Soil acidity affects up to 5.5 million hectares (50%) of Victoria’s agricultural land and soil acidification looms as a major soil
degradation issue (NHT 2001). Soil acidification can be seen is a cost of productive agricultural systems - whether from
product removal, increased potential for nitrate leaching, the build-up of soil organic acids, or from the increased use of
nitrogen fertilizers.
Soil acidity and acidification are mostly ameliorated by applying agricultural lime. Australian Bureau of Statistics (2018)
survey data show the average rate of application of lime is only about 1.5 t/ha, which is considerably less than the general
minimum recommendations of 2.5-7.5 t/ha (Agriculture Victoria 2019). Moreover, few Victorian farmers, about 1,000 (5%),
use variable rate application. Variable rate application is used to apply a wide range of agricultural chemicals, lime being
only one of many, so that the application rate is adjusted to match changing local requirements within the paddock. No
statistics are available on the application of variable rate technology for managing soil acidity, however service providers
supporting variable rate liming are increasingly active.
Agriculture Victoria Research (AVR) studied 10 case-study paddocks in the HRZ of Victoria to demonstrate the net
economic benefits of using intensive point sampling of surface soil pH and the precision application of lime in cropping
systems.
The initial pHCa distribution within each paddock was obtained by sampling at the rate of 100 soil cores per paddock
followed by spatial interpolation to a resolution of 10 square metres.
Discounted cash flow (DCF) analysis was used to generate profit-maximising lime 'prescriptions’ for each homogenous pH
zone (HZ) within the 10 case-study cropping paddocks, and to quantify the net benefits of the precision liming strategy.
These benefits were compared to alternative liming strategies, including traditional approaches and uniform application.
The analysis followed the best-practice method described by Mullen (2001). It involved optimization and simulation; and it
accommodated the dynamic nature of the acidity nature of the soil, in that production in the current year is affected by
current pH and in turn has an impact on pH in the next year.
It was shown that reaping the benefits of the precision liming strategy is difficult, because benefits depend on the
decisions made by farmers and their advisors requiring a high level of data collection and management, interpretation, and
judgement.
When acid tolerant crops are grown, the net benefits of liming can generally be maximised using low-cost traditional
practices. However, if the decision-maker wants the option of planting high-value, acid-sensitive crops then it would pay to
pursue a profit-maximising strategy involving intensive point sampling, pH mapping and variable rate application.
The DCF model described in this report demonstrates the nature of the data, analysis and interpretation involved in the
decision-making process. The model has been prototyped in MS Excel® and uses Evolver, an optimization add-in that is
part of Palisade’s DecisionTools Suite. The DCF model is available from the primary author on request and can be used
with attribution.

The use of cultivation, whether deep or shallow, in 2003, shows no advantage in increasing the grain yield. In fact there may be a penalty in the loss of soil water, particularly at the surface, if the cultivation is performed in a dry autumn, as was the case in 2003.

The data would suggest that Deep Ripping had an effect on increasing the total water content of the soil, thereby making more moisture available to the barley crop during the spring months at a time when the crop was filling the grain. This may have resulted in a higher grain yield for both Ripped and Ripped + Gypsum treatments by comparison to the Direct Drilled and Shallow Cultivation treatments (although yield difference not statistically significant). 

For further conclusions please see the attached trial report.

For results and discussion please see the attached trial report.

Pre-sowing comment: surface crusting with adequate moisture at 3cm.

Early season commment: slow chickpea growth. Field peas ok some ryegrass. Adequte moisture.

Pre sowing comment: surface crusting with adequate mositure at 3cm.

Early season comment: slow chickpea growth. Field peas ok some ryegrass. Adequate moisture.

Artificially applied nitrogen had no significant effect on crop establishment or on early growth as determined from NIR testing 

• For further conclusions please see the attached trial report.

The project on the strategic use of tillage within no-till systems continued at the 4 sites in 2015: Harden, Daysdale (near Corowa), Thuddungra (near Young) and Berthong (near Cootamundra). Soil physical and chemical properties continued to be monitored throughout 2015. Establishment counts, dry matter and grain yields were also measured. The final harvest for the sites occurred in December 2015, except at the Daysdale site where we grew a vetch brown manure crop that was cut for dry matter in October. The final soil sampling at all sites will take place in autumn 2016. 

• Think of a fallow as a risk reducing investment for your property.
• Soil testing after chemical fallow is essential to determine the starting point of available nutrients in the soil.
• Good agronomic practices that maximise plant health and growth will allow crops to use water more effectively, improving yield potential.
• Weed free fallows mean increased moisture conservation leading to potentially higher yielding crops for the following year and more profitable rotations.
• The use of a residual herbicide to help suppress weeds over summer will be beneficial.
• If this trial was to be repeated, results will vary given different seasons and different soil types

• Fertiliser nitrogen (N) rates should be tailored to suit paddock history and soil mineral N levels at sowing.
• Sorghum yields without N fertiliser, although high in a favourable season, were still well below those achieved using additional N fertiliser.
• At Tamworth, in-season rainfall ideally suited a split-N application strategy resulting in the highest yields.
• At Breeza, drier conditions meant that neither split N application nor slowrelease N products boosted grain yields above those reached using urea all applied at sowing.
• Gross margins for most alternative N strategies were greater than that achieved when no N was applied.
   

• Fertiliser nitrogen (N) rates tailored to suit paddock history/ soil mineral N levels optimised N2O emissions.
• At Tamworth, withholding N fertiliser on a high mineral N soil reduced N2O emissions, but did not optimise grain yield.
• At Breeza, most strategies of urea + nitrification inhibitor, polymer-coated urea and split N application substantially reduced N2O emissions. Most alternatives produced similar grain yields to the current practice of urea all applied at sowing, so the N2O emissions intensity per tonne of grain produced was also reduced.
• A 1:3 blend of urea + polymer-coated urea all applied at sowing, increased N2O emissions compared with the urea all at sowing treatment. The treatment also reduced grain yield, so potential slow-release treatments need to be carefully evaluated from both an N2O emissions and grain production point of view.

• Fertiliser nitrogen (N) rates tailored to suit paddock history/ soil mineral N levels optimised N2O emissions.
• At Tamworth, withholding N fertiliser on a high mineral N soil reduced N2O emissions, but did not optimise grain yield.
• At Breeza, most strategies of urea + nitrification inhibitor, polymer-coated urea and split N application substantially reduced N2O emissions. Most alternatives produced similar grain yields to the current practice of urea all applied at sowing, so the N2O emissions intensity per tonne of grain produced was also reduced.
• A 1:3 blend of urea + polymer-coated urea all applied at sowing, increased N2O emissions compared with the urea all at sowing treatment. The treatment also reduced grain yield, so potential slow-release treatments need to be carefully evaluated from both an N2O emissions and grain production point of view.

