The success of break crops to increase wheat production in the Eastern Wheatbelt is dependent on firstly addressing any physical and chemical soil constraints to crop production and where the previous land use is a chemical fallow. In this situation, the grain yield of lupin, chickpea, lentil and field pea was 0.97-1.42 t/ha 0.67-1.1 t/ha, 0.3-0.97 t/ha, and 1.2 t/ha respectively in a below average season. The yield of wheat following legume break crops tended to be higher than either canola or wheat planted in the remaining paddock area. The profitability of double break-crop sequences was negative in many of the sequences evaluated in this study compared to a positive profit for continuous wheat. The profitability of double break-crop sequences can be improved by the inclusion of high value legumes as the second break-crop, but further work is required to lower the risk of growing these species of crops.The yield of wheat following legume break crops tended to be higher than either canola or wheat planted in the remaining paddock area. The profitability of double break-crop sequences was negative in many of the sequences evaluated in this study compared to a positive profit for continuous wheat. The profitability of double break-crop sequences can be improved by the inclusion of high value legumes as the second break-crop, but further work is required to lower the risk of growing these species of crops.

The trial will be going into its 3rd year in 2018 and all trial plots will be sown into wheat. The aim is to determine the difference in grain yield for wheat following a range of single or double break crop rotations, compared to continuous wheat. The site was established in 2016 on a paddock that had very high level of ryegrass that was affecting crop production. This area around this trial has been in pasture for 2017 as the comparison farmer solution for the issue.

The trial was dogged by non-wetting and kangaroo grazing problems and so the bioassay of the residual effect of the original source of P treatments was poor..

Recoveries of applied phosphorus in the surface layers was poorest for the water soluble, plant available source superphosphate which had large leaching losses below 50 cm.  the less immediately available but citrate soluble source retained more P in the surface layers while the very insoluble C ore source produced poor growth but had only very low P leaching to depth.  The compromise in choice of source, between plant availability and leaching into the ground water and subsequently the waterways, is  well illustrated by this trial

As a rule, soil fertility factors (non-wetting, organic carbon, CEC, soil organic nitrogen, acidification etc were all more affected by length of pasture ley than by pasture composition and cumulated production.  Cross plot transfer of surface soil may well have affected this finding..

The West Midlands site had an average yielding year for the Moora area. The Liebe Long Term Research Site had a good growing season in terms of rainfall and seasonal distribution. The average yield was about 50% higher than previous wheat trial years. This was similar to Forrestdale which also had good rainfall and seasonal distribution.

On average, all Bioprime treatments combined resulted in a 4% yield increase. Treatment 2 (foliar Bioprime and granular fertiliser) performed best, achieving a 10% yield increase averaged across the three sites). At the WMG site, five Bioprime treatments resulted in positive yield responses whereas this number was lower at the Liebe site (2 treatments). With data corrected for outliers, all Bioprime treatments resulted in a positive yield response. Given that the Liebe site, relative to the WMG site had a higher soil pH, and higher pre-seeding phosphate and exchangeable cations concentrations (Table 2), an average higher yield was expected and achieved here compared to the WMG (3.36 t/ha and 2.15 t/ha, respectively in unamended control treatments). Thus, the higher soil quality and soil health present at the Liebe site combined with the good 2016 season in terms of rainfall likely narrowed the yield gap.

As such any management options aiming to close the gap between actual and potential yield, would have had less scope to achieve this at the Liebe site in 2016. In contrast, the lower soil fertility at the WMG allowed Bioprime to more consistently improve crop production. The 2016 data suggest the opportunity to improve yield on a poor soil in a poor year is greater than on good soil in a good year.

Ongoing research will continue to further develop Bioprime technology as a tool to improve soil biology and maintain plant health and yield. There is a substantial database of microbiological and yield results which continues to expand with the expectation of understanding the links between root and plant colonization by beneficial bacteria and fungi with Bioprime application and growth improvements.

• In 2016, the soil mixing (grizzly or spader) had a greater wheat yield than the control (0.27-0.42 t/ha), regardless of product applied. The incorporation treatments are still being paid off and therefore have not produced the greatest net margin.
• Limesand/No till returned the best net margin for the 2nd consecutive year due to the low yield increases from either application of product or mixing treatment.
• The lime or dolomite treatments had greater yields (0.22-0.5 t/ha) regardless of mixing treatment.
• Care must be taken in interpretation of results due to pH variation across the site.
•  

A summary of the main results from the first season at the Moora trial are presented in Figures 1 and 2.  Due to technical issues, the trial was not seeded at the same time as the rest of the paddock, which was supposed to be used as an untreated control. For this reason, a comparison of the treatments to a control treatment without tillage and clay spreading is not available.  A statistically significant effect of tillage on early plant establishment was found when analysing the plant counts measured about four weeks after sowing (Figure 1, left). All the treatments with the off-set disc (in combination or not with clay spreading) had more plants per linear meter in comparison to the one-way plough treatments. This is likely due to uneven seeding depth following tillage with the one-way plough (deep tillage) compared to the shallower tillage with the off-set disc. Surprisingly, incorporation of subsoil clay at any given rate did not show any significant effect on early plant establishment although this result could be explained by the wetter than usual weather in April-May reducing the severity of soil water repellence.

Again, when looking at the tiller counts recorded 8 weeks after sowing (Figure 1, right) the addition of clay at different rates did not affect the number of tillers. However, the wheat growing in the one-way plough treatments overcame the initial delay in germination giving higher tiller number than those recorded in the treatments with the off-set disc (except for the treatment with 250 t/ha of clay). This trend continued at harvest, with the one-way plough treatments producing higher yields (4.5-4.6 t/ha on average) than the off-set disc treatments (4.1-4.3 t/ha on average) at any given rate of subsoil clay.

