Abstract:In order to investigate the effects of different organic fertilizers on pear tree growth and soil biological property, a field plot experiment was carried out to study the effects of different fertilizer managements on the aboveground growth, yield, quality of pear and changes of soil microbial biomass carbon and nitrogen and mineral nitrogen in Huangguan pear orchards. There were five fertilizer treatments, no fertilization (CK), traditional fertilizer (TF), bio-organic fertilizer (BOF), chicken manure compost (CM) and organicinorganic compound fertilizer (CF). The results show that the applications of organic fertilizer enhance the leaf area, weight of 100 leaves and length of new shoots. Meanwhile, the contents of fruit soluble solid and soluble sugar and ratio of total sugar to organic acids are also improved, especially in the treatment of BOF. The fruit weights and yields in the treatment of BOF are increased by 17.4% and 33.9%, respectively compared with the CK. Different organic fertilizer treatments could improve the soil microbial quantity and contents of soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN) in the whole growth period compared with the CK and CF. The mineral nitrogen is mainly made up of nitrate and it decreases gradually from the germination stage to the second expanding stage in different fertilizer treatments. At the maturity the content of nitrate in the treatment of BOF is significantly higher than those of the other treatments. In summary, the application of organic fertilizer could promote tree growth, improve soil microbial quantity and ameliorate soil nitrogen supply.