• Fertiliser nitrogen (N) rates tailored to suit paddock history/ soil mineral N levels optimised N2O emissions.
• At Tamworth, withholding N fertiliser on a high mineral N soil reduced N2O emissions, but did not optimise grain yield.
• At Breeza, most strategies of urea + nitrification inhibitor, polymer-coated urea and split N application substantially reduced N2O emissions. Most alternatives produced similar grain yields to the current practice of urea all applied at sowing, so the N2O emissions intensity per tonne of grain produced was also reduced.
• A 1:3 blend of urea + polymer-coated urea all applied at sowing, increased N2O emissions compared with the urea all at sowing treatment. The treatment also reduced grain yield, so potential slow-release treatments need to be carefully evaluated from both an N2O emissions and grain production point of view.

• Very dry conditions during the 2013−14 summer meant that much of the nitrogen (N) fertiliser applied was not taken up by the sorghum crop, especially if it had been applied in-crop at booting. Between 46–65% of the applied N remained in the soil at harvest in 2013−14.
• A following crop of unfertilised sorghum accessed the remaining N for crop growth and, at rates of 100 kg N/ha and above in the 2013−14 crop, increased grain yield and protein above the control. Late N application by topdressing in the 2013−14 crop gave similar crop production results to treatments where N was sidebanded at sowing.
• Two-year gross margins showed a significant benefit from N application as urea either at sowing or incrop.
   

• For three seasons, we applied isotope-labelled urea (15N) to sorghum in small (0.75–1.0 m2) plots, then calculated nitrogen (N) recovery by comparing the amount applied with the total 15N found in grain, crop residues and soil.
• Between 55–85% of the N fertiliser applied was recovered at harvest, meaning a 15–45% loss, presumably during wet soil conditions when nitrate denitrification led to N2 and N2O gaseous losses.
• In very wet conditions, little of the applied N remained in the soil at harvest, while in a dry season there was more of the applied N found in the soil at harvest than in the plant.

• Treatment 1, Nil grazed, moderate stubble yielded the highest, (2.18 t/ha).
• No significant difference in Total Plant Available Water, majority of stored water was below the 50 cm depth.
• There was a significant difference between the eight treatments when comparing available soil nitrogen.
• There was a significant difference in grain quality attributes between the eight stubble treatments.

• Different methods of stubble handling had little impact on yield.
• Early soil testing allowed good decision making for crop nutrition and budgeting.
• Soil biota were more active in the in-row root zone, as opposed to the mid row zone.

No real conclusions can be drawn from 2005 data, although the use of scratch tillage at the Inverleigh and Mingay sites showed some promise, but did come at a financial cost if implemented on raised-beds. 

• For different 2013 treatments, the amount of stubble ranged from 2.4 to 4.0 t DM/ha at harvest and from 1.6 to 3.0 t DM/ha at the subsequent sowing. The only statistically significant effect of 2013 treatments on 2014 pre sowing stubble was a difference between wheat and vetch stubble, 2.7 t DM/ha and 2.0 t DM/ha, respectively, reflecting faster breakdown of vetch than wheat stubble.
• Despite significant differences in the amount and types of stubble generated in 2013, and remaining at sowing in 2014, there was no statistically significant effect of 2013 treatments on 2014 soil moisture at sowing or 2014 crop yields.
• There were significant differences between crop types in 2014. Significantly more wheat plants established than canola (49 and 15 plants/m2 respectively) and wheat had a significantly higher grain yield than canola (1.2 and 0.3 t/ha respectively). Both wheat and canola were affected by the dry spring and associated frosts, plus canola had poor establishment.
• Research conducted previously at Walpeup in the 1980s found that maintaining 2 t/ha stubble increased the amount of water stored in the soil at sowing, at depth 0–140 cm, by 16 mm in 1 year of 3. This increase in soil water availability was not reflected in increased crop yield.
• The recent experiment at Ouyen, together with the previous research at Walpeup, indicate that Mallee crop yields are unlikely to be increased by retaining higher levels of stubble, although there can be benefits of reduced soil erosion.

High stubble loads appear to increase frost damage by reducing the amount of heat radiated from the soil at night, leading to lower canopy temperatures and greater frost severity, duration and damage.

• Since soil moisture was not limiting, and a soft finish to the season was observed, sowing date trials at Minnipa in 2010 showed no differences in yield between stubble treatments under these conditions.
• This trial will be repeated in the same environment to validate across seasons.

• In 2016, a Decile 10 season, stubble load had no effect on soil mineral nitrogen or soil water.
• The presence of stubble resulted in higher soil mineral nitrogen over the summer fallow period.
• Wheat yields were higher following peas or fallow than they were after wheat or canola in 2016.

• On black soil the average wheat yield increase due to zinc was of the order of 240 kg/ha between 1939 and 1949.

• Grain yield at Hill River was increased on two soil types by 12% and 33% through the addition of soil amendments to the surface or subsoil.
• There was no yield difference between applying amendment to the surface or subsoil in 2016, except at one of the seven sites sown to lentils.
• There was little difference between applying large rates of synthetic fertiliser or applying 20 t/ha chicken litter.

• PPS believes that the results in the Jallukar trial show that the technique of sub soil amelioration has potential to produce large increases in productivity in certain soils in the Upper Wimmera region.  
• The drier than average springs allowed for only one dry matter cut each year; more favourable seasons may have altered the results. 
• For further discussion please see the attached trial report.

• Trace elements applied to the soil (either shallow at seeding or deep prior to seeding) two years previously benefitted wheat at a clay spread site.
• Accross all sites and six years of measurements there were no measurable residual responses to deep placed nutrients.

• Incorporating clay that has high calcium carbonate (lime) content has potential to cause extreme manganese deficiency although this can be addressed with addition of micronutrient fertiliser either shallow or deep.

• Chlorsulfuron herbicide was found to reduce wheat yields at some sites.
• Phosphorus (P) responses were closely correlated with soil P levels.
• No significant responses to zinc (Zn) fertiliser were recorded.
• P and Zn nutrition was not found to interact with chlorsulfuron herbicide damage in wheat

• Chlorsulfuron (e.g. Glean) was found to reduce wheat yields at some sites.
• No Zinc (Zn) responses were recorded at any of the sites.
• Phosphorus (P) response was closely correlated with soil P levels.
• Increasing Zn and P nutrition did not reduce the Chlorsulfuron effect.

• The addition of sulphur increased wheat grain yield at both trial sites.
• Grain yield at the clay loam site was consistent for all of the sulphur rates, sources (gypsum and SoA) and application times tested
• In contrast, there was variation in grain yield for the sulphur treatments tested at the sandy dune location due to the poor nutrient holding capacity of this soil type.

