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De-Risking Broadacre Cropping in Northern Australia

In Northern Australia multiple constraints create complex problems requiring multidisciplinary teams and private-public partnerships to build farmers’ skills, and adapt profitable and low risk broad acre cropping practices. This project aims to identify best crop and management options that bridge gaps between present and potential yields.  We are working in a participatory on-farm research program to identify relevant RD&E activities, and support growers adopt proven technologies and practices, in collaboration with Northern Australia growers, Radicle Seeds Australia, Elders, Northern Gulf Resource Management Group, and AgForce.

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Click the picture to download the slides from the final project webinar (25MB)

Click the picture to download the recording of the webinar (65MB)

Click the picture to download the field trial report (65MB)

Click the picture to download the Sorghum Agronomy Guide (628kB)

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Take home messages and recommendations

  • Adopting practices likely to increase rainfall infiltration offer the greatest opportunity to de-risk cropping across northern Australia and improve environment outcomes.  Maintaining ground cover to protect the soil surface structure and subsequently promoting root activity are the main pathways to increase rainfall infiltration while reducing run off and soil erosion. This calls to rethink crop-livestock integration activities in the north and to demonstrate the short- and long-term benefits of managing ground cover on these fragile environments.

  • We can expect different pathways for intensification and diversification across the different types of farms and farmers in northern Queensland. This is, best fit diversification and intensification options, practices and business models will be influenced by several factors, e.g., farmers’ availability of land, labour, skills, water, and capital, as well as by farmers’ previous experience, preference and level of risk aversion and dedication to farming – compared to a more lifestyle preference. For example, mixed cropping – grazing farms that presently manage the grazing and cropping activities separately, invest in irrigation infrastructure, and employ highly skilled staff, will have very different pathways to intensify and diversify, compared to those that extensively graze crop stubbles for long periods of time, or haven’t had previous experience in cropping. Irrespective of those factors, there is need for business models to be profitable, manage economic and financial risks, be sustainable, regenerate the land, and be resilient to climate or market shocks. Understanding the different types of farms and human resources across the region can help design business models that better deliver across economic, social, human, environmental, resilience, and regional development goals. An analysis of typologies across the region is being conducted by PhD student Lipy Adhikari. The results of the analysis will help inform opportunities to de-risk the diversification of farming systems in Northern Queensland.

  • Comparing the results from both Kilcummin and Georgetown three commercial (A66, MR Buster and MR Bazley) and three experimental lines (Rex 007, 100393 and PioExp09) were in the top third yielding rank at both sites.  This shows good adaptation to the northern conditions in both current and materials that are at different stages of commercialisation. The results from the two years of hybrid testing across northern Queensland were recently used by Radicle Seeds Australia to release two new hybrids. The new sorghum hybrids are Anvil and Candela.

  • New experimental red, white and high digestibility grain sorghum hybrids produced grain yields that were similar or higher than the yield of well-known commercial check hybrids. The experimental high digestibility sorghums produced approximately 30% digestible higher energy (MJ/ha) than the commercial hybrids.  This indicates potential for the identification of hybrids of higher market value and adaptability to Northern Queensland. Additional information on the economic value, markets and value chains for these new hybrids is needed.

  • Sorghum yields have not significantly responded to increased N application in both low and median rainfall seasons. This can be a typical result in on-farm trials, low rainfall and hot environments. The use of green manures, improved ground cover, the introduction of forage legumes such as Desmanthus, as a sole crop or in association with pastures and even in intercrops with sorghum should be explored further. An important issue is to achieve good establishments of the green manures, forages, and intercrops. Research is needed to further explore opportunities to more holistically improve the soil fertility (physical, chemical and biological), rather than solely rely on the use of chemical fertilisers.

  • Fall army worm (FAW) remains a significant problem, both to grain and forage crops, especially maize and sorghum north of Emerald. We noticed a trend to use pesticides outside recommended labels, which is a significant risk for the development of resistances. There is also farmers’ interest in the combination of chemical and biological controls. There is need to develop integrated weed and pest control measures and low chemical use farming systems, particularly given the risk of rapidly developing insecticide and herbicide resistances due to mal use of chemicals and the fast cycling of pests and weeds in hot and humid environments.

  • Desmanthus (a perennial leguminous shrub) can persist longer into the dry season than any other crop or weed offering opportunity to increase ground cover during the dry season. Improved Desmanthus establishment rate in sandy loam soils were achieved by broadcasting seed on tilled soil and then rolling. However, opportunities for effective weed control during Desmanthus establishment are limited by slow seedling growth relative to weed vigour and on-set of water stress.  Establishment methods integrating rotations with cash crops, direct drilling, cultural and chemical weed controls require investigation. There are also many varieties showing contrasting adaptation to different environments. There are opportunities to improve the establishment and early vigour of desmanthus stands from identifying better matches between genotypes and practices to site and seasonal conditions.

  • Farmer managed strip trials continue to be a valuable complement to the small plot trials. Strip trials demonstrated similar yields to the small plot trials and highlight the value of small non-significant yield gains between treatments. Supporting farmers run their own experimentation can be an effective use of limited resources in remote areas, and an opportunity to generate discussion and learning “by doing”.

  • A sorghum agronomy guide for Tropical North Queensland farmers (Gilbert & Einasleigh Catchment) was produced, presented, and distributed to farmers. The guide adds to the existing information on the GRDC website. Updates focused on regional achievable yields under dryland and irrigated conditions, the influence of cultivar selection (early, medium or late), the time of sowing, plant population, nitrogen fertilisation, and water requirements if the crop were to be irrigated. The document also addresses specific issues for weed control on light sandy loamy soils, and the high pest pressure.

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