Page 141 - Agroforestry system - book inner (final corrected) - 9.-3-21_Neat

National level e-symposium on “Agroforestry system for augmenting livestock
productivity and empowering resource poor rural farmers”

Ecosystem services

Yet another unique attribute of homegardens is their potenrtial to deliver many ecosystem services. The
quality and magnitude of ecosystem services provided by homegardens differ from those provided by other
types of agroecosystems (Mohri et al. 2018; Calvet-Mir et al., 2012). Major ecological functions rendered by
homegardens include maintenance of soil fertility, regulation of pests and pathogens, wildlife protection, clean
water supply, carbon sequestration, maintenance of rural landscapes and rural lifestyles, and maintenance of
recreational areas for ecotourism (Jeyavanan et al. 2017; Sandhu et al., 2010; Swinton et al., 2007).

Traditional agriculture practices such as homegardens are characterized by maintenance of high agro-
biodiversity (Altieri, 1999; Jackson et al., 2007) which ensures coupling of agricultural productivity with
the delivery of the other adaptable services that biodiversity provides. For instance, maintenance of agro
biodiversity in homesteads leads to enhancement in agroecosystems’ resilience to ecosystem changes mooted
by demographic pressure (Jackson et al., 2007; Pascual et al., 2010). Homesteads essentially a low input
agro ecosystem rely primarily on site-specific biological, edaphic, and climatic conditions there by reducing
dependence on heavy inputs such as machinery, phytochemicals and power thereby reducing related hardships
in terms of soil compaction, water pollution, greenhouse gas emissions etc (Altieri, 1999).

Biophysical interactions triggered by trees provide substantial ecosystem services. Trees with their deep
root system act as nutrient pumps and the fine roots dynamics contribute substantially to enrich the carbon
content and nutrient status of the soil. The multilayered canopy stratification and the high litter production
from the trees cover the soil and protect from insulation. The tree cover moderates the extremes of climate
and biophysical extremes. Yet another environmental function rendered by homegardens is their carbon sink
properties and in so doing take part in climate change mitigation. Homegardens are unique in that they address
all the three mechanisms that qualify agroforestry as GHG reduction strategy viz. carbon sequestration, carbon
substitution and carbon conservation (Montagnini and Nair, 2004; Kumar, 2006). The trees and other perennial
components in the homegardens sequester substantial amount of CO . On a comparative scale homegardens
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sequester C much better than intensively managed crop lands (Saha et al. 2009). For example, cropped land
after slash and burn showed CS values 39 to 52 Mg C ha (Sanchez, 2000) while Indonesian homegardens,

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Sumatra sequester much higher to the tune of 55.8 to 162.7 Mg C ha (Roshetko et al., 2002). Aboveground
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carbon stocks of trees (>20cm girth at breast height) in the homegardens of selected 28 panchayaths of central
Kerala, India were 24.32 Mg ha (Kumar, 2011). Homegardens also stands out as a promising example of
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climate change resilient landuse practice.
Management characteristics

Unsurprisingly, homegardens are less intensely managed systems. Scientific management of these
traditional systems poses serious limits on account of intertwined nature of various components in time and
space. The understorey space utilization for intercropping depends entirely on the tree density and light
availability. A legitimate approach is to manipulate the tree environment rather than the tree itself. Hence
practices such as branch pruning for improving understorey light conditions are a common management
practice in homesteads. For instance, branch pruning of taller trees such as teak (Tectona grandis), Terminalia
paniculata, Sweitenia macrophylla is a common practice in homegardens of Kerala. Other conventional

122 Institute of Animal Nutrition, Centre for Animal Production Studies, TANUVAS
National Bank for Agriculture and Rural Development