Use of neutron moisture meter in soil-plant-water relation studies of rubber(Hevea brasiliensis)

Volumetric moisture content data obtained from 12 positions in relation to planting points over a period of 12 months indicate that the distance varying from 0-120cm from the trunk of young rubber tree are suitable for assessing the water content of the soil profile. Feeder root density was significantly different at different depths with the highest percentage of roots being in the surface soil layers, 0-10cm and 10-20cm, in the region of 120 cm circle. These findings were further confirmed by the co-efficient of variation of volumetric moisture content data obtained at different depths in relation to planting points. Therefore, it is evident that a clear relationship exists between the rooting density of rubber and the moisture readings. Based on the soil moisture data under different management practices, it is possible to overcome the adverse effects of soil moisture deficit by growing appropriate rubber clones, with the use of mulch preferably paddy straw and high levels of potassium, during the immature period of rubber plants