• Durum quality wheat was produced at Lubeck, although high soil N levels pushed protein levels above the maximum for noodle wheat. Milling wheat grown at the same site achieved H2 quality. There was no yield response to N fertiliser at sowing. This demonstration highlights the importance of careful paddock selection when producing specialty wheat.
• While it has been demonstrated that durum wheat can be produced in this part of the Wimmera, durum is a high risk option. A basic economic comparison highlighted the high penalty when downgraded to feed quality if durum specifications are not met.

1. Summer cover crops can be very profitable; improving ground cover and increasing fallow water storage in long fallows to improve grain yields and boost returns in northern farming systems.
2. A later spray-out produced additional levels of a cover that is more resilient and stored more water in the longer fallow. Delaying spray-out too long reduced fallow water storage considerably.
3. Using a summer cover crop saved two fallow herbicide sprays and dramatically improved establishment of the subsequent wheat crop.
4. Yields and returns were increased by the cover crops, and yields were well in excess of those expected from the increased soil water storage alone.

The growing season rainfall in 2019 was below average at Perillup, and the summer cropping demonstration did not suffer from water-logging.

Grain growers in this region believe that the soil drying effects from growing summer crops has the greatest potential benefit to winter cropping yields.

In 2019, there was a 770kg/ha barley yield increase above the control from the plots where cowpea was grown in the summer.

There was a 470kg/ha decline in winter barley yield in the plot that was planted to canola between January 30 and May 9, 2019.

Nutritional requirements of summer crops need to be considered when selecting species. Cowpeas fixed useful nitrogen in the 90 growing days.

2019 Demonstration Key Messages

• The growing season rainfall in 2019 was below average at Perillup, and the summer cropping demonstration did not suffer from water-logging.
• Grain growers in this region believe that the soil drying effects from growing summer crops has the greatest potential benefit to winter cropping yields.
• In 2019, there was a 770kg/ha barley yield increase above the control from the plots where cowpea was grown in the summer.
• There was a 470kg/ha decline in winter barley yield in the plot that was planted to canola between January 30 and May 9, 2019.
• Nutritional requirements of summer crops need to be considered when selecting species. Cowpeas fixed useful nitrogen in the 90 growing days.
• The growing season rainfall in 2019 was above average in Williams, and the summer cropping demonstration site was severely water-logged.
• Buster Radish could also be a perfect non-machinery deep ripping tool with its great root system.

2018 Demonstration Key Messages

• The summer cropping demonstration sites were sown at two different timings. The Ryansbrook trial, 35km south west of Kojonup, was sown 4th October 2018 into moisture and the Woodgenellup trial was dry sown on the 30th January 2019 prior to a predicted rainfall event.
• According to our producer rainfall records, since 2003, every 4 out of 5 years they have had summer rainfall events in January and February. Unfortunately, in the 2018/19 summer there was minimal summer rainfall and the summer crops at the Ryansbrook site failed. The C4 grasses (millet and sorghum) persisted better with little to no moisture in the soil profile compared to the broadleaf crop types (canola and cowpea).
• At the Woodgenellup site germination was patchy however, plants have developed reasonable biomass.
• Winter season in-crop measurements will be taken at the Woogenellup site to determine the effect of the summer crop on water logging. Due to the failure of the summer crop at the Ryansbrook site, no further measurements will be taken at this

• Wheat yield increased from 2.6 t/ha in controls to 3.2 t/ha in plots receiving the equivalent of summer rainfall decile 5 (50mm) or decile 9 (100mm) in a single event in February.
• Stubble treatments (bare ground control, standing 2 t stubble/ha, flat 2 t stubble/ha, flat 5 t stubble/ha) did not affect the dynamics of soil water nor grain yield.

• The presence of stubble did not increase stored soil moisture, regardless of the size and number of irrigation events.
• In 2010 additional soil moisture at sowing did not generally increase final grain yield.
• Additional soil moisture can increase crop demand and response to nitrogen.

• Summer sowing into perennial grasses is showing some promise, but the results are inconsistent.  We need to develop guidelines for the required soil conditions (including soil fertility) and there is a need to reduce weed competition by controlling the seed-set of annual pasture weeds in the preceding year.
• Results from these trials plus a range of other summer sowing sites demonstrate that serradella pods need to be drilled for successful establishment. Broadcasting pod is not a reliable alternative.
• The experimental line of yellow serradella (72.1A) was slow to establish in the first year at Badgingarra but has has really gone ahead in the second year.  This yellow serradella is unique in having a very different hard seed breakdown pattern compared with the commercial yellow serradella varieties (i.e. Yelbini, Charano, Santorini) and is suitable for ‘summer sowing’.  It is earlier flowering (80 to 90 days compared to 105 to 115 for Margurita) and yellow serradella is hardier than French serradella.
• Summer sowing using pod avoids the need for de-hulling, so seed is cheaper, but higher sowing rates are required.  Consequently the concept relies to a large extent on farmers being able to source or to produce their own hard-seeded serradella pod at low cost

• The results for summer sowing into an established perennial grass pasture were encouraging in a season with minimal spring rainfall. The results were negatively impacted by the low rainfall in spring. Drilling pod was more successful than broadcasting pod and then using animals to trample it into the soil.
• This was the first summer sowing trial into perennial grasses in WA so it is too early to develop recommendations, but it appears that you need to use 20 to 40 kg pod/ha to achieve a good seedbank. The mid-March sowing time is at the end of the ‘sowing window’ for summer sowing. Sowing in early February is desirable to maximize the time for hardseed breakdown.
• With summer sowing using pod rather than seed there is no need for de-hulling, so there is a cost saving per kilogram, but higher sowing rates are required as the seedlings need to compete with annual grasses, broadleaf weeds as well as the perennial grasses. The summer sowing method requires relatively high sowing rates and the concept relies to a large extent on farmers producing hard-seeded serradella pod on-farm at a low cost.After these promising results in 2010, similar trials will be undertaken in 2011 with local producers.

• The results for summer sowing into an established perennial grass pasture were encouraging in a season with minimal spring rainfall.  The results were negatively impacted by the low rainfall in spring.
• Drilling pod was more successful than broadcasting pod and then using animals to trample it into the soil.  This was the first summer sowing trial into perennial grasses in WA so it is too early to develop recommendations, but it appears that you need to use 20 to 40 kg pod/ha to achieve a good seedbank.  The mid-March sowing time is at the end of the ‘sowing window’ for summer sowing.  Sowing in early February is desirable to maximize the time for hardseed breakdown.
• With summer sowing using pod rather than seed there is no need for de-hulling, so there is a cost saving per kilogram, but higher sowing rates are required as the seedlings need to compete with annual grasses, broadleaf weeds as well as the perennial grasses.  The summer sowing method requires relatively high sowing rates and the concept relies to a large extent on farmers producing hard-seeded serradella pod on-farm at a low cost.
• After these promising results in 2010, similar trials will be undertaken in 2011 with local producers.

