From the addition of nitrogen at high rates, we have found that yield and grain quality can be influenced. There is also a threshold where nitrogen can be overdone. Based on the results from this demonstration, it appeared that all treatments with a GS37 application of N had a lower test weight as well as higher level of screenings and protein. In most instances this was a significant difference.

The best overall economic return form the use of nitrogen was 200kg/ha applied following seeding, then a top-up 100kg/ha at GS30. Giving a total application of 300kg urea. 

There is much to be learned and optimised in canola agronomy in Tasmania. With good infrastructure in place for irrigated cropping, the Tasmanian midlands hold great capacity for improved canola yields.

Key takeaways from this season and this study are muted yet we can still ascertain a few key learnings.

Long periods of waterlogging impact plants capacity to uptake nitrogen, inability to get on to the crop and deliver nitrogen early enough may have impacted overall yield despite the arial applications.

Management decisions are limited in these conditions, the use of aerial spreading is particularly useful in delicate soils that won’t recover from machinery damage.

Compounding factors in Severely wet years with high rainfall in critical growth times and chemical input windows all impact crop health and weed management, as well as nitrogen.

Following a lucerne crop, the crop was responsive to additional nitrogen inputs. With a background soil nitrogen level of 66kg N/ha, we were able to maximise yield with only the addition N. We saw a significant improvement in yield with the application of 46kg N/ha, however, applications above this were insignificant.

The addition of nitrogen also influenced grain quality. The most dramatic response was the increase in grain screenings with the increasing rates as well as the increasing grain protein with the increased rates of nitrogen.

We struggled to find any standout significant differences with the application timings. Whilst not significant, the plots that received nitrogen at GS00 and GS31 did appear to perform better and showed greater levels of vigour.

GPR are a tool that can be used to manipulate the canopy of a cereal crop to reduce the risk of lodging and head
loss. There was no benefit from applying PGR’s in this circumstance but given more favourable seasonal conditions
and a higher yielding crop benefits in harvestability and yield may have been observed.

Overall the durum trial showed no significant yield or protein changes from the application of PGRs at Z31. It showed
the difference in variety height suggesting that Mataroi is a good candidate for PGR application to reduce lodging in
a situation where soil constraints are not limiting. PGR applied to Vittaroi showed a ‘slight’ increase in protein and
test weight almost pushing it into DR2 grade.

• Drone application of beneficial insects and ViVUS® Max was demonstrated as an alternative to using a plane or helicopter.
• ViVUS® Max could be considered to be a viable option for the control of heliothis.  If it was also applied via overhead irrigation 2-3 applications of ViVUS® Max could be done for the same cost as a single application of Zeal. 
• At sites with a low Two Spotted Mite pressure (Coleambally and Tocumwal) the beneficial insects did control the mites at an equivalent level to Zeal or Abamectin.
• At the high Two Spotted Mite pressure site (Cooma), the trial had to be terminated as the beneficial insects were not able to adequately control the mites.
• No difference in yield was found between the conventional and IPM blocks at Tocumwal and Coleambally.

• Drone application of beneficial insects and ViVUS® Max was demonstrated as an alternative to using a plane or helicopter.
• ViVUS® Max could be considered to be a viable option for the control of heliothis.  If it was also applied via overhead irrigation 2-3 applications of ViVUS® Max could be done for the same cost as a single application of Zeal. 
• At sites with a low Two Spotted Mite pressure (Coleambally and Tocumwal) the beneficial insects did control the mites at an equivalent level to Zeal or Abamectin.
• At the high Two Spotted Mite pressure site (Cooma), the trial had to be terminated as the beneficial insects were not able to adequately control the mites.
• No difference in yield was found between the conventional and IPM blocks at Tocumwal and Coleambally.

Additional N was applied to the entire area during the season, until the 3rd week of January.  The nitrogen level still continued to fall below the desirable range from Reuter & Robinson (1997) even with these applications, with a further decrease observed past the end of January.  This indicates that additional applications of late season N may have been required.

Additional P and Zn was applied to the unlimited strip in both late November and December.  Given this the P level still continued to appear marginal into January.

As the K levels in the plant appeared to be dropping in mid January additional K was applied to the crop.  Following this application the drop in K continued in the plant tissue, although it could be assumed that without this late K application the drop in K may have been to a greater extent.

Despite the tissue tests indicating nutrient requirements, no increase in yield was obtained bny applying additional applied nutrients

• Short season crops like mungbeans (90days) cannot suffer any setbacks, such as poor drainage.
• One metre spacing was too wide formungbeans. The plant population was too low for a plant with poor stem strength. The crop fell into the furrows and late summer rains reduced grain quality.
• Strong, standing stubble is essential for mungbeans. The volume of lodged barley stubble in furrows restricted drainage to the detriment of mungbean crop, and barley grain on the ground contaminated the mungbean sample.
• Drainage is king. Clean paddocks and furrows are critical in surface irrigated systems.
• Maintaining winter crop stubble provided a good mouse breeding environment.
• Yields of 3 t/ha are possible for mungbeans in a favourable year and 2 t/ha crops were achieved in the Murrumbidgee Irrigation district.

At this stage, the risk of poor establishment in the crop, in this case maize, after the sub-soil manuring is a major barrier to farmers adopting this practice.  Farmers require more certainty on how to implement the practice change to ensure no negative impact on the first crop following the amelioration.  More information is required about the benefits in subsequent years.

