The study was conducted using a salt-tolerant rice variety, BR-47 in the net house of the University of Dhaka during April to July, 2011. The soil used in the experiment was collected from Amtoli thana in Barguna district which was located between 20.15080 N latitude and 90.12640 E longitude. The soil was silty clay loam affected by various degrees of salinity, ECe 3.36 dsm-1, pH 5.35, Turbidity 940 mg kg-1, Organic Carbon 1.53%, total N 0.082%, available ammonium N 14.55 mg kg-1, available nitrate N 33.95 mg kg-1, water soluble phosphorus in not detectable range,available K 23 mg kg-1, available sulfur 435 mg kg-1, available Cl 17980 mg kg-1, available Fe 78.5 mg kg-1; available Mn 23.25 mg kg-1; available Zn 4.27 mg kg-1, carbonate 0.1 C mol kg-1, water soluble ions viz. Na 75 mg kg-1, K 19 mg kg-1, Ca 30.5 mg kg-1, Mg 28 mg kg-1, exchangeable cations viz. Ca 346 mg kg-1, Mg 300 mg kg-1, Na 851 mg kg-1, K 201 mg kg-1, SAR 8.01 and ESP 24.65%. Six kilograms of air dried, ground and 5 mm sieved composite soil was filled in each earthen pots (size: 8L). Four seedlings/hill and three hills in each pot in a triangular grid were transplanted. The experiments were conducted following 3 doses of gypsum, 3 doses of rice hull 3 doses of saw dust in a non factorial completely randomized block design with two sampling time and two replications. So in total 1 x 9 x 2 x 2=36 pots were used for the experiments.
Basal dose of N, P2O5 and K2O were applied at the rate of 50 kg ha-1, 40 kg ha-1 and 50 kg ha-1 from Urea, TSP and MP fertilizers, respectively and were mixed with the soil of each pot. The whole TSP, MP and half of the Urea were applied during pot preparation by thorough mixing of the fertilizers with soil. Then the soil in each pot was puddled by hand using almost same amount of tap water per pot and then kept submerged for 3 days. After submergence, fertilizers were mixed thoroughly with soil and again submerged for 2 days. Plant height and number of tillers were recorded at 20 DT (Early Tillering Stage, ETS: 10-25 DT), 40 DT (Maximum Tillering Stage, MTS: 26-55 DT), and 100 DT (Maturity Stage, Mat.: 85-110 DT).The plants were harvested at 1 cm above the soil surface and the plant height, number of tillers, grain and straw yield, nutrient content of plant, and yield components viz. grain to straw ratio, 1000 grain weight of rice, protein content and harvest index were recorded. Total N, P, S & K contents in rice plant were determined. Nutrient uptake was determined from total nutrient content and plant dry matter weight. Statistical analyses such as Analysis of Variance (ANOVA), Duncan’s Multiple Range Test (DMRT) and Least Significant Difference (LSD) of the experimental results were done for interpretation.