The Research On Conditions Optimization Of Humic Acid Extraction From Different Sources And It's Biological Activity

In order to clear the best extract conditions of different sources of low rank coal and their effects on the growth of tobacco and wheat, three kinds of low rank coal from different sources were secected and their best extract humic acid conditions were studied, besides, the extract were made up of seed soaking liquid, studied the low rank coal and humic acid's biological activity. The result showed:1. Effects of different sources of low rank coal on tobacco and wheat experiments showed that the seedling time, agronomic characters, chlorophyll content and substances related to carbon and nitrogen metabolism were better than others when peat, lignite and wood coal's proportion in soil were 4%,6%,6%, which were good for the growth of tobacco seedling. When peat, lignite and wood coal's proportion in soil were 4%,6%,6%, the dry matter accumulaton of wheat seedling increased, which means the growth promoting effect on wheat in obvious and the drought resistance improved. To tobacco and wheat, high low rank coal proportion may have inhibition on the seedling growth, this must be pay more attention in actual production.2. The best humic acid extract conditions of different sources of low rank coal experiments showed that all kinds of low rank coal's extraction rate were increased after pretreatment, the best extract condition of peat humic acid were:nitric acid concentration were 15%, reaction time were 40min in pretreatment, concentration of sodium hydroxide were 3.5%, reaction time time were 70min. The best extract condition of lignite humic acid were:nitric acid concentration were 25%, reaction time were 30min in pretreatment, concentration of sodium hydroxide were 2.5%, reaction time time were 80min. The best extract condition of wood coal humic acid were:nitric acid concentration were 30%, reaction time were lOmin in pretreatment, concentration of sodium hydroxide were 3%, reaction time time were 50min.3. Humic acid seed soaking experiment showed that the tobacco seed had better germination percentage, germination vigor, germination index and seed vigor index when peat, lignite and wood coal humic acid seed soaking concentration were 10,30,50 mg/L, in these conditions, tobacco seedlings had better root activity, chlorophyll content, soluble sugar content and soluble protein content, which were good for the growth of tobacco seedling. When peat, lignite and wood coal humic acid seed soaking concentration were 30, 50,70 mg/L, the germination percentage, germination vigor, germination index and seed vigor index of wheat were the highest, besides, the root activity, chlorophyll content, soluble sugar content and soluble protein content had significant increase which can improve the drouht resistance of wheat seedling.