Due to the low rates of clay spreading and the low cost of the incorporation methods, all treatments provided a positive return of investments in the first year (ROI= ($/ha gain – $/ha total direct costs) / $/ha total direct costs), based on mean values in Table 1. Not surprisingly, the best ROI in the first year was obtained by the one-way plough treatment without clay spreading (1.42 $/ha), followed by the off-set disc without clay spreading (1.22 $/ha) and the treatments clay spread at 50 t/ha incorporated with one-way plough (1.17 $/ha). These estimates are indicative only, as indirect costs and interests on the initial capital investment are not included in the calculations. For more accurate estimates of ROI, yield results from multiple seasons and crops will be collected in the next 3 years.

 

A summary of the main results from the first season at the Moora trial are presented in Figures 1 and 2.  Due to technical issues, the trial was not seeded at the same time as the rest of the paddock, which was supposed to be used as an untreated control. For this reason, a comparison of the treatments to a control treatment without tillage and clay spreading is not available.  A statistically significant effect of tillage on early plant establishment was found when analysing the plant counts measured about four weeks after sowing (Figure 1, left). All the treatments with the off-set disc (in combination or not with clay spreading) had more plants per linear meter in comparison to the one-way plough treatments. This is likely due to uneven seeding depth following tillage with the one-way plough (deep tillage) compared to the shallower tillage with the off-set disc. Surprisingly, incorporation of subsoil clay at any given rate did not show any significant effect on early plant establishment although this result could be explained by the wetter than usual weather in April-May reducing the severity of soil water repellence.

Again, when looking at the tiller counts recorded 8 weeks after sowing (Figure 1, right) the addition of clay at different rates did not affect the number of tillers. However, the wheat growing in the one-way plough treatments overcame the initial delay in germination giving higher tiller number than those recorded in the treatments with the off-set disc (except for the treatment with 250 t/ha of clay). This trend continued at harvest, with the one-way plough treatments producing higher yields (4.5-4.6 t/ha on average) than the off-set disc treatments (4.1-4.3 t/ha on average) at any given rate of subsoil clay.

Due to the low rates of clay spreading and the low cost of the incorporation methods, all treatments provided a positive return of investments in the first year (ROI= ($/ha gain – $/ha total direct costs) / $/ha total direct costs), based on mean values in Table 1. Not surprisingly, the best ROI in the first year was obtained by the one-way plough treatment without clay spreading (1.42 $/ha), followed by the off-set disc without clay spreading (1.22 $/ha) and the treatments clay spread at 50 t/ha incorporated with one-way plough (1.17 $/ha). These estimates are indicative only, as indirect costs and interests on the initial capital investment are not included in the calculations. For more accurate estimates of ROI, yield results from multiple seasons and crops will be collected in the next 3 years.

The topsoil sand at Yanda was severely repellent (Figure 1, left), as measured by the molarity of ethanol droplet test (MED). Clay spreading and tillage (either combined or separated) significantly reduced the severity of water repellency. When the subsoil clay was not incorporated by tillage or was incorporated using an off-set disc, the soil water repellency generally decreased with an increasing amount of subsoil clay. However, low-repellency (MED<1) was obtained only at rates over 150 t/ha of subsoil.

In contrast, spading (either at standard speed of the tractor or at half speed) was the most effective method for the alleviation of soil water repellency. In these treatments, the MED values were completely reduced to zero (non-repellent soil) and, most importantly, this was achieved independently from the presence, or not, of clay-rich subsoil. The significant reduction of the soil water repellency however did not convert to better plant establishment measured five weeks after sowing (Figure 1, Right).  This result could be explained by the wetter than usual weather recorded during April-May 2016 that reduced the impact of the soil water repellency on plant establishment. Nevertheless, tiller counts collected five weeks after plant counts showed a significant effect of tillage on the number of tillers. In particular, the spader treatments (standard and ½ speed) had the most tillers while the control had the fewest.

This trend was repeated with the barley grain yields at harvest time (Figure 2). Both tillage and rate of clay spreading, significantly improved grain yield in comparison to the control treatments (no clay and no tillage). The lowest yield were recorded in the control treatments and in the off-set tillage only (no clay) with an average of 1.41 t/ha and 1.36 t/ha respectively. The shallow tillage (or incorporation) using off-set discs did not yield significantly differently from the treatments with no incorporation at any given rate of subsoil clay. Clay spreading at 250 t/ha followed by spading at standard speed produced the highest yield on average (2.93 t/ha). Nonetheless, all treatments with spading (standard and ½ speed) were able to yield over 2.5 t/ha, even without the addition of subsoil clay (Figure 2). 

Field observations showed that the trial was also affected by frost, which explained the lower than expected yields. Head samples were collected in early November 2016 from all the treatments (except spading at ½ speed) for the assessment of frost induced sterility (FIS= number of sterile florets / total number of florets) and the results are shown in Figure 3.

The results on FIS showed that frost damage might be one of the main reasons of low yields and responsible of the large yield differences between treatments. The control treatments and the off-set treatment (no clay) had over 60% frost induced sterility. Even though increasing amounts of subsoil clay significantly reduced FIS (Figure 3c), the treatments with no incorporation or with incorporation by off-set discs still recorded FIS values above 50%. Spading was the most effective treatment to significantly reduce frost damage to below 40%, regardless of the presence or not of subsoil clay (Figure 3a and b).

Spading was the most successful treatment in this first year of the trial at Yanda. Most importantly, spading was able to produce the highest yields and significantly reduce the frost damage regardless of the addition subsoil clay. This was particularly evident when estimating the simple return of investments on the first year of the trial (ROI= ($/ha gain – $/ha total direct costs) / $/ha total direct costs), based on the mean values presented in Table 3. Because of the high crop-specific costs with barley at Yanda (500 $/ha) and the yield reduction due to frost, spading alone at standard speed was the only treatment that gave a positive ROI on the first year (+0.4 $/ha) followed by negative ROI with spading at ½ speed (-0.18 $/ha) and the control (-0.35 $/ha). These estimates are indicative only, as indirect costs and interests on the initial capital investment are not included in the calculations. For more accurate estimates of ROI, yield results from multiple seasons and crops will be collected in the next 3 years.

