Acid tolerant rhizobia for faba bean grown in south western Victoria

Frank Henry1, Ross Ballard2 and Elizabeth Farquharson2

1 Agriculture Victoria, 915 Mt Napier Rd, Hamilton, Victoria, 3300, frank.henry@ecodev.vic.gov.au

2 South Australian Research and Development Institute (SARDI), Gate 2B Hartley Grove, Urrbrae, SA,5064

Abstract

Poor nodulation of faba beans grown on acid soils (pHCaCl2 < 5.5) is considered a major constraint to increasing the area grown to faba beans, increasing grain yield and reducing dependence on artificial fertiliser. To help overcome this problem, rhizobia bacteria with improved tolerance to acidic soils were developed at SARDI and DPIRD. A number of the new acid tolerant strains of rhizobia were compared to the commercial Group F strain WSW-1455 in trials undertaken between 2016 and 2018 within the Victorian high rainfall zone. Several acid tolerant strains showed improved nodulation and grain yield. The rhizobia strain SRDI-970 had significantly higher grain yield (6.2 t/ha) and nodulation score compared to the current commercial strain Group F WSM-1455 (2.2 t/ha) in 2017. While acid tolerant rhizobia are still two years from commercialisation, doubling the rate of the commercial Group F WSM-1455 inoculant may improve nodulation and grain yield providing an interim solution until a new strain becomes available. Acid tolerant rhizobia are not considered a replacement for lime, but rather a complement to a good lime program.

 

Impact of crop type and sequence on soil water accumulation and use in farming systems

Andrew Erbacher1, Lindsay Bell2, David Lawrence3, Andrew Verrell4, Jon Baird4, Darren Aisthorpe3, Andrew Zull3, Jayne Gentry3, Greg Brooke4, Kaara Klepper5

1 Department of Agriculture and Fisheries, 22-26 Lagoon St, Goondiwindi, Queensland, 4390, andrew.erbacher@daf.qld.gov.au

2 CSIRO Agriculture and Food, 203 Tor St, Toowoomba, Queensland, 4350

3 Department of Agriculture and Fisheries, Queensland (Toowoomba and Emerald)

4 Department of Primary Industries, New South Wales (Tamworth, Narrabri and Trangie)

5 formerly 3Department of Agriculture and Fisheries, Toowoomba, Queensland, 4350 

Abstract:

The efficiency of soil water accumulation during fallow periods, and the availability of that soil water for use by crops are key drivers of northern farming system productivity and profitabilityIn 2015 seven farming systems experiments were established from Central Queensland to Central NSW. Soil water, nitrogen and pathogens were regularly monitored along with crop biomass, grain yield and variable costs, as measures of system performance. A baseline cropping system, representing current commercial practice was established and tested against other systems with higher and lower crop intensity, higher crop diversity, greater inclusion of legumes in the rotation and higher fertiliser inputs. A key driver of northern farming system productivity and profitability is soil water accumulation during fallows periods for use by subsequent crops. We found that winter cereals and sorghum had the highest fallow efficiency (median 0.26), ahead of chickpeas (0.14) and canola (0.19). Short (4-8 months) and long (9-18 months) fallows following wheat had similar fallow efficiency, however lower fallow efficiency was recorded for sorghum stubble with longer fallows (0.33 vs 0.22) Changing cropping intensity had the greatest impact on fallow efficiencies, with increases in Higher intensity systems (0.37) and decreases in Lower intensity systems (0.16) relative to the Baseline (0.22). Varying fallow length has shown increased grain yield and water-use-efficiency for longer fallows, however rainfall use efficiency and gross margin/mm has favoured a 4-6 month fallow. Profitability favours a moderate intensity, with 0.8-1 crops/year providing the greatest return per mm of rainfall.

 

Deep ripping: an effective first step to lift productivity on deep sands in the Victorian Mallee?

Michael Moodie1, Lynne Macdonald2 and Ray Correll3

1 Frontier Farming Systems, 7B Byrne Ct, Mildura, Victoria, 3500, www.frontierfarming.com.au, michael@frontierfarming.com.au

2 CSIRO Agriculture and Food, Locked Bag 2, Glen Osmond, SA, 5064

3 RHO Environmetrics, PO 366 Highgate, SA, 5064

Abstract

Sub-optimal productivity is commonly reported for the deep sands that make up approximately 20-30% of the cropping soils in the low rainfall Victorian Mallee.  Un-used water is evident despite an apparent absence of constraints commonly associated with sandy soils (e.g. non-wetting, acidification).  Poor subsoil fertility and/or physical restrictions to rooting depth may be the primary constraints to production in deep Mallee sands.  To explore the issues further, replicated trials were established across two sites, Ouyen (2017-18) and Carwarp (2018).  These trials have investigated the interactions between physical disturbance (deep-ripping and/or rotary spading) and the incorporation of organic and inorganic inputs.  Alleviating physical barriers to root growth through practices such as deep ripping and rotary spading are providing the most consistent yield increase on sandy soils in the Victorian Mallee, with yield benefits of up to 1.5 t/ha observed over two seasons.  Spading of high nitrogen organic matter sources (vetch hay, chicken litter, compost) has also increased yield. Of the organic amendments, chicken litter has led to the highest cumulative grain yield response (2 t/ha across two seasons).  This response from the application of chicken litter demonstrates the potential to improve crop yields by increasing the fertility of sandy soils.

