Field calibration of the capacitance soil moisture probes for Brown Sodosol

Belyaeva O1, Ward G1, Chen D1, Suter H1.

1 University of Melbourne, Vet and Agri Science, Bld. 184, 30 Flemington Road, Parkville, Victoria, 3052, https://www.unimelb.edu.au, oxana.belyaeva@unimelb.edu.au

Abstract:

Knowledge of soil moisture is needed to understand crop water use and improve water-use efficiency: capacitance probes can be used for this. However, often generic calibrations supplied by the manufacturer the probes are used and this can lead to errors. The aim of this study was to estimate the accuracy of using generic calibration relationships for capacitance probes to monitor soil water. A set of 4 probes (0-120 cm depth) were installed at irrigated and non-irrigated pasture sites and calibrated using the traditional core-sampling technique. For the sandy top soil (up to 30 cm), the factory generic calibration overestimated soil moisture with a significant error of 0.05-0.28 m3/m3. For deeper clay horizons the error between the generic calibration and actual moisture tended to be larger. This increased error in sub-soils can be associated with changing bulk density and porosity down a profile and, on this soil, also presence of voids and cracks. Using the generic calibration would lead to a significant overestimation of volumetric soil water at the high water content (>0.45 m3/m3) and understating at the dry end (<0.17 m3/m3). The findings show that a soil specific calibration of the capacitance probes is required for accurate soil moisture measurements.

Increasing wheat sowing rates can reduce winter weed numbers in a cotton-wheat rotation

Nilantha R. Hulugalle1,2, Benjamin J. Lenehan3,4, Guna Nachimuthu1 and Daniel KY Tan3

1Australian Cotton Research Institute, New South Wales Department of Primary Industries, Narrabri, NSW, Australia,
2 Present address: Fenner School of Environment and Society, Australian National University, Canberra, ACT, Australia,
3 The University of Sydney, Sydney Institute of Agriculture, School of Life and Environmental Sciences, Faculty of Science, Sydney, NSW, Australia
4 Present address: Delta Agribusiness, Harden, NSW, Australia, Email: daniel.tan@sydney.edu.au

Abstract:

Wheat is commonly sown in rotation with cotton in Australian cotton farming systems. Uncontrolled weed growth can inhibit wheat growth and thereby, have a detrimental effect on the following cotton crop. Weeds that are frequently found in wheat crops of north-western New South Wales (NSW) include deadnettle (Lamium amplexicaule L.), sow thistle (Sonchus oleraceus L.), and annual Phalaris (Phalaris paradoxa L.). The objective of our study was to quantify the effects of wheat sowing rates on weed populations and growth, and their impact on wheat growth and yield. An experiment that consisted of wheat sowing rates of 0 (fallow), 30, 60, 120 and 180 kg ha-1 was conducted during 2014 and 2015. Weed biomass, type (broad-leaved or grassy), and species diversity were assessed at wheat anthesis. Wheat phenological events (emergence, anthesis, maturity dates) were recorded and wheat biomass measured at 10 weeks after sowing (2015) and anthesis (2014, 2015), as well as grain yield. Weed populations at wheat anthesis consisted of broad-leaved weeds during 2014 and a mix of broad-leaved and grassy (annual Phalaris) weeds during 2015. Weed biomass decreased sharply when wheat was sown, even at the lowest sowing rate of 30 kg ha-1 and continued to decrease such that at the higher sowing rates it was negligible. Adequate yields can be attained by sowing wheat at rates in the range 30-60 kg ha-1. The costs associated with sowing at higher rates cannot be justified, although significant long-term reductions in the weed seedbank are likely only by sowing at these rates.

Effect of sowing time, sowing rate and soil water regime on yield, water use efficiency and soil water dynamics of faba bean (Vicia faba L.)

Ketema Zeleke

School of Agricultural & Wine Sciences, Charles Sturt University, Boorooma Street, Wagga Wagga, NSW 2650

Graham Centre for Agricultural Innovation, Boorooma Street, Wagga Wagga, NSW 2650, kzeleke@csu.edu.au

Abstract:

Crop yield and water use efficiency are determined by its genotype, environment, GxE and agronomic management. The performance of faba bean (cv. Samira) under different sowing time, sowing rate and soil moisture conditions was evaluated. Sowing time and soil moisture regimes were found to have significant effects on grain yield, water use efficiency and grain quality. Yield penalty associated with delayed sowing was not significant when the crop was irrigated in spring; irrigation water use efficiency was higher for late sown than for early sown faba bean. Late sown faba bean left higher amount of residual moisture in the soil than the early sown faba bean. Faba bean yield and water use efficiency could be improved by timely sowing and/or supplemental irrigation.

