Effect of Calcium Silicate On the Productivity and Silicon Accumulation in the Sugarcane Plant.

Title : Effect of Calcium Silicate on the Productivity and Silicon Accumulation in the Sugarcane Plant S.M. Bokhtiar1*, Yang-Rui Li2 and M .D. Abul Kashem3 1Senior Scientific Officer, Soils and Nutrition Division, Bangladesh Sugarcane Research Institute, Ishurdi 6620, Pabna, Bangladesh 2President, Guangxi Academy of Agricultural Sciences, Nanning 530007, Guangxi, P.R. China 3Director, Project implementation Unit, Bangladesh Agricultural Research Council, Farngate, New Air port Road, Dhaka 1215, Bangladesh Abstract The current study has highlighted the effect of silicon (Si) applied as calcium silicate (Ca-silicate) fertilizer (14% Si) on the productivity and Si accumulation in the sugarcane plant. The major objectives of this study were to quantify responses in growth parameters (dry matter accumulation, cane and sugar yields), leaf nutrient concentrations and soil properties as well. To address these objectives, two experiments were conducted in pot culture under greenhouse conditions using two different types of soil. The two different soils were selected considering pH and nutrient status and designated as soil-1 and soil-2. These trials included, (T0) traditional fertilizer (12 g N + 1.76 g P +10 g K per pot) and six levels of Ca-silicate (T1 - T6 : 20 g, 40 g, 60 g, 80 g, 120 g and 150 g per pot, respectively) in addition to the traditional fertilizer. The experiments were laid out in completely randomized design with three replications. In our 12 months study, we found that the Si content reached up to 2.64% and 1.86 % in dry mass of top visible dewlap leaf tissues when amended with Ca-silicate fertilizer in soil-1 and soil-2, respectively. At soil-1, 66% increase in cane yield was recorded with 60 g/pot ca-silicate i.e. 12 t/ha when compared to the non-amended control (T0). At soil-2, 120 g/pot Ca-silicate i.e. 24 t/ha gave 15% yield increase when compared with the control. Results indicated that with increasing silicate application; iron (Fe), copper (Cu), zinc (Zn) and manganese (Mn) contents significantly decreased in leaf tissues and in both soils. Soil pH, Si, available sulfur (S), exchangeable calcium (Ca), magnesium (Mg), and cation exchange capacity (CEC) were increased significantly whereas aluminum (Al) contents of soil decreased dramatically in both soils when amended with Ca-silicate fertilizers. Nevertheless, the scanning electron microscopy (SEM) with energy dispersive x-ray analysis (EDAX) revealed that different rates of Ca-silicate responded differently in accumulation of Si and other elements in epidermal cells, silica cells and stomata. Our results suggested that application of Ca-silicate fertilizer at a rate of 8-12 t/ha is suitable in achieving higher cane yield for the studied areas. Moreover, a total of 29 samples were collected from three cities (Laibin, Liuzhou and Hechi) of six counties (Luocheng, Yizhou, Rongshui, Rong’an, Xincheng and Huanjiang) in Guangxi Province from sugarcane growing soils for investigation. The soil survey studies have clearly demonstrated that most of the studied sugarcane soils are with low fertility status. Nearly 58% soils for organic matter, 41% for N, 82% for P, 62% for K, 66% for S, 86% for Mg, 62% for Zn, 89% for boron (B) and 76% for Si had below critical level. Nevertheless, about 51% of sugarcane field had low pH 5.5. Such type of soil health is alarming for sustaining sugarcane yield in near future. Considering the results, it is suggested that Si may be treated as an integral part of any fertilizer strategy associated with cane production for ensuring higher yields without degradation in soil fertility. The findings indicated that different soil fertility status and rates of Ca-silicate application are important factors influencing the yield and nutrient contents of sugarcane leaf as well as soil properties. More studies are necessary under field conditions with different types of soil to corroborate the present findings. Keywords: Leaf nutrient, Soil fertility, Chlorophyll, Gas exchange characteristics, Scanning electron microscope, Energy dispersive X-ray analysis