The effectiveness of the nitrification inhibitor dicyandiamide (DCD) in reducing nitrate leaching and nitrous oxide emissions from a grazed winter forage crop in southern New Zealand

2013 ◽  
Vol 175 ◽  
pp. 29-38 ◽  
Author(s):  
R.M. Monaghan ◽  
L.C. Smith ◽  
C.A.M. de Klein
2008 ◽  
Vol 48 (2) ◽  
pp. 160 ◽  
Author(s):  
L. C. Smith ◽  
C. A. M. de Klein ◽  
R. M. Monaghan ◽  
W. D. Catto

A study was conducted in Southland, New Zealand to: (i) measure nitrous oxide (N2O) emissions and nitrate (NO3–-N) leaching losses from a cattle-grazed, winter forage crop; and (ii) quantify the effect of dicyandiamide (DCD) in reducing these losses. Drainage losses were measured for 12 months (December 2005–November 2006) from a December-sown kale crop using 12 hydrologically isolated drainage plots at the Woodlands Research Station. N2O emissions were measured for 6 months (June–November) following simulated grazing of the crop in mid-June. N2O emissions from the bare ground following grazing of the crop amounted to 3.6 kg nitrogen (N)/ha for the winter–spring period. This figure is higher than that measured for pasture on the same soil type over a similar period. DCD application significantly reduced N2O emissions for the whole crop area by 25% over this period and reduced the N2O emission factor for urine by 54%. DCD application increased the length of time mineral N (0–10 cm soil depth) was maintained in the ammonium form and significantly reduced soil NO3–-N levels for 6 weeks following the simulated grazing. Annual NO3–-N losses in drainage under this winter forage crop were relatively high at 79 kg N/ha.year, with the majority of this (67%) being lost over the wet summer months (December–January rainfall 434 mm or 200% of normal) during crop growth. The application of DCD following the grazing resulted in a 47% decrease in NO3–-N leached over the winter–spring period (26 kg N/ha v. 14 kg N/ha) with this equating to a 29% decrease over the full 12-month measurement period. This study suggested that winter forage crops are major contributors to N losses from livestock farming systems in Southland and that DCD application following the grazing of such crops by cattle can significantly reduce N2O emissions and leaching N losses.


2008 ◽  
Vol 48 (2) ◽  
pp. 147 ◽  
Author(s):  
Coby J. Hoogendoorn ◽  
Cecile A. M. de Klein ◽  
Alison J. Rutherford ◽  
Selai Letica ◽  
Brian P. Devantier

Urine deposited by grazing animals represents the largest source of N2O emissions in New Zealand. Sheep-grazed hill pastures are an important component of New Zealand pastoral land, but information on N2O emissions from these areas is limited. The purpose of this study was to investigate the effect of increasing rates of fertiliser nitrogen and of a nitrification inhibitor on N2O emissions from urine patches. The study was carried out in grazed paddock-scale trials at the Ballantrae and Invermay Research Stations, New Zealand. The fertiliser N treatments were 0, 100, 300 and 750 (500 for Invermay) kg N/ha.year. Nitrous oxide measurements were conducted in the spring of 2005 and 2006, following applications of synthetic sheep urine with or without dicyandiamide (DCD) in these four N treatments. In both years and at both sites, N2O emissions increased with N fertiliser application rate in both urine and non-urine affected areas. The addition of DCD to the synthetic urine reduced N2O emissions from the urine affected areas during the measurement period by 60–80% at Ballantrae and by 40% at Invermay. The N2O emission factors for the artificial sheep urine (expressed as N2O-N lost as % of N applied) ranged from 0.01 to 1.06%, with the higher values generally found in the high N fertiliser treatments. The N2O emission factors were generally less than or similar to those from sheep urine applied to flat land pasture.


Soil Research ◽  
2017 ◽  
Vol 55 (6) ◽  
pp. 547 ◽  
Author(s):  
Terry J. Rose ◽  
Stephen G. Morris ◽  
Peter Quin ◽  
Lee J. Kearney ◽  
Stephen Kimber ◽  
...  

Although there is growing evidence that the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) can lower soil nitrous oxide (N2O) emissions in temperate environments, there is little evidence of its efficacy in subtropical or tropical environments where temperatures and rainfall intensities are typically higher. We investigated N2O emissions in field-grown aerobic rice in adjacent fields in the 2013–14 and 2014–15 seasons in a subtropical environment. Crops were topdressed with 80 kg nitrogen (N) ha–1 before rainfall, as either urea, urea + DMPP (at 1.6 kg DMPP t–1 urea: ‘urea-DMPP’) or a blend of 50% urea and 50% urea-DMPP in the 2013–14 season, and urea, urea-DMPP or polymer (3 month)-coated urea (PCU) in the 2014–15 season. DMPP-urea significantly (P < 0.05) lowered soil N2O emissions in the 2013–14 season during the peak flux period after N fertiliser application, but had no effect in 2014–15. The mean cumulative N2O emissions over the entire growing period were 190 g N2O-N ha–1 in 2013–14 and 413 g N2O-N ha–1 in 2014–15, with no significant effect of DMPP or PCU. Our results demonstrate that DMPP can lower N2O emissions in subtropical, aerobic rice during peak flux events following N fertiliser application in some seasons, but inherent variability in climate and soil N2O emissions limited the ability to detect significant differences in cumulative N2O flux over the seasonal assessment. A greater understanding of how environmental and soil factors impact the efficacy of DMPP in the subtropics is needed to formulate appropriate guidelines for its use commercially.


2005 ◽  
Vol 73 (2-3) ◽  
pp. 213-226 ◽  
Author(s):  
Stephen M. Thomas ◽  
Stewart F. Ledgard ◽  
Glyn S. Francis

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