The experiment was carried out at the Soil Science Field Laboratory, Bangladesh Agricultural University, Mymensingh during July to December, 2010 to evaluate the effects of organic and inorganic fertilizers on the growth and yield of a rice variety Binadhan-7. The soil belonged to Sonatala series under the AEZ-9 (Old Brahmaputra Floodplain). The soil was silt loam in texture having pH 6.18, organic matter content 2.15%, total N 0.124%, available P 6.51 ppm, exchangeable K 0.074 me%, available S 14.85 ppm and CEC 12.5 me%. There were altogether seven treatment combinations consisting of NPKS fertilizers applied as urea, triple superphosphate (TSP), muriate of potash (MoP) and gypsum, respectively in association with three sources of manure such as cowdung, poultry manure and compost. The rate of cowdung (CD), poultry manure (PM) and compost (Com) used was 5, 3, and 5 t ha-1, respectively. The inorganic fertilizers were applied following the Fertilizer Recommendation Guide (BARC, 2005). The treatments include T0 (control), T1 (100%RFD), T2 (75%RFD + CD 5 tha-1), T3 (75%RFD + PM 3 t ha-1), T4 (75%RFD + Com 5 t ha-1), T5 (75%RFD + CD 2.5 t ha-1 + PM 1.5 t ha-1 + Com 2.5 t ha-1) and T6 (50%RFD + CD 2.5 t ha-1 + PM 1.5 t ha-1 + Com 2.5 t ha-1) . The RFD indicates recommended fertilizer dose.The experiment was laid out in RCBD with three replications. The total number of unit plots was 21 and the size of unit plot was 5 m × 4 m. Total amount of P, K and S fertilizers was applied as basal during final land preparation and urea was applied in 3 equal splits. Rotten cowdung, decomposed poultry manure and compost were applied 7 days before transplanting. Twenty-five days old seedlings were transplanted in the experimental plots maintaining three seedlings per hill and 20 cm × 20 cm plant spacing. Usual intercultural operations like weeding, watering, etc. were done as and when required. At maturity, the crop was harvested and the data on plant height, panicle length, effective tillers hill-1, field grains panicle-1 and 1000-grain weight were recorded. Grain yield was recorded at 14% moisture basis and straw yield at sun dry basis. The grain and straw samples were analyzed for N, P, K and S contents following standard methods. The nutrient uptake as well as nutrient use efficiency were calculated with the following equations:
Nutrient uptake = [Nutrient content (%) x Yield (kg/ha)] x 100
Nutrient use efficiency (NUE): = (Gy+N – Gy0N) / FN
Where, Gy+N = grain yield in treatment with particular nutrient application
Gy0N = grain yield in treatment without that particular nutrient application
FN = amount of fertilizer nutrient applied (kg/ha).
Initial and post-harvest soil samples were analyzed for physical and chemical properties following standard methods. Organic matter was determined by Walkley and Black method, soil pH (1:2.5 soil-water) by glass electrode pH meter method, total N by Semi-micro Kjeldahl method, available P by Olsen method, exchangeable K by Flame Photometer after extraction with 1N NH4OAc at pH 7.0, available S by extracting soil samples with CaCl2, solution (0.15%) and by measuring turbidity by Spectrophotometer method and CEC by Sodium saturation method. All the data were statistically analyzed by F-test and the mean differences were adjudged by DMRT.