Evaluation On The Test Method Of Humic Acid In Humic Fertilizer

It is more concerned about the organic fertilizer that plays an important part in agricultural production. The organic matter content in fertilizer could not be as a absolutely standard for verifying the quality of organic fertilizer, with the increasingly varieties and the intensively commercialization of organic fertilizer. Humic acid is active matter existed in organic fertilizer, but there is no unified standard method for testing the content of humic acid. For the profit protection of farmers and enterprises, we should standardize the test method of humic acid in fertilizer.It is studied that several test methods of humic acid in some fertilizers were compared, in which three different immersible reagents were used to extract dissoluble organic matter (DOM) and humic acid (HA). It is showed that the content of DOM and HA in sample immersed in sodium pyrophosphate is the highest, second is that immersed in alkali solution, the lowest is immersed in water. It is rapid, simple and accurate that the common capacity method determine the content of DOM, but which is affected by carbon coefficient. Sinking heavy methods and sinking capacity method could reduce the effect of organic matter with tiny molecule and chloridion on the content of humic acid, compared with common capacity method. Experiment supports that the content of humic acid tested by sinking capacity method is equal to that by sinking heavy method from the same sample, but the former costs half time less than the latter. The testing conditions in common capacity method have a large effect on the content of humic acid. Nitric acid treatment could reduce the effect of tiny carbohydrate in sample on the testing data.