Increasing irrigation efficiency in rice paddies using Azolla compost under water deficit conditions

A pot experiment was conducted to determine the effect of composted Azolla on reducing soil moisture stress in water deficit condition and on growth and yield of rice in Rice Research Institute of Iran (RRII) in 2011. The experiment was in a factorial experiment in a randomized complete block design (RCBD) whis 8 irrigation regimes (A1, A2… and A8) as the first factor and use of different values of composted Azolla as second factor in 4 levels (B1= control, without compost, B2 = 2.5 %, B3 = 5% and B4 = 7.5% by weight of soil in pot), which was conducted in three replicates. The results showed significant effect by different irrigation regimes on panicle length, plant height, number of tillers and grain yield and also on nitrogen and phosphorus and potassium uptake in paddy and rice straw, but had no significant effect on the other properties. The effect of composted Azolla had significant effect on panicle length, panicle weight and grain yield, and on salinity, pH, organic matter, nitrogen, phosphorus and potassium of the. The overall results of the project showed that treatment A2B4 (irrigation as soil saturation during the growing season with 2.5 % of Azolla compost) is one of the best treatment. Use of this management, especially in water deficit condition can increase water use efficiency by 19.37 percent and soil fertility too. Use of compost can be a good alternative instate of chemical fertilizers in Long-term rice cultivation, environmental health and sustainable agriculture.