 

Using the highest label rate of either Aviator Xpro or Prosaro in the first application for sclerotinia lowered the level of sclerotinia infection and recorded a higher $ROI/ha in this trial. Increasing the rate of fungicide increases early activity on active disease but will also increase the length of protection from reinfection. 

The use of higher rates under high sclerotinia disease pressure is recommended not only in a single spray application to extend the window of protection but as recorded in this trial it can provide benefits to a two spray strategy. Improvements in length and strength of sclerotinia control from the use of a higher rate in the first application have been recorded across multiple commercial trials conducted by Bayer Crop Science across Australia in the 2016 season.

Over all four trials both Sakura treatments maintained a positive $ROI/ha with Sakura + trifluralin ($78.50) slightly ahead on average $ROI/ha to the standalone Sakura ($73.48)

Sakura 118 g/ha recorded a $55.08 increase in $ROI/ha over Boxer Gold across the four trials. Boxer Gold $ROI was generally in line with that of the prosulfocarb treatments in three of the sites, except from Waddy Forest where prosulfocarb 2.5 L/ha recorded a higher yield. Why this occurred is not clear as results were cross checked back with the contractor to ensure there was not a transcription error.

Trifluralin, due to its poor weed control, especially at Cunderdin, returned a slight positive $ROI/ha ($7.20) across the four trials.

All four sites to some extent were affected by frost which may have affected yield outcomes.

Getting weed control right is the key to ensuring the longevity of any herbicide but it also allows the crop it’s best possible chance of achieving its yield potential. Using a program of effective knockdowns and a product with a long residual activity like Sakura can deliver higher yields and returns across a variety of soil types and locations as seen across the four trials conducted during the 2016 season.

The trial establishment was variable early due to some non-wetting soil and the crop was sown too deeply due to furrow fill from significant rain after sowing. Early crop vigour as a result was low with blackleg further reducing plant establishment; this coupled with high levels of Vegetable beetle damage also reduced the evenness of the plots.

According to the DAFWA sporacle model spore maturity occurred on approximately the 22nd May which meant this trial was at very high risk of significant disease risk as emergence coincided with high spore levels being released from last year’s stubble.

Yield differences of 2*st. dev. are significant. Within plot variability was large (st. dev. about 0.3 to 0.4 t/ha) but there is an apparent response to ripping, but not to depth of ripping.  More information is needed to interpret these results. 

At the time of first visit (30th May), plants were at ~3 leaf stage and no foliar disease was evident.  Seedling establishment showed no spatial differences, with average emergence of >100 plants / m2 in all treatments except those with triadimenol seed treatment where >20% reduction in emergence was noted.

Minimal foliar disease was evident at 7th July (~Z31) assessment, minor levels of Stagonospora nodorum (septoria nodorum blotch) (SNB) were evident in the lower canopy but severity was too low for fungicide differences to be assessed.  

Trace levels of powdery mildew (PM) were evident on stems and lowest canopy leaves of untreated plots at booting (27th July) when the second foliar spray was applied. Development of PM was slow and on 15th September (~Z69) average severity in untreated controls was <1% leaf area affected on top 3 leaves, with infection primarily restricted to Flag-2 (Table 1).

PM was also present on heads and stems at low severity at this time, however the distribution of disease, particularly on heads, was patchy across the trial making differentiating between treatments difficult. At this time only the booting foliar spray provided consistent significant reduction in incidence of powdery mildew on stems and leaves.

SNB was present at low levels throughout the season, assessments at head emergence (23rd August) showed a small but significant effect of foliar treatments (Z31 and Z45) and flutriafol and Uniform in-furrow on necrotic leaf area. Assessments 3 weeks later at Z69 indicated that flutriafol in-furrow, triadimenol seed dressing and both foliar spray timings were providing a small reduction (~8-15% leaf area) in necrosis associated with SNB infection (Table 1).

With late and patchy onset of PM, yield responses to fungicides were 0-320kg/ha, with only the flutriafol in-furrow treatment having significantly greater yield than the untreated control, this response is likely due to the reduction of SNB rather than any effect on powdery mildew. Neither foliar spray timing gave significant yield response. Reduced emergence in triadimenol treated plots resulted in a 15% yield reduction (Table 2).

At two other sites (Geraldton, Dalwallinu), where powdery mildew infection commenced during stem elongation, all tested seed dressing and in-furrow fungicides had significant impact on disease severity and incidence. At the one site (Geraldton) where powdery mildew was yield limiting, in-furrow and foliar fungicide treatments gave a significant yield response.

A trial was established west of Moora in 2016 to investigate in season potassium response in barley. The main objective was to compare Lokomotive, a liquid potassium product, to the more commonly used granular muriate of potash (MoP).  Both soil and plant sample analysis showed the site to be marginal/deficient in potassium. Treatments were applied at GS 32. This timing was chosen as potassium deficiency is most commonly identified late in the growing season, when visual symptoms appear, and confidence in an economic response to applications of MoP in the current season is diminishing. At the time of application there were typical potassium leaf deficiency symptoms on the lower leaves. 

Good growing conditions were experienced in Moora in 2016 and resulted in high barley yields of 4.17 to 4.39 t/ha. There was a small yield response (1.7% to 5.3%) from both Lokomotive and MoP however this was not significantly different to the untreated control. The small response to potassium in 2016 may be attributed to the wet spring conditions that would have made potassium in the soil more available to the crop. Further evaluation of in season potassium application is required when spring conditions aren’t as favorable as 2016.  

 

 

• The results presented in this report are from the first year of a three-year study that investigates the effect of break-crop sequences on wheat grain yield. The site was selected due to its high background levels of ryegrass control, and crop rotation treatments have been designed around weed control as the main rotational factor.
• Grain yield was relatively low compared to the growing season rainfall of 253 mm. Grain yield was affected by severe frost that occurred during grain fill.
• This project will continue with the second crop in rotation for the 2017 season, followed by wheat across all plots in 2018 to assess the benefit of a stacked rotation for subsequent wheat grain yield.

