Fig. 2: PMD-based network and the proportion of molecules of specific biochemical categories in the network.

a CK plots with no fertilization and complete removal of crop straw, b NP plots with urea and calcium–magnesium phosphate, c NK plots with urea and potassium chloride, d NPK plots with urea, calcium–magnesium phosphate, and potassium chloride, e NPKst plots with NPK chemical fertilization plus rice straw; f NPKpm plots with NPK chemical fertilization plus pig manure, and g NPKgm, plots with NPK chemical fertilization plus green manure.