Abstract: A field experiment was conducted to study the effects of different combinations of organic and inorganic nitrogen fertilizers on yield, quality and economic benefit of pakchoi and lettuce for three consecutive years from 2011 to 2013. Six treatments were included: no fertilizer (CK), no nitrogen fertilizer (PK), chemical fertilizer (NPK), organic and inorganic fertilizer 1 (20% pig manure N + 80% chemical fertilizer N, NPKM1), organic and inorganic fertilizer 2 (20% biogas manure N + 80% chemical fertilizer N, NPKM2), and organic and inorganic fertilizer 3 (20% pig manure composting N + 80% chemical fertilizer N, NPKM3). The results showed that the combined applications of organic and inorganic nitrogen fertilizer significantly increased vegetable yield. The yields of pakchoi and lettuce were in order of NPKM3 > NPKM1 > NPKM2 > NPK > PK > CK. Compared with the NPK treatment, the yield of NPKM1, NPKM2, NPKM3 treatments increased by 19.84%, 8.31%, 27.38% for pakchoi, and 48.66%, 22.13%, 53.76% for lettuce, respectively. The economic benefit of pakchoi and lettuce ranked in order of NPKM3 > NPKM1 > NPKM2 > NPK > PK > CK. Compared with the NPK treatment, the economic benefit of NPKM1, NPKM2, NPKM3 treatments increased by 21.83%, 9.52%, 23.15% for pakchoi, and 50.46%, 23.10%, 53.50% for lettuce, respectively. Furthermore, the combined applications of organic and inorganic nitrogen fertilizers increased vitamin C and soluble sugar contents, and decreased nitrate and crude fiber contents of pakchoi and lettuce, so as to improve the nutritional quality and taste of vegetables, especially in NPKM3 treatment. In conclusion, the pig manure composting treatment was beneficial to the highyield and highquality of pakchoi and lettuce cultivation, and thus improved economic benefit.

Key words: priming agent., primed defense, plant anti-herbivore resistance, induced defense