Effects of deep ripping on soil compaction and crop performance in Mallee sands

Brian Dzoma1, Nigel Wilhelm2, Peter Telfer3 and Kym Zeppel1

1SARDI Loxton Research Centre. P O Box 411, Loxton SA, 5333,
2SARDI Waite Research Precinct. Building 11A Hartley Grove, Urrbrae, SA 5064,
3Turretfield Research Centre. Holland Road, Rosedale, SA 5350

Abstract:

Soil compaction on sandy soils is one of the major problems facing modern farming systems because of frequent use of heavy machinery which comes with intensive cropping. Deep ripping on Mallee sands is becoming a common option to reduce hard pans and ameliorate compacted layers. The challenge facing growers is determining the optimal ripping depth and tine spacing for their soils.  Aims of this project were to assess the impact of deep ripping on subsoil compaction and performance of several crop species and to determine the optimal ripping depth x tine spacing for Mallee sands. Our trials showed that ameliorating compacted sandy soils in low rainfall environments can lead to improved shoot DM and grain yield, and should subsequently lift farm productivity and profitability. In terms of grain yield, ripping at narrow or wide tine spacing gave similar outcomes and wider tine spacings can therefore be considered in order to use less machinery horsepower. Our trials also show that when the soil in question is compacted to depths beyond 40cm, then ripping deeper is better for grain yield, provided there are no other chemical constraints below the compaction zone.

Promoting soil health in dryland agriculture by increasing cropping intensity

Alwyn Williams1, Lindsay W. Bell2

1 School of Agriculture and Food Sciences, The University of Queensland, Gatton, QLD 4343, alwyn.williams@uq.edu.au,
2 CSIRO, 203 Tor Street, Toowoomba, QLD 4350

Abstract:

Extended fallow periods are implemented in dryland cropping systems to allow recharge of soil moisture for the subsequent crop. Over time, fallow periods deplete soil carbon (C), a foundation of soil health that affects soil microbial activity and the long-term capacity of soils to store moisture. Reducing fallow periods by increasing cropping intensity (e.g. cover or double cropping) can promote soil health and thereby contribute to the long-term sustainability of dryland cropping systems. However, the agronomic feasibility of increasing cropping intensity in dryland systems is unknown. Using a cropping systems experiment in southeast Queensland, we investigated the impacts of cover and double cropping on indicators of soil health and sorghum grain yields in comparison to conventional fallow-based cereal production systems. Both cover and double cropping systems increased concentrations of soil C compared with the conventional systems. In the cover crop system, this was associated with greater soil microbial activity and improved surface soil moisture storage at crop establishment. Additionally, sorghum grain yield in the cover crop system did not differ significantly from those in the conventional systems. In contrast, the double crop system depleted soil moisture reserves leading to dramatic yield loss as well as reduced nitrogen- and water-use efficiency. Our results demonstrate that reducing fallow periods via cover cropping is a potentially feasible method for promoting soil health in subtropical dryland cropping systems. Longer-term research is required to determine the trade-offs and tipping points associated with the use of cover crops in drylands.

Addressing subsoil acidity in the field with deep liming and organic amendments: Research update for a long-term experiment

Guangdi Li1,3, Richard Hayes1,3, Jason Condon1,2,3, Sergio Moroni2,3, Ehsan Tavakkoli1,3, Helen Burns1, Richard Lowrie1, Adam Lowrie1, Graeme Poile1, Albert Oates1, Andrew Price1 and Alek Zander2

1 NSW Department of Primary Industries, Pine Gully Road, Wagga Wagga, NSW 2650, www.dpi.nsw.gov.au, guangdi.li@dpi.nsw.gov.au,
2 Charles Sturt University, Boorooma Street, Wagga Wagga, NSW 2650,
3 Graham Centre for Agricultural Innovation, Albert Pugsley Place, Wagga Wagga, NSW 2650

Abstract:

A long-term field experiment was established in 2016 to manage subsurface soil acidity through innovative amelioration methods with the aim to increase productivity, profitability and sustainability. Deep placement of lime increased soil pH and reduced exchangeable Al% at the depth where lime was placed, but there was no evidence to show vertical alkalinity movement during the first 3 years of the experiment.  Deep placement of lucerne pellets did not increase soil pH as much as expected, but reduced exchangeable Al%. Significant yield improvement was recorded from deep placement of lucerne pellets in a wet year (2016) but not in dry years experienced in 2017 and 2018, although large amount of mineral nitrogen was measured in autumn in 2017. Crop performance and soil chemical, physical and biological properties will be continually monitored to understand plant-soil interactions, the factors driving the differences in crop response to various treatments, and the long-term residual value of soil amendments.

Pasture legumes offer promise to control barnyard grass in delayed permanent water systems in rice

Jhoana Opena1, James Pratley1, Jeffrey McCormick1, Hanwen Wu12, and Deirdre Lemerle1

1 Graham Centre for Agricultural Innovation (Charles Sturt University and NSW Department of Primary Industries), School of Agricultural and Wine Sciences, Locked Bag 588, Wagga Wagga, NSW, 2678, jopena@csu.edu.au,
2 NSW Department of Primary Industries, Wagga Wagga, NSW, 2650

Abstract:

Australian rice growers endeavour to reduce water use in their rice crops due to high competition for scarce water resources. One method increasing in popularity is to drill sow rice and delay the application of permanent water. This water saving method however, provides an opportunity for the global weed barnyard grass to proliferate. Farmer anecdotes have suggested that the resultant barnyard population is determined to some extent by the lead-in crop or pasture. This paper considers the impact of particular pasture legumes on the barnyard grass seedbank and seedling establishment. Data show that there is some validity in the farmer experience with barnyard grass being inhibited by legume species as the lead-in ‘crop’.

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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.

Photo Credits

David Marland Photography david_marland@hotmail.com Graham Centre for Agricultural Innovation, Charles Sturt University

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