Competitive wheats: does more vigour early matter?

Cathrine H Ingvordsen1, David J Smith2, Tina Rathjen1, Gurjet Gill3, Leslie A. Weston4, Washy Gapare1, Greg J Rebetzke1

1 CSIRO, Black Mountain Science and Innovation Park, Canberra, ACT, 2601, http://www.csiro.au/en/Research/AF/Areas/Plant-Science, cathrine.ingvordsen@csiro.au

2 CSIRO, Agriculture and Food, Private Mail Bag, Yanco, NSW, 2703

3 The University of Adelaide, Waite Campus PMB 1, Glen Osmond, SA, 5064

4 Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW, 2678

Abstract

Weeds are an ongoing challenge and herbicide-resistant weeds are on the rise. Incorporating weed-competitive varieties in the non-herbicide integrated weed management toolbox, make up a low cost and low risk approach to decrease the $4.3 billion weed costs Australian growers every year. We have assessed the competitive ability of a diverse set of 100 entries. The 100 entries vary from historic and modern wheat varieties to wheat lines developed to have wide leaves and greater biomass at stem elongation. Among the entries were also durum wheat, triticale and barley. The 100 entries were grown under field conditions in seven environments over three seasons with and without competition from oat or barley used as a weed-surrogate. Through in season measurements and separation of wheat grains and weed-surrogate grains after harvest we identified that wheats with wide leaves and greater biomass at early stem elongation only experienced yield decreases of 4-10% when grown in competition with weed-surrogate, whereas the best varieties decreased yield by 14% and worst decreased yield by 35%. Weed suppression was greatest in the high vigour lines.

What makes a ‘good’ seasonal forecast? Delivering actionable climate outlooks for grains farming

Patrick J. Mitchell1, Jaclyn N. Brown1

1 CSIRO Agriculture and Food, College Rd, Sandy Bay, Tasmania, 7005, Patrick.Mitchell@csiro.au

Abstract

The prediction of climate patterns and weather conditions at the farm scale represents an important innovation for managing within season and year-to-year variability in crop production. Assessing skill and potential value of long-range, seasonal climate forecasts hinges on answering the fundamental questions: “Should I use this forecast when making my decision and how ‘good’ is it?” Here, we use model output from the new seasonal forecasting system, ACCESS-S1 to compare forecast approaches for deriving relevant and credible seasonal climate information for Australia’s cropping regions. This evaluation addresses the role of two important components: categorisation of the model output and anchoring the forecast using antecedent conditions (fallow season rainfall). Overall, the model had relatively low accuracy at predicting correct forecasts across much of the forecast locations and seasons, whereas it had greater skill in the avoidance of false alarms i.e. false negative outcomes. The percentile categories used to derive the expected forecast had a large effect on the skill in terms of the rate of false alarms and the choice of categories can be matched to user requirements of both accuracy and resolution. Anchoring rainfall forecasts on antecedent conditions can reduce false alarms across the growing season and may be a useful guide when presented alongside a forecast based solely on in-season predicted rainfall. The next generation of climate data products and services for agriculture need to consider how a forecast system interacts with both on-farm biophysical drivers of yield and decision-making preferences of the user.

Identifying potential areas of subsoil P and K deficiencies in Western Australia

Andreas Neuhaus, James Easton

CSBP Limited, Kwinana, Perth, WA 6966 Email andreas.neuhaus@csbp.com.au, james.easton@csbp.com.au

Abstract

Research projects around Australia have diagnosed subsoil constraints including nutrient deficiencies that cause yield limitations. This study reports the mapping of subsoil phosphorus (Colwell P) and potassium (Colwell K) values to generate awareness of these subsoil constraints among advisors and growers. Surface (0-10cm)- and subsoil analytical results (10-20 cm and 20-30 cm) from CSBP’s laboratory have been used to highlight P and K availability The maps identified a heterogenous soil nutrient profile, revealing subsoil limitations of P and K in many areas of Western Australia. A trend towards a higher contrast of P levels at depth was noted especially for the heavier textured soils in the medium to high rainfall zone. More subsoil or plant tissue testing is recommended to confirm the decline in P and K availability from subsoils. Regular soil sampling of the top 30cm of soil that contains the main root volume for nutrient uptake of most broadacre crops grown in WA is recommended to better understand nutrient requirements.