Delayed harvest affects lentil quality grade

Richie Mould1, Christine Walela2, Larn McMurray3, Helena Oakey4, Penny Roberts5

1 SARDI, 70 Farrell Flat Road, Clare, SA, 5453, richie.mould@sa.gov.au, 2SARDI, Waite Campus, 2b Hartley Grove, Urrbrae SA 5064, 3Global Grain Genetics, 21 Laroona Drive, Quantong, VIC, 3401, 4SAGI, University of Adelaide Waite campus, 5SARDI, 70 Farrell Flat Road, Clare, SA, 5453

Abstract:

Lentil receival grade is highly dependent on grain quality, which then determines the export value and financial return for the grower. Grain quality can be affected by a number of factors including growing season conditions and environmental conditions post-maturity. Field research was undertaken to assess the impact of delayed harvest on seed quality of lentil crops in the medium rainfall zone of South Australia. The research was conducted from 2016-2017, at three sites. Seed quality assessments were undertaken for grain weight, screenings, seed coat colour, and wrinkle for three times of harvest. We found significant decreases in lentil harvest quality due to weathering as a result of delaying harvest time with some varietal differences. Generally, the smaller sized lentil varieties retained better quality characteristics compared to larger seed size varieties when harvest was delayed. In this study, rainfall was the most important factor in quality reduction. While the ability to withstand post-maturity weathering is present in some lentil varieties, timely harvest of lentil crops is necessary to ensure a successful and profitable lentil harvest.

 

Precision planting in canola and lentil

Glenn McDonald1, Claire Browne2, Sarah Noack3, Stefan Schmitt4

1 School of Agriculture, Food and Wine, University of Adelaide, PMB 1 Glen Osmond SA, 5064, Email: glenn.mcdonald@adelaide.edu.au,
2 Birchip Cropping Group, 73 Cumming Ave, Birchip, Victoria, 3483,
3 Hart Field Site Group, 155 Main North Road, Clare. SA 5453, 4Ag Consulting Co, 120 Long Road, Auburn SA, 5451

Abstract:

Recent surveys of canola and lentil crops in the southern and western regions have shown that crop establishment percentage can be low and variable. The speed and evenness of establishment influences interplant competition and sometimes yield.  Two experiments were conducted at Hart, South Australia and Birchip, Victoria to test the value of precision planting on crop establishment and yield.  Experiments compared a conventional plot seeder and a precision planter over six plant densities and in narrow (23 cm) and wide (30 cm) row spacings.  Crop establishment using a precision planter was similar to or worse than that with a conventional seeder.  Nevertheless, there was a significant improvement in lentil and canola yields at Hart with precision planting; no differences were evident at Birchip. Canola yield was more sensitive to plant density than lentil. Achieving an adequate plant population in canola (greater than 30-40 plants/m2) was more important to grain yield than in lentil.

Growers identify that knowledge and confidence in management decisions are major constraints to profitable productivity improvement in the higher rainfall areas of Western Australia

G.P. McDonald

Department of Primary Industries and Regional Development, 444 Albany Highway, Albany, WA, 6330, www.dpird.wa.gov.au, glenn.mcdonald@dpird.wa.gov.au

Abstract:

During the 2010 season, grain growers from across the Western Australian southern higher rainfall areas were consulted in a series of interactive workshops designed to identify constraints to improving productivity and profitability. More than 94% of the growers believed there was significant room for improvement in their business. Similar constraints were grouped with the most important groups of these being soil management with 54% of all votes cast by workshop participants. Specific constraints of high importance were non-wetting soils and herbicide resistance. Other common constraints in order of decreasing priority included input efficiencies, soil acidity, soil constraints knowledge, soil water storage, and waterlogging. Growers identified more than 50 constraints during the workshops that can be grouped into four key themes; knowledge, confidence, time and money. Although the latter two, lack of time and insufficient money, can be neutralised by greater knowledge and improved confidence. For the adoption of any new technology or information to overcome a constraint all of these four themes must be adequately addressed.

