Effects of long-term application of various organic amendments on soil particulate organic matter storage and chemical stabilisation of vertisol soil

ABSTRACTCurrent understanding of the effects of long-term application of various organic amendments on soil particulate organic matter (POM) storage and chemical stabilisation remains limited. Therefore, we collected soil samples from the soil profile (0–100 cm) under six treatments in a 31-year long-term fertilisation experiment: no fertiliser (CK), mineral fertilisers (NPK), mineral fertilisers plus 3.8 or 7.5 t ha−1 year−1 (fresh base) the amount of wheat straw (1/2SNPK and SNPK) and mineral fertilisers plus swine or cattle manure (PMNPK and CMNPK). Long-term incorporation of wheat straw and livestock manure amendments significantly (p < 0.05) increased crop yield and sustainable yield index, and POM storage compared with CK and NPK treatments. The mole ratios of H/C in the POM under organic amendment treatments significantly (p < 0.05) decreased by 13.8% and 37.1%, respectively, compared with the NPK treatment. Similarly, solid state NMR spectroscopy showed that the O–alkyl carbon content of POM was g...