Effect of planting density on the growth of rubber in the Vellanikkara estate

Abstract

The present observations on the influence of different planting densities on the performance of two clones namely RRII 105 and RRII 118 are in conformity with the results of other field experiments reported earlier. In lower planting densities, trees produced good girth, high yield per tree, thick virgin bark and high rubber content. Whereas, high planting densities contributed to poor tree girth, high yield per tree, thick virgin bark and high rubber content. Whereas , high planting densities contributed to poor tree girth, thin virgin bark and lower yield per tree. However, planting density is dependent on various other factors viz. topography of the land, system of planting to be adopted, the planting materials, cost of labour and price of rubber. Anyway, a comprise between labour cost and rubber price is needed. As far as small holders are concerned, a higher stand per hectare is preferred, since the question of labour does not arise. Therefore, for small holding sector a higher stand is recommended in order to get high per hectare yield. But there should be an optimum stand. In Malaysia, for small holders having available family labour, a planting density of approximately 740 trees per hectare is recommended. However, indepth studies are required for a meaningful recommendation in our country.

Salient results The trees were taller in high density planting

The trees were more vigorous in low density planting. The highest mean girth of 64.7 cm was recorded by RRII 118 at a population density of 420 plants/ha.The percentage of weaklings increased with increase in population.The highest weakling percentage of 35.8 was recorded by the planting density of 824 plants per hectare.

Poor bark growth in high density planting

Per tree yield was more for low density planting whereas per hectare yield was less. With regard to high density planting , per tree yield was less and per hectare yield was more.

Dry rubber content (drc) was more in low density planting. The highest percentage of 44.5 was recorded by RRII 118 at a planting density of 420 plants/ha.

Light penetration was more in low density planting. The maximum light penetration recorded was 110.0 micromole/sec/m2 at a density of 420 plants per hectare.