Dynamic organization of two agroforestry systems in the semi-arid region of Paraíba and their contribution to improving the socio-economic conditions of farming families

ABSTRACT: The socio-economic vulnerability of family farmers in Brazilian semi-arid regions, combined with the intense degradation of the Caatinga biome, entails the use of alternatives that allow people to remain in the countryside while recovering the environment. Are agroforestry systems (AFS), which are based on the ecological, economic, and social interactions existing in a production system, an alternative? The present study described the structure, organization, and floristic composition of two AFS and analyzed the soil fertility of the two AFSimplanted in the semi-arid region of Paraíba. This study revealed that the farmers consider the AFS to be less harmful to the environment as it provides greater protection to the soil and better-qualityfood. Thegreatest challenges wereobtaining water during drought season and the need foran extra workforce. Nevertheless, the produce from these systemswas sufficient to provide for the families. Several varieties of fruit species were found in both the AFS studied, and Malpighia emarginata (acerola) was the most predominant. The soils of the two AFS presented a practically neutral pH the and high percentage of base saturation,thereby falling under the category of eutrophic soil with high fertility, and are ideal for growingany type of crop.


INTRODUCTION
The semi-arid regions of the Brazilian Northeast are characterized by challenging edaphoclimatic conditions, such ashigh temperatures, irregular rainfall in time and space, soils with low levels of weathering (shallow), and low production of plant mass.Other challenges include the adoption of total extractive systems, and overgrazing with animals above the carrying capacity of the soils in cattle ranching.Furthermore, practices such as agriculture that is based on deforestation and burning and practices such as extraction of firewood and wood to meet the energy demands of families, ceramic industries, and bakeries, which are unfavorable to the local ecological dynamics, contributing enormously to the reduction in the Caatinga vegetation due to the lack of regeneration (AGUIAR et al., 2006).
Within this context, the agroforestry systems (AFS) are a viable alternative for the different ecosystems of the Brazilian semi-arid tropics.Conceptual discussions about agroforestry or ABSTRACT: The socio-economic vulnerability of family farmers in Brazilian semi-arid regions, combined with the intense degradation of the Caatinga biome, entails the use of alternatives that allow people to remain in the countryside while recovering the environment.Are agroforestry systems (AFS), which are based on the ecological, economic, and social interactions existing in a production system, an alternative?The present study described the structure, organization, and floristic composition of two AFS and analyzed the soil fertility of the two AFSimplanted in the semi-arid region of Paraíba.This study revealed that the farmers consider the AFS to be less harmful to the environment as it provides greater protection to the soil and better-qualityfood.Thegreatest challenges wereobtaining water during drought season and the need foran extra workforce.Nevertheless, the produce from these systemswas sufficient to provide for the families.Several varieties of fruit species were found in both the AFS studied, and Malpighia emarginata (acerola) was the most predominant.The soils of the two AFS presented a practically neutral pH the and high percentage of base saturation,thereby falling under the category of eutrophic soil with high fertility, and are ideal for growingany type of crop.Key words: soil analysis, floristic composition, sustainability.
Among the most widely used concepts, the one proposed by MEdRAdO (2000) stands out; the author refers to AFS as a sustainable land management system that increases its yield by combining the production of forest plants with crops and/or animal farming, simultaneously or consecutively, in a liberated manner, on the same unit of land, involving management practices in line with the local population.MICCOlIS et al. (2016) indicated that AFS generate a series of environmental and socio-economic contributions, protecting and nurturing biodiversity, mitigating climate change and increasing adaptive capacity to its effects, regulating hydrological cycle, containing erosion, and helping in the cycling of nutrients and soil fertility.In addition, AFS generates a series of products that can be consumed and traded, improving the income and quality of the life of producers.
Such benefits can have positive impacts on the lives of farming families when they adopt the AFS as a production system on their properties.AGUIAR (2011) emphasized that family farming plays an important role in food production, job creation, and distribution of income and land.The economic and socio-environmental practices employed in the routine of family farmers intend to optimize the production system by diversifying it and making good use of the soil, to meet their primary needs, making family objectives compatible with environmental interaction and production integration.
In this context, it is necessary to understand how agricultural production models based on agroforestry systems practiced by family farmers can contribute to the improvement of socio-economic and environmental conditions in the semi-arid region of Paraíba, given the intensification of the environmental degradation process in the region.This consequently results in loss of the productive capacity of the soil and the creation of social problems, such as rural exodus.The causes of this process come from a long history of removing native vegetation for monocultures, coupled with extensive use of soil without proper management, in addition to the uncontrolled use of chemical inputs, depleting the land and rendering it unproductive.
Given this situation, it is important to develop research that presents the particularities of productive systems based on agroforestry systems and understand how they interact with the surrounding environment and improve environmental conditions of the semi-arid region, and the quality of life, and income of the farmers.
A detailed study on the subject is necessary for effective improvement in the techniques adopted by farmers, identifying the measures adopted through their knowledge and practices to interact with the environment while coping with the adversities in a sustainable manner.The intention is to combine it with academic scientific knowledge, with similar objectives such as minimizing the anthropic impacts in the semi-arid region, especially to the Caatinga biome, and contributing to the socio-economic and environmental development of the region.
Thus, the present study described the structure, floristic composition, and organization of two agroforestry systems in the semi-arid region of Paraíba and analyze the fertility and properties of the soils under the systems.