• The benefit of summer weed control can vary across soil types and conditions.
• Conserving summer soil moisture is generally money in the bank and can prove invaluable when there is a dry finish, although the benefits seem to differ according to soil type.
• Higher glyphosate prices meansthat growers need to become more efficient when controlling weeds. Targeting weeds while they are young and fresh will help with reducing glyphosate rates. The addition of residual herbicides, such as Ally, will reduce the need for follow-up spraying.

Results from a demonstration in December of 2012 suggest weed control had an impact on stored soil moisture and consequent yield in 2013 across a range of soil types at seven locations across the Eastern Wheatbelt. Another factor that could have been quantified in this work, was the effect of weed control on nitrogen status (and consequent effect of N on yield). Opening values were collected at the beginning of the trial but no closing N values were measured. Removing summer weeds has an impact on the nitrogen levels in the soil, and this will be further quantified with more field work in 2014.

• Controlling summer weeds improves crop yield.
• Summer weeds like Heliotrope use large amounts of stored soil water and nitrogen, which is then not available to the following crop.

• Time of weed removal at the high rainfall site did not affect canola yield but the canola had a higher biomass when weeds were removed earlier.
• The medium rainfall site had consecutively higher wheat yields with earlier times of weed removal; however these were not significantly different.
• At the low rainfall site plots sprayed for summer weeds had significantly higher oat yields than unsprayed plots. Timely control of summer weeds increased soil moisture and nitrate conservation.

• In dry regions, summer fallowing is not just about controlling weeds but mainly about conserving moisture!
• Cultivation conserved the most amount of soil moisture over the summer period. ƒ
• The three treatments which controlled summer weeds: (i) cultivation every three weeks; (ii) cultivation when required; and (iii) knockdown when required, had a significantly higher yield (0.4 to 0.7 t/ha) compared to the treatments where there was no or poor summer weed control. ƒ
• Greater than 80mm of available moisture was lost under heavy heliotrope and melon populations

• Trials are underway investigating the effects of rotational grazing versus set stocking of stubble residues on surface cover and soil characteristics in arable paddocks.
• Early rain in 2014 disrupted the trial’s implementation but initial results on a stubble / self-sown pasture grazed in June indicated no difference between set stocking and rotational grazing on surface cover.

During 2006 and 2007, a field trial designed to quantify the effect of two different surface drainage strategies of pasture (hump & hollow and raised beds) on farm productivity, profitability and sustainability was conducted on a commercial farm near Derrinallum. Under the rainfall conditions experienced for the two years of the trial, it is concluded that the use of raised beds for the growing of pastures for grazing has little to offer the sheep industry. On the basis of the data obtained in this trial, it is recommended that the hump & hollow system is the preferred method of surface drainage for sheep grazing systems in this environment and should be promoted in the region. Major findings included:

• In both years, total annual pasture dry matter (DM) yields from the raised bed treatment were substantially less than for the undrained and the hump & hollow treatments.
• In the drought year of 2006 the raised bed treatment grew 37% (2.8 t DM/ha) less while the hump & hollow treatment grew only 7% (0.6 t DM/ha) less than the undrained (total of 7.6 t DM/ha).
• In the higher rainfall 2007 year the raised bed treatment produced 15% (1.6 t DM/ha) less pasture than the undrained. In contrast, the hump & hollow grew 10% (1.1 t DM/ha) more than the undrained (total of 10.7 t DM/ha) in 2007.
• The reasons for the lower than expected pasture yields on the raised beds are speculated to be a combination of low yields in the furrows, poorer plant establishment and density on the beds, and a reduction in the water holding capacity of the soil relative to the other treatments.
• Soil physical health was however considerably better on the raised beds than the other treatments. Aeration porosities at field capacity in November 2007 were a very healthy 16.3% in the raised beds, a moderate 11.8% for the hump & hollow and a poor 7.0% for the undrained.
• No significant differences in ewe or lamb weights at weaning were found between treatments in either year. This was most likely due to the set stocked sheep having pasture on offer in excess of requirements for most of the spring. In 2006 however, the raised beds were stocked at around 1 ewe/ha less due to the lower pasture growth rates.
• From a catchment and general environmental health perspective, the water run‐off results raise some concerns about the environmental impact of growing and grazing pastures on raised beds.
• The raised beds proved to be very effective in removing excess water from the pasture. Over 2007, the raised bed treatment (47.1 mm) had 170% more runoff water than the undrained (17.4 mm) while the hump & hollow (26.7 mm) had 53% more runoff.
• Both drainage treatments had considerably higher concentrations of, and total loads of phosphorus (P) and nitrogen (N) in runoff water. Of particular concern were the losses of 0.5 and 0.4 kg P/ha for the raised bed and hump & hollow treatments respectively compared to 0.1 kg P/ha for the undrained in 2007. For N, corresponding losses were 6.3, 2.1 and 0.9 kg N/ha for the raised beds, hump & hollow and undrained respectively.
• It is recommended that if raised beds are to be used for grazed pastures, then the best practice recommendations developed for raised bed cropping also be applied to pasture.

UWA trials on an MLA funded project showed that using more disease-resistant or disease-tolerant cultivars across Australia in 2015 and 2016 significantly increased plant productivity by up to 4 to 5-fold. This opportunity to identify cultivar resistances and cultivar field tolerances to the soil borne pathogen complex offers the best and most cost-effective, long term, and economically feasible means of managing damping-off and root diseases in subterranean clover across southern Australia. However, despite this tremendous opportunity to benefit producers, this opportunity is unlikely to be realised unless there is ongoing commitment by Industry funding to support such an approach and to realise this potential.

• Inoculum are living bacteria.
• Survial of rhizobia is vital for inoculation and effective nodulation of crop and pasture legumes.
• Chemicals and fertilisers can affect survival and persistence of rhizobia in the soil.
• Therefore, ensure high numbers of rhizobia are sown, especially where chemicals are used.

In 2001 the Rankins Springs CWFS plan to sow lupins across all treatments with the exception of organic treatment, which is considering vetch. The original plan was for barley in 2001, but at the last meeting a motion was passed for lupins to be sown this year to aid soil nitrogen levels.

The Sustainable Land Management Demonstration Sites in the Mallee have been established to demonstrate improved farming practices through a better understanding of crop management and water use to reduce groundwater recharge and soil erosion.

