การตรึงอะโซโตแบคเตอร์แบคทีเรียตรึงไนโตรเจนในอากาศด้วยวัสดุธรรมชาติและผลต่อการเจริญเติบโตของผักกวางตุ้งในดิน

Nitrogen is an essential nutrient for plant growth. When the plants have been grown for a long-term effect to decreased nitrogen in soil and insufficiency of the plant growth. One biological method for increasing the nitrogen content in soil is utilize of free nitrogen-fixing bacteria Azotobacter. Therefore the objective of this research was to search natural material suitable for Azotobacter fixation. The 10 natural materials were observed physical structure and investigated the ability of natural materials for Azotobacter fixation. The results showed that water hyacinth and bagasse stalks were fixed the Azotobacter of 2.43x108 and 1.94 x108 CFU per gram of each natural material respectively. After that the selected fixed Azotobacter of water hyacinth and bagasse stalks were studied the growth of Brassica Chinensis. This experiment was designed to 4 treatments. The first treatment was mixed of water hyacinth stalks and the Azotobacter. Second treatment was mixed of bagasse stalks and the Azotobacter. The third treatment was the Azotobacter only. The last treatment was soil only. The results indicated that the average of plant growth include height leaf number root length fresh weight and dry weight of the mixed of water hyacinth stalks and the Azotobacter had significantly higher growth rates than other treatments. The total nitrogen was also increased 1.4 fold in the soil. All results suggest that the water hyacinth stalk is alternative for the fixation of the free nitrogen-fixing bacteria Azotobacter as induce nitrogen in the soil and plant growth promotion.