Silicon mitigates drought stress in lentil through enhancing photosynthetic activity and yield related traits

Sajitha Biju1, Sigfredo Fuentes1, Dorin Gupta1

1 School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences,

  The University of Melbourne, Parkville, Victoria-3010, Australia

Abstract:

Drought stress is one of the major constraints leading to significant production losses in lentil. Silicon (Si) application has been shown to be a promising management strategy in improvement of drought tolerance in crops. Consequently, the present study aims to investigate the role of Si in mitigating drought stress in lentil. Measurements of chlorophyll fluorescence, photosynthetic pigments, infrared thermal canopy temperature (IRTc), gas exchange parameters and yield traits explained the possible role of Si in alleviation of drought stress effects in lentil.  Experiments were conducted in field conditions with selected drought tolerant and sensitive lentil genotypes, which were subjected to severe drought stress at the onset of the flowering stage. Results showed that Si attenuated drought stress-mediated effects on light absorption of photosystem II (PSII) by increasing the effective quantum yield of PSII photochemistry and concentration of photosynthetic pigments along with maintenance of cooler canopies. Additionally, negative effects induced by drought stress on gas exchange were also mitigated by Si application. Increased growth and grain yield of Si-treated drought stressed plants could be related to the increased photosynthetic activity. Overall, Si supplementation could be used as a potential drought stress mitigation strategy in lentil plants.

The impact of future climate change on the contribution of legume fixed N to the subsequent crop in the rainfed cropping systems in Southern Australia

Hongtao Xing, Mark Richards, Guangdi Li, Rohan Brill, De Li Liu, Allison Blake, Deb Slinger

NSW Department of Primary Industries, Wagga Wagga NSW, Australia

Abstract:

Legume crops are one of key rotation components in agricultural systems, supplying nitrogen (N) to following crops and potentially increasing farm profitability. However, with the increasing atmospheric greenhouse gas concentrations, Australia will become warmer and dryer in the future. This greatly threatens Australian crop production and brings uncertain impacts on the profitability of adding legumes into non-legume crop sequences. In this study, we optimised the crop model, APSIM, using 4-year experimental data, collected in Wagga Wagga, New South Wales, Australia. The optimised model was then used to predict lupin biological N2 fixation (BNF) and the contribution of fixed N to the subsequent canola under historical and future climatic conditions in the rainfed cropping systems. The simulation results showed that, when there was no N fertilizer applied to canola in lupin-canola rotations, BNF increased about 3% by 2071-2100 under the higher greenhouse gas emission scenario, comparing to 1961-2000. This results in about 20% of increase in the contribution of lupin fixed N to the subsequent canola seasons (NC). However, these benefits will be reduced to zero when N fertilizer applied in canola seasons is over 40 kg N/ha for BNF and 60 kg N/ha for NC, respectively, by 2071-2100 for RCP8.5. This indicates that future climate change would enhance the N contribution of legume fixed N to subsequent crops only when the non-legume crops received lower N fertilizer in the legume added rotation cropping systems.

Metabolic responses relating to changes in N2 fixation of lentil (Lens culinaris MEDIK.) under contrasting growing seasons in a Free-Air CO2 Enrichment (FACE) facility

Shahnaj Parvin1 2 3, Shihab Uddin4 5, Markus Löw5, Ute Roessner6, Sabine Tausz-Posch9, Garry O’Leary7, Glenn Fitzgerald5 7, Roger Armstrong7 8, Michael Tausz9

1Southern Cross University, Lismore, NSW, Australia

2 Charles Sturt University, Wagga Wagga, NSW, Australia

3School of Ecosystem and Forest Sciences, The University of Melbourne, Creswick, VIC, Australia.
4NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga, Australia.

5Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Creswick, VIC, Australia.

6School of BioSciences, The University of Melbourne, Parkville, VIC, Australia.

7Agriculture Victoria, 110 Natimuk Road, Horsham, VIC 3400, Australia.

8Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, VIC, Australia.

9Department of Agriculture, Science and Environment, School of Health, Medical and Applied Sciences,

CQUniversity, Rockhampton, QLD, Australia.

Email: sparvin@student.unimelb.edu.au           

 

Abstract:

Elevated CO2 (e[CO2]) can stimulate N2 fixation of legumes via increases in photosynthetic carbon supply to symbionts. N2 fixation mechanisms are highly sensitive to drought but little is known about changes in nodule metabolism under e[CO2] and water restriction. To address these challenges, N2 fixation and changes of carbohydrate and nitrogen metabolic profiles were investigated in lentil (Lens culinaris MEDIK.) grown under ambient [CO2] (~400 ppm) and e[CO2] (~550 ppm) in the Australian Grain Free Air CO2 Enrichment (AGFACE) facility over two seasons with strongly contrasting rainfall. Elevated [CO2] stimulated N2 fixation to a greater extent in a wet season than in a dry season. The lower stimulation during a dry season was associated with decreased sugars and organic acids but increased concentration of sugar-alcohols and certain amino acids in nodules. Metabolic changes under e[CO2] may have contributed to mitigating drought impacts on N2 fixation of lentil.

Analysis of the vegetable value chain and gender roles in vegetable production in northwest Cambodia

Rebecca Fong, Rebecca Cross, Robert Martin and Daniel K.Y. Tan

The University of Sydney, Sydney Institute of Agriculture, School of Life and Environmental Sciences, Faculty of Science, Sydney, NSW 2006, Australia

Tel: 61 2 8627 1052 Email: daniel.tan@sydney.edu.au, rebeccaweilyn@hotmail.com 

Abstract:

Consumer demand for vegetables has been on the rise in the past 10 years due to their reported nutritional and health benefits. In addition, vegetables provide crop diversification for rice-based production systems, being suitable for crop rotation and therefore contributing to minimising the spread of plant disease and improving the quality of soil. Within the Cambodian market there is a strong, local preference for vegetables produced in Cambodia as they are recognised to be of high quality relative to those imported from neighbouring countries.  This project aims to analyse the scalability of best practice in vegetable production, by conducting a value chain analysis (VCA) to map and evaluate each actor in the vegetable supply chain within Cambodia, including farmers, collectors and wholesalers. In addition, the degree of gender equality in vegetable production is assessed to determine if there has been progress with women empowerment in the production sector. The VCA was conducted using the mixed method approach, which included interviews with 140 farmers and surveys with 524 household representatives in the Cambodian provinces of Battambang and Banteay Meanchey. Challenges that actors in the VCA face are a lack of resource-base and technical knowledge. Cambodian men do most of the heavy labour activities such as land preparation and the application of both pesticides and herbicides, while women are more predominantly involved in monetary decision making such as managing the household finances and selling the produce. Women play a key role in vegetable production; integrated models that recognise women’s potential to capitalise on and value-add to vegetable products will advance the vegetable industry in Cambodia.

An alternative method of managing perennial ryegrass for greater persistence

Anthony Leddin

Valley Seeds, 295 Maroondah link Highway, Yarck, Victoria, 3719, www.valleyseeds.com, aleddin@valleyseeds.com

Abstract:

Perennial ryegrass (Lolium perenne) has been the main perennial temperate grass sown in high rainfall zones (+650 mm annual rainfall) since the release of the first varieties in Australia in the early 20th century.  With the drier conditions that farmers are now experiencing in these regions, there has been a decrease in the persistence of this species.  Previous grazing management methods have encouraged the use of leaf growth stage to determine the right time to graze a perennial ryegrass pasture.  The appropriate time for grazing was identified to be at the 2½-3 leaf stage of growth.  However, under dry summer conditions these parameters are not met as farmers push their paddocks for as much production as possible and hence persistency is decreased.  This paper wishes to open discussion on identifying new methods of management, such as allowing perennial ryegrass varieties to set seed in their first year of establishment to allow greater root development and allow a seed bank that can last up in the soil for up to 3 years.  This seed setting management should then be repeated every 3 years when the seed bank has expired (Oregon State University, 2003).  For this management method to be successful, careful selection of the appropriate heading date of a variety to match the annual rainfall of the environment is critical.