MATERIALS AND METHODS
This qualy-quantitative research comprised a survey of shrub/arboreal species, evaluation of soil fertility, and application of questionnaires to gain knowledge about the experiences of family farmers with the agroforestry system.

Characterization of the study areas
The present study evaluated two experiences with agroforestry systems (AFS) implemented and developed by family farmers in the semi-arid region of the state of Paraíba.One is located in the municipality of Patos, in the Trincheiras farm (6°58ʹ10″S, 37°16ʹ34″W; AFS 1), and the other in the municipality of São José do Sabugi, in the Nova Conquista farm (6°46ʹ35″S, 36°51ʹ59″W; AFS 2).The selection of family units for the research was based on the experience of successful implementation of agroforestry systems.
The two municipalities are characterized by a Bsh climate, classified as hot and dry, with two well-defined seasons, one rainy and the other dry, with average annual precipitation of 600 mm, an average temperature of 30 °C, and relative air humidity of approximately 55% (AlVARES et al., 2013).Table 1 shows the monthly rainfall data of the two regions during the research period.In these areas, the predominant vegetation formation is called open hyper xerophilous shrub-arboreal Caatinga, which is dense in small isolated areas and has been intensively exploited by cotton cultivation and extensive livestock (EMBRAPA, 2002).

Data collection and analysis
data collection began with the delimitation of the two areas and their topographic characterization.This procedure was performed using a GPS, GARMIM ETREEX 30, with a precision of 1 to 2 m at each point.After this procedure, the floristic composition of the fruit tree and shrub species was surveyed to identify their uses within the production chain of the two properties.
The degree of soil fertility in the two studied areas where the AFS were developed was verified using the composite sampling method described by CAVAlCANTI (1998).At each area site, a zigzag walking was used to obtain 20 simple samples per area at a depth of 0-0.20m.Then, the simple samples were homogenized into a soil composite for each site.The composite samples were identified and sent to the Soil and Water Laboratory (lASAG) of the Federal University of Campina Grande (UFCG), Campus of Patos-PB, where the following soil chemical attributes were analyzed: pH, organic matter, available phosphorus and potassium; exchangeable aluminum, calcium, and magnesium.
Qualitative data were collected using a semi-structured questionnaire to describe each experience and evaluate the contribution of the AFS to improve the income of the families involved in the productive systems.The data collected were tabulated and inserted into electronic spreadsheets, presented in tables, and discussed according to the results found by other authors in studies related to semi-arid region.

Establishment and management of agroforestry systems (AFS)
The first agroforestry system (AFS1) was implemented in 2016.The family that practiced it said that before they used agroforestry on their property, their livelihood came from hiring thirdparty properties, and they felt exploited.The situation led them to start planting fruit species among the trees that existed on the site, with the aim of marketing the fruit mainly.Today, the family lives solely on what they produce on the property.The second agroforestry system (AFS2) was implemented in 2012 when a family was awarded an underground dam through the "One land and Two Waters (P1+2)" program.In the project, one of the family members learned about agroforestry, and decided to implement it in the area of the underground dam.
Both AFS were implemented without technical monitoring and did not follow a predetermined spacing between species.The absence of spacing does not mischaracterize the system as agroforestry, but it is important to implement management strategies and consequently improves productivity of the system.Currently, both AFS followed the advice from the Technical Assistance and Rural Extension Company (EMATER) and civil society institutions, such as the diocesan Social Action of Patos (ASdP).
Regarding the sources of water for maintenance, in AFS1, the water comes from the river that cuts through the property.This water source is used only for irrigating the species existing in the system since the water is not considered drinkable for human consumption.AFS2 was implemented in an area with an underground dam; however, a drip irrigation system, whose water comes from a well powered by wind energy, existing in the area (windmill) to maintain sufficient soil moisture for existing species in the system.Table 2 presents the advantages and difficulties faced by the farmers in AFS.
The perception that the quality of life improved confirmed the results obtained by ARAÚJO FILHO et al. (2010), who verified the optimization of the nutrient renewal cycle in soil and increase in net family income, and by COSTA et al., (2002), who highlighted the use of the family system as the predominant labor, favoring self-management of activities and ecological associations close to natural ecosystems.

