MSc

In India, especially in Kerala State, now-a-days rubber has become a small holder crop. Owing to its long gestation period, rubber plantations are under great pressure for intercropping during the immaturity period. Multitudes of intercrops are being grown by small rubber growers without having the knowledge of how they affect the growth and development of the main crop. Their only concern is to fetch maximum income from immature rubber plantation during which period no income from rubber is possible.
Intercropping of selected intercrops is being recommended by the Rubber Board during the initial three years of planting. However, the selection of intercrops depend on agroclimatic conditions of the locality and regional preference for the intercrop. In northern parts of Kerala, usually, banana, ginger and tapioca are preferred.
The present study was intended to elucidate the pattern and economics of intercropping in immature rubber plantations in Trichur taluk. The investigations also envisaged the assessment of the effect of different intercrops on the growth of rubber based on which the best economically viable intercrop could be selected.
For the study, 75 sample holdings intercropped with banana (Nendran and Poovan), tapioca or ginger and 25 sample holdings without any intercrop were selected and the relevant data collected by personal interview using a pre-tested questionnaire during January-June 1993. The salient results emanated from the study are summarized here under:
All the units surveyed were planted with the clone RRII 105 and except in one case the planting material used was polybag plants.
Cover cropping was adopted to the tune of 47 per cent mainly with Peuraria phaseoloides.
More than 50 per cent of the intercropped area was cofined to the class 0.21 to 0.50 hectare.
Out of the gross intercropped area, 57 per cent was accounted by banana var. Poovan followed by Nendran (23%), ginger (13%) and tapioca (7%).
With regard to yearwise intensity of intercropping, 75 per cent of the farmers have done intercropping during first year, which was reduced to 20 per cent during second year and 5 per cent during third year.
Tapioca intercropping was found to be limited to first year of planting rubber.
Nendran banana was found to be the most profitable intercrop with a BCR of 1.63 followed by Poovan (1.47) and ginger (1.24). The lowest BCR (1.17) was recorded in the case of tapioca intercropping.
The growth of immature rubber in terms of girth was found to be favourably influenced by intercropping banana and ginger.
Tapioca intercropping in general adversely affected the girthing of rubber.
Intercropping resulted in increased height of rubber.
First branching of rubber plants occurred at higher level (2.61 m) in the case of plots with no intercrops.
Lowest branching height (2.38 m) was observed in the case of Nendran intercropped plots.
Considering the higher benefit cost ratio and the favourable effect on the growth of rubber, banana variety Nendran can be recommended as the best suited intercrop in the young rubber plantations in Trichur taluk. Next to Nendran, Poovan and ginger can also be recommended. However, the present practice of tapioca intercropping may be discouraged because of its adverse effect on growth of young rubber.