Beneficial Effects of Silicon Fertilizer on Growth and Physiological Responses in Oil Palm

Vigorous and well-established nursery seedlings are an important component of sustainable oil palm production. We postulated that Si fertilization at the seedling stage could help to achieve improved performance of oil palm seedlings leading to healthy and vigorous nursery establishment. In this study, we evaluated the growth and physiological responses of oil palm Tenera hybrid seedlings under three Si fertilization treatments and a control including (i) 0 g Ca2SiO4 (T0), (ii) 0.5 g Ca2SiO4 (T1), (iii) 3.5 g Ca2SiO4 (T2), and (iv) 7.0 g Ca2SiO4 (T3) per plant per month. Ca2SiO4 was used as the Si fertilizer source and was applied for four consecutive months. Nondestructive data including stem diameter, plant height, leaf length, photosynthetic rate, leaf angle, and leaf thickness and destructive data including leaf, stem, and root fresh weight and dry weight, as well as chlorophyll a, Si, and nitrogen contents, were recorded before treatment (0 DAT), as well as 60 (60 DAT) and 120 days after treatment (120 DAT). Results indicated that Si fertilization enhanced Si accumulation in oil palm seedlings, and maximum accumulation was observed in the aerial parts especially the leaves with the highest accumulation of 0.89% dry weight at T3. Higher Si accumulation stimulated the growth of seedlings; a total fresh weight of 834.28 g and a total dry weight of 194.34 g were observed at T3. Chlorophyll a content (0.83 gm(-2)) and net photosynthetic rate (4.98 mu M CO2.m(-2).s(-1)) were also observed at T3. Leaf morphology was not significantly influenced under Si fertilization, whereas the nitrogen content of seedlings was significantly increased. Correlation analysis revealed a highly significant and positive association among Si accumulation, chlorophyll a content, photosynthetic rate, total fresh weight, total dry weight, and nitrogen content of seedlings, indicating that Si fertilization enhanced the performance of these attributes. On the basis of the research evidence, it was concluded that Si fertilization should be considered for improved nutrient management for oil palm seedling and nursery production.