The information contained in this publication is based on knowledge and understanding at the time of writing (July 2017) and may not be accurate, current or complete. The State of New South Wales (including the NSW Department of Industry), the author and the publisher take no responsibility, and will accept no liability, for the accuracy, currency, reliability or correctness of any information included in the document (including material provided by third parties). Readers should make their own inquiries and rely on their own advice when making decisions related to material contained in this publication. The product trade names in this publication are supplied on the understanding that no preference between equivalent products is intended and that the inclusion of a product name does not imply endorsement by the department over any equivalent product from another manufacturer.
Researcher(s) |
Annabelle McPherson (NSW DPI) Graeme Schwenke (NSW DPI) |
---|---|
Year(s) | 2016 |
Contributor | Department of Primary Industries NSW |
Trial location(s) |
Gunnedah, NSW
Emerald, QLD |
Further information | View external link |
To assess the efficacy of two nitrification inhibitors, 3,4-dimethylpyrazole (DMP) and nitrapyrin, when applied directly into the anhydrous ammonia stream during pre-plant nitrogen (N) application for commercial irrigated cotton production.
Conclusions:
In a season such as that experienced at the Emerald 2016–17 site, there were only minor environmental benefits from using a nitrification inhibitor in conjunction with anhydrous ammonia. However, these experimental conditions may not be typical as pre-plant fertiliser is usually applied earlier in the year at Emerald than it was at this site. A longer period of time between pre-plant application and plant establishment would provide greater opportunity for N2 O losses to occur, although the potential for heavy winter rainfall tends to be low in the Emerald region. While both inhibitor products clearly reduced emissions during the first two measurement periods, it was apparent that the effectiveness of these products had dissipated by the time of the second irrigation. The additional inhibitor application with the side-dressed urea boosted the N2 O reduction period for the DMPP treatment, while the application of untreated urea to the other treatments allowed further losses matching those of the untreated control after the initial pre-plant N application. The 2016–17 Gunnedah experiment provided the perfect testing conditions for nitrification inhibitors as the soil was very wet at application, and received frequent heavy rainfall during the next 3 months. These inhibitors were designed to retain mineral N from applied N fertiliser in the soil during periods of excessive rainfall that may otherwise lead to large losses of nitrate N through denitrification and leaching. Leaching occurs through downward movement of nitrate with water in the soil, but we found no evidence of this having occurred in the soil core samples we took just prior to sowing. For heavy clay soils such as this one at Gunnedah, denitrification of soil nitrate during periods of anaerobic soil conditions is the most likely major N loss pathway. The results of the gas sampling campaigns highlighted the almost complete mitigation of N2 O emissions during this period by adding nitrification inhibitors. The Big N-sure® inhibitor appeared to remain active for longer in the soil than the N-serve®.
Lead research organisation |
Department of Primary Industries NSW |
---|---|
Host research organisation | N/A |
Trial funding source | DPI NSW AOTG14013; 2013–17 |
Trial funding source | DAWR AOTG14013; 2013–17 |
Related program |
Determining optimum nitrogen strategies for abatement of emissions for different irrigated cotton systems |
Acknowledgments |
This experiment was part of the project Determining optimum nitrogen strategies for abatement of emissions for different irrigated cotton systems (AOTG14013; 2013–17), with joint investment by NSW DPI and DAWR, and administered by CRDC. Thanks to Ross Burnett and Rod Smith for providing the experimental sites and for applying the anhydrous ammonia and urea in field, and to Amanda Noone for carrying out the field work at Emerald, Pete Perfrement, Tim Grant and Wayne McPherson at Gunnedah. Technical assistance with the application of both inhibitors was provided by the Incitec-Pivot Big-N team and is gratefully acknowledged. Incitec-Pivot provided the Big N-sure® inhibitor and ENTEC®-urea, and Dow Agrosciences provided the N-serve® inhibitor. All soil and plant N analyses were carried out by Clarence Mercer in the ISO9001-accredited laboratory at Tamworth Agricultural Institute, NSW DPI. |
Other trial partners | Co-operators: Ross Burnett (Emerald), Rod Smith (Gunnedah), Incitec-Pivot Big-N team |
Crop type | Other crop: Cotton |
---|---|
Treatment type(s) |
|
Trial type | Experimental |
Trial design | Randomised,Replicated,Blocked |
Sow date | 20 August 2016 The Emerald site was sown with Sicot 746B3F on 20 August 2016. The Gunnedah site was sown with Sicot |
---|---|
Harvest date | 13 February 2017 Cotton picking at Emerald was on 13 February 2017. Picking at Gunnedah was not yet done at the time |
Plot size | Not specified |
Plot replication | 3 |
Plot blocking | Randomised complete block |
Plot randomisation | Randomised complete block design with three treatments (T1 = ammonia, T2 = ammonia + DMPS [Big N-sure®], T3 = ammonia + nitrapyrin [N-serve®]) and three replications. A Raven SideKick Pro direct injection system was used to apply nitrification inh |
Sow date | Not specified |
---|---|
Harvest date | Not specified |
Plot size | Not specified |
Plot replication | Not specified |
Plot blocking | Not specified |
Plot randomisation | Not specified |
SILO weather estimates sourced from https://www.longpaddock.qld.gov.au/silo/
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.