Agroforestry practices for enhancing food security and climate change resilience in Rajaf county, South Sudan

Abstract

Agroforestry (AF) is being practiced traditionally as a sustainable land- use option, in many agro-ecological zones of Sub-Saharan Africa. Agroforestry is important as incorporating trees and shrubs in food crop systems can help address food insecurity issues and reduce vulnerability of agricultural systems to climate change. The purpose of this study was to investigate the current agroforestry practices and their relevance to enhancing food security and climate change resilience among rural communities in Rajaf County. Household surveys using structured and semi-structured questionnaires, Key informants interviews (KIIs) and Focused Group Discussions (FGDs) were used as tools to collect survey data in which 332 household respondents were sampled and interviewed. Results indicated that most people practiced agrisilvicultural and agrisilvopastoral AF systems with scattered trees on farms, boundary plantings, homegardens, and woodlots as their on-farm arrangements. While goats and chicken were most reported domestic animals; sorghum, beans, groundnuts, cassava, maize, and simsim were the most reported food crops. The most preferred tree species were Mangifera indica, Azadiractha indica, Balanites aegyptiaca, Mahogany spp, Acacia spp, etc for distinguished uses. Over 350 trees were inventoried by non-destructive methods through systematically established line transects and circular sample plots. The tree species parameters (DBH, H & CR) were measured and used to determine their diversity, abundance and carbon sequestration potentials. It was found that average DBH of trees in AF farms was 12.68cm with a minimum and maximum DBH of 5.0 cm and 62.9 cm respectively. Densities for respective species were calculated and above-ground biomass (AGB) equations or models were then used to generate results to estimate carbon sequestration potential of AGB. Chave 2014 was taken as the baseline model to compare among the other models used and select the best fitting model for computation of aboveground carbon (AGC). From the calculated AGB, it is revealed that most carbon sequestration stock accrued from boundary planting (183.1 tons/ha), homegardens spp (142.5 tons/ha), scattered trees in farms (132.2 tons/ha). Tree diversity was not uniform as few species are found in other AF sites although there was abundance of some species such as citrus spp, Mangifera indica, Psidium guajava, Acacia spp and Tectona grandis. The values of Shannon diversity indices varied among the sites: Kolye west (2.211), Gumbo (1.726), Kolye East (2.268) and Tokiman Island (1.699). Agroforestry practices have the potential to food security and climate change because it holds more components as compared to conventional Agriculture and Forestry, resulting into diversified alternative sources despite its intensive labour requirements i.e there is always a secured next component in case of failure of one component. Therefore, farmers should be encouraged to practice AF that results to food availability and accessibility.