Abstract: A field experiment was conducted to study the effects of maize residue return and its combination with biocontrol actinomyces agent S024 (Streptomyces sp.) on the soil microbial population, wheat sharp eyespot (Rhizoctonia cerealis), and wheat yield. Returning maize residue into soil had significant effect on the increase of the amounts of soil bacteria and actinomyces. The combination of maize residue return with S024 inoculation increased the amount of actinomyces at shooting stage by 50% and decreased the amount of wheat sharp eyespot by 20%, compared with the control (no maize residue return). Returning maize residue into soil showed a better control effect on wheat sharp eyespot at shooting stage, and the treatment of doubled residue return (9000 kg·hm^-2) combined with S024 inoculation had the best effect, with the disease index decreased by 57.4%. Returning maize residue into soil had definite effect in increasing wheat yield. Doubled residue return combined with S024 inoculation increased the yield most, and the increment reached 23.1%.

Key words: Volatile oil, Chromolaena odorata, Chemical composition, Plants, Fungi, Insects, Growth