Msc

The survey was conducted in Kooropada village of Kottayam taluk with an intention to assess the shade effect of other tree species on growth and performance of rubber. The small holdings with area in the range of 0.30 to 1.64 ha were surveyed. The holdings differed very much in number of other trees related (10.8 to 28.0) and the average number of other trees retained in the units was 19.58. Among the other plants coconut occupied the prime position (14.0) followed by anjali (2.48) jack (0.72) teak (0.64) arecanut (0.64) and miscellaneous trees (1.10). Also it was noticed that majority of other trees (780/0) was located inside the plantation.
The data on biometric characters of rubber plants indicated that branching height was enhanced and girthing of rubber plants was found to be reduced by interplanting. In immature period upto 4th year there was no girth reduction due to proximity of other trees. In majority of cases the first round of rubber plants near the other tree became weaklings and did not attain tapping girth in later years also. Branching and canopy was not found to be influenced highly by interplanting.
Conditions favourable for phytophthora, pink and panel diseases were induced by shaded situation resulting from interplanting. The disease intensity was more aggrevated in tapped area when compared to untapped area.
Comparison made between coconut and anjili on girth of rubber plants, revealed that coconut palm with its special orientation of leaves is a more compatible combination than ever green trees like anjili. To ensure optimum growth and girthing of rubber plants, the other trees should be spaced at 14 m from the rubber plants. It was also observe that if coconut alone be the interplant the average girth of rubber plant was almost similar to the pure crop.
Interplanting was not beneficial in reducing wind damage and weed flora.
Tapping age was found to be enhanced by interplanting and that too with lesser percentage of trees attaining tapping girth. So cumulative yield and the income since the commencement of tapping was found to be high in pure planted area when compared to interplanted. In early years of tapping interplanted areas recorded higher income.
From the results it is deduced that the shade induced by interplanting adversely affects the growth and performance of rubber. From the economic point of view, yield of rubber was substantially reduced by interplanting and monoculture of rubber is more profitable and advantageous than interplanting. Disease intensity especially phytophthora, pink disease and panel diseases were aggrevated by interplanting. So the present study does not indicate the scope for further enhancing the limits of other trees permitted in rubber plantation.
Rubber is only an industrial crop and the production of food crops and timber crops are also equally important in a state like Kerala with over crowding population. Rubber plantation occupy nearly 15% of the cultivable area in Kerala. Hence this is a potential area to be utilized for companion cropping with least harm to the main crop. Considering this aspect, the other trees may be located along the road sides and boundaries at 14 m distance from rubber. Among the other trees coconut is to be prefereed which impart minimum shade by the special orientation of leaves. Due to severe deforestation timber species are being exhausted and hence these tree species can also find a place in cultivation provided adequate distance is maintained from the rubber trees.