Browsing by Author "Di Bella, L"

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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.
Herbert Water Quality Monitoring Project: final Report 2011/003
(Sugar Research Australia Limited, 2015) Nash, M; O'Brien, D; Brodie, J; Di Bella, L
The Herbert River Catchment is situated in the Wet Tropics Region of Far North Queensland and covers approximately 10,000 square kilometers and unlike many other coastal streams in the wet tropics, the Herbert River has a significant inland component dominated by areas of relatively low rainfall (< 1000mm per annum) This program aimed to provide scientifically robust water quality (WQ) data to be used in association with previously collected WQ data to estimate loads on a catchment scale for the validation of models, as well as to provide insight into relative concentrations of reef pollutants on a sub-catchment and paddock scale for use by extension staff and catchment managers to improve sustainable land management practices which will lead to improved WQ to the Great Barrier Reef (GBR). This program aims to address knowledge gaps on water quality issues in the region identified in the Herbert Healthy Waters Management Plan (draft) such as land use specific contributions and pollution hot spots within the catchment. The HWQMP also provided the necessary catalyst for managers and industry to engage and assist landholders in the Herbert in future decision making by identifying specific issues that contribute to WQ degradation within the catchment. Further, the data collected has been a significant contribution to the assessment of actions and priorities identified as part of the new Wet Tropics Water Quality Improvement Plan improved land management practices (BMPs) which will deliver the greatest gains in improved Water Quality flowing to the Great Barrier Reef Lagoon. Results obtained demonstrate that there are clear differences in the impact of land use on local water quality within the upper and lower catchments. The upper catchment does not contribute significantly to contaminant levels in the water quality observed within the lower catchment. Within the lower catchment sugarcane and urban land use have considerable influence on local water quality that is comparable to that observed in other north QLD catchments. Sediment concentrations measured within the Herbert catchment were low compared to concentrations reported in neighbouring catchments (Burdekin and Tully). Nutrient concentrations were highest in waters draining from sugarcane sites, with urban land use also contributing significantly to the levels of dissolved bioavailable phosphorus within the Herbert River. Overall, the range and average concentrations of nutrients and suspended solids measured in samples discharging from sugarcane sites during event conditions are comparable with those reported in waters sampled in other Australian sugarcane growing regions. The HWQMP was integrated into a number of other P2R programs, including paddock scale; Rainfall Simulation trials and demonstration sites within the Herbert Catchment. The results from these programs have all been integrated into extension programs to better facilitate the transfer of the knowledge obtained among the local industry representatives. The project was supported by two Regional Councils (HSC, TRC); Sugar Research Development Corporation (SRDC); and the Queensland Government (DEEDI & DNRM) and was funded to undertake monitoring for a period of three (3) years between July, 2011 and July, 2014. Work has commenced to continue monitoring on a reduced scale within the lower catchment under the direction of the Herbert Cane Productivity Services Ltd.
Incidence and economic effects of ratoon stunting disease on the Queensland sugarcane industry : ASSCT peer-reviewed paper
(ASSCT, 2021) Magarey, RC; McHardie, R; Hession, M; Cripps, G; Burgess, D; Spannagle, B; Sutherland, P; Di Bella, L; Milla, R; Millar, F; Schembri, A; Baxter, D; Hetherington, M; Turner, M; Jakins, A; Quinn, B; Kalkhoran, SS; Gibbs, L; Ngo, C
Ratoon stunting disease (RSD) has had a significant influence on productivity and profitability in the Australian sugarcane industry for at least the last 76 years. There have been few attempts to objectively quantify the incidence and economic influence of the disease across the industry. Most Cane Productivity Service (CPS) groups routinely monitor RSD in plant sources and, in some cases, in commercial crops. Surveys by 12 Queensland CPSs were conducted in 2017- 2020 with sampling of different proportions of commercial crops (5-25% of farms) in each region. The latest molecular technology was adopted to assay samples. RSD incidence varied between 0 and 60% in commercial crops and 0 and 41% in plant source inspections. The data suggest that implementation of the three pillars of RSD management (disease-free seed-cane, equipment sanitation and planting into fallow ground devoid of volunteers) were essential to minimise RSD incidence. Failure to adequately address any one of these pillars often compromised RSD management. An economic analysis suggested that RSD led to an annual loss of $25m in the study areas in the 2019 crop. This is significant, but it is unlikely to be the largest single disease constraint on productivity.
Optimising productivity and variety recommendations through analysis of mill data : ASSCT peer reviewed paper
(ASSCT, 2016) Stringer, JK; Croft, B; Di Bella, L; Sefton, M; Nielsen, R; Larsen, P; De Lai, R; Davies, I
Production peaked in the Herbert River mills in 2005 but since then productivity has declined. Analysis of mill data in the Herbert has successfully identified groups of farms with similar productivity over time and the major factors associated with these groupings. The major finding of the study was that those growers who have adopted new farming systems had significantly higher productivity than those who use traditional practices. The impact of the Pachymetra resistance of previous varieties on yield of the current crop was also significant, suggesting this may be a major factor contributing to poor ratooning in the Herbert. In the small farm size groups, low and high performing growers had similar levels of % plant, % young crops, % old crops and % old varieties. However, the low and high performing groups varied significantly in terms of new varieties, suggesting that the small farm size low performing group were not adopting the new, more productive varieties to the same extent as the small farm size high performing group. Manager’s age was also an important factor associated with cane yields. Growers who regularly (five or six years out of six) obtained clean seed had more than 10% higher yields than growers who never or infrequently obtained clean seed and greater than 6% higher yields than growers who only obtained clean seed in three or four years out of six. Results from this research has allowed the Herbert Cane Productivity Services Limited (HCPSL) to design targeted extension strategies with the region. This will result in better variety recommendations and increase productivity.