Reference
Ecological Rationalities of the Traditional Homegarden
System in the Chao Phraya Basin, Thailand, Agroforestry systems, 1999
Authors :
Jiragorn Gajaseni and Nantana Gajaseni
Department of biology, faculty of science, Chulalongkorn University
Summary :
Although the homegarden systems in the
tropics are claimed to sustain basic community needs without environmental
deterioration, the ecological rationalities behind the harmony between the
humans, homegardens, and the environment are not well understood. Four study
sites (Sukhothai, Srisatchanalai, Ayudhaya and Nonthaburi) representing the
four Thai eras in the Chao Phraya Basin were selected for studying these
rationalities. The size and physical stature of the homegardens, their plant
association and community features, physical environmental factors, nutrient
and soil fertility parameters, and cultivation pratices were studied. The
major factor that determines species selection in homegardens is the
utilization of the products, while the various pratices within the
homegardens are determined by such factors as the species, the system and
the environment. All homegardens had four vertical stratifications, with
physical structures almost similar to that of dry dipterocarp forest, but
with lower height for each layer, lower diversity of plants and sparser
crown layer. The analysis also shows a high possible utilization efficiency
for space, light, water and nutrients in the soil in the homegardens.
Shannon-Wiener's indices of species diversity of the homegardens were close
to those of dipterocarp forest. The homegardens are in-situ
reservoirs for biodiversity at genetic – species- and ecological level.
There was no complete harvesting from these homegardens. This practice
ensured minimal nutrient export from the systems, while high amounts and
diversity of litter biomass should contribute to high efficiency of nutrient
cycling. Futhermore, phosphorus availability could be better in homegardens.
The homegardens had more favorable microenvironment with lower soil and
atmospheric temperature and higher relative humidity than outside. There has
been no single incident of a pest outbreak at a treatening level.
Keywords :
Microenvironments, nutrient cycling, species diversity,
Thai settlements
Contacts :
gjiragor@pioneer.netserv.chula.ac.th
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