• This large scale on-farm demonstration has shown how soil inversion with a mouldboard plough can provide wheat yield benefits on sandplain soil.
• The mouldboard ploughing reduced the soil water repellence by about a third, but moderate repellence was still present. In this trial frost affected the mouldboard plough treated area more than the untreated area which is opposite to what some growers have reported who felt that crops on mouldboard ploughed soil were less affected by frost.
• Soil type, soil moisture, crop biomass and timing of the frost event may have had an impact in 2014.
• Short-term grain yield responses to cultivation on sandplain soils are typical and the potential benefits need to be studied for several more seasons before the value of the practice can be properly assessed.
• Other deep soil cultivation practices, such as deep ripping, can also give wheat yield responses in the first year.

The value of starter P for early crop vigour was clearly demonstrated in 2014 by the decreased growth of wheat plants when P fertiliser was omitted. This effect continued through the grain development stages and was very evident in the final grain yield differences. If P application over the previous four years averaged 12 kg/ha or less, there is a good value return from applying P.  Although the highest yield was seen at 24 kg P applied in 2014, looking at historical trends shows that continual application of P at greater than 12kg/ha can provide yield gains but little or no margin and should not be considered unless low P application history, confirmed by soil P tests associated with P binding capacity, has resulted in low soil P levels. Results indicate a P recommendation of greater than 6 kg/ha to be appropriate for soils and conditions in the vicinity of the trial site, pushing up to 10-12 kg/ha if the input cost is affordable.

Insufficient frost events occurred at Wickepin during the susceptible windows in 2014 to cause significant frost damage. Temperature results demonstrated that low in the landscape retained stubble increased the severity of the frost in one of the 10 frost events, but also increased the duration of frost events. Results from 2014 were not conclusive at Wickepin to demonstrate whether retaining stubble increases the incidence or severity of frost.

Temperature results from both sites have demonstrated that stubble loads above 2t/ha increased the severity and duration of some frost events. Analysis of results on yield and frost damage is ongoing and will be presented.

Temperature results from both sites have demonstrated that stubble loads above 2t/ha increased the severity and duration of some frost events. Analysis of results on yield and frost damage is ongoing and will be presented.

• Seeding rate had a bigger impact on wheat establishment than soil wetting agents
• High seeding rates on soils with low yield potential were sometimes a disadvantage; optimal seeding rates would need to account for yield potential as well as the degree of soil water repellence.
• Delaying sowing providing an opportunity to get a knockdown of weeds was important on water repellent soils where staggered weed germination, and reduced herbicide activity, reduces efficacy of in-crop and pre-emergent applications.
• In these trials soil wetting agents did not consistently improve wheat establishment and despite some evidence of benefits to vegetative growth this generally did not translate into a grain yield benefit.

• Both N and K have influenced wheat growth at the site, to varying degrees.
• Summit’s complex soil test interpretation model recommended 90 kg N for a 3 T/ha wheat crop based on the soil sample analyses at this site. With a growing season rainfall of 300 mm and the responses in this trial, an N recommendation of 80 kg/ha appears appropriate.
• Potassium recommendations from the Summit model were 20 kg K for a 3 T/ha wheat crop. Potassium recommendations will be much more dependent on soil characteristics and laboratory test results, but even on the duplex soil at the site, 10 to 20 kg K/ha looks to be of benefit in helping plants to maximise the potential growth benefits from top-up nitrogen applications.
• Mace wheat utilises N nutrition for yield, on the whole, but protein does increase somewhat with increasing N application and targeting higher delivery grades is possible if desired.

• In 2013 there was no evidence of changes in soil condition or organic carbon associated with the application of compost at up to 3 t/ha in 2012. Potential changes in soil organic carbon and other soil properties will be determined in February 2014.
• This trial will be continued in 2014 to assess changes in soil condition and future production.

Overall, moderate grazing up to Z25-Z30 and clip grazing at and after Z25-Z30 had little to no significant impacts on yield. However,assessing the value of grazing to the farm system is complicated as grazing can affect time of flowering and frost impacts. It can also increase water use efficiency, allow pasture paddocks to be deferred, reduce the need for supplementation and allow increased stock numbers and/or crop area.

Light grazing was shown to leave most of the crop residue horizontal and detached but there were similar amounts of residue to the ungrazed plots. Grazing over summer and winter reduced crop yield at one site and further work on this may be required.

In high yielding environment with yield potential around 5 t/ha, Cobra (AH) yielded similar to Mace (AH) in both May and June sowings. New variety Trojan (quality grade not yet known in WA) outyielded Mace by 8% across both time of sowings. Selecting two or three varieties with different traits should help to manage production risks and to achieve yield stability.

Although the Wickepin site did not experience damaging frost events in 2013, results show that the severity (minimum temperature) and duration (hrs <0°C) of frost increased at positions lower in the landscape and was less severe under cultivation. Standing stubble treatments also showed colder temperatures than removed stubble treatments. These results also supported the two other trials conducted in Western Australia during 2013 that showed stubble can have an influence on crop canopy temperature.

Early differences in Yellow Spot (YS) infection were evident at seedling/tillering stage, infection was greatest in the susceptible variety Yitpi; however, seasonal weather conditions and WSMV infection reduced any further impact from fungal leaf disease. Wheat streak mosaic virus (WSMV) and High Plains Virus (HPV) caused yellowing and stunting of plants across the trial with >75% WSMV infection evident in all plots, differences between varieties in incidence of infection were not significant. However, yield was greatest in varieties with lowest incidence of WSMV infection. WSMV and drought stresses severely reduced yield and as such results are not conclusive for nitrogen and fungicide applications in wheat on wheat systems. Similar DAFWA research in Northern Region (having no WSMV) reported that wheat with sub-optimal nitrogen and no fungicide application is more vulnerable to fungal leaf spot diseases, particularly in a susceptible variety, and may suffer yield losses (compared to optimal N and fungicide) in wheat on wheat systems. Further collaborative work will be planned in 2013 to determine the value of nitrogen and fungicide on the profitability of new wheat varieties with different disease resistances in wheat on wheat system.

Carbon is generating plenty of interest at present and the project aims to answer questions around increasing organic carbon in agricultural soils through the addition of carbon source. It would be expected that the results will show minimal impact on soil carbon levels in the first year of trialling however will to be tested by the Facey Group in continuance to the project. Harvest results however require further investigation with such variance between the remainder of the paddock and the treatments within the trial.

• Moderate grazing up to Z30 and clip grazing after Z30 did not appear to have significant impacts on yield in 2012 when compared to early sown crops.
• However, assessing the value of grazing to the farm systems is complicated as grazing can affect time of flowering and frost impacts. It can also increase water use efficiency, allow pasture paddocks to be deferred, reduce the need for supplementation and allow for increased stock numbers and/or crop area.

The occurrence of frost and subsequent frost damage to grain crops is a complex phenomenon. The factors affecting frost damage in wheat crop include seasonal conditions (temperature, humidity, and wind), soils characteristics (topography, soil type), variety (maturity and flowering window) and agronomic management (sowing date, row spacing, and seed and fertiliser inputs). In 2012, frost had significantly damaged and reduced the grain yield for all varieties at two different sowing dates at Wickepin. On average the later sowings (8 June) yielded 1 t/ha greater than the earlier sowings (18 May). Comparatively longer season varieties such as Magenta and Calingiri flowered late, avoided some of frost damage and yielded the highest at both sowings. Preliminary results indicate varieties differed in their relative performance and resilience (i.e. ability to yield) in response to stresses of radiant frosts in both time of sowings. More comprehensive results on variety performance and frost damage will be available after measuring grain quality and sterility estimates.