2006-07 - Kerala Forest Research Institute

Kerala Forest Research InstituteAnnual report 2006-07The various intra-and inter-disciplinary projectsundertaken in different Divisions, bothcompleted and ongoing during 2006-07 aregiven below....................................................................................................................................................................................COMPLETED PROJECTSManagement of soils of teak plantationsfor sustainable productivity. KFRI ResearchReport No. 279 (Balagopalan, M. and Rugmini,P., 2006).This study was undertaken to examine thephysical and chemical properties of soils ofteak planta-tions of different site quality classesin various age groups and also to evaluate thesoil properties affecting the site quality class.Teak plantations belonging to three age groups,5-25 years, 25-45 years and more than 45 yearsand upto 60 years in Forest Divisions ofAchencoil, Konni, Ranni, Thenmala, Nilambur(North & South) and Wyanad (North & South)were selected for the study. In each of theselected plantations, plots were marked alongrandomly laid out transects running through thecentre of the plantations. Girth at breast heightof all trees in the plots was measured. Treeshaving the largest height, smallest height andthree trees in between the range were selectedfor measurement of height in each plot. Soilanalyses were carried out for particle-sizeseparates, bulk density (BD), particle density(PD), soil pH, organic carbon (OC), maximumwater holding capacity (WHC), available N, P,K, Ca and Mg and CaCO 3. Discriminantanalysis was done to identify the factors bywhich the soils under different site qualityRESEARCH PROJECTSclasses differed significantly under each agegroup.It was observed that there was no general trendwith respect to the variation in soil propertiesin relation to different site quality classes.Particle density, bulk density, available P andCa in the age group 5-25 years and CaCO 3,organic carbon, available K and silt in the agegroup 25-45 years discriminated the soils underdifferent site quality classes. In the age group>45 years, CaCO 3, available P, Ca and Mg andparticle density discriminated the soils underdifferent site quality classes. In other words, inthe age group 5-25 years, soil physical propertiesand nutrients were the discriminating factorsby which the soils belonging to various sitequality classes differed significantly. Soil texture,alkalinity, nutrient and fertility status were thediscriminating factors by which the soils underthe four site quality classes differed significantlyin the age group 25-45 years. In the age group>45 years, soil alkalinity, nutrients and physicalproperties discriminated the soils belonging tovarious site quality classes.It was also noticed that available Ca was thecommon discriminating soil variable in the agegroups 5-25 and >45 years while CaCO 3wasthe common discriminating soil variable in theage groups 25-45 and >45 years. Since calciumcontent in the soils was the discriminating factorbetween site quality classes, retaining calciumin the soil at optimum level by constantapplication is required for management ofsoils of teak plantations for sustainable productivity.11