Figure 1.
Average soil pH in the different fertilizer treatments.
CK: no fertilizer; SR: straw returning rice field; NPK: chemical fertilizer; OM: organic manure and GM: green manure.
Figure 2.
Dynamics of soil pH in the different fertilizer treatments during 1998–2009.
Soil samples for 1999–2002 were not analyzed (dashed lines).
Figure 3.
Average SOC and TN in the different fertilizer treatments.
CK: no fertilizer; SR: straw returning rice field; NPK: chemical fertilizer; OM: organic manure and GM: green manure.
Figure 4.
Dynamics of SOC and TN in the different fertilizer treatments during 1998–2009.
Soil samples for 1999–2002 were not analyzed (dashed lines).
Figure 5.
Average C/N ratios in the different fertilizer treatments.
CK: no fertilizer; SR: straw returning rice field; NPK: chemical fertilizer; OM: organic manure and GM: green manure.
Figure 6.
Dynamics of soil C/N ratios in the different fertilizer treatments during 1998–2009.
Soil samples for 1999–2002 were not analyzed (dashed lines).
Figure 7.
Average soil AN, AP and AK in the different fertilizer treatments.
CK: no fertilizer; SR: straw returning rice field; NPK: chemical fertilizer; OM: organic manure and GM: green manure.
Figure 8.
Dynamics of soil AN, AP and AK in the different fertilizer treatments during 1998–2009.
soil samples for 1999–2002 were not analyzed (dashed lines).