Promotion of the Growth and Quality of Chinese Cabbage by Application of Biogas Slurry of Water Hyacinth

Biomass and quality index of Chinese cabbage were investigated under the following treatment, control (CK), 25% biogas slurry + 75% fertilizer (Z-25%), 50% biogas slurry + 50% fertilizer (Z-50%), 75% biogas slurry + 25% fertilizer (Z-75%), and 100% biogas slurry (Z-100%). The results indicated that Z-25% significantly increased shoot height and fresh weight. But shoot height and fresh weight significantly decreased in a time-dependent manner when the concentration of the biogas slurry was greater than 50%. Vitamin C, soluble sugar, protein, and nitrite were measured to evaluate the effect of biogas slurry on the quality of Chinese cabbage. Z-25% treatment could remarkably increased the content of dehydroascorbate (DHA) and total Vc, whereas did not significantly affect reduced ascorbate (AsA) content compared to the CK for 60 d. The content soluble sugar and protein were significantly enhanced under Z-25% treatment. In addition, Z-25% effectively reduced nitrite content in Chinese cabbage. Biogas slurry with concentration more than 50% could not promote quality index of Chinese cabbage. To sum up, biogas slurry of water hyacinth could improve the growth and quality of Chinese cabbage under the optimal applied concentration.