• There were no significant differences between cultivation treatments at the Martin site.  There was a significant effect from lime applied, as expected. There is an interesting trend of increasing pH over the 3 years in the limed treatments, suggesting that the lime applied in 2013 is still acting to reduce soil acidity after three years. 
• There were no significant differences between cultivation treatments at any depth in either year at the Brown site. 
• There were no significant differences between cultivation treatments at any depth at the McAlpine site. 

The results from this trial show the importance of ripping below the hard pan with deeper ripping. The hard pan at this site measured to a depth of 400mm prior to the ripping treatments going in. Ripping to 300mm, without spading, has not improved yield in either of the first two seasons as plant roots are slowed through the hard pan. For return on the dollars spent deep ripping it is important to understand where the hardpan is in your paddock before starting the program.

It is likely that the topsoil slotting plates are impacting the inter-row soil strength during the ripping process. Therefore the design needs investigation. It may be that additional shatter is required through winged points allowing the plates to pass through with less impact.

Monitoring of this trial continues during 2017 and 2018 seasons.

• Unfortunately, crop was only sown at 40kg/ha, half the intended seeding rate. Low seeding rate and sever sub-soil compactions resulted in relatively low yields.
• There were only low levels of yellow leaf diseases.
• The site responded to N and K. With fungicide applied, there was a 0.7t/ha response to 85 kg N/ha (trt 3 v 4), and a 0.5t/ha response to 68kg K/ha (trt 2v9).
• There was a significant response to fungicide at the high rate of N, but only with K applied. This suggests the benefits of fungicide are greatest where nutrient deficiencies are overcome.
• Hectolitre weights were 74-77 kg/l and screening less than 5%
•  

• Plant tests indicated marginal potassium (K) supply but there were no obvious visual responses.
• An independent analysis of NDVI imagery showed that K-Till Extra Plus was more effective than the MAP/MoP blend, and this was supported by significant yield differences.
• K-Till Extra Plus outyielded the MAP/MoP blend by 170 kg/ha.
• Grain quality was not affected by treatment – proteins were about 11.4%, hectolitre weights 80 kg/hL and screenings 4%.

 

On deep sandy profiles subsoil compaction and acidity are major constraints. At this site the limited cropping history resulted in an expectation that the site would not be compacted but compaction was severe, indicating how susceptible these pale sands can be to compaction. For many deep sands, liming followed by deep ripping with topsoil slotting may be one of the most economical ways of effectively overcoming subsoil compaction and acidity to depths of 40-60cm.

On severely repellent sands however, it may be that deep ripping alone is inadequate and options which overcome the repellence and assist with weed control while at the same time addressing subsoil compaction and acidity may be required to get sustained productivity benefits (Davies et. al. 2017). The impact of deep ripping on highly repellent soils is variable with anecdotal reports that ripping can sometimes worsen the expression of repellence and result in poorer crop establishment. Other reports indicate substantial productivity gains can also be achieved (Blackwell et. al. 2016). Deep ripping may help overcome soil water repellence by: 1) creating a rougher soil surface allowing water to pond and infiltrate over time; 2) loosening the dry topsoil making it a more effective mulch, reducing soil moisture loss from the subsurface soil; 3) delving some seams of subsoil to the surface which act as pathways for water entry, with some ripper tine designs and attachments facilitating this more than others. Conversely the negative effects of deep ripping can include: 1) enhanced drying of the repellent topsoil from the loosening action; 2) increased expression of the water repellence when the soil is ripped when it is quite dry. Repellence severity, or expression, is increased with these negative effects which was the case for this site. For other sites where repellence is more moderate any benefits of deep ripping may outweigh the negative impacts. The mixed effects of deep ripping on repellent soils needs further research to be better understood. It is likely that rippers with C-shaped or parabolic shaped tines with broader points and wider ‘face’ plates will achieve more subsoil delving into the topsoil. Some rippers can also be fitted with wings which can also increase the degree of soil mixing. A greater degree of subsoil delving could result in development of more effective infiltration paths and longer lasting reductions in topsoil water repellence.

In this study rotary spading and modified one-way ploughing were effective in improving water infiltration on severely repellent sand even if they did not remove the deeper compaction. Second-hand one-way disc ploughs have a relatively low capital and operating cost (Table 1) and are relatively cheap to modify into a simple but robust tool for partial soil inversion (Davies et. al. 2016), although good seed bed preparation is still essential.

Barley yields exceeded 5 t/ha with strong responses to lime and potassium fertiliser.

The 1.0 t/ha response to potassium (K) was not as strong as in the previous two wheat crops (1.4 t/ha in 2013 and 2.4 t/ha in 2014). This was probably partly due to better control of ryegrass in plots without K fertiliser compared to previous years.

The response to lime applied in 2011 and 2014 was also 1.0 t/ha. This followed a 0.35 t/ha response in 2014 wheat. Like 2014, lime did not affect response to K.

Compared to topdressing potash, banding K increased early crop vigour, but 140 kg/ha K-Till Extra (15K) did not supply enough K to satisfy demand of the high yield potential.

This trial has highlighted the importance of maintaining K inputs (if required) when undertaking liming programs.

Ongoing responses to lime are likely to increase future demand for K because soil reserves will be depleted at an increasing rate.

• This trial produced a 0.9 t/ha yield response to potassium (K) fertiliser (trt 1 v 6).
• Early rains and a wetter than average season contributed to waterlogged growing conditions through June/July and most likely to significant leaching losses of nitrogen (N).
• Topdressed MoP treatments lacked the early vigour of plots sown with potassium (K) banded with K-Till Plus. This was despite about 50mm of rain falling between the date of topdressing (12 April) and sowing (16 May).
• As the season progressed, crop growth improved up to the highest rate of MoP (144 kg/ha) applied.
• There were no significant yield differences between strategies supplying between 9 and 24 kg K/ha (trt 2, 3, 4, 5).
• There was no response to magnesium (Mg) supplied by kieserite (trt 7).

