2.2. Selection of AFS Cocoa
Seventy-two farms implementing Agroforestry Systems (AFS) with cocoa crops were selected. An identification process was carried out through visits to the plots of each producer and exhaustive tours to identify irrigation areas, houses, water sources, and the tree species associated with cocoa. In addition, the slope of the land was evaluated, and the total area of each farm was determined during this sampling process.
The georeferencing of the plots, considered Agroforestry Systems (AFS), was carried out with a GPS, where the taking of points was carried out in the central part of the production unit. The inventory of species was also carried out through the application of an interview with each producer in their plots. The information collected lists the tree species found within the farm. Then, plant material of bark, leaves, flowers, and fruits was collected for their respective identification by Tobias Fremont, Researcher of the Bioversity International Alliance – CIAT, an agroforestry, ecology, and tree biodiversity expert.
2.3. Of the Diversity of Forest Species Associated with Cocoa AFSs
The distance between the furrow and the plant was measured to calculate the density of tree species per hectare (ha), considering the type of agroforestry design. In addition, dasometric measurements were carried out that included total height (ht) and commercial height (hc), crown height, horizontal distance, crown angle, base angle, and diameter at chest height (DBH), using a hypsometer according to the methodology of [
19]. Regarding the measurements of the DAP, a DAP greater than 5 centimeters and a height of 1.30 meters was considered. It began by measuring the circumference with a tape measure, and then the DAP was calculated. In addition, the crown radius was measured with tape from the trunk to the shaft. The following equation was used to calculate the DAP:
Likewise, tree species were evaluated to determine their use characteristics, such as wood, firewood, food, fodder, medicine, etc. Finally, information on the age of each forest tree was collected and subsequently used to give it an economic value.
The relative abundance of the different species associated with cocoa on the farms was determined by the following equation:
To identify and quantify the different tree species that make up the structure of the AFS with cocoa, the Shannon equity index was used with the following equation:
Where E = Shannon Equity Index
H ́ = Shannon Diversity Index
H'max = the maximum possible level of diversity within a given population
lnS = Natural logarithm of species richness.
The accumulation curve of the different tree species associated with cocoa was determined using the following equation:
Where:
E(S)= expected number of species
N = total number of individuals in the sample
Ni = number of individuals of the i-th species
n= standardized sample size
The range-abundance curve of the different tree species associated with cocoa was calculated using Shannon's equity index, Simpson's and Margalef's index, using the following equation:
Where:
N=total number of individuals in the sample
Ni-number of individuals of species i
Where:
S = Total number of species
N = total number of individuals in the sample
The Importance Value Index (IVI) of [
20,
21] was used to describe a dominant species in the plots. The IVI was determined by adding its relative frequency (RD+RCC+RF) using the following equation:
2.4. Economic Assessment of Conventional and Forested Agroforestry Systems
For the economic evaluation, specific adjustments and modifications were made according to the particular needs of this study by the methodology of [
22].
The economic analyses were carried out using a comparison between the income and expenditure curve, incorporating the net profits with a focus on a conventional AFS and with an arrangement. Conventional AFS is an agroforestry system installed without technical criteria, while AFS with an arrangement is the ideal agroforestry system. The first three years of the AFS with cocoa are characterized by substantial investment in installation, maintenance, fertilization, and pruning, among other activities, with no income recorded.
The cost analysis covered different components, starting with direct costs, which include the expenditure associated with cocoa seedlings, inputs for production, land preparation, and other tree species in the Agroforestry System (AFS). Likewise, direct labor was considered, which includes activities such as slashing and felling, burning, cleaning, construction of drains, application of agricultural lime, alignment, pruning, sucking, underpinning, removal of diseases and sprouting, as well as the installation of cocoa, opening of holes and planting of other tree species. Finally, indirect costs, such as phytosanitary control and other expenses, were included, representing 10% of total expenditures.
The income from the sale of cocoa in slime was considered, establishing a price of S/3.50 per kilogram. In addition, the income generated from the sale of tree species that have commercial value in the market within the study area was considered since the sale of forest products provides greater economic stability to the producer.
An analysis considered one hectare for producing an Agroforestry System (AFS), comparing a conventional AFS with an AS arrangement. The projection was made over 25 years, starting with installation in year 1, projecting cocoa production starting in year four and initially representing 50% of the plant's total yield. For fruit species, the year they begin to produce after their installation in the AFS was considered, and yields were projected for the following years. Similarly, forest species' usable age was assessed, considering an investment to obtain a return by selling wood. It is important to note that during this period, the total harvesting of the wood of a species is not carried out. Instead, a specific amount is kept to be later replaced, thus ensuring the continuity of the AFS cycle.
The net present value was calculated using the following formula:
Where:
NPV: Net Present Value
BN-i.: Net profit in period i
I: Initial Investment
n: Shelf life
i: Period
A: Discount Rate
Thus, a NPV > 0 means that the investment in the study area has profits above the required return (discount rate), while a NPV < 0 demonstrates the existence of losses. To find the Internal Rate of Return (IRR), the discount rate was calculated by zero-matching the NPV. An IRR > r refers to the fact that the system gives a return above the opportunity cost or discount rate, while if the IRR < r, it shows that the profitability does not reach the minimum required.
To calculate this indicator, it was necessary to consider the net benefits and investment costs. It was evaluated taking into account the following: Whether the C/B >1 is considered to be profitable. Whereas, a C/B ≤ 1 needs to be changed. The formula used was as follows:
Where:
BN: Net Profit
CI: Investment Costs
The comparison of the profitability indicators between a conventional Agroforestry System (AFS) and one with design, the Net Present Value (NPV), and the Internal Rate of Return (IRR) were evaluated considering a discount rate of 20%. This choice is justified by the nature of the rural agricultural activity, which is characterized by considerable risk arising from several factors. Based on the methodology of Zavala et al. (2018), a reference rate greater than 15% was used due to the risks and uncertainties in a cocoa agroforestry arrangement, both in the flat and lowland parts and to the flooding of rivers, diseases, and pests, in this particular case a reference rate of 20% was used.
Cash flow was calculated as the difference between income and expenditure in each year during the projected 25 years for both a conventional agroforestry system and an arrangement system.
Composition and Spatial Distribution of Trees in AFS With Cocoa
Based on [
24]'s methodology, ShadeMotion 5.1.47 software was used to model the sun's position for an entire year, calculating its azimuth and elevation angle every hour from 9 am to 3 pm. Using the coordinates and characteristics of the trees, cast their shadows on the ground, considering the opacity of the canopy and foliage. The shading frequency of each cell in the grid was determined, allowing shadow overlap. This facilitated the identification of an ideal agroforestry system, considering the shape and position of the shadows according to the tree species, flat or sloping terrain, and various crown shapes. Slopes of 0° and 7° were evaluated in a 1 Ha study area.
An analysis of variance between groups was performed with a margin of error of 5%. Linear correlation analysis was then performed using Pearson's Correlation Coefficient [
24]. In addition, ShadeMotion 5.1.47 software was used for the characterization, and R software was used for ANOVA support. For the calculation of the diversity indices, Shannon and Simpson used the packages BiodiversityR, vegan, ggplot2, FactoMineR, corplot, and factoextra.