Influence of Blue-green Algae and Nitrogen Fertilizer on Rice Yield in Saline Soils

Abstract

               A pot experiment was conducted to determine the effects of blue-green and nitrojen fertilizer on growth and yield of rice variety RD7. grown on a Kularonghai soik series (Natraqualfs, sandy loam, EC 2.75 mmho/cm and organic matter 0.40%). Pots were arranged in randomized complete block design with 4 replications and 6 treatments. The treatments were absence and presence of algal inoculant which was a mixture of Anabaena sp., Nostoc sp., Hapalosiphon sp. No. 697 and Stigonema sp. No. 617, nitrogen fertilizer (urea) at level of 30 and 60 kg N/rai alone or combinations of the two levels of nitrogen fertilizer and blue-green algae.

                Results indicated that
                1. Application of nitrogen fertilizer at the lower level (30 kg N/rai) in saline soil was more effective in improving the growth and yield of rice than that at the higher level (60 kg N/rai)
                2. Blue-green algal growth could be observed in saline soil inoculated with algal biofertilizer. The nitrogen content in straw, grain yields and the protein content of rice was significantly increased in algalized pots. Grain yield was increased from 5.1 to 6.1 grams in pots by algal biofertilizer. The protein content of rice grain increased from 8.3 to 10.6%
                3. The combination of algal biofertilizer and nitrogen fertilizer was more effective in increasing rice yield that the application of nitrogen fertilizer alone. Application of 30 and 60 kg N/rai in combination with blue-green algae gave grain yields of 11.2 and 8.1 g/pot, whereas application of 30 and 60 kg N/rai alone gave 8.8 and 6.8 g/pot, respectively.