Strategies for mitigating N2O and N2 emissions from an intensive sugarcane cropping system
In sugarcane cropping systems, high rates of N fertiliser are typically applied as sub-surface bands creating localised zones of high mineral N concentrations. This in combination with high levels of crop residue (trash) retention and a warm and humid climate creates conditions that are known to pro...
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Veröffentlicht in: | Nutrient cycling in agroecosystems 2023-03, Vol.125 (2), p.295-308 |
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Zusammenfassung: | In sugarcane cropping systems, high rates of N fertiliser are typically applied as sub-surface bands creating localised zones of high mineral N concentrations. This in combination with high levels of crop residue (trash) retention and a warm and humid climate creates conditions that are known to promote soil denitrification, resulting in high emissions of the potent greenhouse gas N
2
O. These losses illustrate inefficient use of N fertilisers but total denitrification losses in the form of N
2
and N
2
O remain largely unknown. We used the
15
N gas flux method to investigate the effect of cane trash removal and the use of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on N
2
and N
2
O emissions on a commercial sugarcane farm at Bundaberg, Australia. High gaseous N losses were observed under the standard grower practice where cane trash retention and N fertiliser application (145 kg N ha
−1
as urea) resulted in N
2
and N
2
O emissions (36.1 kg N ha
−1
) from the subsurface N fertiliser band, with more than 50% of these losses emitted as N
2
O. Cane trash removal reduced N
2
emission by 34% and N
2
O emission by 51%, but had no effect on the N
2
O/(N
2
+ N
2
O) ratio. The use of DMPP lowered N
2
and N
2
O emission by 35% and 98%, respectively, reducing the percentage of these losses (N
2
+ N
2
O) emitted as N
2
O to only 4%. We conclude that the use of DMPP is an effective strategy to reduce N losses, minimise N
2
O emissions, while keeping the benefits of cane trash retention in sugarcane cropping systems. |
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ISSN: | 1385-1314 1573-0867 |
DOI: | 10.1007/s10705-023-10262-4 |