More than a third of growers and advisers in northern New South Wales and southern Queensland have changed their approach to nitrogen rate, application method or timing in wheat crops during the past five years, according to a new survey.
The 2018 Northern Grower Alliance Nitrogen Management in Wheat Survey received responses from 100 growers and advisers overseeing more than 1.6 million hectares of wheat production along the Queensland-NSW border.
A key aim of the survey was to determine whether growers and advisers in the region had changed nitrogen (N) management strategies in the past five years and if so, what had been the driving motivation behind the adoption of new agronomic practices.
The survey was conducted by the Northern Grower Alliance (NGA), a Grains Research and Development Corporation (GRDC) grower solutions group investment. During the past six years, a total of 25 NGA trials have focused on N management in wheat, as part of a broader national investment by the GRDC into N efficiency.
NGA Chief Executive Officer Richard Daniel said 26 per cent of survey respondents were growers and 66 per cent were private or reseller agronomists, with both groups indicating similar levels of practice change when it came to determining N application rate, application method and timing.
“Confidence for spreading N in-crop has changed quite dramatically in the past five years. This has been apparent from the increased use of spreaders, both for in-crop but also prior to planting application,” Mr Daniel said.
“Of the growers and agronomists who participated in the survey, more than 70 per cent reported they were more confident with the potential to spread urea in-crop than they were five years ago.
“Respondents indicated they were also more confident with their ability to spread urea in fallow, although most would only consider this approach in lower risk scenarios.
“Growers and agronomists are always searching for opportunities that can improve profitability, but still remain cautious about applying N in fallow and I think that is a sensible thing.
“Our understanding of the importance and magnitude of volatilisation loss has changed markedly in the past few years, but we still need to better identify and understand the ‘no-go’ situations.”
More than a third of survey respondents indicated their preferred timing for N application had also changed. Most growers and agronomists in the survey preferred a combination of in-fallow with top-dressing, or early in fallow, three-to-six months before planting.
When it came to method of N application, 32 per cent indicated their preferences had changed since 2013.
Banded application of granules or prills in the fallow was still clearly the dominant method, but many were now frequently spreading and incorporating N either in fallow or at planting or even simply spreading in fallow.
The majority of survey respondents said improvements in logistical and/or operational efficiency and/or lower application costs were the reasons for this change.
More than a third of respondents had also altered their approach to determining N rate during the past five years.
“The survey results confirmed the key factors guiding application rate were: yield and protein targets for the next crop, soil moisture availability and seasonal forecasts, and agronomist or adviser advice,” Mr Daniel said.
In a summary of survey results about why respondents’ approach to N rate had changed, Mr Daniel said the predominant responses were:
- Long term N needs of rotation rather than a single crop;
- Use a consistent rate pre-crop and top up as needed;
- Accommodate risk management;
- Use replacement value of nutrition removed.
“A key message from the survey was more than 85 per cent of the growers and agronomists believed NGA had improved their level of knowledge and confidence when it came to N management strategies for wheat,” Mr Daniel said.
“And importantly this survey showed practice changes have been made on more than 800,000 hectares of wheat growing country, so more than 45 per cent of the area managed by growers and agronomists who completed the survey.
“For those completing the survey the major benefits to changing their N programs were improvements in on-farm logistics, input cost savings, risk management and crop performance.”