Effect Of Long-term Fertilization On Soil Fertility And Organic Carbon Stability Of Gray Desert Soil

The long-term fertilization positioning test includes five fertilization treatments:non-fertilization[CT];chemical fertilization as nitrogen,phosphorus and potassium fertilizer[NPK];pig and cattle manure addition only[M];fertilization with 1/2 NPK and 1/2 M[1/2NPKM,50%N from chemical N fertilizer and 50%N from manure];total NPK and total M[NPKM].We used the FT-IR,13C-NMR and EDS/TEM to analyze the soil fertility,calcium morphology,dissolved organic carbon morphology,and aggregate stability.The main conclusions of this study are as follows:-Long-term application of organic fertilizer improves soil fertility,carbon content of micro-aggregates and stability of aggregates in gray desert soil,and the combined application of organic and inorganic is better.-Fertilization enhances the abundance of carbonyl,hydroxyl and methyl groups in soluble organic carbon,and increases C-N related group compounds,and the effect of NPK treatment is more significant.-Combined application of organic and inorganic materials improves the stability of particulate organic carbon and increases the abundance of particulate organic carbon hydroxyl,amide,carboxyl and aromatic groups in gray desert soil.-Long-term application of organic fertilizer promotes the transformation of soluble organic carbon crystalline key elements from Fe and Mn to Ca and Mg,and amorphous key elements from Na to P.-Chemical fertilizers reduce the abundance of particulate organic carbon hydroxyl groups,amide groups,carboxyl groups and aromatic groups,and the application of organic fertilizers increases their abundance.-Carboxyl compounds tend to accumulate in macro-aggregates,while macro-aggregates are not easy to protect silyl and aromatic compounds.