.

• Sandplain soil with Colwell K analysis lower than 30 mg/kg is highly likely to be responsive to K.
• Potassium applied at 13-17 kg/ha in the compound NPK+traces fertiliser, Vigour, banded below the seed improved yields compared to NP+traces compound alone, and yields were further enhanced by applying additional 12.5 kg/ha K as MOP.
• Optimised returns will depend fertiliser and grain prices at the time. In the present trial, the greatest increase in returns were seen with Vigour 140 kg/ha at seeding plus 25 kg/ha MOP applied PSPE.

In the field the ability for the QST713 strain to colonise the root zone and improve the active interface between the soil, plant roots, bacteria and some of the exudate biochemical has been widely recorded. This delivers benefits across a wide range of crops (in WA benefits have been recorded in avocado, citrus, potato and leafy greens trials to date) with increases in nutrient levels in leaves and fruit to assist quality and shelf life among the improvements recorded. The application timing of the product is vital across crop type in order to achieve effective root colonisation. Generally timing should coincide with root flush timings for the respective crop but will also be influenced by the following factors:

Crop type and season length

Application method

Irrigation frequency and volume

Pests to be targeted

As a crop health product in horticulture, more research must be done and as grower experience increases with the product we will find out its BMP and how to best apply within different systems to get the optimum results.

Benefits to look for in potatoes are:

Yield consistency

Tuber size and grade %

Skin finish

Shelf life

The defining element that governs $ROI/ha in the trial is the pack shed pricing for various potato grades. This will fluctuate as will the demand for various grades which can see some of the results above skewing the $ROI. An example is a higher price for gourmet, chats and plain grade in 2016 due to shortages on the east coast which would cause the lower three grades to lose money in the trial as compared to the treated but overall the GM would still be positive.

• For this trial, the N-calculator prediction optimised yield and gross margin in Mace wheat.
• In Season N Calculator model predictions were
• Getting mid-season N decisions right can have a significant impact on profitability since optimal top up N rates indicatively increased yields by 480 kg per hectare and net returns by $70 per hectare.
• The value of split N applications was shown and the trial provides more weight to the building confidence that the N calculator can provide real and robust N recommendations that are not in excess of crop requirement and produce maximum or near maximum margin returns from mid-season N applications.

This demonstration clearly showed that by adding a small amount of barley (16kg/ha) to serradella when re-seeding, early winter feed for livestock can be significantly increased.  However, as the photos from early September indicate, the serradella growth in spring can be held back due to competition from the barley. Increasing the frequency and intensity of grazing would help, as would the application of a grass selective herbicide to kill the barley in early spring when feed is becoming abundant. If the season was very poor, the barley might be left to increase total pasture production and groundcover for summer.  

This is the first experiment to evaluate the effect of canopy architecture on wheat yield in Australia. The results show that leaf erectness appears to be an important trait for wheat in Western Australia. Erect leaves allow greater light penetration into the lower canopy.  As a result a larger leaf area and longer duration of greenness is maintained in the canopy over time (Fig. 2), both of which could increase photosynthesis and improve yield (Fig. 3). More data across a wide range of environments are needed to prove the hypothesis, and test other effects on weed competition and disease incidence. We will continue to evaluate this hypothesis with WMG in 2017, and look to broaden our evaluation with future projects beyond that.

Crop establishment and nutrient supply had a greater effect on crop growth than soil water repellence at this site. Interestingly, grain yield showed a weak, slightly positive relationship with our measurements of water repellence e.g. grain yield was highest at points that had higher levels of water repellence (data not shown here). The positive relationship between soil water repellence reflects the role of soil water repellent organic matter and soil nitrogen supply. Our results suggest nitrogen supply was a major limitation to growth therefore it is reasonable that higher grain yields occurred where soil organic carbon (soil nitrogen supply) was high. Water repellence may have had a minor effect because it was not severe at this site; the MED values ranged from 0.1 (Low water repellence, King 1981) to 2.1 (Moderate water repellence) and the average was 1.0 (Moderate water repellence). However, the samples for MED measurement were taken in winter when the expression of soil water repellence is lowest.

Gamma thorium provided a reasonable prediction of shoot K concentration and gravel content and provides a feasible method for delineating K management zones on sandy gravels in the Badgingarra area. Figure 2 shows that high shoot K concentration is associated with gravel content and vice versa. The critical shoot K concentration for wheat at anthesis is 1.5%; based on the data shown in Figure 2 the areas where gamma Thorium is less than 40 ppm would be responsive to potassium fertilizer application.

The gravel measurements separated into 2 clusters; non-gravelly soil where the fraction of gravel was less than 15% by weight and gravel soil where the fraction was greater than 15%. The mean Colwell K 0 to 10 cm was 17 mg kg which is well below the critical range of 51 to 57 for high yield potential on deep grey sands. Based on current prices and a wheat yield potential of 2t/ha, the DAFWA K calculator shows profit would be maximized with 40 kg K/ha applied. However, the efficacy of topdressed K on this sand may be low. The mean Colwell K for the gravel soil was 24 mg / kg which is also well below critical levels but shoot K concentration was adequate. This suggests that the crop is accessing K from the subsoil and that tissue testing may be an important component of assessing nutrient supply from different parts of the sandy gravel landscape.

These grower scale on-farm soil amelioration demonstrations have been managed by the growers according to standard practice. Both soil types are highly water repellent and in general the amelioration treatments have improved crop establishment, vigour and grain yield. Economic analysis indicates that the return on investment has been large as the benefits from the treatments have tended to last for at least 5-years or more at these sites. While it is possible to improve establishment, water and nutrient use efficiency and crop productivity using these techniques it is important to recognise that other constraints such as poor water and nutrient holding, soil acidity and compaction can still limit the yield potential of these soils and this needs to be considered when investing in amelioration. Liming to improve the soil pH and very deep ripping to remove compaction below 30-40 cm may well provide further yield gains beyond those achieved through amelioration of the top 10-30 cm only, and this may also help sustain the benefits of amelioration over a longer time.

