The improvement of SOC sequestration mediated by soil structure in the
greenhouse vegetable soil converted from paddy field
Abstract
Objective of investigation: Land use conversion strongly alters soil
structure and substantially affects soil organic carbon (SOC)
sequestration. Changing from an anaerobic paddy field (PF) to a dry land
easily causes SOC loss due to stimulation of C decomposition. However,
no evidence of SOC loss from PF to intensive vegetable cultivation has
been certainly presented. Experimental material: This study was
conducted on the long-term cultivated open-field vegetable (OFV) and
greenhouse vegetable (GHV) planting area converted from old PF in China.
Undisturbed soil cores, natural structured soil, and disturbed soil from
top soil layers were using for further analyses. Methods of
investigation: To comprehensively investigate SOC and soil structure
change in the land use conversion of PF to OFV and PF to GHV, we used
13C-CPMAS NMR spectroscopy to classify the SOC fractions. The soil
macropores (> 50 μm) was valued by X-ray computed
tomography, and soil aggregates distribution was determined by wet
sieving method. Data collection: Data were obtained from the
above-mentioned measurements and statistically analyzed in R. Results:
The result showed that the SOC stock increased 1-fold from PF to GHV.
SOC stability increased with recalcitrant C (aromatic-C and carbonyl-C)
raised by 21 %–27 % in GHV bulk soil. Both macropores and
macroaggregates (> 250 μm) increased in GHV, accompanied by
an accumulation of recalcitrant C in large macroaggregates. Conclusions:
we confirmed the expanded GHV cultivation sequestered more belowground
SOC than PF, associated with the amplified physical protection by
enhancing soil aggregation and by redistributing of soil macropores.