Objective  The influence and mechanism of equal application of organic fertilizer and fertilizer on maize (Zea mays L.) biomass under drought stress conditions were studied, which would provid a theoretical basis for the proposed technical measures of drought resistance in maize.

  Method  The experiment was carried out in the greenhouse based on the field soil of a 9-year long-term location experiment. Three factors of fertilization, microorganisms and water were set. The fertilization factors included no fertilization, cow manure treatment (9000 kg hm⁻²) and chemical fertilizer treatment (with cow manure equal nutrient content) . The microbial factors included two levels of sterilization and non-sterilization. And the moisture factors included two levels of drought (soil water content of 16%) and dry (soil water content of 28%), a total of 12. The maize was harvested 45 days after planting, and the above-ground plant, root biomass, soil aggregates, soil nutrients and microbial indicators were measured.

  Result  (1) Compared with CK, chemical- and organic-fertilizer significantly increased the aboveground biomass (155% and 278%), root biomass (71% and 122%) and total biomass (125% and 221%). Only under sterilization conditions, drought significantly reduced maize biomass (30%−34%). (2) Fertilization significantly improved the content of available phosphorus and potassium in soil, but it had no significant effect on mineral nitrogen. Drought significantly reduced the soil available potassium content by 43.8%. Fertilization had no significant effect on total phospholipid fatty acids and bacterial biomass, while improved fungal biomass and true fine ratio. Drought did not significantly change soil microbial biomass. (3) With the increase of available phosphorus in soil, the total biomass of corn increased significantly.

  Conclusion  Drought significantly reduced maize biomass, and this drought effect only appeared on the sterilized soil, indicating that soil microorganisms could enhance plant resistance to drought stress to a certain extent; Under drought conditions, the application of organic fertilizer significantly increased the maize biomass mainly through the increase of soil available phosphorus content.