fruit trees Canarium schweinfurthii and Dacryodes edulis did not improve soil fertility compared with unshaded cocoa”
Claim · model-written summary
Dacryodes edulis association did not improve cocoa soil fertility compared with unshaded cocoa.
- Taxon
- CocoaTheobroma cacaoe0
- Treatment
- Dacryodes edulise0
- Interactor
- Dacryodes edulis
Pachylobus edulise0other - Outcome
- soil fertilitye0
- Direction
- did not improvee0
- Comparator
- unshaded cocoae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cocoa association with the fruit trees Canarium schweinfurthii and Dacryodes edulis did not improve soil fertility compared with unshaded cocoa”
Claim · model-written summary
Albizia adianthifolia association significantly improved soil nitrogen and phosphorus availability.
- Taxon
- cocoaTheobroma cacaot0
- Treatment
- Albizia adianthifoliae0
- Interactor
- Albizia adianthifolia
Albizia adianthifoliae0other - Outcome
- soil N and P availabilitye0
- Direction
- improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“associations with the legume tree Albizia adianthifolia, or the timber trees Milicia excelsa and Ceiba pentandra significantly improved soil N and P availability.”
t0“cocoa agroforestry”
Claim · model-written summary
Milicia excelsa association significantly improved soil nitrogen and phosphorus availability.
- Taxon
- cocoaTheobroma cacaot0
- Treatment
- Milicia excelsae0
- Interactor
- Milicia excelsa
Milicia excelsae0other - Outcome
- soil N and P availabilitye0
- Direction
- improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“associations with the legume tree Albizia adianthifolia, or the timber trees Milicia excelsa and Ceiba pentandra significantly improved soil N and P availability.”
t0“cocoa agroforestry”
Claim · model-written summary
Ceiba pentandra association significantly improved soil nitrogen and phosphorus availability.
- Taxon
- cocoaTheobroma cacaot0
- Treatment
- Ceiba pentandrae0
- Interactor
- Ceiba pentandra
Ceiba pentandrae0other - Outcome
- soil N and P availabilitye0
- Direction
- improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“associations with the legume tree Albizia adianthifolia, or the timber trees Milicia excelsa and Ceiba pentandra significantly improved soil N and P availability.”
t0“cocoa agroforestry”
Claim · model-written summary
Lower litter recalcitrance was strongly associated with increased soil nitrogen and phosphorus availability.
- Taxon
- cocoaTheobroma cacaot0
- Organ / stage
- littere0
- Outcome
- soil N and P availabilitye0
- Direction
- increasese0
- Qualifier
- low litter recalcitrancee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“low litter recalcitrance was strongly associated with increases in soil N and P availability”
t0“cocoa agroforestry”
Claim · model-written summary
Soil pH and carbon content increased with litter calcium restitution from C. pentandra.
- Taxon
- cocoaTheobroma cacaot0
- Interactor
- C. pentandraCeiba pentandrae0other
- Compound
- Cae0
- Outcome
- soil pH and soil C contentse0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soil pH and soil C contents increased with litter Ca restitution from C. pentandra”
t0“cocoa agroforestry”
Claim · model-written summary
The authors conclude that specific trees selected for soil quality and goods can support cocoa agroforestry multifunctionality and sustainability.
- Taxon
- cocoaTheobroma cacaoe0
- Outcome
- cocoa AFS multifunctionality and sustainabilitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“using specific trees for soil quality and compatible with cocoa, and other trees for the provision of goods, can ensure cocoa AFS multifunctionality and sustainability.”