Table 1.
Fertilizer rates in control (CK), chemical fertilizer (NPK), and the combination of manure and chemical fertilizer (MNPK, 1.5MNPK) treatments for each crop.
Fig 1.
Soil organic C and N concentrations and their C/N ratios in bulk soil in the control (CK), chemical fertilizer (NPK), and combined manure and chemical fertilizer (MNPK, 1.5MNPK) treatments in the top 40 cm of the soil profile.
Values at each soil depth are the mean of three replicates. The horizontal lines denote the least significant difference values at the 0.05 level (LSD0.05) among different treatments at each soil depth. LM, SM, free-m, and free-SC represent large macroaggregates (> 2000μm), small macroaggregates (2000–250 μm), microaggregates (53–250 μm), and silt-clay (< 53 μm); cPOM, inter-m, and inter-SC represent coarse particulate organic matter (POM), microaggregates within macroaggregates, and silt-clay within macroaggregates; fPOM, fiPOM, and intra-SC represent fine POM, fine intra POM and intra silt-clay within inter-m.
Fig 2.
Change in organic C and N concentrations and their C/N ratios in water stable aggregate fractions (WSA) of control (CK), chemical fertilizer (NPK), and combined manure and chemical fertilizer (MNPK, 1.5MNPK) treatments in the top 40 cm of the soil profile.
Values at each soil depth are the mean of three replicates. The horizontal lines denote the least significant difference values at the 0.05 level (LSD0.05) among different treatments at each soil depth. Symbols of aggregate fractions: see Fig 1 footnote.
Fig 3.
Change in organic C and N concentrations and their C/N ratios in large macroaggregate (LM) fractions of control (CK), chemical fertilizer (NPK), and the combined manure and chemical fertilizer (MNPK, 1.5MNPK) treatments in the top 40 cm of the soil profile.
Values at each soil depth are the mean of three replicates. The horizontal lines denote the least significant difference values at the 0.05 level (LSD0.05) among different treatments at each soil depth. Symbols of aggregate fractions: see Fig 1 footnote.
Fig 4.
Change in organic C and N concentrations and their C/N ratios in small macroaggregate (SM) fractions of control (CK), chemical fertilizer (NPK), and combined manure and chemical fertilizer (MNPK, 1.5MNPK) treatments in the top 40 cm of the soil profile.
Values at each soil depth are the mean of three replicates. The horizontal lines denote the least significant difference values at the 0.05 level (LSD0.05) among different treatments at each soil depth. Symbols of aggregate fractions: see Fig 1 footnote.
Fig 5.
Change in organic C and N concentrations and their C/N ratios in microaggregates within large macroaggregate fractions of control (CK), chemical fertilizer (NPK), and combined manure and chemical fertilizer (MNPK, 1.5MNPK) treatments in the top 40 cm of the soil profile.
Values at each soil depth are the mean of three replicates. The horizontal lines denote the least significant difference values at the 0.05 level (LSD0.05) among different treatments at each soil depth. Symbols of aggregate fractions: see Fig 1 footnote.
Fig 6.
Change in organic C and N concentrations and their C/N ratios in microaggregates within small macroaggregate fractions of control (CK), chemical fertilizer (NPK), and combined manure and chemical fertilizer (MNPK, 1.5MNPK) treatments in the top 40 cm of the soil profile.
Values at each soil depth are the mean of three replicates. The horizontal lines denote the least significant difference values at the 0.05 level (LSD0.05) among different treatments at each soil depth. Symbols of aggregate fractions: see Fig 1 footnote.
Fig 7.
Relationships between C inputs and C and N stocks and their C/N ratios in POM, selected large and small macroaggregate fractions in the top 40 cm of the soil profile of the different treatments.
Values are the mean of three replicates. C input sequence on the x-axis is CK, NPK, MNPK, and 1.5MNPK treatments, respectively; * and **, P < 0.05 and P < 0.01; R2 is calculated using all replicates of the treatments. Symbols of aggregate fractions: see Fig 1 footnote.