Long-term manure amendments reduced soil aggregate stability via redistribution of the glomalin-related soil protein in macroaggregates

摘要

Glomalin-related soil protein (GRSP) contributes to the formation and maintenance of soil aggregates, it is however remains unclear whether long-term intensive manure amendments alter soil aggregates stability and whether GRSP regulates these changes. Based on a three-decade long fertilization experiment in northeast China, this study examined the impact of long-term manure input on soil organic carbon (SOC), total and easily extractable GRSP (GRSP_t and GRSP_e) and their respective allocations in four soil aggregates (>2000?μm; 2000–250?μm; 250–53?μm; and e and GRSP_t in soil and SOC in each aggregate generally increased with increasing manure input, GRSP_t and GRSP_e in each aggregate showed varying changes with manure input. Both GRSP in macroaggregates (2000–250?μm) were significantly higher under low manure input, a pattern consistent with changes in soil aggregate stability. Constituting 38~49% of soil mass, macroaggregates likely contributed to the nonlinear changes of aggregate stability under manure amendments. The regulatory process of GRSP allocations in soil aggregates has important implications for manure management under intensive agriculture.