2008-'09 - Kerala Forest Research Institute

Annual Report 2008-09
agroforestry systems and annual crop-based systems. Among different landuse
systems, the semi-evergreen forests with 67 tree species are rich in tree species diversity.
On the other hand, moist deciduous forest patches are being repeatedly disturbed.
Forest patches closer to the agricultural lands are highly degraded. In teak
plantation, density and basal area of teak are significantly less in water-logged
area than in uplands.
The moist deciduous forests located near human habitation possess sparse vegetation and
nutrient poor compact soil. These forests showed relatively higher ant diversity and density.
Thus ants, particularly Lobopelta sp. and Leptogenys sp., could be considered as indicator
species of forest disturbance. Among the endogeic earthworms Parryodrilus lavelee and
Pontoscolex corethrurus showed maximum availability in a variety of landuse patterns. Since
these two species have a wide tolerance to landuse changes, they may be suitable for land
restoration purpose.
Comparatively high diversity of AM fungi in soils of cashew plantations, degraded
forests and teak plantations indicate that conditions in these soils are highly suitable
for the proliferation of a host of mycorrhizal fungi. The available data show that
plant dependency on mycorrhiza is apparently more in highly degraded sites. It
was recorded that in the unmanaged systems the root colonization of VAM fungi
were more than in some of the well managed monocropping systems. Thus it was
clear that in unmanaged systems, plants are more dependent on mycorrhiza for
growth. Further analysis of data indicated that majority of the landuse systems
were not significantly different from the unmanaged plantations in terms of per
cent root colonization by mycorrhiza indicating that these plots are also poorly
managed. Results showed that the rhizobial population in polyculture systems was
significantly more than in annual crop based systems. Among the thirteen species
of naturally growing legumes in the study area, Desmodium triflorum produced
most profuse nodulation. Thus the wild legumes such as Desmodium triflorum
could be a potential source of green cover crops.
In Chaliyar River watershed, a faster rate in landuse and land cover changes was recorded.
The farming community also expressed the view that the conversion of one cropping
system to another was more frequent resulting in the increased soil erosion and runoff
rates. Considering these aspects, four strategies viz., a) application of green leaf manure,
b) application of plant growth promoting microorganisms and earthworm rich
compost, c) reduction of nutrient loss from the croplands, and d) growth of
leguminous and/ or biomass transfer species in the crop lands for maintaining soil
fertility, sustainable yield and to enhance density and diversity of soil biota in
different cropping systems, have been identified.
Forestry sector analysis for the State of Kerala- Phase II. KFRI Research Report
No. 317 (Jayaraman, K.; Anitha, V. and Sivaram, M. 2008)
Kerala Forest Research Institute
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