Water Salinity Should Be Reduced for Irrigation to Minimize Its Risk of Increased Soil N 2 O Emissions

Qi Wei, Junzeng Xu, Linxian Liao, Yawei Li, Haiyu Wang and Shah Fahad Rahim
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Qi Wei: State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China
Junzeng Xu: State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China
Linxian Liao: College of Agricultural Engineering, Hohai University, Nanjing 210098, China
Yawei Li: College of Agricultural Engineering, Hohai University, Nanjing 210098, China
Haiyu Wang: College of Agricultural Engineering, Hohai University, Nanjing 210098, China
Shah Fahad Rahim: College of Agricultural Engineering, Hohai University, Nanjing 210098, China

IJERPH, 2018, vol. 15, issue 10, 1-14

Abstract: To reveal the effect of irrigation salinity on soil nitrous oxide (N 2 O) emission, pot experiments were designed with three irrigation salinity levels (NaCl and CaCl 2 of 1, 2.5 and 4 g/L equivalence, Ec = 3.6, 8.1 and 12.7 ds/m), either for 0 kg N/ha (N0) or 120 kg N/ha (N120) nitrogen inputs. N 2 O emissions from soils irrigated at different salinity levels varied in a similar pattern which was triggered by soil moisture dynamics. Yet, the magnitudes of pulse N 2 O fluxes were significantly varied, with the peak flux at 5 g/L irrigation salinity level being much higher than at 2 and 8 g/L. Compared to fresh water irrigated soils, cumulative N 2 O fluxes were reduced by 22.7% and 39.6% (N0), 29.1% and 39.2% (N120) for soils irrigated with 2 and 8 g/L saline water, while they were increased by 87.7% (N0) and 58.3% (N120) for soils irrigated with 5 g/L saline water. These results suggested that the effect degree of salinity on consumption and production of N 2 O might vary among irrigation salinity ranges. As such, desalinating brackish water to a low salinity level (such as 2 g/L) before it is used for irrigation might be helpful for solving water resources crises and mitigating soil N 2 O emissions.

Keywords: brackish water irrigation; N fertilizer; nitrogen oxide; water-filled pore space; electrical conductivity (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2018
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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