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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机译：研究了非注水控制灌溉（NFI）对土壤有机碳（SOC）溶解度和淋溶风险的影响。与淹水灌溉相比，表层土壤的水可提取有机碳（WEOC）和溶解有机碳（DOC）增加，但深层土壤减少。 NFI田的DOC淋失量为63.3 kg C ha -1 ，比FI田减少了46.4％。这表明，NFI稻田中的多次干湿循环增强了表层土壤中SOC的分解，并且由于较少的渗滤，较少的碳向下移动至深层土壤。这也导致NFI稻田的表层土壤的SOC低于FI稻田，这意味着NFI稻田的表层土壤向大气释放了更多的碳。 SOC在NFI稻田中的溶解度变化可能会导致土壤肥力和可持续性，温室气体排放以及微量金属或有机污染物的生物利用度发生潜在变化。
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