Between genotype variation of lucerne (Medicago spp.) in grazing preference by sheep

Meredith Mitchell1, Kym Butler2, Lysandra Slocombe2, Steve Clark2, Viv Burnett1, Reto Zollinger2, Greg Seymour1, Zhongnan Nie2

1Agriculture Victoria, Department of Jobs, Precincts and Regions, 124 Chiltern Valley Road, Rutherglen, Victoria, 3685, www.djpr.vic.gov.au, meredith.mitchell@ecodev.vic.gov.au

2Agriculture Victoria, Department of Jobs, Precincts and Regions, 915 Mount Napier Road, Hamilton, Victoria, 3300

Abstract:

Lucerne (Medicago sativa L.) is a highly desirable forage species in temperate regions of the world.  With the many lucerne cultivars currently available and/or emerging onto the Australian market, producers may find it difficult to determine which cultivar(s) will best suit their needs.  An understanding of how these cultivars are selected and grazed by sheep may be useful for producers to make management decisions.  It was hypothesised that there will be substantial differences in sheep grazing preference among diverse cultivars. Grazing preference was evaluated on forty-seven entries (commercial cultivars and pre-release lines) at Hamilton, Victoria, in summer, winter and spring of 2017. The plots were rated using a seven-point scoring system (1 = not grazed to 7 = completely grazed) over a 27 h grazing period. The average grazing scores indicated that, with minor qualifications, all lucerne entries evaluated in this study were palatable to sheep.

Deep soil water-use determines the yield benefit of long cycle wheat

BM Flohr1, JR Hunt2, JA Kirkegaard3, B Rheinheimer3, T Swan3, L Goward3, JR Evans4, M Bullock3

 1CSIRO Agriculture and Food, Adelaide, South Australia, Australia, bonnie.flohr@csiro.au

2Department of Animal, Plant and Soil Sciences, AgriBio Centre for AgriBiosciences, La Trobe University, Melbourne, Victoria, Australia

3 CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia

4 The Australian National University, Research School of Biology, Canberra, ACT 2601, Australia

Abstract:

The yield advantage of early sown slow developing (long cycle) wheat cultivars over fast developing cultivars sown later (short cycle) is variable. This variable response is likely due to environmental factors, but the precise set of conditions that confers an advantage to long cycle treatments is not known. We compared short and long cycle wheat cultivar x time of sowing combinations over four seasons in Temora, NSW. Two seasons (2011, 2012) had over 400 mm of summer fallow (December-April) rain which filled the soil profile to depth, and two seasons had summer fallow rain that was less than the site average of 208 mm (2015, 2016). Rainfall 30 days prior to the start of flowering (approximating the critical period for yield determination) in each year was 8, 6, 14, 190 mm respectively. We observed that there was only a yield benefit in long cycle treatments in seasons where there was soil water stored at depth, and there was little rain during the critical period for yield determination in wheat, forcing greater reliance on stored soil water for crop growth (2011, 2012). In these seasons the higher yield of long cycle treatments could be attributed to greater soil water extraction from deep in the profile (<1.0 m), and consequently greater dry-matter production, grain number and grain yield. In the other seasons, lower evaporation and higher biomass accumulation in long cycle treatments traded off against inferior harvest index such that yields were equivalent to short cycle treatments.

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Host

The Australian Society of Agronomy is the professional body for agronomists in Australia. It has approximately 500 active members drawn from government, universities, research organisations and the private sector.

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