• Test your soil- soil testing individual paddocks for nutrient status and plant available water at the start of the season allows you to determine the paddocks yield potential and requirements. Knowing this information at sowing can assist in making decisions throughout the season.
• Yield Prophet- the crop simulation model is a great tool for assessing crop risk and predicting potential yields.

The results to date from the systems trial are broadly summarized in the attached tral report.

• Pioneer® 45Y88 (CL) was the highest yielding variety, averaging over 4 t/ha, with Nuseed Diamond and Pioneer® 45Y25 (RR) also achieving high yields.
• Sowing on 5 April resulted in higher grain yield, reduced lodging and lower oil content compared with sowing on 26 April.
• A plant population of 35–56 plants/m2 resulted in higher grain yields than populations of 18 plants/m2 or 68 plants/m2.
• Applying 200 kg N/ha resulted in higher grain yields than 150 kg N/ha when the soil available nitrogen (N) at sowing was 64 kg/ha. Nitrogen rates above 200 kg N/ha resulted in no extra yield.
• Increasing N application rates above 200 kg N/ha reduced oil concentration.
• Crop lodging increased with plant populations above 35 plants/m2 and N rates above 150 kg N/ha.

One way plough and Grizzly Offset discs appear to be the most efficient, practical most cost effective method of incorporating lime into the topsoil in the eastern wheatbelt wodjil soils.

• Substantially better brome control and seed set reduction is possible by using pre-emergence options other than trifluralin.
• The costly Sakura+Avadex treatment is likely to be the most effective.
• Consistency of performance of all pre-emergence herbicides for brome remains a problem
• On-row seeding on non-wetting sand showed that it can substantially improve early crop emergence.
• One reason for this is the likely wetter surface soil in rows at time of seeding.
• Seasonal conditions such as the long-wet season of 2016 will affect efficacy of both pre-emergence herbicides and the impact of additional crop competition on brome seed set suppression.
• Maintaining low seedbanks and having alternative options for weed seed control when faced with a risk of ‘blowouts’ in brome seed set is important given the chance of particularly poor control in some seasons.

• Substantially better brome control and seed set reduction is possible with pre-emergence options other than trifluralin.
• The costly Sakura+Avadex treatment is likely to be the most effective.
• Consistency of performance of all pre-emergence herbicides for brome remains a problem
• On-row seeding on non-wetting sand can substantially improve early crop emergence in part due to increased surface soil water accumulation in rows at time of seeding.
• Seasonal conditions such as the long wet season of 2016 will affect efficacy of both pre-emergence herbicides and the impact of additional crop competition on brome seed set suppression.
• Maintaining low seedbanks and having alternative options for weed seed control when faced with a risk of ‘blowouts’ in brome seed set is important given the chance of particularly poor control in some seasons.

• The later seeding had very poor crop establishment, resulting in significantly higher brome seed production (115% more panicles) than early seeding, but seeding time did not interact with herbicide treatment effects.
• Only the treatments including Sakura resulted in significantly (P<0.01) better brome control than trifluralin alone (measured by number of panicles/m2).
• Sakura alone resulted in 55% less brome panicles than trifluralin alone, and Sakura + Avadex resulted in 72% less brome panicles than trifluralin alone.
• Sakura’s extended residual soil activity, which can restrict root growth of brome, combined with the dry spring, was probably responsible for the reduced seed set.
• Substantially better brome control and seedset reduction is possible by using pre-emergence options other than trifluralin. The additional herbicide cost needs to be evaluated against the better level of control, including the longer-term seedbank benefits.

Changes in pasture composition, groundcover, stocking rate and stock condition are being monitored at each grazing site. Soil moisture is being measured at one pasture site (to 1.2m) and one cropping site (to 1.6m). Water quality will be monitored at one pasture site opportunistically depending on flow. Photo points were established and soil pH and nutrient testing was undertaken at all sites.

• Canola and peas only produced half the yield of wheat, but barley performed very well.
• Ryegrass is becoming a problem in wheat on wheat plots.
• Pastures performed well where seed reserves had been increased in 2011.
• All options had good soil moisture (40mm) at the start of the season.

Topdressing pulses with nitrogen does not pay; inoculation does. Nitrogen topdressing of pulses resulted in little or no net growth or yield benefit. Inoculating pulses is most effective if the soil is moist and if residual soil nitrogen and soil rhizobia populations are low. The current study indicated that a return on investment of up to $60 can be achieved from the inoculation of chickpeas in the absence of soil rhizobia.

Soil organic matter consists of a labile (non-permanent) and stable (humus) fraction. No-till increases the labile fraction of soil organic matter, but not the stable fraction. Additional nutrients will be required to ‘fix’ the labile fraction to humus.

Whilst the streaming of UAN modestly reduced annual ryegrass (ARG) N percentage in the tissue, no difference in annual ryegrass seed production was evident. Due to the dry conditions in 2019, the application of supplementary UAN did not significantly increase wheat canopy closure or yield. Interestingly, UAN placement did affect the total nitrogen uptake in the ryegrass population, potentially increasing ARG competitiveness. Banding UAN to the crop row was found to increase ARG N uptake. As seeding systems provide herbicide free bands on otherwise herbicide treated soil for safe wheat establishment it was found that the majority of ARG emerged from these crop rows. Concentrating N applications to these regions may have inadvertently increased the N uptake in ARG. This study was conducted in York over the 2018 and 2019 seasons. A multi- environment trial analysis for the combined data to be completed.

• Quality of on-farm lime and distance from coastal limesand sources are important factors in determining economic advantage over coastal limesand
• Cultivation of sources resulted in higher net present values after the 20 year iLime simulation, and improved return on investments at 5 and 10 years compared to when uncultivated
• In 2019 cultivation consistently improved yield and the high rates of local dolerite and limesand improved yield by 0.55t/ha and 0.57t/ha respectively.
• Due to the 2020 season and in season challenges there were no significant differences in yield between sources and cultivation

A harvest-time knockdown to kill summer weeds has been shown to conserve significant soil moisture prior to seeding in a series of trials across the eastern wheatbelt this year.

• A replicated trial was conducted to compare grain yield of early sown Revenue wheat (cut and uncut for fodder) with that sown at a more traditional time, May.
• Both cutting and later sowing significantly reduced grain yield compared with the early sown uncut treatment.
• The most significant effect was the ability of the early sown plots to better tolerate the very wet conditions. With a root system actively depleting moisture from the soil profile in late autumn the early sown treatments entered winter with a depleted soil moisture bank whereas May sown plots struggled over winter due to additional water logging.
• March sown plots that were cut did not recover as well as in drier seasons. It is likely that the prolonged water-loggin created an addional stress on top of cutting to the detriment of crop recovery and grain yield.