Prior to treatments being imposed aluminium toxicity was visually identified as a constraint by digging up plants and examining the roots. It was evident from the roots sideways growth that root pruning was occurring, affecting plant growth by limiting access to nutrients and water. Compaction was thought not to be an issue as it was possible to push a 1cm rod to a depth of 140cm by hand.

When the Grizzly treatments were being implemented it was difficult to have an even depth throughout the plot due to plot size. The discs were only achieving maximum depth (30-35cm) in the centre of the plot however; the average depth achieved within the plot was 25-30cm.

At seeding it was difficult to establish an even seed bed which led to uneven germination in both the Spaded treatments and the Grizzly treatments. This resulted in these treatments having lower plant establishment numbers over the no till (Control).

Throughout the season it was visually evident that the incorporation treatments had major effects on crop growth and health. The Grizzly and spaded treatments had better vigour and larger head sizes when compared to the control treatments. This is likely due to the lower plant numbers, leading to less competition for water and nutrients in the cultivated plots. Although this didn’t translate to significant yield increases in the first year, the second year of the trial is expected to show more as the seeding bed will have settled allowing for an even germination. 

• A Predicta B sample taken from the site indicated a medium risk of rhizoctonia although patches did not express during the season.
• Early establishment across the site was severely impacted by non-wetting affected all plots across the trial with the worst of it commencing around plot 215 and increasing in severity throughout replicate 3.  Early dry conditions further staggered the crop emergence.
• Good rains through late July and into early August ensured the crop was growing well albeit patchy across the trial with high levels of disease present at both the Z31 and Z39 applications. Only 48.9 mm of rain fell from the second Z39 application to the end of October reducing the benefits to yield of the different fungicide treatments.
•  Increasing variability in the trial due to the sub-soil issues from plot 215 into replicate 3 was a significant factor. Yield data should be treated with caution due to the variability of the site with disease control is the most accurate assessment of treatment efficacy.

• The trial area was seeded in June 2015 to wheat by Peter Negus, while he was seeding the surrounding paddock.  Unfortunately, the seeder ran out of seed as the trial was being sown.  The result was that there were large unseeded strips running through the trial. 
• Rainfall at the site was very poor in September and October 2015; approximately 70% below average for that period.  As a result, cereal crops on soils with low water holding capacity were badly affected, with yields well below average.
• Analysis of the harvest results (excluding plots affected at seeding) showed no significant differences, leading us to conclude that either (a) the tillage and lime treatment effects have ‘worn out’ at the site, or that (b) poor rainfall in September and October severely reduced yields, obscuring any other effects.  We believe that (b) is more likely.
• This trial will be sown to lupins in 2016.

The pH results from this trial show some interesting trends. 

The treatments with greater disturbance at depth (spade, deep rip + spade, mouldboard) tend to decrease surface pH.  This is of concern if the ‘new’ topsoil pH is acidic enough to inhibit root development. 

The treatments with greater disturbance at depth (spade, deep rip + spade, mouldboard) tend to increase midsoil pH most rapidly.  This is the effect hoped for.  The differences between treatments are generally not significant, but more intensive sampling may tease out differences.

The treatments with greater disturbance at depth (spade, deep rip + spade, mouldboard) tend to increase subsoil pH most rapidly.  This is the effect hoped for.  The differences between treatments are generally not significant, but more intensive sampling may tease out differences.

Deep cultivation strips on growers’ properties did not show much in the way of early responses and so did not excite much grower interest as a direct diagnostic of the hardpan conditions in their paddocks. However, at responsive sites, there was a lot of grower interest to the level where it might be worth funding another year of this direct diagnostic approach in the hope that early season conditions are conducive to major nitrogen growth responses.

The Long Bottom Boots functioned reasonably well at first, but tended to plug with soil from underneath after multiple passes and on finer textured soil to the south of the trial area.

We think that a design that was wider at the back (60 – 80 mm) and therefore more open would improve soil flow down the boot, and reduce the risk of plugging.

All cultivation treatments reduced crop establishment significantly below “Nil” cultivation. 

Poor rainfall in September and October 2015 meant that the trial yielded very poorly (~0.5 T/ha), with no significant differences between treatments.

Soil test results are not yet available.

Our results so far suggest that there is an important interaction between year (timing and distribution of rainfall) and soil and nutrient management. There were no significant treatment effects on grain yield in 2013 and 2015, but there were in 2014 and this may be related to autumn rainfall. At the end of March, 75 and 57 mm had fallen in 2013 and 2015 respectively (Figure 3), however, only 16 mm had fallen at this time in 2014. In 2014, soil water repellence as measured in a laboratory test was significantly higher in the no-till control treatments compared to the rotary spader treatments. Seedling density in 2014 was highest in treatments that had the highest soil water repellence, however, this effect did not carry through to grain yield which was lowest in the no-till control. This trial will continue for at least one more year.

 

• Fungicide seed treatment or in-furrow did not affect germination or emergence.
• Root disease levels were too low for fungicide responses to be evident.
• Foliar assessments at Z25 & Z30 indicate low levels of necrotrophic disease, both yellow spot (YS) and Stagonospora nodorum (SNB) present with SNB dominant, with no significant impact of at-seeding fungicides on disease expression.
• Foliar fungicide applications at Z31 and Z39 significantly reduced foliar disease severity (YS and SNB) at flag leaf and head emergence.
• Warm dry spring conditions limited fungicide response to late fungicide (Z55) application.
• Yield and quality results were not available.

• Total seasonal biomass production from all of the annual pasture legumes was relatively poor as a result of the poor start. It begs the question, should Serradella, given its useful tolerance to the Imidazolinone group of herbicides, be sown with a fast growing Imidazolinone tolerant cereal such as Scope CL barley to improve early season feed production? If the season is good, the cereal could be grazed early and then sprayed out with a grass selective herbicide to stop it out-competing the Serradella later on. If the season is poor, the cereal could be left to provide valuable winter and spring feed.
• Residues of Imidazolinone group herbicides can affect the performance of the following year’s crops and pastures, so be aware and plan ahead. 

