Organic manuring: its effect on rice yield and soil properties in tidal flooded ecosystem of Bangladesh

Abstract

Field experiment was conducted in coastal soil (Barisal silt) of Bangladesh during July 2007 to May 2009 for determining the effect of organic manuring on soil organic matter and rice yield under tidal flooded ecosystem.Two rice crops of T. Aman (wet season; July - November) and Boro (dry season; December - May) were grown in the experimental fields in each year. Six treatments consisting of poultry liter application (2.0 t ha^-1) before Boro crop (T₁), Sesbania incorporation before T. Aman (T₂), Lathyrus sativas (L) incorporation after T. Aman (T₃), red clover (Melilotus alba, L.) incorporation before T. Aman (T₄), Chemical fertilizers (T₅ = 84-14- 48- 8 kg N, P, K & S ha^-1) and absolute control (T₆) were compared in randomized complete block design. Each treatment was replicated for three times. Test rice varieties in T. Aman and Boro season were BRRI dhan44 and BRRI dhan29, respectively.The first T. Aman crop was damaged due to SIDR before harvest. The second T. Aman crop gave 3.96 to 4.39 t ha^-1 grain yield across the treatments and their treatment effect was not significant (P > 0.05). Boro crop in both the years showed consistently significant response to fertilizer and manure application. Means of two years results show that the absolute control plot yielded 3.66 t ha^-1, which increased to 6.09 t ha^-1 receiving chemical fertilizer alone (T₅). Application of organic residues increased rice yield compared with chemical fertilizer alone. The highest yield at the value of 6.71 t ha^-1 was obtained with T₁ followed by 6.56 t ha^-1 in T₃. After two years, soil analysis showed an insignificant increase in soil organic matter (SOM) due to the application of organic residues. However,long-term application of organic residues is expected to increase SOM in tidal flooded soil and which may contribute to soil health as well as rice yields.