• Despite visual differences there is no major impact on soil structure, water holding capacity or water infiltration from grazing in summer or winter when soils are water logged.
• Grazing in the previous winter or summer does not affect the following crop establishment or grain yield.
• Any yield losses after winter grazing are the result of moisture stress in the period immediately after grazing through to flowering.
• Annual ryegrass and wild raddish populations did not increase because of grazing, although the sites only had low levels of infestation to being with. However, farmer observations do not support this and further work is needed.

• Despite visual differences there is no major impact on soil structure, water holding capacity or water infiltration from grazing in summer or winter when soils are waterlogged.
• Grazing in the previous winter or summer does not affect the following crop establishment or grain yield.
• Any yield losses after winter grazing are the result of moisture stress in the period immediately after grazing through to flowering.
• Annual ryegrass and wild raddish populations did not increase because of grazing, although the sites only had low levels of infestation to begin with. However farmer observations do not support this and further work is required.

• In 2015, two spring irrigations produced the highest wheat grain yield (7.61 t/ha), but one irrigation provided the highest water use efficiency (1.7 t/ML).
• Ponding irrigation water for 48 hours to induce waterlogging did not reduce grain yield in this experiment, but increased water use and reduced water use efficiency by 25%.
• If the number of spring irrigations is limited, it is important to find a balance between irrigating before significant moisture stress occurs and ensuring adequate moisture is available during flowering.
   

• Higher seed manganese content increase growth and yield of barley on manganese deficient soil.

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).

• Variety phenology and sowing date need to match to avoid plants flowering and podding during periods of severe frost. The highest yield in 2017 came from the 6 April sowing of the long season varieties Archer and ATR WahooA that flowered in early August.

• ATR Stingray and Nuseed® Diamond flowered earlier than the optimum start of flowering (OSF) date (28 July) from both the 6 April and 20 April sowing dates with significant frost damage incurred at both sowing dates.

• Canola varieties have the ability to recover from severe frost damage where soil water is not limited.

• Sowing canola early (6 April) on 200 mm applied water reduced the time to the start of flowering by up to two weeks, compared with a later sowing (7 May).
• Significant yield increases were recorded across all varieties (for both sowing dates) where 200 mm water was applied pre-sowing, compared with 70 mm and 0 mm.
• The highest yield resulted from sowing a mid season hybrid (Pioneer® 45Y91 (CL)) early on 200 mm applied water.
• Sowing canola early on 200 mm applied water yielded around 900 kg/ha more than sowing later with the same amount of applied water, averaged across all varieties.

• Each stubble incorporation prior to sowing lead to better weed control in the crop as we were able to create an early germination of ryegrass. 
• There was considerable difference in soil moisture and its distribution through the profile at establishement.
• Straw length at harvest was the biggest drawback in incorporating and establishment.
• Previous trial cropping areas, on other parts of the padock, still showed up the biggest difference in the crop's establishment.

• Soil inversion with a mouldboard plough, rotary spader and one way plough created equally patchy soil.
• The one-way plough created the most vertical redistribution of the surface 10 cm of soil.
• At least ten soil samples are required to gain a reliable mean for soil pH after inversion.

• Grain and soil samples were collected from 13 field experiments where zinc deficiency had been identified as a problem.
• Zinc was applied in the field experiments at rates of 0-20 kg zinc/ha.
• Application of zinc (2.5 - 5 kg/ha) reduced grain cadmium concentraitons by up to half.

• Most of the endogenous zinc in the soil was associated with silicates while zinc added as fertiliser was associated with iron, aluminium and manganese oxides.
• Zinc recently added to soil in the EDTA extractable fraction decreased over time.
• Zinc recently added to soils was found to be mor reactive than zinc already in the soil.
• The transformaiton of reactive zinc to less reactive zinc was primrily attributed to diffucion of zinc cations into microporous solids.
• Dryindg and rewetting at high temperature may reduce the availability of zinc in soils.

1. Most farming systems extract more nutrients than are supplied by common fertilisation strategies.
2. Increasing the frequency of legumes doesn’t necessarily reduce nitrogen inputs required across the crop sequence and increases export of potassium.
3. Higher fertiliser application has maintained higher soil mineral nitrogen levels but rarely increased grain yield or total system nitrogen use.

• Increasing siphon pipe diameter used for flood irrigation, from 42 mm to 63 mm halved irrigation time, reduced the amount of water applied per irrigation, and increased cotton lint yield and lint quality.
• The longer irrigation time increased soil water content for up to a week post irrigation, and likely led to waterlogging effects on cotton plant growth.
• The maximum daily nitrous oxide (N2O) emissions occurred in response to the first irrigation event after pre-plant nitrogen (N) application and continued for more than a week after irrigation.
• The highest N2O emissions in each plot came from the non-irrigated side of the plant bed where surface soil nitrate concentrations were also highest – despite pre-plant N fertiliser being applied evenly to both sides of the plant bed.
• Postharvest, excess soil nitrate was found to depth in the non-irrigated side of the plant bed, indicating that nitrate moved both sideways and downwards during the season.
   

• Grain yields increase with higher crop inputs and, after grazing, further improve following a sown legume pasture and a more intensive grazing system.
• There is no measured change in soil organic carbon as a result of either varying crop and pasture inputs or grazing compared with not grazing stubbles or pastures.

• Grain yields increased with higher crop inputs and following grazing, they were further improved following a sown legume pasture and a more intensive grazing system.
• There has been no measured change in soil organic carbon over the 4 year project as a result of varying crop and pasture inputs or grazing compared to not grazing crop stubbles or pastures.

• The high input pasture treatment provided the opportunity to carry 8 DSE/ha with an estimated gross margin of $240/ha, however it was unable to utilise plant available water above 50% of potential water use efficiency (WUE).

• The 2009 production has provided the opportunity for grazing over the 2009/10 summer to commence comparative grazing treatments.
• Over the next few seasons appropriate analysis will be carried out to measure any changes to soil or crop performance in the farming systems, followed by financial assessment to evaluate the merits of each system.

• It appears that once disease suppression is achieved in low rainfall farming systems of upper EP and inoculum levels are low, it is quite robust and will be maintained despite systems with substantially different amounts of mineral N.
• Fallow, Medic/Fallow and Peas all lowered rhizoctonia inoculum levels in 2010, and Fallow and Peas lowered levels in 2009.
• Continuous cereals produced the highest inoculum levels but all levels were low at this site.
• Even high mineral N (118 kg N/ha) in the top 60 cm (measured in April after spraytopped medic) did not increase Rhizoctonia patches in 2010.
• Trichoderma fungus and the beneficial PEM microbes are present in the MAC N12 system.

