Effect of the cyanobacteria biogas slurry on the vegetable yields,quality and the substitute for chemical fertilizer

In this paper,differences of yield,nitrate content,Vitamin C of pakchoi were compared by the field tests of cyanobacteria biogas slurry instead of chemical fertilizer and different amount of biogas slurry.The results showed as follows: ① Two continuous rotation of pakchoi were conducted together with the application of cyanobacteria biogas slurry,the yield of first crop and second crop treated by biogas slurry were at the same level with chemical fertilizer in which were 72.3% and 85.6% of biogas slurry,the rate of chemical fertilizer substitution of first crop was increased by 18.4% than that in second crop.② Biogas slurry application at the same amount of nutrient with chemical fertilizer could reduce the nitrate content and increase the Vc content,improve the Vitamin C content with aftereffect under continuously applying,while have not significant effect on nitrate content reduction.③ There were significantly conical relationships between the application amount of biogas slurry and the sweet pepper yield and quality,and there was also a positive linear relationship between the application amount of biogas slurry and the vegetable nitrate content,and 134.1~138.9 t·hm-2 was an optimal application amount of biogas slurry considering the balance of yield and quality.