Comparison of integrated chemical and organic fertilizer management on rice growth and yield under system of rice intensification (SRI)

A field experiment was conducted during the 2011 growing season at Caspian sea costal area using local high quality variety (Tarom) with 9 treatments consist of different combinations of organic fertilizer and Azola-compost with urea fertilizer using system of rice intensification(SRI). SRI principles were implemented in the all plots. During the growth phase at tillering, Panicle initiation and flowering stages, the average SPAD value, plant height and stem number were measured for the nine sets of nutrition methods. At maturity, the final plant height, yield and yield components were assessed. The results indicated more tiller number (28%), more chlorophyll content at panicle initiation stage (28%) and flowering time (13.5%), more panicle/m2 (60%), number of filled grains/m2(20.6%), spikelet per panicle (19.6%) and more grain yield (30.6%) with combined use of organic and chemical fertilizer compared with chemical fertilizer alone. Interestingly, grain yield of Azola compost alone a little bit was higher than chemical fertilizer alone and there was no significant difference between chemical fertilizer and organic fertilizer alone. However, highest yield with 4772.4 kg ha-1 was belong to combination of organic fertilizer BIOL555 (1 ton ha-1) + Urea application 50 kg ha-1 (25% as basal and 25% at PI).