Abstract:

A potting culture experiment with optimal hybrid regression design (311-A) was carried out to study the growth response of cloned teak (Tectona grandis) seedlings to calcium (0-1.2 g·kg^-1),boron (0-0.8 mg·kg^-1) and nitrogen (0-1.2 g·kg^-1) supply in acidic lateritic red soil.Extremely significant differences were found in growth of seedling height,root collar diameter,and oven-dry weights of leaves，stems and roots between 11 treatments.Ca,a major nutrient element,was identified to be a limiting factor for teak seedling growth in acidic lateritic red soil.B had no remarkable impact on seedling growth and no interaction with Ca,whereas,there was interaction between N and Ca.The seedling height,root collar diameter and total dry mass were evidently restrained by addition of N when no or little Ca was applied.To manage teak in strongly acidic lateritic red soil,it is necessary to apply enough Ca and less N.The optimal nutrient rate in pots was Ca 1.2 g·kg^-1,B 0.4 mg·kg^-1 and N 0.3 g·kg^-1,equivalent to CaO of 1.68 g·kg^-1,H₃BO₃ of 2.3 mg·kg^-1,and (NH₂)₂CO of 0.65 g·kg^-1.

Key words: Tectona grandis clone, acidic lateritic red soil, calcium, boron, nitrogen, eedling growth