Root morphology and development in rattans. 3. Root system development in Calamus thwaitesii Becc. and Calamus rotang L. in relation to the physical properties of a degraded lateritic soil

The suitability of any vegetation to a particular soil is greatly controlled by the establishment and proliferation of the root system in that soil, which in turn is decided by the nature and properties of the soil. As part of an attempt to introduce Calamus from natural forests to degraded lateritic soils of Kerala, this study was conducted to evaluate the root system development of two species of Calamus, viz., Calamus thwaitesii and C. rotang, grown in a degraded lateritic soil at Palappilly range in the Chalakkudy Forest Division of the State. Both species had been planted in plots of 90 m × 4.5 m size with a spacing of 1.5 m × 1.5 m. For collecting soil samples, five 3-year-old plants from each species were selected from the central row of each plot. Root parameters such as root length, rooting density, total root weight and fine root weight were determined in soil core samples collected from different depths (0-15 cm, 15-40 cm and 40-60 cm) and radial distances from the base of the plant (0 cm, 10 cm and 30 cm) at three randomly selected sampling points around a single plant. Various physical properties of these soil samples were determined using standard procedures and their relation with root parameters were determined. Results revealed that radial distance from the plant inversely affected the root growth in both the species especially within a soil depth of 0-60 cm rather than at different soil layers considered separately. Depth of soil also had an inverse relationship with root growth in both the species. Among the different soil physical properties, soil moisture and gravel were negatively correlated with all the root parameters while positive correlation was seen with sand. No definite relationship was observed with the bulk density in both the species.