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Solubility and leaching risks of organic carbon in paddy soils as affected by irrigation managements.

Xu J, Yang S, Peng S, Wei Q, Gao X - ScientificWorldJournal (2013)

Bottom Line: The DOC leaching loss in NFI field was 63.3 kg C ha⁻¹, reduced by 46.4% than in the FI fields.It indicated that multi-wet-dry cycles in NFI paddies enhanced the decomposition of SOC in surface soils, and less carbon moved downward to deep soils due to less percolation.That also led to lower SOC in surface soils in NFI paddies than in FI paddies, which implied that more carbon was released into the atmosphere from the surface soil in NFI paddies.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China.

ABSTRACT
Influence of nonflooding controlled irrigation (NFI) on solubility and leaching risk of soil organic carbon (SOC) were investigated. Compared with flooding irrigation (FI) paddies, soil water extractable organic carbon (WEOC) and dissolved organic carbon (DOC) in NFI paddies increased in surface soil but decreased in deep soil. The DOC leaching loss in NFI field was 63.3 kg C ha⁻¹, reduced by 46.4% than in the FI fields. It indicated that multi-wet-dry cycles in NFI paddies enhanced the decomposition of SOC in surface soils, and less carbon moved downward to deep soils due to less percolation. That also led to lower SOC in surface soils in NFI paddies than in FI paddies, which implied that more carbon was released into the atmosphere from the surface soil in NFI paddies. Change of solubility of SOC in NFI paddies might lead to potential change in soil fertility and sustainability, greenhouse gas emission, and bioavailability of trace metals or organic pollutants.

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Related in: MedlinePlus

Percolation volumes from paddy soils under different irrigation managements (*indicates difference between NFI and FI that is significant at P < 0.05).
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fig5: Percolation volumes from paddy soils under different irrigation managements (*indicates difference between NFI and FI that is significant at P < 0.05).

Mentions: Ten-day deep seepage ranged from 2.3 mm to 46.2 mm in NFI fields, which was significantly lower than the corresponding values (from 7.2 mm to 72.6 mm) in FI fields except in later June and middle October (Figure 5). Seasonal percolation in NFI paddies was 368.8 mm, which was reduced by 42.9% compared with the FI treatment. Seasonal leaching loss of DOC was 63.3 kg C ha−1 from NFI soils, which was reduced by 46.4% compared with those from FI fields (118.1 kg C ha−1). Although DOC concentration in surface soil (0–20 cm) and soil solutions (7–14 cm) was increased in NFI fields, the reduced percolation in the NFI fields led to lower risk of DOC leaching loss than in FI fields. Several studies focused on DOC losses from forest soil [21, 43]. However, few studies on DOC leaching losses in rice paddies have been reported. In the current study, the seasonal leaching losses of DOC from FI paddies fell in the range reported by Katoh et al. (2004) [44] in typical rice fields in Japan (85 to 170 kg C ha−1). The seasonal DOC leaching losses of FI paddies were less than the lower limit of 85 kg C ha−1.


Solubility and leaching risks of organic carbon in paddy soils as affected by irrigation managements.

Xu J, Yang S, Peng S, Wei Q, Gao X - ScientificWorldJournal (2013)

Percolation volumes from paddy soils under different irrigation managements (*indicates difference between NFI and FI that is significant at P < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3713366&req=5

fig5: Percolation volumes from paddy soils under different irrigation managements (*indicates difference between NFI and FI that is significant at P < 0.05).
Mentions: Ten-day deep seepage ranged from 2.3 mm to 46.2 mm in NFI fields, which was significantly lower than the corresponding values (from 7.2 mm to 72.6 mm) in FI fields except in later June and middle October (Figure 5). Seasonal percolation in NFI paddies was 368.8 mm, which was reduced by 42.9% compared with the FI treatment. Seasonal leaching loss of DOC was 63.3 kg C ha−1 from NFI soils, which was reduced by 46.4% compared with those from FI fields (118.1 kg C ha−1). Although DOC concentration in surface soil (0–20 cm) and soil solutions (7–14 cm) was increased in NFI fields, the reduced percolation in the NFI fields led to lower risk of DOC leaching loss than in FI fields. Several studies focused on DOC losses from forest soil [21, 43]. However, few studies on DOC leaching losses in rice paddies have been reported. In the current study, the seasonal leaching losses of DOC from FI paddies fell in the range reported by Katoh et al. (2004) [44] in typical rice fields in Japan (85 to 170 kg C ha−1). The seasonal DOC leaching losses of FI paddies were less than the lower limit of 85 kg C ha−1.

Bottom Line: The DOC leaching loss in NFI field was 63.3 kg C ha⁻¹, reduced by 46.4% than in the FI fields.It indicated that multi-wet-dry cycles in NFI paddies enhanced the decomposition of SOC in surface soils, and less carbon moved downward to deep soils due to less percolation.That also led to lower SOC in surface soils in NFI paddies than in FI paddies, which implied that more carbon was released into the atmosphere from the surface soil in NFI paddies.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China.

ABSTRACT
Influence of nonflooding controlled irrigation (NFI) on solubility and leaching risk of soil organic carbon (SOC) were investigated. Compared with flooding irrigation (FI) paddies, soil water extractable organic carbon (WEOC) and dissolved organic carbon (DOC) in NFI paddies increased in surface soil but decreased in deep soil. The DOC leaching loss in NFI field was 63.3 kg C ha⁻¹, reduced by 46.4% than in the FI fields. It indicated that multi-wet-dry cycles in NFI paddies enhanced the decomposition of SOC in surface soils, and less carbon moved downward to deep soils due to less percolation. That also led to lower SOC in surface soils in NFI paddies than in FI paddies, which implied that more carbon was released into the atmosphere from the surface soil in NFI paddies. Change of solubility of SOC in NFI paddies might lead to potential change in soil fertility and sustainability, greenhouse gas emission, and bioavailability of trace metals or organic pollutants.

Show MeSH
Related in: MedlinePlus