Overall the site experienced low starting rainfall with staggered plant emergence and then with further rainfall plot populations were within 75 to 85% of targeted plants/m2. All pests and diseases were controlled to an acceptably high level.

Prior to seeding the trial in 2015, the site was extensively soil sampled to a 60 cm depth by Precision SoilTech.  An area with the capacity to accommodate the treatments with minimal variation in soil pH between plots was identified, however due to the nature of this site and the layout of the treatments (designed to be practical for the landowner to implement and maintain), there are inconsistencies within the trial which need to be carefully considered when assessing treatment effects. There were no systematic differences between the lime treatments in crop establishment and harvest yield, seemingly as a result of variability in soil pH and other characteristics between plots, complicated further by the layout of the trial, rather than a treatment effect.

It was observed that incorporation by both offset discs and one way plough did not reduced or cause uneven germination compared to knife-point at seeding, and during the season it was not visually evident that incorporation treatments had a major effect on crop growth and health compared to the control treatment.

While it may not be expected that shallow incorporation of lime would result in significant differences between lime treatments on a forest gravel soil type in the first year of a trial, it is imperative going forward into the next two seasons that a professional statistician helps analyse current and future data to ensure that subsequent interpretations can be improved, given the apparent impacts of site variability, and as treatment effects may become more pronounced.  It is expected that the ongoing plot soil testing conducted prior seeding each season will be the primary indicator used to determine whether incorporation of lime using either offset discs or one way plough can reduce soil acidity on a forest gravel at depth more quickly than the district practice of top-dressing, while yield responses will determine any economic benefits.

This first year study has shown that the adoption of a strategic tillage practice (one-way plough) provided a significant improvement in terms of crop establishment and grain yields on a moderately repellent sandy gravel. The adoption of other agronomic options, such as paired-row sowing or wetters, in this instance did not provide any noticeable improvement in comparison to the control treatments. In fact, in one case (wetter 1), the cost of the treatment was not covered by the yield increase.

Without doubt, the tillage proved to be the most effective treatment for reducing SWR but at this stage it is not possible to evaluate the extent to which this improvement alone contributed to the significant increase in yields.

With this long term experiment, we expect the following seasons to give us more information to better understand what changes drive the yield increase and possibly the potential longevity of these improvements.

In the first growing season, the one-off tillage treatments showed to reduced significantly the water repellency of the soil. Significantly better plant establishment and grain yield were obtained in all the tillage treatments. In terms of grain yield, better results were achieved with the tillage treatments that mixed the soil more efficiently, such as the “Deep ripping + Spading” and the “Mouldboard plough” treatments. The “Deep ripping” treatment, which effectively targeted only subsoil compaction, provided the lowest improvements in terms SWR and the lowest grain yield.

The greatest profit in the first growing year was achieved using the “Modified one-way plough” thanks to its low capital cost which reduces its operating cost. Nonetheless, further growing season will be necessary to establish its long term profitability in comparison to the “Deep ripping + Spading” and the “Mouldboard plough” treatments.

Changes in the soil pH profile were also observed after the tillage treatments, with increased acidity in the topsoil. That was particularly the case with the “Mouldboard plough” treatment and the management of soil pH with addition of lime after the tillage needs to be considered.

We expect the next four growing seasons to give us more information to better understand the long term effects of these soil modifications on soil productivity.

 

Longer-season wheat with later flowering time produced higher yield than early flowering wheat. However, the high correlation between the time to anthesis and the time to terminal spikelet initiation makes it difficult to evaluate the relationship between yield and CPD independently. Increasing biomass from longer-season wheat is probably more promising trait than lengthening CPD to achieve higher yield in the high rainfall area.

• The site was very responsive to nitrogen (N) fertiliser. Increasing N inputs from 12 to 75 kg N/ha increased yields by about 0.36 t/ha
• NUlogic suggested very little response to P and K after soil testing. It is important to be soil testing at least every 3-4 years so that fertiliser rates recommended are applied for maximum economic returns to the grower.
• Tissue tests on the 3rd July indicated marginal S deficiency in the no S treatments but there was no yield response.
• Wind and rain after seeding caused furrow fill resulting in poor germination (5-15 plants m²).
• Yield potential  probably limited by low soil pH
• Decile 1 rainfall year for the area, interpret results accordingly.
• Quality analysis not yet available.

All tillage treatments had a little effect on the management of SWR and plant establishment in the severe water repellent gravel sand at Moora. Nevertheless, yield improvements were recorded, in particular with the “Large offsets” and the “Modified one-way with standard discs” treatments.

At this stage, it is not possible to clearly state what changes drove the yield increase. Given the little effect that the cultivations had on the SWR it is possible that improved soil structure, increased nutrient availability and nitrogen mineralisation may have played a role on the increased productivity.

The yield potential of the canola crop in 2015 was low given it was sown relatively late, plant numbers were low and there was a dry finish, this may have compromised the response to the tillage treatments. Observation of the trial in the following growing seasons and the response of a cereal crop in 2016 will help us to better understand the long term effect of the treatments on crop growth.

• Mace wheat responded positively to K.
• Source of K (SOP or MOP product) and timing had minimal impact on growth or yield response.
• Drilled MOP at 100 kg/ha produced the greatest yield and returns but evidence that drilled K is better overall than topdressed applications was not conclusive.
• SummitQ soil test modelling gave an accurate prediction of optimal K fertilizer rate.
• Grain quality was characterized by low hectolitre weights, but increasing K application improved both hectolitre and screenings quality aspects.

There has been a major response to ripping but little response to nitrogen above and beyond the farmer dressings.  The ripping treatment markedly improved crop emergence numbers and timing.  The very dry nature of the season after seeding has meant no leaching of nitrogen and therefore no improvement in nitrogen uptake efficiency due to faster root penetration on the ripped plots. Plant counts, estimated biomass levels and yield components are shown in the table of results, above.

