Unreasonable land use methods severely affect soil erosion on sloping farmland. The central government has proposed to promote a pilot farmland crop rotation and fallow system. To explore the influence of annual rotation and fallow patterns on the glomalin-related soil protein and aggregate stability, this study set up four treatments: vetch-maize rotation, pea-maize rotation, fallow-maize, and year-round fallow through field experiments. Subsequent changes to soil aggregate, glomalin-related soil protein(GRSP), and organic carbon(SOC) under these different planting patterns were analyzed. The results showed that the large aggregates(>0.25 mm)content and aggregate stability in the annual fallow treatment were higher than those in other treatments. The GRSP and SOC content in vetch-maize rotation, pea-maize rotation, and year-round fallow treatment were higher than those in fallow-maize treatment; in particular, those in the yearround fallow treatment were highest. The structural equation model analysis indicated that GRSP had a direct positive effect on SOC and DOC, and an indirect effect on aggregate stability. The effect of each factor on MWD was in the order: WSA0.25(>0.25 mm water stable aggregate)>DOC>total GRSP>SOC>easily-extractable GRSP. Correlation analysis showed that GRSP was linearly positively correlated with SOC in different aggregate sizes, but the correlation coefficients were different in different sizes. In summary, a reasonable crop rotation and fallow pattern can help restore soil fertility, improve the quality of cultivated land, and reduce soil erosion.
