Soil health and nutrient management

Permanent URI for this collectionhttp://elibrary2.sugarresearch.com.au/handle/11079/13842

Research outcomes: Soil health is improved with a resulting positive impact on the environment and yield growth. Improved reputation and relationship between industry and environmental groups.

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2015 - 20193

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Author: search.filters.author.Verburg, K

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    Decision support for choice of enhanced efficiency fertilisers - Herbert catchment pilot study : Final report 2017/015
    (Sugar Research Australia Limited, 2019) Verburg, K
    Enhanced Efficiency Fertilisers (EEF) are of interest to the sugarcane industry because they have the potential to increase N use efficiency and reduce nitrogen (N) loss. However, agronomic and environmental benefits are proving to be highly variable and condition specific. Therefore, tactical use of EEF will be a more economically sustainable strategy than use of EEF in every crop and season. This requires decision support for growers and advisors based on understanding of the conditions leading to benefits from EEF.
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    Role of controlled release fertilizer in Australian sugarcane systems: final report 2014/011
    (Sugar Research Australia Limited, 2017) Verburg, K
    Controlled release fertilisers (CRFs) are promoted as a means to optimise the productivity achieved per unit of fertiliser nitrogen (N) input and lower environmental impacts from N leaching, runoff and emission losses. Through review of experimental results, characterisation of N release patterns of commercially-available CRF products, and modelling to assess environmental, agronomic and economic benefits this project has confirmed that CRFs can play a role in Australian sugarcane systems. They can reduce N losses and provide agronomic benefits in the form of reduced N application rates and under some circumstances increased yield. The agronomic benefits are, however, highly variable from season to season. The percentage of seasons that result in measurable benefits is affected by climate, soil, crop class and timing of fertiliser application. As a consequence CRFs do not provide a consistent economic advantage over conventional fertilisers across all soil, management and climate conditions. This can be improved when the cost of environmental benefits is included or use of CRF can be targeted to those seasons where agronomic benefits are most likely. Commercially-available CRF products have different N release patterns and temperature responses. These need to be taken into account when designing fertiliser management (product choice, application and timing) in order to maximise the benefits. Development of regional decision support for growers and advisors, based on an understanding of the dynamics of local soils and cropping systems as well as seasonal climate and CRF product response to these, will be important for the successful adoption of CRFs.
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    A review of nitrogen use efficiency in sugarcane
    (2015) Bell, MJ; Biggs, J; McKellar, LB; Connellan, J; Di Bella, L; Dwyer, R; Empson, M; Garside, AJ; Harvey, T; Kraak, J; Lakshmanan, P; Lamb, DW; Meier, E; Moody, P; Muster, T; Palmer, J; Robinson, N; Robson, A; Salter, B; Schroeder, B; Silburn, M; Schmidt, S; Skocaj, DM; Stacey, S; Stanley, J; Thorburn, P; Verburg, K; Walker, C; Wang, W; Wood, A
    The Great Barrier Reef (GBR) is the world's largest coral reef ecosystem, providing both substantial economic benefit to Australia and significant international ecological value. The health of the GBR is under pressure from sediments, pesticides and nutrients (especially nitrogen) discharged from nearby catchments. Discharge of nitrogen is of particular concern as it stimulates outbreaks of the Crown of Thorns Starfish, a major predator of GBR corals. Recent research has shown that the amount of nitrogen fertiliser applied in excess of crop uptake is an important determinant of nitrogen discharge from catchments, so increasing the efficiency of nitrogen use in cropping systems is an important step in protecting the economic and ecological benefits provided by the GBR. Importantly, an increase in nitrogen use efficiency (NUE) also offers opportunities to improve productivity and profitability of agricultural industries, with such benefits a major incentive for industry adoption and practice change. The Australian sugarcane industry is a significant contributor to the anthropogenic loads of nitrogen entering the Great Barrier Reef lagoon, with recent estimates in the Reef Water Quality Protection Plan (2013) suggesting it contributes 18% and 56% of particulate and inorganic nitrogen loads, respectively. A focus on improving NUE in the Australian sugar industry to reduce these loads wherever possible is a logical outcome from these statistics. While the relative impact of dissolved inorganic nitrogen (DIN) and particulate nitrogen (PN) is still uncertain, recent NUE forums in the sugar industry in 2014 identified clear target reductions in DIN that would be needed in order to significantly improve water quality in line with Reef Plan (2013-18) targets. The forum also identified a clear need for a joint industry-government funded research program to improve NUE in sugarcane cropping systems. The review conducted for this report was commissioned and funded by the Australian Government Reef Programme to provide a foundation for this joint NUE research program. The review was tasked with providing an improved understanding of past and current research effort and available field trial information (both published and unpublished) relating to nitrogen management in the sugar industry. From this perspective the review was then tasked with identifying research gaps and opportunities for future research projects and field trials that would collectively contribute to improving NUE from both agronomic and production perspectives as well as delivering significant reductions in nitrogen lost to waterways and the Great Barrier Reef lagoon. It is widely recognized that in any crop, the demand for N is determined by the size of the crop and the fundamental efficiency with which that crop produces a unit of biomass or harvested product from a kg of acquired N (N use efficiency - NUE). Therefore a good understanding of yield potential at the spatial scale of the productivity unit (i.e., farm, several blocks of similar productivity, individual blocks or within-block) about which N fertilizer management decisions (rate, form, placement, timing) are made is required, along with an understanding of how that yield potential varies with seasonal conditions. Collectively, this could be called seasonal 'block' (or productivity zone) yield potential, and it will produce a crop N demand that may vary from year to year. The sugar industry is currently operating at the district level (generally comprising several thousand cropped hectares across variable soil types and landscapes), and basing N demand for all growers in the district on the best farm yield ever achieved over a 20 year time frame. It is apparent that overall NUE could be improved by basing N fertiliser inputs on the seasonal yield potential of the productivity unit.