STUDY OF SOILS IN NON-CONVENTIONAL AREAS OF RUBBER CULTIVATION IN KERALA AND THEIR EFFECT ON GROWTH AND YIELD OF HEVEABRASILIENSIS

摘要

Rubber (Hevea brasiliensis) is being cultivated in non-conventional areas viz.,upland paddy fields,lowlands and coastal sand belts within the traditional region of Kerala,India.These areas differ in soil characteristics and production potential among themselves as well as from the traditional rubber growing slope lands.Present study examines the difference in soil characteristics and yield of rubber plantations raised in these land forms and their relationships besides leaf nutrient content.The texture of soil of upland paddy fields varied from sandy loam to clay while low land soils were sandy clay loam to clay loam.Coastal sandy soils contained higher amount of sand throughout the profile.Moisture content at field capacity (FC),permanent wilting point (PWP) and available water content showed wider variations between land forms.The silt and clay had a significant positive influence on FC and PWP.The study showed that the performance of rubber in upland paddy fields and low lying areas is appreciable with respect to growth (gestation period) and yield.With appropriate agromanagement practices,good growth of rubber was observed in sandy soils also,though conventionally sandy soils are considered unsuitable.Significant difference between group variability in mean yield was observed indicating the difference in production potentials of land forms studied.