There was a marked establishment and growth response to ripping and variability was much more marked on the non-ripped plots than on those which were ripped.  Measures of surface soil wettability showed no difference between ripping so the better establishment was probably due to better and more uniform wetting on the rougher, more disturbed, ripped soil. 

Ripping gave better early growth but also better finishing conditions as reflected in higher harvest indices and lower screenings.  The ripped strip samplings emphasized this point so it seems that the ripping allowed better access to stored sub-soil moisture over the harsh finish to the season. Plant samples from on and off the ripped strips showed no difference in K status.

We sampled on and off visually obvious windrows north of trial (2) on 10 July and south of trial (3) on heavier country on 18th August.  Both sites showed unambiguous K deficiency which again was reflected in better grain size and lower screening measures on the K adequate windrow.  The sandy site had more severe K deficiency and bigger responses than the loamy site which had a higher soil K status.  Both areas would respond to K fertilizer applications.

Legumes are an important tool in a perennial sward to supply a nitrogen source and maintain production. Serradella can be successfully established and persist in an established perennial pasture; this includes persisting as part of a crop/pasture rotation in perennials.

In the more favorable year of 2013 serradella biomass and pod production was higher. There is a yield penalty for serradella when sown into perennials, the penalty though will vary depending on the seasonal conditions. Perennials are still actively growing in March and April before the cooler weather starts to suppress their growth and they become less competitive. An indecisive Autumn break can allow active perennials to deplete moisture reserves that would normally allow germinating serradella to survive. These results clearly demonstrate the advantage of a successful early germination and establishment, although an indecisive break and low rainfall year will exaggerate the yield penalty when serradella is sown into perennials. Additionally, the suppressive effect of a grass selective on perennial growth may reduce competition with annual pasture species and can be used as a tool to increase annual legume production.

This year there was no big benefit from variable rate fertilizer in relation to yield. This is not unexpected given the dry season.

This trial gives some confidence that cutting fertilizer in particular P back on the low zone did not impact yield and had the best gross margin, therefore is a good strategy to reduce costs on the lower performing parts of the paddocks. This is consistent with current DAFWA and GRDC research findings that less phosphorus can be applied on soils with good P history without penalizing yield. Similarly it demonstrated the potential to reduce rates on the higher production zones depending on the season as tissue tests indicated adequate nitrogen just prior to the late N application. It is likely there was also more nitrogen available as a result of ripping increasing nitrogen mineralization and plant root access to water and nutrients. Reducing N applied after ripping is a recommended strategy to reduce the risk of the producing high biomass and the crop haying off early with a dry finish.

The estimated yield potential of the zones was not reached with the high zone about 1.5 t/ha below potential. This is consistent with farm observations that found there was a penalty of about 1 t/ha for crops sown later than 7 days from the 22nd May crops in this dry season.

High resolution six meter imagery was found to be very useful to identify management issues and map non-wetting soils, particularly the early July image which highlighted emergence issues. The non-wetting areas can be mapped and treated by ploughing those areas paddock not the whole reducing the cost of treatment. Ground-truthing showed the 6m resolution was high enough to identify problems with the bar such as running out of fertilizer. These are management issues that can be adjusted to improve efficiency and production to improve yield. 

In the case study paddock the imagery has highlighted issues that were not evident from the yield maps such as residual compaction from old corners and where the ripper and spader lifted over a water pipe (the red line in the top north east corner). This paddock has been deep ripped twice but old compaction is still visible suggesting it is beyond the current ripping depth of 400mm. The late season imagery was too late to see any big differences in biomass. An optimal time to capture imagery appears to be mid-July.

Applying low fertilizer to the low production zone is both a good economic strategy to improve profitability and prevents over fertilizing that increases the risk of nutrient leaching in these pale sands that have limited capacity to store nutrients.

Traditionally sowing wheat in Western Australia was not recommended until after Anzac Day.  A date based on the yield performance and maturities of commercially available wheat varieties in the 1990s. Since then growers have seen the release of Mace, a high yielding and very adaptable variety which at 67% dominates the area sown to wheat in WA in 2015 (Data courtesy of CBH group). Growers are now set up and keen to take advantage of any summer rainfall, but there is limited information on which wheat varieties to grow with a very early sowing opportunity.

Research carried out by James Hunt et al. (2014) suggested that the faster maturing winter wheat Whistler appeared well adapted to WA. When sown in mid-April Whistler was able to yield equivalent or better than Mace planted in late May (Crop Updates 2015). Results from Dandaragan and Katanning trials do support this suggestion but this research also suggests there are commercial varieties currently available in WA which can yield similar or higher and have a superior grain quality classification compared to Whistler. However these varieties can still be at the risk of frost and grain quality problems associated with very early sowings.

At all three sites in this trial series, barley out yielded wheat with both the mid-April and the early May planting (note we have included the predicted yield for barley with mid-April planting at Dandaragan of 7t/ha in this assessment). Barley was over 1.5t/ha better than wheat with both mid-April and early May planting. Whilst this research continues to highlight the need for a wheat variety which is more suitable for early sowing opportunities in Western Australia, growers looking for a cereal to sow in April could consider barley as being their new wheat variety until such wheats are released. Whilst this is only one year of observations there are many reasons to consider barley particularly with mid-April planting ahead of planting a wheat variety, including reduced (but still possible) frost risk.

The feed barley varieties Lockyer, Oxford, Rosalind and Urambie did not provide any yield advantage over those with a ‘malt’ classification at Dandaragan in 2015. The ‘malt’ varieties would therefore have been more profitable than the feed varieties as they were received with a premium over the feed barley varieties (either Malt 1 or Malt 2) at a similar grain yield.

With any early planting opportunity growers need to factor in increased fungicide costs. At Dandaragan powdery mildew and barley leaf rust in the barley plots and yellow spot in the wheat plots had to be controlled, particularly in the mid-April planting.