Effects of Nutrient Deficiencies on the Root Regenerating Potential and Growth of Pinus caribaea and Pinus kesiya Seedlings

Successful plantation establishment requires the production of seedlings with high root regenerating potential (RRP) to beplanted in an enviroment which facilitates the production of new roots. Numerous factors in the nursery and in thefield influence RRP. This study examines the effects of a deficiency of two important essential elements, nitrogen and orphosphorus commonly deficient in tropical soils, on the RRP and growth of Pinus caribaea and Pinus kesiya seedlings. Given an adequate supply ofnutrients before transplanting in nutrient deficient sites, P. caribaea and P. kesiya showed a high capacity to regenerate root following root pruning and replanting into conditions oflimited nutrient supply (-N, -P& -NP). Seedlings grown inF (full nutrients) and -P conditions were taller and had thicker stem diameter than in -N or -NP. The results also show that P. kesiya had a higher RRP than P. caribaea despite the shorter mean height of the former species at the start ofthe experiment. The practical implication of the results to nursery cultural practices and tree establishment is discussed

Effects of Paclobutrazol and Daminozide on the Growth of Acacia mangium Seedlings

Low concentrations of paclobutrazol and daminozide at 0, 5, 10 and 15 mgt] were foliar sprayed on 12 week old A. mangium seedlings at three different frequencies of application i.e. 1 (week 0), 2 (week 0 & 4) and 3 (week 0, 4 & 6). Either chemical was effective in controlling growth but paclobutrazol was more potent than daminozide. A low concentration of 5 mgt] paclobutrazol at 1 application was sufficient to cause a significant reduction in height growth compared to daminozide which required a minimum concentration of 10 mgt] with 2 applications. In general, the main effects of the chemicals increased with increasing concentration and frequency of spray

Potential of paclobutrazol for controlling excessive growth of acacia mangium and storing recalcitrant dipterocarp seedlings for forest rehabilitation

Acacia mangium seedlings often overgrow in size when the timing between plant production and field planting cannot be synchronized. Dipterocarp seeds, on the other hand, are short-lived and when available need to be sown immediately for the production of planting stocks. Since conventional storage methods have not been proven to be successful in maintaining the viability of these seeds, storing their seedlings at a slow growth phase with paclobutrazol and applying gibberellic acid to induce growth recovery when needed for field planting is an attractive option. This paper reports the results of various experiments on the use of paclobutrazol and gibberellic acid for A. mangium, Shorea leprosula and S. parvifolia seedlings. The results are discussed with implications for practical application

Growth Response of Teak (Tectona grandis L.f.) Seedlings to Nitrogen, Phosphorus and Potassium Fertilizers

Teak (fectona grandis L.f) is one of the high quality timber species in the world. A greenhouse experiment was conducted to determine the growth response of teak seedlings to N, P, K fertilizers. The results of the present study indicated that root weight, leaf area and total plant weight of the teak seedlings were significantly affected by all the three main factors i.e. N, P and K Height increment, leaf weight, shoot weight and root length showed statistically significant responses to N and P fertilizers. The main effects of N and K but not of P were statistically significant for diameter increment. There was significant main effect of N only far root-shoot ratio. The present study also revealed that the application of 564 kg/ha ammonium sulphate, 300 kg/ha triple superphosphate and 75 kg/ha muriate ofpotash are required to enhance height and diameter growth and total plant weight of teak seedlings at nursery stage

Fertilizer Requirements of Newly Planted Teak (Tectona grandis L.f.) Seedlings

The results of the present study indicated that height and diameter increments of newly planted teak seedlings were significantly affected by N and P fertilizers. Leaf weight, shoot weight, root weight and total dry matter production showed statistically significant responses to fertilizer application at harvest, one year after planting. Root-shoot ratio decreased as a result of fertilizer application. The present study also revealed that the application of 300 kg/ha triple superphosphate and 200 kg/ha ammonium sulphate are required to enhance the height and diameter growth and total plant weight of newly planted teak seedlings on Penambang soil series

Proceedings of a Regional Symposium on Recent Developments in Tree Plantations of Humid / Subhumid Tropics of Asia

Meeting: Regional Symposium on Recent Developments in Tree Plantations of Humid / Subhumid Tropics of Asia, 5-9 June, 1989, Serdang, M