Structure, floristic composition, and uses of species in agroforestry systems
Figure 1 shows the topographic survey of the Trincheiras farm, where the AFS1 is inserted.Ciência Rural, v.53, n.4, 2023.
Lucena et al.
The property has 19 ha, and the area that comprises the agroforestry systems within the property is approximately 0.50 ha.AFS1 is located next to a plantation of Pennisetum purpureum Schum.(capim elefante) with an area of 1.1 ha.The plantation is connected to the system by functioning as a windbreak, and it is used as a source of fodder for the animals on the property.
AFS2 is inserted in a property of 4.0 ha, a considerably smaller area in relation to AFS1 (Figure 2).However, the area that comprises the agroforestry systemsis relatively larger than that of AFS1 (0.75ha).Structurally, it differs from AFS1 in that it is located with in an underground dam of 1.95 ha.

Questions
Considering that AFS1 was implemented in an area where native species already existed, the predominance of Mimosa tenuiflora indicates that the area had been previously exploited since the species is considered a pioneer species and often establishes it self in areas where vegetation has been removed.The fruit species Malpighia emarginata has a good marketability and is well adapted to the soil and climate conditions of the region, which facilitates management.
Table 4 shows the results of the characterization of the species reported in AFS2.There were 330 individuals of 19 different species, 38.79% of which were shrub/trees and 61.21% were fruit species.
Regarding the number of species, AFS2 also showed a greater diversity of shrubs/trees compared to the diversity of fruit trees, being 52.63% and 47.37%, respectively.Leucaena leucocephala (leucena) was the dominant tree species with 64 individuals, corresponding to 19.39%.Of the fruit species, the acerola was dominant with 143 individuals and corresponded to approximately half of the individuals of all fruit trees (43.33%) (Table 4).
In both AFS, the primary use of shrub/ arboreal species is for ground cover.In other words, these species provide environmental conditions, mainly shading, for the fruit trees to develop, and these are the ones that provide part of the livelihood of the family, because they sell them fresh or their pulp.
According to ROSA et al. (2007), besides the food issue, cultural tradition is another factor that influences the floristic composition of these areas, since traditional knowledge about the cultivation and use of plants is transmitted from generation to generation.It is important to note that, in both AFS, there is cultivation of forage species, such as Pennisetum purpureum (capim elefante) and Sorghum bicolor (sorgo), both intended for the production of silage to feed the animals on the properties during the dry season.
In AFS2 cultivation of temporary crop species (corn and beans) is carried out only for domestic consumption contributing to the family's food and nutritional security.After arvest, the stubble remains in the area to decompose and are incorporated into the soil.

Analysis of soil fertility in agroforestry systems
The soils of the two systems (AFS1 and AFS2) are chemically balanced (Table 5), probably due to the management practices applied in both areas, such as the non-burning of land for land preparation and subsequent planting, a common practice adopted by farmers in the semiarid region.In addition, the crops present in the AFS areas show some dynamics as there is greater diversification of crops in the cropping systems, unlike what occurs in monocultures.Moreover, there is maintenance of soil cover.

Figure 1 -
Figure 1 -Topographic survey of the area of Trincheiras farm, municipality of Patos-PB, with the location of AFS1 within the property.

Figure 2 -
Figure 2 -Topographic survey of the Nova Conquista farm, municipality of São José do Sabugi-PB, with the location of AFS2 within the property.

Table 2 -
Farmers' responses on the advantages, difficulties, maintenance costs, and implantation of agroforestry systems.

Table 3 -
Characterization of shrub/arboreal and fruit species found in AFS1, located in Trincheiras farm, Patos-PB.

Table 4 -
Characterization of shrub/arboreal and fruit species found in AFS2, located in Nova Conquista Farm, São José do Sabugi-PB.

Table 5 -
Results of chemical analysis of soils of agroforestry systemslocated in AFS1 and AFS2.