Browsing by Author "Connellan, J"

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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.
BSES technical report TE11004 - Burdekin nitrogen project - September 2011
(2011) Connellan, J; Bateman, S; Schroeder, BL
In response to the introduction of the regulated method of determining N, some canegrowers in the Burdekin district (which produces approximately 25% of Queensland's sugarcane) expressed concern that sugarcane yields could be negatively affected by the permissible N application rates. Growers and Sucrogen (the milling company that operates in the Burdekin region) were also of the opinion that additional research was needed to ensure that any regulated N application would not compromise the profitability and/or supply security of the local sugarcane industry. As a result of grower and industry concerns the Department of Environment and Resource Management (DERM) contracted BSES Limited to undertake a series of trials across the Burdekin district to determine the adequacy of the regulated N for sugarcane production on different soil types and at different on-farm locations. To date BSES has established ten trials, five of which are located in the Delta and five in the Burdekin River Irrigation Area (BRIA).Replicated nitrogen rate strip trials have been established in plant sugarcane blocks on commercial farms in the Delta and BRIA. These sites were selected after considering a number of factors such as block size, shape, soil uniformity, irrigation systems employed and pest control measures. Consideration was also given to yield history of the blocks.At the conclusion of this work, partial net grower returns per hectare for each N application rate will be calculated per crop and for the complete crop cycle. The optimum N application rates that maintain the profitability of sugarcane production will be identified with due consideration to the potential impact on the environment.
Support of cane farmer trials of enhanced efficiency fertiliser in the catchments of the Great Barrier Reef : Final report 2016/807
(Sugar Research Australia Limited, 2022-01) Connellan, J; Thompson, M
There is growing pressure from community and government for farmers located within the Great Barrier Reef catchments to reduce nutrient losses. Enhanced Efficiency Fertilisers (EEFs) provide an opportunity to improve nitrogen (N) fertiliser uptake by sugarcane crops by better matching N supply with crop demand. Complementary benefits from improving fertiliser N uptake efficiency are the resultant improvements in nitrogen use efficiency (NUE) and reduced risk of nitrate losses.