Abstract

A project was undertaken to study the effect of different nutrients N, P, K, Ca and Mg on the growth of teak plantations belonging to different rotations. Study sites were selected in one and two year old third rotation plantations at Aravallikkavu and Valluvasseri in Nilambur Range of Nilambur North Forest Division and 11 year old first and second rotation teak plantations, the former at Pathiri in Chedleth Range of South Waynad Forest Division and the latter at Nellikkutha in Vazhikkadavu Range ofNilambur North Forest Division. In each site, experimental plots of five hectares were laid out and 15 soil pits, three from each ha, were taken and soil samples were collected. The samples from each layer of the three pits were then pooled into one composite soil sample, resulting in five composite soil pits from each site. The soils were loam except in the Aravallikkavu plantations where the texture was sandy loam in the surface and 20-40 cm layers and loamy sand in the 40-60 cm layer. The soils were medium acid in all the layers in the Pathiri, Aravallikavu and Valluvasseri plantations. they were slightly acid in the surface and medium acid in lower layers in the Nellikkutha plantations. The site in the Aravallikavu plantation was highly deteriorated and it was possible to see hard laterites in the surface in certain pockets. Nutrients, N, P, K, Ca and Mg, each 0, 15, 30 and 45 g/tree were added through commercial fertilisers. The fertilisers added were Urea for N, Mussorie rock phosphate for P, Muriate of potash for K, Quick lime for Ca and Magnesium sulphate for Mg. There were 64 nutreint treatments confounding all three and higher order interactions. These nutrient treatment were laid out in randomised complete block design, which were replicated three times in the one year old plantation at Aravallikkavu, one and two year old plantation at Valluvasseri and elevan year old plantation at Pathiri whereas they were replicated two times in the two year old (1990) plantation at Aravallikkavu and 11year old plantation at Nellikkutha. The study revealed that there was significant difference in increment in height of trees in younger plantations while increment in height, basal area and volume of trees in older plantations showed non significance dueto nutrient treatments. Among the different treatments, comparison among means test showed that N2P2K2Ca2Mg2 treatment was found to be the best in younger plantations. The nutrients have to be added in split doses in the first year during south-west and north-east monsoon periods and double the above amount in split doses in the second and third years during the two monsoon periods. The nonsignificant effect on increment in height in one younger plantation in the thrid rotation showed that site evaluation and detailed soil analyses have to be carried out before nutrient recommendation. In other words, nutrient dose is site specific