Liming changes more than the pH – A field study on wheat and pasture species

Daniel Kidd1,

1 University of Western Australia, 35 Stirling Hwy, Perth, W.A, 6009, daniel.kidd@uwa.edu.au

Abstract:

This experiment was conducted to investigate the enduring effects of prior liming of an acidic duplex soil. In 2018, the response of cereal crops (wheat and cereal rye) and pasture legumes (serradella, subterranean clover and lucerne) spanning a range of susceptibility to acid soil was assessed. Despite the site having uniform nutrient additions and crop management over a number of years, nutrient availability (particularly nitrogen, phosphorus and potassium) was still significantly lower in the unlimed strips compared with the limed strips. Of the root diseases assessed, most were more prevalent under cereals and had a greater disease risk rating in limed plots. There was no effect of lime on shoot and root DM of acid soil tolerant varieties (i.e yellow serradella and cereal rye). Acid soil tolerant varieties are a good option in these soil types but the potential use of higher yielding, acid soil sensitive varieties combined with the longevity of the liming effects in low rainfall environments should be taken into account when considering the economics of soil amelioration by liming.

The potential of forage brassicas to produce herbage for mixed farming systems

Lucy Watt1, 4, Lindsay Bell1, Brett Cocks1, Tony Swan2, Andrew Toovey3

1 Agriculture & Food, CSIRO, 203 Tor Street, TOOWOOMBA, QLD, 4350

2 Agriculture & Food, CSIRO, Black Mountain, 2-40 Clunies Ross Street, ACTON, ACT, 2601

3 Agriculture & Food, CSIRO, 147 Underwood Avenue, FLOREAT, WA, 6014

4lucy.watt@csiro.au

Abstract:

Forage brassicas are not commonly utilised in Australian mixed farming systems. Integrating forage brassicas into these systems may improve crop rotations and livestock productivity, but their adoption is limited mostly due to a lack of knowledge of the most suitable species and the potential systems benefits from their use. In seven field experiments carried out in 2011-2013 (Phase 1) and 2018 (Phase 2) across a range of environments, including Eastern and Western Darling Downs QLD, North West and Central West NSW, and Avon Wheatbelt WA, the biomass production of a range of forage brassica species were compared with other annual forage benchmark species. In Phase 1, forage rape cultivars were able to produce 80-90% of the biomass of forage cereal controls, but there were some differences between the diverse forage brassica types across growing environments. In Phase 2, Experiments 4, 5 and 7, several of the forage brassicas produced similar (P > 0.05) maximum biomass as forage oats. Conversely, in Experiment 6, maximum biomass of forage oats was higher (P < 0.001) than all other species. Maximum biomass of raphanobrassica cv. Pallaton and forage rape cv. HT-R24 were similar (P > 0.05) to forage oats at three of the four sites, whilst performance of the other forage brassicas was variable between sites.

 

Grid soil mapping to define the variability in multiple soil properties.

Kirsten Barlow1, Sebastian Ie2, Ben Fleay2

1 Precision Agriculture, 113 Main Street, Rutherglen, Vic, 3685, www.precisionagriculture.com.au, k.barlow@precisionagriculture.com.au  

2 Precision Agriculture, PO Box 691, Ballarat, Vic 3353, www.precisionagriculture.com.au,

Abstract

Soil constraints such as acidity, sodicity and nutrient availability can cause significant losses in production, limit crop choice, and further reduce the health of our soil resources if untreated. Grid soil sampling is a proven strategy to identify and enable targeted amelioration of soil constraints across a paddock. This paper presents the results of grid soil mapping on 289 commercial paddocks, investigating the relationships between soil pH, CEC, ESP and soil test P observed in the grid mapped surface soil data. The results highlight the variability within individual paddocks for these soil characteristics. Whilst some soil characteristics (e.g., pH and CEC) were well correlated in some paddocks, for most other characteristics up to 75% of paddocks had no consistent trends between the soil test data with correlation coefficients of between -0.5 to 0.5. Grid soil sampling allows the different patterns of spatial variation to be determined for individual soil properties, and enables separate variable rate strategies to be developed.

