Sugarcane Nitrogen Recommendations. How they generally play outâ¦. ⢠Yield potential is used to determine nitrogen ra
Using production unit yield potential and enhanced efficiency fertilisers to improve the efficiency of sugarcane N use Tony Webster, Mike Bell, Phil Moody, Danielle Skocaj, John Markley, Jayson Dowie, Bronwyn Masters, Chelsea Stroppiana 20 November 2017
Background • Video of GBR here • The GBR is great!
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Dissolved Inorganic Nitrogen
Nitrite 4 | Enhanced Efficiency Fertilisers | Tony Webster
Nitrate
Ammonium
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Know and understand your soil Understand nutrient processes Regular soil testing Adopt soil-specific nutrient guidelines Check the adequacy of nutrient inputs Keep records and modify where necessary
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Sugarcane Nitrogen Recommendations How they generally play out…. • Yield potential is used to determine nitrogen rate • 1.4 kg N per tonne for the first 100 t/ha of potential plus 1.0 kg N per tonne thereafter • Adoption of district wide yield potential
• Discount to nitrogen rate based on soil organic carbon (0-200 mm) • Look up table
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Urea
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What happens to urea in soil (1)
Urea
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Water
Ammonium
What happens to urea in soil (2)
Nitrosomonas
Ammonium
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Nitrobacter
Nitrite
Nitrate
Enhanced Efficiency Fertilisers Urea
Water
Ammonium
STOP Bacteria
Nitrate 13 | Enhanced Efficiency Fertilisers | Tony Webster
Nitrate
Hypothesis: The use of Block Yield Potential and / or Enhanced Efficiency Fertilisers will allow reduced nitrogen application rates to sugarcane, maintain yield and reduce nitrogen losses in comparison to District Yield Potential and Urea
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Results Burdekin hand harvest (200 days) Treatment
Biomass (tonnes / ha)
Crop N uptake (kg / ha)
Zero N
77 c
88 b
200 N as urea (DYP)
115 b
141 a
150 N as urea (BYP)
95 bc
114 b
150 N as EEF (BYP)
135 a
141 a
170 N as urea
114 b
110 b
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Results Burdekin machine harvest Treatment
Yield (tonnes / ha)
Crop N uptake (kg / ha)
Zero N
64 b
45 b
200 N as urea (DYP)
122 a
189 a
150 N as urea (BYP)
115 a
179 a
150 N as EEF (BYP)
123 a
217 a
170 N as urea
115 a
200 a
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Results Silkwood hand harvest Treatment
Yield (tonnes / ha)
Zero N
31
100 N as urea (DYP)
55
16
52 N as urea (BYP)
45
13
52 N as EEF (BYP)
44
5
160 N as urea
56
160 N as EEF
80
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N runoff (kg / ha)
15
Results Kamerunga hand harvest 100 90
Biomass (t/ha)
80 70 60 50
EEF
40
Urea
30
20 10
0 0
50
100
150
Nitrogen rate (kg N/ha)
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200
250
Results Kamerunga soil mineral nitrogen Ammonium
Soil Nitrate (mg/kg) in 0-150 mm
10 9 8 7 6 5
EEF
4
Urea
3
2 1
0 0
5
10
15
20
25
Days after fertilising
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30
35
Soil Ammonium (mg/kg) in 0-150 mm
Nitrate 50
45 40 35 30 25
EEF
20
Urea
15 10 5
0 0
5
10
15
20
Days after fertilising
25
30
35
Laboratory incubation study
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Summary of results • Block Yield Potential can maintain productivity compared with District Yield Potential • EEF fertiliser treatments can yield higher than urea at higher rates of fertilisation • Maximum yield (plateau) may be reached at lower rates of application for EEF compared to urea • EEF retains fertiliser as ammonium for longer than urea (and urea has higher nitrate concentrations) • Losses of nitrogen are higher with urea than EEF for the same rate
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Outcomes from the work to date The project and project team have contributed to the design and implementation of 60 trials across the sugarcane industry (Reef Trust IV) testing the efficacy of EEFs at Block Yield Potential in comparison to urea at District Yield Potential.
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