MSc

Tropical homegardens are time-tested land use systems which have evolved
through generations of crop intensification. Homegardens of Kerala are traditional
agricultural systems that were closely related to the livelihood and nutritional
security of small and marginal farmers of Kerala. A study was carried out to
investigate the functional and structural status of the homegardens in Thrissur
District, Kerala. Study was conducted in selected homegardens of 10 panchayths
and one peri urban area of Thrissur district. The study was based on comparison
of homegardens of three size classes such as small (<0.2 ha), medium (0.2-0.4 ha)
and large (>0.4 ha) from three eco regions (highland, midland and coastal land)
and one peri urban area (municipality). A total of 330 homesteads were selected
from selected panchayths based on a stratified random sampling.
There was a great variability in diversity, abundance and standing stock of
different tree species belongs to different use categories among three homegarden
size classes and across different eco regions. There were 163 total species present
in the entire Thrissur district that included 122 trees species and 41 agricultural
crop species. Contrary to earlier studies, consistent decline in diversity was
observed with decrease in homegarden size.
Highest number of taxa was
observed from large homegardens (102 species) which was followed by medium
(95 species) and small (85 species). Population pressure and skewed land
availability may have negatively affected the species diversity in homegardens.
Most abundant functional group of trees found in surveyed homegardens were
medicinal trees (62 species) followed by timber species (53 species).
Economically important functional groups such as timber, fodder, fuel, green
manure and other MPTs were abundant in large homesteads. Eco-region wise
comparison of tree diversity suggested high diversity in the midland and highland
regions while lower in coastal land and peri-urban areas. Mangifera indica was
the predominant timber tree species in terms of abundance and standing stock in
Thrissur district with a total stand number and standing stock projected to the
Thrissur district as 15,98,849 and 18,84,356.3 m3 respectively. Other dominant
timber trees in terms of standing stock were Artocarpus heterophyllus, Tectona
grandis, Swietenia macrophylla, etc. Standing stock per hectare of total timber
species identified in Thrissur district was 55.12 m3 ha-1 and projected standing
stock of all timber species in the district was 81,38,931.6 m3. Vertical diversity of
the studied homegardens suggested high species richness associated with middle
storey. Also all three strata of large homegardens were more diverse than medium
and small homegardens irrespective of eco-region. In total there were 41 species
of agricultural crops and medicinal plants identified from selected homegardens.
Musa sps., Areca catechu and Cocos nucifera were the predominant species of all
size holds. Simpson Index and Shannon Diversity Indices of agricultural crops of
all size holds showed no large difference.
Attempts to study the socio-economic factors of homegarden functioning
revealed land fragmentation as the principal agent of their decline. The most
frequent constraints of homegardens included high wage of the labourers involved
in homegarden maintenance, less labour availability, large expense/less profit,
pest and disease, etc. Wood quality assessment of Tectona grandis, Artocarpus
heterophyllus and Swietenia macrophylla using NDT showed that oven dry
specific gravity (SPGo.d) has no influence on eco-regions and tree size classes.
The dynamic modulus of elasticity (MOEdyn) showed significant differences for
Artocarpus heterophyllus and Swietenia macrophylla across eco-regions.
However, this was not prominent for Tectona grandis.
On the whole, the
functional and structural analysis of the homegardens in Thrissur district of Kerala
revealed their potential contribution to the agro-biodiversity. However concerted
efforts are required to revitalize these unique traditional agricultural practices in
terms of their ecological and economic viability.