• Soil mineral nitrogen (N) values were low across all sites, which was indicative of the wet seasonal conditions and high nitrogen losses.
• There were no significant differences in mineral nitrogen values between the stubble treatments due to high variability (likely due to transient waterlogging across the sites).
• The project has been extended to enable the research to be repeated during 2017.

• While significant differences in mineral nitrogen (N) values were measured between stubble treatments, these differences were small and unlikely to elicit a plant growth response.
• No consistent trends were observed between trial sites.
• Delayed plant growth and development under no-till stubble retained (NTSR) systems in the Riverine Plains region is unlikely to be due to decreased mineral nitrogen availability as a result of immobilisation.

The data from this trial supports the theory that an early sowing date will increase DM and total N fixation in Percy and Morava.

• Summer weeds use significatn amounts of stored soil water.
• The long-term impact of summer weeds amounts to a loss in production of 1t/ha in cereal yield in the southern Mallee.
• In a changed climate scenario, where our region is likely to receive more summer rain at the expense of spring rain, the impact of summer weeds on potential crop yield is likely to increase.

• Although time of heading and flowering are considered the most sensitive stages for frost damage in cereals, sensitivity to early frost damage occurs from the start of stem elongation and is referred to as ‘stem frost’.

• Stem frost can be minimised by matching sowing date and cultivar phenology so that stem elongation starts after the period of greatest frost risk.

• Varieties that started stem elongation early (fast developing varieties sown early) were exposed to an increased number of frosts during the susceptible development stages, whilst winter types sown early had an extended vegetative period and were not exposed to the same frost risk, which reduced damage from stem frost.

• Crops can recover from stem frost where there is moisture available to support new tiller growth. However, the resulting effect on phasic development stage synchrony leads to delayed maturity and harvest issues.

• There was no observed difference in frost tolerance of specific cereal species observed in 2017.

In 2019, the three trial sites experienced vastly different rainfall and crop germination patterns. The Kojonup site had good soil moisture throughout the growing season resulting in a rapid crop germination. The York and Miling sites however were seeded into completely dry conditions with the wheat germination in the TOS 1 treatments occurring more than six weeks after seeding. The bioassay experiment showed that at all sites, Sakura was the most persistent herbicide. This was evident in the field results where the persistence and activity of Sakura resulted in lower ryegrass emergence, lower seed production and a higher wheat yield. Furthermore, the results showed that at the Kojonup site, which was sown into excellent soil moisture, Trifluralin was also very effective.

The TOS response was variable; the first time of seeding showed better weed control and wheat yields at Miling and York whereas the delayed time of seeding was advisable at the moist Kojonup site. It was also found that increasing the wheat density increased crop competition which in turn reduced ryegrass emergence, ryegrass biomass and ryegrass seed production for all herbicide treatments studied. 

• Select crops best adapted to the soil and climatic conditions of your region; faba bean is the pulse crop best adapted to soils prone to waterlogging.
• Avoid soils with acidic subsurface layers and/or shallow topsoil that limit root development and impermeable subsoil that restrict drainage.
• Test soil pH at 5cm intervals to a depth of 20 cm, to detect subsurface acidity.
• Select paddocks at least two years before sowing acid-sensitive crops to allow time for applied lime to react and increase soil pH, if required.
• Sow early in the recommended sowing window for your location, to encourage effective nodulation, early vigour and biomass accumulation before the onset of cold, wet conditions.

• Widespread manganese toxicity a function of soil acidity.
•  A few reports of manganese deficiency in rapeseed, field pea, sunflower and soybean in NSW.

Phosphorus was applied as Triple Super drilled with seed. The result was lower plant densities as phosphorus rates increased.

For an interpretation of results please see the attached trial report.

Executive summary

Recently interest in the role of renovation cropping in the farming systems of the Western Australian wheatbelt has increased.  It has been proposed as a means of addressing the apparent decline in soil quality in some intensively cropped areas and the increased incidence of herbicide resistance. 

Renovation cropping involves either turning a crop into the soil at flowering or cutting the crop and leaving it on the soil surface.   This is done to maximise the amount of organic matter added to the soil and to control weeds most effectively.  In the Western Australian wheatbelt the focus has been on using pulses, although a range of crops can be used.  The pulse phase of a rotation is favoured as pulses improve the nitrogen status of the soil. In addition the returns to pulses are lower relative to cereals and canola, so the forgone profit in the year of renovation cropping is lowest.

Renovation cropping leads to changes in soil conditions that persist for at least the following season.  It reduces weed numbers in the following crop by reducing seed set, increases the availability of nutrients and may improve soil structure.  Lower weed numbers reduce the carry-over of root diseases thus providing a disease break for the following cereal crop.  Recent trials have shown likely yield increases of 20-30% above those after a pulse crop and increased grain protein levels in the following cereal.

The main cost of green manuring is the income lost by sacrificing grain production.  The loss in income plus any additional costs associated with soil renovation need to be recouped in the following season(s).  Therefore the income from the yield increase(s) in the subsequent year(s) needs to be equal to or greater than the total costs of renovation, including the income forgone.

Despite the increase in interest in renovation cropping, no comprehensive economic analysis has been undertaken to determine its role in Western Australian farming systems.  This study investigates circumstances under which renovation cropping is likely to be profitable and estimates the needed increase in farm profit, given the variability of yields that result from seasonal influences.

To investigate the consequence of risky yields historical rainfall data was used to generate yield distributions for different rainfall zones, soil types and crops.  The yield distributions were used as input to a simulation model to determine the distribution of income, resulting from renovation cropping, in a lupin:wheat:wheat rotation.  The mean yield boost resulting from renovation cropping was estimated to be 3% based on trial results (F. Hoyle, pers. comm.). 

The results of the analysis showed that there is a 30-40% chance of increasing profit if yield is increased by 30% on average.  However, the results were very sensitive to the average increase in yield.  The probability that profit will be increased was halved when yield boost was reduced to 20%. 

The yield increase required to make renovation cropping profitable can vary between 100% under the worst case and below 10% under the best case.  The variability depends on grain prices, grain yield in the renovation phase (if a commercial crop had been was harvested), and the cost of renovation and grain yields in the following crop phase.

The likelihood that profit will be increased depends largely on minimising income forgone relative to the increase in income in the following years.  Therefore green manuring will be most profitable when done in years when the grain yield of the pulse crop is low, and/or when the following cereal yield is very high. 

Weather forecasts are not yet sufficiently developed to predict potentially good years over 12 months ahead, so renovation needs to be undertaken in poor years to maximise the chances of increasing profit.

Identifying poor yielding years prior to renovation does present some difficulty although weather forecasts may improve the chances of undertaking renovation in the 'right' year.  .  Also yield potential is determined directly by biomass of the crop, so this may be used as an early indicator of yield.  Where waterlogging or disease has caused low vegetative growth, resistant weeds are widespread in a paddock, or where frost has damaged the crop green manuring is more likely to be a profitable option. 

