Characterization of Chinese Cabbage Growth and Soil Biological/Chemical Properties with Molasses Treatments.

This study was carried out to investigate the effects of molasses treatment on the mineralization of nitrogen (NH₄-N and NO₃-N contents), on oxygen consumption rate of microbe in soil and Chinese cabbage growth characteristics under the incubation with several different concentrations (0, 2.5, 5, 7.5, 10, 12.5 and 15%) of molasses in combined with 6 % of N, 3 % of P₂O₅ and 4% of K₂O for 12 weeks as slow-release fertilizers. To examine the effect of molasses on Chinese cabbage growth characteristics, length of leaf, wide of leaf, number of leaf and fresh weight were measured under molasses treatment. Fresh weights of Chinese cabbage were highly increased with increasing application rate of molasses at both 30 days (early growth) and 85 days (late growth) after treatment. Yield was highest at 7.5~10% of molasses (average 1124~1191.9g at 30 days and 3912.7~3649.2 g at 85 days after treatment per one plant) in comparison with control (average 835.6g at 30 days and 3249 g at 85 days after treatment per one plant), showing around 20 ~30% increase. Total contents of the biomass-C in soil were gradually increased until 10 weeks with increasing application rates (5~15 %) of molasses. Contents of NH₄-N and NO₃-N by treatments of molasses were slightly decreased. However, total contents of nitrogen (T-N) were not much changed. To investigate the effect on microbial activity, accumulated oxygen consumption rate in soil was measured. Accumulated oxygen consumption rate of microbes was increased with increasing application rates (5~15 %) of molasses, suggesting that adding of molasses could affect the microbial activity in soil. Taken together, our results suggested that molasses could be used for slow-release fertilizer with concentration of around 5%~12.5% for plant growth and soil characteristics.