Homegardens as a Multi-functional Land-Use Strategy in Sri Lanka with Focus on Carbon Sequestration

Abstract

This paper explores the concept of homegardens and their potential functions as strategic elements in land-use planning, and adaptation and mitigation to climate change in Sri Lanka. The ancient and locally adapted agroforestry system of homegardens is presently estimated to occupy nearly 15 % of the land area in Sri Lanka and is described in the scientific literature to offer several ecosystem services to its users; such as climate regulation, protection against natural hazards, enhanced land productivity and biological diversity, increased crop diversity and food security for rural poor and hence reduced vulnerability to climate change. Our results, based on a limited sample size, indicate that the homegardens also store significant amount of carbon, with above ground biomass carbon stocks in dry zone homegardens (n = 8) ranging from 10 to 55 megagrams of carbon per hectare (Mg C ha -1 ) with a mean value of 35 Mg C ha -1 , whereas carbon stocks in wet zone homegardens (n = 4) range from 48 to 145 Mg C ha -1 with a mean value of 87 Mg C ha -1

Quantification of carbon stock and tree diversity of homegardens in a dry zone area of Moneragala district, Sri Lanka

“…The positive relationship between the SWI index and AGB carbon stock for small-sized gardens in relation to the slightly negative relationship for large homegardens and AGB carbon suggests that small-sized homegardens hold higher carbon stock and species diversity, in line with Kumar (2011) and Pushpakumara et al (2012). Therefore, expanding homegardens into degraded and low-productive lands (such as shifting cultivation lands) for increased ecosystem services and carbon stocks as suggested by Mattsson et al (2013) would thus be more beneficial through the provision of small homegarden units rather than larger units. Also, the traditional use of homegardens has been around homesteads inherently meaning close to where people live.…”

“…However, Mattsson et al (2013) Homegarden diversity is by large controlled by ecological and socio-economic factors such as altitude, homegarden size, age of gardens, and personal preferences by the gardeners, market access and production intensity (Karyono 1990;Abdoellah et al 2006;Nair and Kumar 2006;Peyre et al 2006;Torquebiau and Penot 2006;Wiersum 2006;Pandey et al 2007;Kehlenbeck and Maas 2008 The wet zone homegardens are considerably smaller in extent than dry zone homegardens but the total number of trees recorded within the wet zone is much higher due to the higher tree density (average of 260 trees ha -1 ) than those in the dry zone (average 125 trees ha -1 ). Higher species density has also been found in small homegardens than large homegardens (McConnell and Dharmapala 1973;McConnell 2003;Pushpakumara et al 2012).…”

“…Homegardens also store higher amounts of carbon than other agriculture systems in the above-and below-ground biomass and soils, but usually inferior to mature forests at the same site (Schroth et al 2011;Mattsson et al 2013). The provisioning role of agroforestry and homegardens to maintain species diversity may also facilitate more stable and longer term stability of carbon stocks as well as diversification of homegarden derived products (Yachi and Loreau 1999;Brookfield et al 2002;Henry et al 2009).…”

What is good about Sri Lankan homegardens with regards to food security? A synthesis of the current scientific knowledge of a multifunctional land-use system

“…Previous studies show that homegardens have good capacity for carbon storage in above ground biomass, similar to secondary forests (Mattsson et al 2013;Mattsson et al 2014). Climate finance could therefore be a new source of funds -via climate intervention programmes focused on reduced deforestation and reforestation.…”

Climate Change Impacts, Agroforestry Adaptation and Policy Environment in Sri Lanka

“…Home gardens in Sri Lanka contain a significant fraction of the total above-ground biomass carbon stock in the terrestrial system, and this proportion has increased from almost one-sixth in 1992 to nearly one-fifth in 2010. Home gardens store significant amount of carbon, with above ground biomass carbon stocks with a mean value of 35 Mg•C•ha −1 in dry zone while 87 Mg•C•ha −1 in wet zone in the terrestrial system in Sri Lanka (Mattsson et al, 2013). The tree density per hectare ranged from 338 in dry zone home gardens to 2108 in wet zone home gardens; these values are reflected in the higher carbon stock estimates within the wet zone home gardens (Mattsson et al, 2012).…”