Variable rate lime for cropping systems in the HRZ: an economic analysis

Kirsten Barlow1, Kerry Stott2, Sebastian Ie1

1 Precision Agriculture, 113 Main Street, Rutherglen, Vic, 3685, www.precisionagriculture.com.au, k.barlow@precisionagriculture.com.au  

2 Agriculture Victoria Research, AgriBio, 5 Ring Road, La Trobe University, Bundoora Vic, 3083

Abstract

Soil acidity affects 50% of Australia’s agricultural land and significantly affects crop production. Results from grid soil sampling (0-10 cm) for pHCa across hundreds of cropping paddocks in the high rainfall zone (HRZ) in Victoria highlight the variability in soil pH across a paddock, where the coefficient of variation averaged 4.7% and ranged from 0.7 up to 16%. The range in soil pH and the coefficient of variation from the field data were used to develop eight hypothetical paddocks. A discounted cash flow model was used investigate the economics of grid soil mapping and variable rate lime application to ameliorate surface soil acidity. Both variable rate and fixed rate lime addition had a positive net present value (NPV) across the hypothetical scenarios, with the inclusion of a pH-sensitive pulse crop increasing the NPV. With a pulse crop in the rotation, variable rate lime had a greater NPV in six of the eight hypothetical paddocks, while in the remaining two paddocks variable rate and fixed rate applications produced similar NPV results.

Heat impact on yield components of fertile primary tillers in wheat can inform crop modelling for future climates

Karine Chenu, Florianne Oudin

The University of Queensland, Queensland Alliance for Agriculture and Food Innovation (QAAFI), Toowoomba, QLD, Australia
Email: karine.chenu@uq.edu.au

Abstract

In recent decades, rising temperatures have increasingly affected wheat crops in major producing regions around the world. Climate models predict further increases in mean temperature and in the frequency of temperature extremes for the near to mid-future.

The impact of heat on wheat at different periods of the crop cycle was studied in two experiments conducted with finely controlled temperatures in a glasshouse. While heat shocks affected the main stem and primary tillers of a plant differently, a common response to heat was found for all stems (irrespective of their rank), when considering the timing of the stress relative to stem anthesis. The greatest impact on grain number was observed for stress applied ~10 days before stem anthesis. The impact of pre-anthesis stress on grain set were slightly compensated by an increase in individual grain weight. Overall, grain yield was substantially affected for early pre-flowering stress and early-to-mid post-flowering stress. The results of this study have been used to improve estimations of heat impact in crop modelling and thus improve the accuracy of crop simulations for future climate scenarios.

Evidence of nutrient, not soil pH, stratification in pasture soils in the Australian Capital Territory

Susan Orgill 1, 2, Sally McIntosh 3, Belinda Hackney 1, 2 and Anna van Dugteren 3

1 NSW Department of Primary Industries, PMB, Pine Gully Rd, Wagga Wagga, NSW 2650

2 Graham Centre for Agricultural Innovation, Charles Sturt University and NSW Department of Primary Industries, Pugsley Place, Wagga Wagga, NSW, 2650

3 ACT NRM, Environment, Planning and Sustainable Development, ACT Government, GPO Box 158 Canberra, ACT, 2601

Abstract:

There has been an increasing interest in the stratification of soil nutrients and pH, and the need to revise sampling depths to better diagnose soil surface and subsurface constraints to crop and pasture production. Twenty-three commercial paddocks were sampled in the Australian Capital Territory (ACT) to diagnose soil chemical constraints to 30 cm. There was little evidence of pH stratification, but strong evidence of phosphorus (P), sulfur (S) and potassium (K) accumulation in the surface (0-5 cm) soil. Nutrient concentrations were highest at 0-5 cm and declined significantly with depth, consistent with the trend in soil organic matter (indicated by total carbon and nitrogen concentration). Sixty six percent of paddocks had available P (0-10 cm) in excess of the critical value, while 61% were deficient in S (0-10 cm). There was no evidence of S accumulation in subsurface soil layers to 30 cm and overall 61% of paddocks were deficient in S in the 0-30 cm profile sampled. Therefore, even if S has accumulated deeper in the profile (>30 cm) it is likely to be below the root zone of most annual species until late in the growing season. Our results indicate nutrient stratification may limit pasture production more than pH stratification in the ACT.

Effect of rate and placement of phosphorus on vetch performance

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:

Phosphorus (P) is an essential nutrient which influences plant growth. Inadequate P restricts root and shoot growth and other functions that reduce N fixation by legumes. Vetch (Vicia sativa), a versatile pasture legume crop that can be used for grain, pasture, hay/silage or green manure, is being grown on naturally infertile Mallee soils which are often quite deficient in P. Consequently, it struggles to achieve optimum productivity and hence less fixed nitrogen is returned to the system. This project evaluated the impact of P on vetch productivity and nodulation and also investigated placement of P at sowing on nodulation, root and shoot dry matter (DM) production. Results showed that there are productivity gains to be realised from applying P fertilisers when sowing vetch on soils with low P reserves. Application of 32 units of P resulted in shoot DM increases of 239% and 45% at Loxton and Peebinga respectively. Results also showed that deep placement of P is beneficial to early and late DM production, but can set back nodulation as the plants need the P upfront. P applications, however, need to be matched against expected productivity gains for different soil types and rainfall regions to make sure that the fertiliser applications are economically justifiable

