PhD

An investigation entitled 'Techno economic study on intercropping
medicinal plants in oil palm plantations' was carried out at Kulathupuzha oil
palm estate during the period 1999 - 2002, to study the adaptability and
performance of ten medicinal plant species as intercrop in oil palm plantations
of different age groups. The specific objectives were to standardize the
optimum spacing for the potential species under the different oil palm canopy
shade levels and to study the morphological, anatomical, physiological and
biochemical mechanism of shade tolerance ofthe selected species.
In the study, the pattern of distribution of solar energy indicated that
there was considerable variation in the interception of sunlight, by palm
canopies of different age groups. The range of light condition available in the
plantation was grouped as, young palms with moderate light transmission (PAR
42 % of open), medium and mature palms having poor light transmission,
improving with increase in palm height and also change in leaf orientation
(PAR 19 and 22 % of open respectively).
The experiment revealed the feasibility of growing medicinal plants as
intercrop in oil palm plantations of all age groups studied. The performance of
all ten species with regard to morphological characters and yield were better
under the young oil palm canopy. The per plant yield of species grown under
open condition was on par with that under medium and mature oil palm canopy.
The net income per hectare and benefit cost ratio of the medicinal plant species
were the highest when they were grown under the young palms. The study
suggests that among the different oil palm canopy shade levels, young oil palm
canopy is the ideal condition for intercropping medicinal plant species.
Intercropping of shade tolerant medicinal plants under medium and mature oil
palm canopy is also beneficial for getting reasonable additional income from
the plantations.






Among the ten medicinal plant species evaluated, Kacholam emerged as
the most profitable intercrop for oil palm plantations under southern Kerala
conditions. Other profitable intercrops identified were Chittadalodakam,
Chittaratha, Karimkurinji and Sathavari.
The spacing trial of Kacholam under the different shade levels
prevailed in oil palm plantations of various age groups revealed that 20 x 10 cm
spacing was the ideal planting distance in young, medium and mature
plantations for getting highest yield and profit. The highest net profit was
recorded when Kacholam was grown under young oil palm canopy and the
profit was slightly higher than that obtained from open crop. The net profit from
other two shade situations was also not much lower than under open condition.
This indicated the suitability of Kacholam as intercrop in oil palm plantations of
all age groups. A higher net profit was obtained from the lowest spacing of 20 x
10 cm under all situations. The spacing, 20 x 10 cm can be recommended as the
optimum spacing for intercropping Kacholam in oil palm plantations. Based on
benefit cost ratio, it can be concluded that the ideal shade condition for
intercropping Kacholam is under young oil palm canopy followed by medium
and mature canopy.
An analysis of the morphological, physiological, anatomical and
biochemical characters of Kacholam revealed its shade tolerant nature.
Lncreased number of leaves, tillers, total leaf area and increased fresh weight of
. .
all plant parts clearly indicated the superior performance of Kacholam under
shade. Physiological attributes like, total dry matter production, leaf area index,
specific leaf weight and water potential were also found to be higher under
shaded condition compared to open, indicating its shade tolerant behaviour.
Lower stomatal density, decreased epidermal and mesophyll thickness and
lower number of vascular bundles noticed in Kacholam leaves grown under
shade, compared to open, are clear indications of the adaptive mechanism of
Kacholam under shade. Higher content of chlorophyll 'a', 'b' and total
chlorophyll recorded under shade also indicated the biochemical mechanism of
shade tolerance in Kacholam.


Analysis of the yield data of oil palms in the experimental plots before
and after the experiment revealed that the yield of young, medium and mature
palms was not affected by intercropping with medicinal plant species.