Growth and development of industrial hemp (Cannabis sativa L.) in response to irrigation treatments

Induni Vijay Kumar1, Tina Botwright Acuna1, Shaun Lisson1, Marcus Hardie1

1 University of Tasmania, Churchill Ave, Hobart, TAS, 7005

Abstract:

Opportunity exists for Australian growers to develop a commercial cannabis/hemp industry to meet global demand for seed, fibre and pharmaceutical products.  Development of a commercial scale hemp industry requires improved knowledge of hemp crop water relations to maximise yield, understand irrigation requirements in new production regions, and for scheduling of harvest. Currently little is known of the hemp plant-water relations. This study sought to evaluate the growth, development and physiology of industrial hemp under varying irrigation treatments. A preliminary greenhouse experiment was conducted to monitor response of industrial hemp cultivar Ferimon 12 to different irrigation treatments (2, 4, 6, 8 and 10 day intervals). We found significantly taller plants for 2 day compared with the 8 and 10 day irrigation intervals. Significantly higher above ground dry biomass was observed for plants irrigated with 6, 8 and 10 day intervals compared to the 2 and 4 days interval at 42 DAS. Significantly higher PSII photochemical capacity (Fv/Fm) and leaf chlorophyll content (SPAD value) was observed for plants irrigated with 6 and 10 day intervals compared with the 2 day intervals. There for 6 day irrigation interval is probably the best frequency of irrigation. Results from the preliminary experiment will be used to inform the design of future research which will be used to develop irrigation recommendations and refine the hemp crop simulation model to further support farmer decision making regarding water management.

 

 

Frost response in lentil. Part 1. Measuring the impact on yield and quality

Audrey Delahunty1, Eileen Perry2,3, Ashley Wallace4, James Nuttall4

1Agriculture Victoria, Cnr of Koorlong Avenue and Eleventh Street, Irymple, Victoria, 3500, audrey.j.delahunty@ecodev.vic.gov.au, 2Agriculture Victoria, Cnr Midland Highway and Taylors Street, Epsom, Victoria, 3498, 3The University of Melbourne, Parkville, Victoria, 3000, 4Agriculture Victoria, 110 Natimuk Road, Horsham, Victoria, 3400

Abstract:

Radiant frost limits production of lentil in southern Australia, reducing grain yield, causing deformation of grain and reducing grain quality.  Increased understanding of the impacts of frost at different growth stages and severities are important factors to enable effective management to limit financial losses.  Frost chambers were used to apply frost treatments to field-grown lentil (cv. PBA Jumbo 2) to define the response of yield components to frost exposure at different growth stages and intensities.  Lentil crops differentially affected by frost also provided a backdrop for testing the utility of remote sensing to detect damage.  Lentil was most susceptible to frost during the pod filling stage, when every degree hour below zero, reduced yield by 2%.  This compared to a response at flowering, where a threshold of 31°C.hr (<0°C) was reached prior to yield reduction, and after which yield declined at 3.8% per °C.hr.  Importantly, the current methodology effectively created a backdrop of lentil differentially effected by frost which could provide utility to breeding and agronomic programs to characterise in-field frost damage.

In-field differentiation of frost and heat stress in wheat

Alexander Clancy1, Audrey Delahunty2, James Nuttall1, Eileen Perry3,4

1Agriculture Victoria, 110 Natimuk Road, Horsham, Victoria, 3400 alexander.clancy@ecodev.vic.gov.au, 
2Agriculture Victoria, Cnr Koorlong Avenue & 11th Avenue, Irymple, Victoria, 3498, 3Agriculture Victoria, 1-7 Taylor Street, Epsom, Victoria, 3551, 4The University of Melbourne, Parkville, Victoria, 3000

Abstract:

Frost and acute high temperature are both extreme temperature events that have a significant impact on crops grown within Mediterranean-type climates. During the late spring period which coincides with dryland crops flowering, frost and high temperature can occur within days of each other, and often confound interpretation of which causes a yield penalty. As a means of assessing the effect of the two stresses on wheat and defining the main and interactive effects of heat and frost, a factorial trial was established in a wheat crop at Horsham, Victoria. Insulated chambers were utilised to apply artificial frost during the evenings at two intensities. Following one day of recovery, daytime high temperature treatments at two intensities were applied, using heat chambers, to plots with and without previous frost treatments. The results of the trial show a significant (P <0.001), linear relationship between cumulative frost (C.hr (<0 oC)), yield and components. No significant relationship was found for heat or frost by heat interaction on yield, most likely due to a lack of intensity for the heat treatments applied. This work provided a backdrop to collect non-destructive, remote sensing data, as a potential tool for rapid assessments of crop damage to extreme temperature events.

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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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