Abstract:
Comparative studying of making composts were done by mixing rice straw with different nitrogen sources such as molasses waste water, citric acid wastes, ammonium nitrate and water, which was used as control. The results showed that molasses waste water was the best nitrogen source. Since after 128 days of decomposition C:N ratio of rice straw mixing with molasses waste water was reduced to 10.92 which is the lowest C:N ratio, when compared with using citric acid waste, ammonium nitrate and water, which were reduced to 21.78, 15.42 and 28.73 respectively. Microbiological quantitative studies showed that rice straw mixed with 4500 grams of molasses waste water gave the highest count of bacteria and fungi, which were 7.7x1010 and 4.0x107 colony per gram of rice straw when incubated at 30oC respectively. It also gave the highest count of bacteria and fungi, which were 1.15x1010 and 8.0x106 colony per gram of rice straw when incubated at 45 oC respectively. It also found that composting rice straw only gave the highest number of actinomycetes, which were 1.2x104 colony per gram of rice straw at 45 oC. Isolation and selection of cellulose decomposing fungi found that Aspergillus sp. Gave highest enzyme activity of cellulose, carboxymethylcellulase and B-glucosidase, which were 4.82x101, 8.7x101 and 44.2x101 unit per ml, respectively. Additional inoculums of Aspergillus sp. To rice straw mixed with molasses waste water, rice straw with ammonium nitrate and rice straw without nitrogen source then compared with rice straw only. The early period of decomposition showed that additional Aspergillus sp. To rice straw mixed with molasses waste water or rice straw only could be increasing decomposition rate that the one without adding Aspergillus sp. Comparing decomposition rate between rice straw mixed with ammonium nitrate and Aspergillus sp. and without Aspergillus sp. showed no different significant.