EFFECT OF BIOCHAR ON THE ACTIVITY OF ENZYME IN THE NUTRIENT CYCLE OF TYPICAL SOIL AGGERGATES IN NORTHEAST CHINA

This study used a potted experiment to apply biochar to black soil (BCS) and saline-alkali soil (BSAS) in Northeast China, with a dosage of 0 and 300 g biochar/pot applied, respectively. The original black soil (CS) and saline-alkali soil (SAS) were used as controls to investigate the effects of different particle sizes of soil aggregates on the activity of enzymes related to carbon, nitrogen, and phosphorus cycle. Compared with CS and SAS, the soil organic matter (SOM) values for biochar added into the black soil (BCS) and saline-alkali soil (BSAS) treatments were increased significantly by 41.86 % and 31.98 %. Compared with CS, BCS significantly increased the polyphenol oxidase and beta-1,4-glucosidase activity. Polyphenol oxidation activity, endo-1,4-beta-D-glucanohydrolase activity, beta-1,4-glucosidase activity and xylanase activity are more active in particles with a diameter of >2 mm. The alkaline phase activity and Coenzyme activity with BCS treatment was highest in soil aggregates with sizes of 1 similar to 2 mm and >5 mm, respectively. Mantel test analysis shows a highly significant effects between SOM and total nitrogen content (TN) with soil nitrogen, phosphorus, and potassium cycling. Therefore, from the perspective of soil enzyme activities, application of biochar is more effective in promoting soil bio-fertility in northeastern soil of China. Biochar to the soil is more likely to promote the improvement of soil biological fertility.