Abstract

Soil and water loss through surface run-off from a three year old teak (Tectona grandis) plantation at Nilambur and a two year old eucalypt (Eucalyptus tereticornis) plantation at Thrissur have been quantified through a 3 year study. Both the sites have humid tropical climate with intense and high energy bimodal monsoomnal rains. Loss of water through run-off depended mainly on amount of rainfall and its distribution. Run-off water loss from the teak plantation on lateric and its distribution. Run-off water loss from the teak plantation on lateritic soil with 8-12 slope was found to be 25-26 of the rainfall. It was estimated to vary from 5220 to 8310 meter cube per hectare. The corresponding loss of soil was 4-15 metric tons per hectare. Loss of nitrogen varied from 5-17 kg/ha while that of potassium, 0.4-2.3 kg per hectare. The eucalypts plantation on lateritic soil with 15-20 slope was found to lose 19-20 rain water through surface run-off; 4460-5675 m power of 3 per hectare water ran off the site which carried 31-46 metric tons of soil along with it. Nitrogen loss through sediment was found to be 30-52 kg per hectare and potassium loss 8-10 kg per hectare during the study period