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Grains Research & Development Corporation

GRDC Research Updates

Grains Research Updates              Agribusiness Crop Updates

 

This page contains papers from the GRDC Update series for both growers and advisers.

For further information Updates and, please visit the following sites:

To view any paper in full,  click on the title below:

  • Windrow timing and direct heading in canola - effects on yield and oil

    12.04.2012

    • Windrowing timing can have a significant impact on yield and profitability of canola
    • Yield increases up to 0.5t/ha have been seen over relatively short periods of only 8 days
    • Windrowing timing has a limited effect on oil potential in canola
    • Direct heading is a viable option to harvest canola and in many could maximise profitability.
    • An economic benefit of over $200/Ha can be gained from choosing the best method and timing of canola harvesting

  • Agronomy for high yielding cereal environments: varieties, agronomic strategies and case studies

    12.04.2012

    - Longreach CrusaderPBR symbol and KennedyPBR symbol were the most consistently high yielding APH varieties across irrigated experiments (in which diseases were controlled). Longreach CrusaderPBR symbol had less lodging than KennedyPBR symbol under high N rates. Lower quality varieties MerindaPBR symbol (AH) and GBA RubyPBR symbol (AGP) yielded well in some environments with minimal lodging.

    - Varieties responded differently to various canopy management techniques (delayed N application and plant growth regulators) in this first year of testing, and further research is needed to identify the best agronomic strategy for different varieties under high yielding conditions.

    - Experimental varieties exist that possess substantially higher yield potential and lodging resistance compared to the best APH commercial varieties, but they have poor grain quality.

    - An 8.01 t/ha commercial irrigated wheat yield was verified by weigh-bin at Brookstead, using Longreach CrusaderPBR symbol in conjunction with several canopy management techniques.

     

  • Impact from Pratylenchus thornei

    12.04.2012

    1. Multi-crop and variety trials were conducted over strips of ‘low’ and ‘high’ Pratylenchus thornei (Pt) pressure
    2. Excellent growing conditions experienced with exceptionally high yields produced:
      • - No impact from Pt on crop establishment
      • - ‘High’ Pt strips significantly reduced NDVI readings in field peas, chickpeas and in some wheat trials
      • - ‘High’ Pt strips significantly reduced yield in field peas by 8% (~280kg/ha)
      • - However negligible yield impact from Pt apparent even in intolerant wheat varieties under these conditions

  • Interpreting soil tests in the light of P, K and S research

    12.04.2012

    Soil moisture is critical in determining when subsoil responses to applied P and K fertiliser are observed. Further work is necessary to confirm and refine the opinions presented in this paper!

     

  • Using Colwell and BSES extractable phosphorus to predict Faba bean (Vicia faba L.) response

    12.04.2012

    The Colwell-P soil test is still the best measure of plant available P for crop uptake. Colwell-P extractions in the subsoils can provide a useful indicator of plant available P, however, the effect may be more substantial in drier years. Regardless of BSES-P status, soils that have less than 26 mg/kg of Colwell-P may require fertiliser to maximise growth. The BSES-P fraction is still a useful indicator for total P reserves. When other soil parameters such as P mineralogy and dissolution rate are known, the BSES-P extraction may provide useful information for slowly available P pools.

     

  • How much of the soil P is available for plant uptake?

    12.04.2012

    Diagnosis of soil P status for rain-fed cropping systems requires an understanding of the crop demand pattern for P, knowledge of the zone of active root acquisition of P, and soil P tests that are sensitive to the relevant soil P supply characteristics. Because the root surface area for P absorption increases as the crop grows, it is likely that slowly available P sourced from sparingly soluble soil minerals and fertiliser reaction products (‘reserve P’) becomes increasingly important as the crop matures. While these reserve P sources can be quantified using an acid soil P test such as the BSES-P test (0.005 M sulphuric acid extractant), the actual quantity of this P that is available is uncertain. Results from recent soil P depletion experiments undertaken with forage sorghum in glasshouse trials indicated close relationships of both crop P uptake and relative yield with Colwell-P, confirming that this soil test is the best indicator of available P. In the case of soils with low Colwell-P (and therefore likely to be P deficient) but high BSES-P, a small, variable proportion of this acid-extractable P was available. However, even very high concentrations of BSES-P (>100 mg/kg) at low Colwell-P were insufficient for maximum crop growth, and supplementary P fertiliser would be required. Incubation experiments indicated that about half of the P applied to P-depleted clay soils as DAP or MAP entered the bicarbonate extractable P fraction (Colwell-P) and was therefore available. However, in two soils, more than half of the P added as DAP (but not MAP) entered the acid-extractable fraction and was of unknown availability. The reasons for these soil type and P form effects on P availability are being investigated.

     

  • Root-lesion nematodes: distribution, wheat yield and crop sequence impacts on mycorrhiza

    12.04.2012

    In 2011, root-lesion nematodes (Pratylenchus thornei and P. neglectus) were identified in 84% of paddocks across the northern grain region Root-lesion nematodes are likely to be in your paddocks too.

    Wheat varieties with tolerance will out-yield intolerant varieties, but you need to know which nematode species is present in your paddock Test your soil for nematodes before choosing a tolerant wheat variety.

    Canola is resistant to P. thornei however it is not a host of beneficial mycorrhizal fungi. In low phosphorus soils in the northern grain region, reduced mycorrhizal levels can limit growth and yield of wheat and chickpea Grow P. thornei-resistant crops but consider the mycorrhizal dependency of future crops.

     

  • Spray adjuvants - we need to be specific

    12.04.2012

    Spray adjuvants can significantly affect performance of post-emergence herbicides. Effectiveness of adjuvants cannot be generalised as these are affected by herbicide formulation, herbicide rate, weed species, growing conditions, carrier volume, water quality and spray quality. Performance of nominally similar spray adjuvants may be influenced by attributes of base materials and minor differences in functional groups. Spray adjuvants can enhance but also detract from herbicide activity.

    Some novel adjuvants show promise in combinations with glyphosate on hard-to-kill grass weeds.

    Adjuvant recommendations should be situation specific and where possible based on relevant data generated for specific herbicide formulations.

     

  • Harvest weed seed control

    12.04.2012

    High weed seed retention at crop harvest ensures the value of harvest weed seed control techniques

     

  • What percent of northern weed seed might it be possible to capture and remove at harvest time? A scoping study

    12.04.2012

    • Wild oat, fleabane, sowthistle and several other weed species all retained high proportions of total seed production above harvest cutter height at maturity of wheat and chickpea crops.

    • There is potential for harvest weed seed control techniques to be used in restricting weed seed bank inputs from sprayed survivors in winter grown crops of the northern region.