Abstract: The transformation after returning of stalk to field was a complicated biochemical process.Investigating the(dynamic) change rule of soil biochemical properties after returning of stalk to field was of great significant to evaluate the(effect) of technical measures of stalk return to the field since the biological effect it produced had an effect on the transformation of soil interior matter and energy.A 2-years experiment was conducted on cinnamon soil rotated by winter wheat and summer maize at eastern parts of Hebei province to study the biological effect of maize stalk return to field under(different) decay conditions on the yield of wheat and maize.The soil chemical properties was: 15.47g/kg of organic matter,86.7mg/kg of alkali-hydrolysable N,14.4 mg/kg of available P,and 68.5 mg/kg available K and 6.7 of pH.(Accretion) decay biologicals,which contained Streptomyces microflavus、 Aspergillus niger and other microorganisms,was prepared by our research team.In time of application,the residue of mushroom medium was used as dispersed carrier without nutrient.The application rate of the residue of mushroom medium was 30 kg/ha,and it was mixed thoroughly with fined soil before applying.The results were as following: under the condition of combining maize stalk with chemical fertilizer and adjusting C/N,applying accretion decay biologicals could raise yield with statistical significant level compare with control,Soil microbial biomass and soil enzyme activities also was promoted at each growth duration.Stalk(return) to field directly with sitting in integrated judgment on soil microbial biomass,enzyme activities,N and P dynamic change,NPK fertilizer as basal fertilizer,and adjusting the proportion of C/N from 15∶1 to 35∶1,the dynamic changes of soil microbial biomass and soil enzyme activities and N nutrientand P nutrient contents had no remarkably different.On the basis of adjusting the proportion of stalk C/N,application effective microorganisms quickened the process of stalk's transformation,and advanced the date of the N net release and the P net release again.And it did good to crop growth and field formation.