Md Maniruzzaman
Department of Agricultural Chemistry, Faculty of Agriculture, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh.
Md Akhter Hossain Chowdhury
Department of Agricultural Chemistry, Faculty of Agriculture, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh.
KM Mohiuddin
Department of Agricultural Chemistry, Faculty of Agriculture, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh.
Tanzin Chowdhury
Department of Agronomy, Faculty of Agriculture, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh.
Stevia, N requirement, Leaf biomass Yield, Critical N
Department of Agricultural Chemistry, Bangladesh Agricultural University, Mymensingh.
Crop-Soil-Water Management
A pot experiment was conducted at the net house of the Department of Agricultural Chemistry, Bangladesh Agricultural University, Mymensingh during March to July, 2012 to examine the effects of different levels of N on the growth, leaf yield, N content and its uptake, determine N requirement and critical leaf N concentration of stevia. Two soils viz. acid and non - calcareous of contrasting physical and chemical properties were used. Approximately 40 kg soils from each location ( Madhupur for acid soil and BAU farm for non - calcareous soil ) were collected from 0 - 15 cm depth of selected fellow land for the experiment. The samples were made free from plant residues and other extraneous materials, air dried, ground and sieved through a 2mm sieve. 500g sieved soil from each source was preserved in a polythene bag and the physical and chemical properties were determined following standard procedure. Eight kg processed soil was taken in each earthen pot of 23 cm in height with 30 cm diameter at top and 18 cm at bottom leaving 3 cm from the top. In vitro produced 45 day old stevia seedlings ( Stevia rebaudiana Bertoni) were collected from brac biotechnology laboratory, Joydebpur, Gazipur and used for the experiment. One stevia seedling was planted in each pot during 1st week of March, 2012. P, K, S, Zn and B were applied as basal doses @ 100, 200, 30, 3 and 1 kg ha-1 from TSP, MoP, gypsum, zinc sulphate and boric acid, respectively. Six levels of N viz. 0, 100, 150, 200, 250, and 300 kg ha-1 were applied from prilled urea, 1/3rd during pot preparation, 1/3rd at 15 days after planting (DAP) and 1/3rd at 30 DAP. The experiment was laid out in completely randomized design with three replications. Total number of pots was 36 (6 treatment X 2 soil X 3 replication). Intercultural operations like irrigation, soil loosening, weeding, insect pest control, removal of flowers etc. were done as and when necessary. Data were collected at 1 5, 30, 45 and 60 DAP. The crop was destructively harvested at 60 DAP. After harvesting the crop, leaf samples were separated, cleaned, dried at 60 ºC for 72 hours, weighed, ground and stored. Plant height, branches plant-1, leaves plant-1, leaf area plant-1, fresh and dry leaf weight of stevia leaves were studied. N content was determined by micro Kjeldahl method. Uptake was calculated from N content and leaf dry yield. N requirement and critical N concentration was also estimated. The results obtained were subjected to statistical analysis using standard method of analysis. The differences among the treatment means were compared by using Duncan Multiple Range test (Gomez and Gomez, 1984).
Res. Agric., Livest. Fish.3(1): 87-97, April 2016, ISSN: 2409-0603
Journal