Prolonged Flooding followed by drying increase greenhouse gas emissions differently from soils under grassland and arable land uses

Abstract

    Under the predicted climate change scenarios, heavy precipitation could result in prolonged flooding (PF) and flooding-drying (FD) of soils in agriculture. The influence of PF and FD on soil greenhouse gas fluxes and nitrogen (N) dynamics of arable and grassland soils, which are the dominant land use types in UK soil, is still unclear. Two months of soil incubation experiments were conducted to find out the impact of PF and FD on soil nitrogen dynamics and greenhouse gas fluxes from arable and grassland soil. The result showed the developed ion selective electrodes (ISE) sensor was working to measure NH₄⁺ in the first 5 days of real-life application under both grassland and arable soil. There were less N₂O-N emissions in grassland and arable soil when soil moisture was higher than 100% water-holding capacity (WHC). Arable soil had more N₂O-N emissions when soil moisture was higher than 100% WHC compared to grassland soil due to a low pH. Grassland soil had more N₂O-N emissions when soil moisture was lower than 100% WHC compare to arable soil due to a high carbon and nitrogen source. When soil moisture was greater than 100% WHC, the available NO₃^--N in the soil controlled N₂O-N emissions of grassland more effectively. The N₂O-N emissions of grassland soil were more controlled by soil stable NH₄⁺-N and NO₃^--N when soil moisture was lower than 100% WHC. The emissions of N₂O-N and CO₂-C were increased with the time of FD. FD significantly increased N₂O-N, CO₂-C, and CH₄-C emissions in grassland soil compared to arable soil by 0.93, 2.15, and 37.29 times, respectively. Converting arable land use to grassland could increase the greenhouse gas (GHG) emissions under climate change (heavy rain). Further research needs to be done to find out how to reduce the GHG emissions under climate change after transfer arable to grassland.