Abstract:
Objective The effects of different kinds of organic materials returning to field on black soil quality were studied, and the soil quality was quantitatively evaluated, which provided theoretical basis for sustainable utilization of black soil resources.
Method This research was based on the black soil field experiment in the middle of Jilin Province. Seven treatments were selected as follow: no fertilizer (CK), single fertilizer (NPK), fertilizer combined with corn straw (NPK + JG), fertilizer combined with compost (NPK + DF), fertilizer combined with cow manure (NPK + NF), fertilizer combined with chicken manure (NPK + JF) and fertilizer combined with pig manure (NPK + ZF). The thirteen basic physical and chemical indices of topsoil layer (0-20 cm) under different kinds of organic materials returned to the field were measured. The changes of soil parameters after organic material treatments were described, and the full data set for soil quality evaluation was established. The minimum data set was selected by principal component analysis and Pearson analysis, so that the soil quality index (SQI) of each treatment was calculated.
Result The different kinds of organic materials had different effects on soil basic physical and chemical indices. The contents of soil organic matter and active organic matter in NPK + DF treatment were significantly higher than those in other treatments, while the highest values of total nitrogen and total phosphorus appeared in NPK + DF and NPK + JF treatments, respectively. The minimum data set of soil quality evaluation was composed of three indices: total phosphorus, bulk density and cation exchange capacity. The soil quality index calculated based on the minimum data set is as follows: NPK + JF (0.780) > NPK + ZF (0.765) > NPK + DF (0.741) > NPK + NF (0.735) > NPK + JG (0.699) > NPK (0.503) > CK (0.292). Greater soil quality level was found in chicken manure or pig manure combined with chemical fertilizer treatments, followed by compost or cow manure combined with chemical fertilizer treatments, the lowest soil quality level was observed in straw combined with chemical fertilizer treatment among organic materials treatments.
Conclusion Combined application of chemical fertilizer and organic materials was an effective way to improve soil quality,where chicken manure or pig manure were more effective than compost, cow manure and straw in black soil of Northeast China.