Mohammad Abdus Sattar
Soil Science Division, Bangladesh Institute of Nuclear Agriculture, Mymensingh 2200, Bangladesh
Mohammad Fazlar Rahman
Soil Science Division, Bangladesh Institute of Nuclear Agriculture, Mymensingh 2200, Bangladesh
Dipak Kumar Das
Soil Science Division, Bangladesh Institute of Nuclear Agriculture, Mymensingh 2200, Bangladesh
Abu T.M.A. Choudhury
SUNFix Centre for Nitrogen Fixation, Faculty of Agriculture, Food and Natural Resources, University of Sydney, NSW 2006, Australia
Azotobacter, Azospirillum and cyanobacteria, Nitrogen for rice production, Bangladesh
Agronomy Experimental Farm of Bangladesh Agricultural University, Mymensingh, Bangladesh
Crop-Soil-Water Management
Fertilizer and manures, Rice
Experiment with Azospirillum and Azotobacter on boro rice Site and soil The experiment was conducted at the Agronomy Experimental Farm of Bangladesh Agricultural University, Mymensingh, Bangladesh (with soil of the Sonatala series under the agroecological zone of Old Brahmaputra Floodplain) at a mean elevation of 18.0 m above sea level. The initial soil was, texturally, a silty loam with pH 6.8, organic matter 1.42%, total N 0.13%, available phosphorus (P) 23.48 mg/kg and cation exchange capacity (CEC) 7.5 cmol/kg. Analysis of the soil was conducted following standard procedures (Black 1965). Basal doses of triple superphosphate (26 kg P/ha), muriate of potash (60 kg K/ha), gypsum (13 kg S/ha) and zinc sulfate (3.58 kg Zn/ha) were applied during final land preparation 1 day before transplanting rice seedlings. Inoculants and inoculation procedure There were four inoculation treatments— uninoculated, Azotobacter, Azospirillum and a mixed culture of Azotobacter and Azospirillum. The Azospirillum and Azotobacter cultures, obtained from the Soil Microbiology Laboratory of the Bangladesh Institute of Nuclear Agriculture (BINA), were grown in Okon’s broth and Jensen’s broth, respectively, for 5 days under aerated conditions. The mixed culture was prepared by mixing equal quantities of each of the culture broths with a concentration of 109 cells/mL. Roots of 43-day-old seedlings were dipped in respective culture solutions (10 mL of the inoculant broth with 1 L of sterilised water) for 1 hour before transplanting. N levels The response of the rice (variety BRRI dhan29, a high-yielding variety developed by BRRI) to inoculation was examined against five levels of N (0, 60, 80, 100 and 120 kg N/ha) applied as urea in three splits (at 15, 45 and 55 days after transplanting). Experimental design The experiment was laid out in a split-plot design with four replications, assigning N levels in the main plots and inoculations in the subplots at random. The size of each subplot was 5 m × 4 m. Data collection and analysis Data on grain and straw yields were recorded at maturity. Grain yield was adjusted at 14% moisture content while straw yield was recorded on an ovendry basis. Chemical analysis for N in grain and straw was conducted using the micro-Kjeldahl procedure (Yoshida et al. 1976). The analysis of variance for different parameters was done following the computer package MSTAT. Mean differences among the treatments, in the case of significant F values, were compared using Duncan’s multiple range test (DMRT) as mentioned by Gomez and Gomez (1984). Experiment with cyanobacteria on transplanted aman rice Site and soil The experiment was conducted at the Soil Science Experimental Farm of BINA, Mymensingh, Bangladesh (with soil of the Sonatala series under the agroecological zone of Old Brahmaputra Floodplain). The initial soil was a silty loam in texture with organic matter 1.71%, pH 6.5, total N 0.11%, available P 20 mg/kg and CEC 7.5 cmol/kg. Analysis of the soil was conducted following standard procedures (Black 1965). Basal doses of P (18 kg P/ha) as triple superphosphate and K (15 kg K/ha) as muriate of potash were applied during final land preparation. Inoculants and application procedure There were five inoculation treatments—uninoculated, BGA local 1, BGA local 2, BGA exotic and a mixed culture of all the BGA inoculants. Two locally isolated strains of cyanobacteria (Anabaena sp.), designated as BGA local 1 and BGA local 2 and obtained from BINA, Bangladesh; and one exotic strain of Nostoc sp. obtained from the Microbiology Division of the Indian Agricultural Research Institute, New Delhi, India, were grown separately in Fog’s N-free medium, followed by preparation of a straw-based BGA biofertiliser. The mixed culture inoculant was prepared by mixing equal quantities of all the BGA inoculants. The inoculants were applied at 1 kg/ha 10 days after transplanting the rice seedlings. N levels The response of a low-input rice (variety Binashail developed by BINA through an irradiation technique) to inoculants was investigated against four levels of N (0, 20, 30 and 40 kg N/ha) as urea. Urea was applied in two equal splits at 15 and 35 days after transplanting. Experimental design The design of the experiment was split-plot, assigning N levels in the main plots and inoculation treatments in the subplots with three replications. The unit subplot size was 3.5 m × 4 m. Data collection and chemical analysis of samples Grain and straw yields were recorded at maturity. Grain yield was adjusted at 14% moisture content while straw yield was recorded on an oven-dry basis. Nitrogen contents of the grain samples were analysed following the same procedure used for the experiment on boro rice above. All data were analysed statistically and the means were compared by DMRT as above.
Efficient nutrient use in rice production in Vietnam achieved using inoculant biofertilisers, ACIAR Proceedings 130
Report/Proceedings