Effect of sowing date on phenology, plant morphology and yield components in linseed grown in northern NSW in 2015

K A Hertel

NSW Department of Primary Industry

PMB 19, Trangie NSW 2823

  1. kathi.hertel@dpi.nsw.gov.au

Abstract:

Linseed (Linum usitatissium) is a profitable oilseed crop recognised for its role within a rotation for managing cereal crop diseases and pests such as the economically important root lesion nematode species. Consultation with growers and agronomists in northern NSW identified a range of views regarding the ideal sowing window, and a significant knowledge gap of available linseed varieties. A linseed phenology experiment was conducted in 2015 to evaluate the effect of sowing date (SD) on the phenology and yield components of four linseed varieties sown at five SDs (17 April, 8 May, 28 May, 22 June, 13 July). In general, as SD was delayed, the length of key phases such as start of flowering were reduced, plant height and height of lowest capsules decreased and thousand seed weight (TSW) declined. The results show the temperature-driven response of growth and development of four varieties, providing baseline data that could be utilised in crop growth simulations of variable climate scenarios for regional adaptation.

Untangling and unifying adaptive and productivity traits in canola

Harsh Raman1, Rosy Raman1, Yu Qiu1, Brett McVittie1, Simon Diffey2, David Tabah3, and Andrew Easton3,4

 1NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga, NSW, 2650, Australia, https://www.dpi.nsw.gov.au/, harsh.raman@dpi.nsw.gov.au

2National Institute for Applied Statistics Research Australia (NIASRA) University of Wollongong, NSW 2522, Australia

3Advanta Seeds Pty Ltd, Toowoomba, QLD, Australia, 4Present address: Technigro Pty Ltd, Yatala, Queensland, Australia 

Abstract:

Understanding and manipulating the variation for various traits involved in adaptation is essential for sustainable production of canola in diverse environments. We investigated the naturally-occurring variation in flowering time, resistance to blackleg and pod shattering, tolerance to manganese, fractional ground cover, carbon isotope discrimination, water soluble carbohydrate accumulation, and grain yield across diverse growing environments to gain insight of the genetic architecture for these traits. Through extensive phenotyping and genetic analysis, we have untangled genomic regions associated with these traits. We are now developing improved pre-breeding germplasm by combining different genomic regions for stable canola production.

Genetic mapping of flowering time in two interspecific RIL populations of chickpea

Rosy Raman1, Neroli Graham2, Jess Simpson1, Annie Warren2, Sean Bithell2, Dave Wheeler3, Laney Davidson2, Mark Richards1, Kristy Hobson2

1NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga, NSW 2650, Australia rosy.raman@dpi.nsw.gov.au

2NSW Department of Primary Industries, 4 Marsden Park Rd, Tamworth, NSW 2340, Australia

3NSW Department of Primary Industries, 1447 Forest Road, Orange, NSW 2800, Australia

Abstract

Chickpea (Cicer arietinum) is grown under diverse environments in Australia and often faces various yield limiting abiotic stresses such as low (chilling) temperatures, drought and heat during the reproductive phase. Understanding the genetic control of flowering time, a key adaptive trait is essential for wider adaptation and productivity of chickpea varieties. Currently, our knowledge on the genetic control of flowering time in Australian chickpea varieties is very limited. We utilised two recombinant inbred line (RIL) populations; RB (derived from an early flowering variety, Rupali and late flowering interspecific breeding line (a backcross derivative from Cicer echinospermum), 04067-81-2-1-1) and YB (derived from mid-flowering variety, Yorker and 04067-81-2-1-1). The RB RIL population was evaluated under two sowing times (early and mid-season) at Tamworth and the YB population was evaluated at Wagga Wagga in 2018 to identify genomic regions (quantitative trait loci: QTL) controlling flowering time. One significant QTL was identified on chromosome Ca5 in the RB RIL population and explained up to 16.8% and 11.9% of the phenotypic variation for flowering time in an early and mid-season sowing time, respectively. In the YB RIL population, two significant QTL were identified on chromosomes Ca4 and Ca8 and explained 9.6% and 11.2% of the phenotypic variation. We have also identified that the Australian chickpea varieties Rupali, Sonali and Sona carry the mutated form of the early flowering ELF3 gene on Ca5 (caelf3a). Markers associated with the QTL for early and mid-flowering will accelerate the development of varieties suitable for a wider range of growing environments.

 

 

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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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