It would be beneficial to have a soil specialist advising on the soils that would benefit from amelioration, as well as the timing and implementation of the practice.  In this focus paddock, the low lying nature of the site has made it prone to waterlogging, so drainage may need to be addressed as well.

The paddock has various amendments applied at depth, surface and incorporated, after visually not noticing any differences throughout the growing season in any year, soil tests were conducted to understand what was going on in the paddock. While the yield did not vary, the area that had Chicken Litter strip tilled was able to maintain a higher level of Nitrogen in the soil, this did not alter yield response though.

When choosing an area to ameliorate you need to be sure you are targeting low performing areas to see any financial return on the time and amendment costs. Some soils are achieving capacity through crop type, therefore focus on the areas within your farm that are under performing.

While there was no significant results within the 3 years of this project it remains an area of interest for our growers and we would like to understand the impact of irrigation on the Nitrogen Banking in cropping season.

The grower practice of applying Nitrogen topdressing is a risky option in wet years. Higher densities mixed with high N rates both contribute to a higher risk of disease. Added to good fertility already residing in this soil, such practice should be used with caution.
The trial should be conducted over a few years and different soil types to gain an understanding of Best Practice Management guidelines. Additional data will give growers a comfort factor to adopt such practices in the future.

The 2019/20 season was regarded as one of only moderate mite pressure, Two Spotted Mite control of some form was required at Byrneside in Northern Victoria. 

The commercial release of Persimilis could be considered as a viable alternative to the application of a foliar miticide, although timing, and crop monitoring is essential. The effectiveness of Califonicus needs further investigation. It is typically released earlier in the season, almost as a prophylactic treatment in that it can survive on pollen & stops mite numbers from building up.

Economics: 

Cost of one application of Zeal® (product and application/ha) = applied 350 ml/ha via helicopter = $56.61+$42= $98.61 (plus GST)

Cost of Persimilis (insects and drone application/ha) = $210 (plus GST)

Cost of Califonicus (insects and drone application/ha) = $150 (plus GST)

In a typical pest pressure year more than one application of Zeal® would be expected, whereas only one application of Persimilis may be required as once established they would keep building up within the field over the season.  This would need to be evaluated in a high pest pressure year though prior to growers considering commercial adoption.

Late (Z39+) application of N resulted in yield and protein increase over the control.

There is a difference between maximising biomass and the optimal biomass for maximum yield in a particular environment.

Maximising biomass creates agronomic problems such as increased foliar disease and early weed competition.

Irrigation can supply moisture during grain fill but cannot control the temperature - many of the winter wheats mature too late to avoid heat stress during grain fill. 

There is a difference between maximising biomass and the optimal biomass for maximum yield in a particular environment.

Maximising biomass creates agronomic problems such as increased foliar disease and early weed competition.

Irrigation can supply moisture during grain fill but cannot control the temperature - many of the winter wheats mature too late to avoid heat stress during grain fill. 

Bannister was the highest yileding variety from either sowing date.

The theoretical N contribution from faba stubbles is 20 kg N/tonne of stubble. However this assumes all residue is mineralised. 

Stubble retained on the soil surface is broken down more slowly than residues present in the soil.

A 6 t/ha bean crop resulted in approximately 140 kg N/ha being released for the following season. 

The faba crop contributed a significant amount of N, resulting in less symptoms of waterlogging during winter, reduced N applied through the season but insignificant yield effects and changes to barley grain quality.

Increased rates of N resulted in increased biomass, but the relationship between stubble N content and applied N was poor.

Higher applied  N resulted in higher Harvest Index

Harvest Index ranged from 0.45 to 0.47. 

Adding 70 kgN/ha prior to stubble incorporation addressed in crop N tie-up.

No fertiliser had any effect at any rate on the establishment of canola when watered up.

Lodging was reduced in scout wheat with the application of Moddus Evo at GS31, but yield was not affected.

 

The PGR trinexapac ethyl reduced plant height and improved lodging resistance but no PGR influenced yield.

Only the Chlormequat + Tebuconazole treatment reduced crop height (100 mm). No lodging, yield or grain quality differences where significant.

No PGR had any effect on plant hieght, lodging or yield.

Trinexapac-ethyl resulted in shorter crop height and higher screenings from th late application. There were no effects on yield or crop lodging.

The high rate of gypsum (3.0 t/ha) was the best ameliorant, with all other ameliorants and rates performing better than the control (no ameliorant).

• The ameliorants were applied in 2014, where 3.0 t/ha of gypsum proved to be the most effective in increasing establishment.
• However all treatments have had no effect in subsequent seasons.

Fungicides had no effect on grain yield.

No treatment resulted in any yield effects. No disease was detected on the controls throughout the season.

Consistent performance from Cobra, Beaufort and Scout.

The wet winter and subsequent waterlogged conditions through June and July resulted in reduced tillering, particularly in the earlier maturing varities, and overall yield performance was reduced.

Early sowing resulted in excessive vegetattive growth and also provided excelelnt conditions for ryegrass that proved difficult to control.

No treatment resulted in any yield effects. No disease was detected on the controls throughout the season.

The Plant Growth Regulator trinexapac-ethyl (Moddus Evo) has been shown in previous trials to increase yield in irrigated barley, but not necessarliy due to reduced lodging. This trial appears to indicate that the PGR resulted  increased tiller survival in lower plant populations of certain varieties. 

Some varities have shown no yield response to PGR application.

Selection of a variety that is not prone to lodging may be a better choice than applying a PGR.