Chiang Mai Journal of Science

Bio-fertilizer has been used as an alternative of the chemical fertilizer, Klebsiella oxytoca in organic fertilizer can convert nutrients in the soil to the available form for plant growth. This study was aimed to investigate the effects of Klebsiella oxytoca in the forms of bio-fertilizer and liquid organic fertilizer on the growth of Ipomoea aquatica, Brassica integrifolia and Brassica rapa chinensis. These trials were carried out in four replications of the randomized complete block design (RCBD) in the greenhouse. Results showed that by applying organic fertilizer in I. aquatica, plant growth parameters, soil nutrients and microbial activities were approximately in chemical fertilizer treatment excepted for the nutrient content in plant. The nutrients in B. integrifolia plant that grown in liquid organic fertilizer was lower than soil that apply chemical. On the other hand, these values in B. rapa chinensis which applied with liquid fertilizer was equal (applying fermentation fruit waste) and significant higher (applying molasses) than in the chemical fertilizer application. The result from this study indicated that  B. rapa chinensis responsed better B. integrifolia when applied liquid organic fertilizer. The microbial activities of microorganisms were in inverse ratio to the amount of chemical applying. The highest number nitrogen fixing bacteria, phosphate and potassium solubilization bacteria, and Klebsiella oxytoca were found in the soil supplemented with liquid fertilizer. The treatment of 50% of chemical fertilizer in combination with liquid fertilizer could increase the I. aquatica yield and improved soil nutrient.