TY - JOUR

T1 - Nitrate leaching and nitrous oxide emissions from maize after grass-clover on a coarse sandy soil

T2 - Mitigation potentials of 3,4-dimethylpyrazole phosphate (DMPP)

AU - Nair, Drishya

AU - Baral, Khagendra R.

AU - Abalos, Diego

AU - Strobel, Bjarne W.

AU - Petersen, Soren O.

PY - 2020

Y1 - 2020

N2 - Cropping of maize (Zea mays L.) on sandy soil in wet climates involves a significant risk for nitrogen (N) losses, since nitrate added in fertilizers or produced from residues and manure may be lost outside the period with active crop N uptake. This one-year lysimeter experiment investigated the potential of Vizura (R), a formulation for liquid manure (slurry) with the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP), to mitigate nitrous oxide (N2O) emissions and nitrate (NO3-) leaching from a coarse sandy soil cropped with maize. Maize followed grass-clover (Lolium perenne L.-Trifolium pratense L.) with spring incorporation and was fertilised with cattle slurry. A total of 12 treatments in triplicate were included in a factorial experiment with 1 m(2) large and 1.4 m deep lysimeters: 1) with or without spraying the above-ground biomass of grass-clover with DMPP before incorporation; 2) application of cattle manure with or without DMPP, or no fertilization; and 3) natural rainfall or extra rain events to represent wet spring conditions, which were simulated with an automated and programmable irrigation system. Around 20 kg N ha(-1) was returned to the soil in grass-clover above-ground biomass, and 145 kg N ha(-1) in cattle manure. Cumulative annual N2O emissions ranged from 0.4 to 1.3 kg N ha(-1), with between 49 and 86% of emissions occurring during spring, Manure application increased N2O emissions, while extra rainfall had no effect. The mitigation of N2O emissions by DMPP ranged from 46 to 67% under natural, and from 44 to 48% under high rainfall conditions. Total annual NO3- leaching ranged from 65 to 162 kg N ha(-1). The extent of NO3- leaching to 1.4 m depth during spring was low, and instead most (72-83%) of total annual NO3--N leaching was recorded during autumn before harvest. The extra rainfall during spring increased NO3--N leaching in the pre-harvest period, but it is not clear to what extent this was associated with the N in grass-clover residues or manure applied in spring, or from N mineralisation below the root zone. Despite evidence for a reduction of NO3- leaching in three of four scenarios, overall this effect was not significant. No DMPP was detected in leachates. In conclusion, DMPP significantly reduced N2O emissions from cattle manure on this sandy loam soil independent of rainfall, while there was no significant effect on NO3- leaching. The results indicate that N2O emissions and NO3--N leaching were partly derived from below-ground sources of N not affected by DMPP, which should be further investigated to better predict the mitigation potential of nitrification inhibitors.

AB - Cropping of maize (Zea mays L.) on sandy soil in wet climates involves a significant risk for nitrogen (N) losses, since nitrate added in fertilizers or produced from residues and manure may be lost outside the period with active crop N uptake. This one-year lysimeter experiment investigated the potential of Vizura (R), a formulation for liquid manure (slurry) with the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP), to mitigate nitrous oxide (N2O) emissions and nitrate (NO3-) leaching from a coarse sandy soil cropped with maize. Maize followed grass-clover (Lolium perenne L.-Trifolium pratense L.) with spring incorporation and was fertilised with cattle slurry. A total of 12 treatments in triplicate were included in a factorial experiment with 1 m(2) large and 1.4 m deep lysimeters: 1) with or without spraying the above-ground biomass of grass-clover with DMPP before incorporation; 2) application of cattle manure with or without DMPP, or no fertilization; and 3) natural rainfall or extra rain events to represent wet spring conditions, which were simulated with an automated and programmable irrigation system. Around 20 kg N ha(-1) was returned to the soil in grass-clover above-ground biomass, and 145 kg N ha(-1) in cattle manure. Cumulative annual N2O emissions ranged from 0.4 to 1.3 kg N ha(-1), with between 49 and 86% of emissions occurring during spring, Manure application increased N2O emissions, while extra rainfall had no effect. The mitigation of N2O emissions by DMPP ranged from 46 to 67% under natural, and from 44 to 48% under high rainfall conditions. Total annual NO3- leaching ranged from 65 to 162 kg N ha(-1). The extent of NO3- leaching to 1.4 m depth during spring was low, and instead most (72-83%) of total annual NO3--N leaching was recorded during autumn before harvest. The extra rainfall during spring increased NO3--N leaching in the pre-harvest period, but it is not clear to what extent this was associated with the N in grass-clover residues or manure applied in spring, or from N mineralisation below the root zone. Despite evidence for a reduction of NO3- leaching in three of four scenarios, overall this effect was not significant. No DMPP was detected in leachates. In conclusion, DMPP significantly reduced N2O emissions from cattle manure on this sandy loam soil independent of rainfall, while there was no significant effect on NO3- leaching. The results indicate that N2O emissions and NO3--N leaching were partly derived from below-ground sources of N not affected by DMPP, which should be further investigated to better predict the mitigation potential of nitrification inhibitors.

KW - Grass clover

KW - Maize

KW - Nitrification inhibitor

KW - DMPP

KW - N2O emission mitigation

KW - NO3- leaching

KW - Rainfall

KW - SILAGE-MAIZE

KW - NITRIFICATION INHIBITORS

KW - MINERAL NITROGEN

KW - CROPPING SYSTEMS

KW - USE EFFICIENCY

KW - N2O EMISSIONS

KW - CATCH CROPS

KW - DENITRIFICATION

KW - FERTILIZER

KW - MANURE

U2 - 10.1016/j.jenvman.2020.110165

DO - 10.1016/j.jenvman.2020.110165

M3 - Journal article

C2 - 32090850

VL - 260

JO - Journal of Environmental Management

JF - Journal of Environmental Management

SN - 0301-4797

M1 - 110165

ER -