Abstract: Understanding the effects of combined application of vermicompost and chemical fertilizer on yield and quality of vegetables is important for guiding the rational fertilization in cleaner vegetable production. We examined the effects of combined application of vermicompost and chemical fertilizer on yield, nitrate content, amino acid content and composition of Lactuca sativa in a pot experiment. The results showed that, compared with the single application of chemical fertilizer, combined application of appropriate amount vermicompost and chemical fertilizer increased the yield, while reduced the water content of L. sativa by 1.02%-2.46% and nitrate content by 20.78%-30.30%. The combined application of vermicompost and chemical fertilizer significantly increased the contents of total amino acids, essential amino acids, delicious amino acids, sweet amino acids, and pharmacodynamic amino acids. Under the conditions of equal amount of nitrogen, 30%-50% of nitrogen from vermicompost was the optimal. Therefore, the combined application of vermicompost and chemical fertilizer is feasible for the improvement of both yield and quality of L. sativa.

Key words: oil-sunflower field, nitrous oxide, organic and inorganic fertilizer, soil water, ammonium.