A STUDY TO DETERMINE FERTILIZATION RATE AND WATER QUANTITY SUITABLE FOR GROWTH AND QUALITY OF TUBEROSE PLANTS CULTIVATED IN SOME SOIL TYPES

Abstract

A study was consummated under the full sun at Orman Botanical Garden, Giza, Egypt during 2007 and 2008 seasons to find out the response of tuberose (Polianthes tuberosa L.) plants grown in 20-cm-diameter black polyethylene bags filled with 2.5 kg sandy, loamy or calcareous soils to the different quantities of irrigation water (100, 150 and 200 ml/plant), as well as different rates of kristalon (0, 2 and 4 g/plant) and their interactions. The obtained results indicated that sprouting date (days) was not affected by kristalon treatments, but was greatly reduced with increasing water amount to reach the minimum period in plants grown in either loamy or calcareous soil and irrigated with 150 ml of water/plant, while for those grown in sandy soil, 200 ml/plant was the best. Vegetative and root growth [expressed as leaf No./plant, leaf length (cm), and fresh and dry weights (g) of the leaves and roots], flowering [as No. days from planting to first flower open, spike length (cm), rachis length (cm), No. flowers/spike, No. spikes/plant and vase life (days)], as well as bulbs productivity [No. bulblets/plant and the fresh and dry weights (g) of the replacement clump], were significantly improved in response to all individual treatments or their combinations applied in this study, with a notice that the best results in loamy and calcareous soils were obtained when the plants were irrigated with 150 ml of water/plant and fertilized with 2 g of kristalon/plant, while in the sandy soil, that was true when the plants received the highest rates of both watering and fertilization (200 ml and 4 g/plant, respectively). The superiority in all previous traits was for planting in the loamy soil, followed by planting in calcareous one, and then planting in the sandy soil that gave the least records. A similar trend was also gained with regard to leaves content of chlorophyll a, b and carotenoids (mg/g fresh weight), as well as the percentages of total carbohydrates, N, P and K. Hence, it could be recommended to fertilize tuberose plants grown in sandy soil with 4 g kristalon/plant plus irrigation with 200 ml of water/plant, while in the loamy and calcareous soils, it is preferable to fertilize with 2 g/plant and irrigate with 150 ml/plant. It is also better to cultivate in loamy soil than cultivation in either sandy or calcareous ones.