This suggests a role for tactical use of renovation cropping so that it is undertaken in years where the forgone income is minimised (i.e. it is done in poor yielding years).  The results of the analysis show that only small yield increases in the following cereal crop are necessary to break even in these circumstances. 

The analysis highlighted gaps in the knowledge of the impact of renovation cropping that may be important for more comprehensive economic analysis, or information that may improve the grower’s ability to undertake the practice profitably.  Further research into green manuring could include:

• Determining whether the profitability of green manuring can be increased using long term weather forecasts.  Improving the estimates of the probability of achieving different yields may allow farmers to renovate soils in years that have lower risk.
• More information on the effects of green manuring on yield and protein for different crops under different conditions is required to better assess the economic advantages of green manuring
• The profitability of green manuring relative to other methods of improving sustainability of cropping also needs to be addressed.

 

Executive summary

Recently interest in the role of renovation cropping in the farming systems of the Western Australian wheatbelt has increased.  It has been proposed as a means of addressing the apparent decline in soil quality in some intensively cropped areas and the increased incidence of herbicide resistance. 

Renovation cropping involves either turning a crop into the soil at flowering or cutting the crop and leaving it on the soil surface.   This is done to maximise the amount of organic matter added to the soil and to control weeds most effectively.  In the Western Australian wheatbelt the focus has been on using pulses, although a range of crops can be used.  The pulse phase of a rotation is favoured as pulses improve the nitrogen status of the soil. In addition the returns to pulses are lower relative to cereals and canola, so the forgone profit in the year of renovation cropping is lowest.

Renovation cropping leads to changes in soil conditions that persist for at least the following season.  It reduces weed numbers in the following crop by reducing seed set, increases the availability of nutrients and may improve soil structure.  Lower weed numbers reduce the carry-over of root diseases thus providing a disease break for the following cereal crop.  Recent trials have shown likely yield increases of 20-30% above those after a pulse crop and increased grain protein levels in the following cereal.

The main cost of green manuring is the income lost by sacrificing grain production.  The loss in income plus any additional costs associated with soil renovation need to be recouped in the following season(s).  Therefore the income from the yield increase(s) in the subsequent year(s) needs to be equal to or greater than the total costs of renovation, including the income forgone.

Despite the increase in interest in renovation cropping, no comprehensive economic analysis has been undertaken to determine its role in Western Australian farming systems.  This study investigates circumstances under which renovation cropping is likely to be profitable and estimates the needed increase in farm profit, given the variability of yields that result from seasonal influences.

To investigate the consequence of risky yields historical rainfall data was used to generate yield distributions for different rainfall zones, soil types and crops.  The yield distributions were used as input to a simulation model to determine the distribution of income, resulting from renovation cropping, in a lupin:wheat:wheat rotation.  The mean yield boost resulting from renovation cropping was estimated to be 3% based on trial results (F. Hoyle, pers. comm.). 

The results of the analysis showed that there is a 30-40% chance of increasing profit if yield is increased by 30% on average.  However, the results were very sensitive to the average increase in yield.  The probability that profit will be increased was halved when yield boost was reduced to 20%. 

The yield increase required to make renovation cropping profitable can vary between 100% under the worst case and below 10% under the best case.  The variability depends on grain prices, grain yield in the renovation phase (if a commercial crop had been was harvested), and the cost of renovation and grain yields in the following crop phase.

The likelihood that profit will be increased depends largely on minimising income forgone relative to the increase in income in the following years.  Therefore green manuring will be most profitable when done in years when the grain yield of the pulse crop is low, and/or when the following cereal yield is very high. 

Weather forecasts are not yet sufficiently developed to predict potentially good years over 12 months ahead, so renovation needs to be undertaken in poor years to maximise the chances of increasing profit.

Identifying poor yielding years prior to renovation does present some difficulty although weather forecasts may improve the chances of undertaking renovation in the 'right' year.  .  Also yield potential is determined directly by biomass of the crop, so this may be used as an early indicator of yield.  Where waterlogging or disease has caused low vegetative growth, resistant weeds are widespread in a paddock, or where frost has damaged the crop green manuring is more likely to be a profitable option. 

This suggests a role for tactical use of renovation cropping so that it is undertaken in years where the forgone income is minimised (i.e. it is done in poor yielding years).  The results of the analysis show that only small yield increases in the following cereal crop are necessary to break even in these circumstances. 

The analysis highlighted gaps in the knowledge of the impact of renovation cropping that may be important for more comprehensive economic analysis, or information that may improve the grower’s ability to undertake the practice profitably.  Further research into green manuring could include:

• Determining whether the profitability of green manuring can be increased using long term weather forecasts.  Improving the estimates of the probability of achieving different yields may allow farmers to renovate soils in years that have lower risk.
• More information on the effects of green manuring on yield and protein for different crops under different conditions is required to better assess the economic advantages of green manuring
• The profitability of green manuring relative to other methods of improving sustainability of cropping also needs to be addressed.

 

• Significant responses in lucerne seed yield were achieved with foliar manganese applications on 2/5 irrigated lucerne sites at Keith.
• Plant tissue analysis prior to the application of manganese show the concentrations at both responsive sites were less than 14 mg per kilogram in the youngest open leaf and whole shoots.
• this contrasted with concentrations from 3 other sites we seeded did not respond to manganese, the mean concentration being greater than 18 mg per kilogram in youngest open leaves and 14 mg per kilogram manganese and whole shoots prior to treatment.

• Stubble rentention increased the severity of frost events in experiments over two years
• There was no difference in floret sterility due to stubble treatment, but grain yield was highest where stubble was removed by burning. 
• Stubble rentention reduced the amount of heat stored in the soil during spring. With less heat stored there is less capacity for energy release at night to buffer against frost damage.
• Consider management strategies that avoid frost (e.g. crop choice, sowing date, variety choice) where high stubble loads are retained at sowing. 

The application of compost at 2 t/ha did not result in higher returns and the response under compost plus fertiliser treatments could be attributed to the application of fertiliser. Spading did not return any further gains in terms of yield or quality at this site in 2013. The high cost of spading and compost in the first year, have negatively influenced profit outcomes. Depending on future yield improvements, these treatments may pay for themselves over the longer term.

No measureable changes in soil condition as a result of adding 2 t/ha compost were measured in 2013 and 2014 that would add value to the long term profit of this site.

Machinery used for applying compost caused some compaction and due to the dry post-sowing conditions, crop germination was very patchy. The trial site experienced significant moisture stress early in the season and may not be representative of seasons experiencing an average or wetter start.