Lessons learnt from the dairying
Accounting for Nutrients project
Warwick Dougherty
Drivers of refined nutrient management
1200
900
Triple super ($US/MT)
Urea ($US/MT)
800
1000
700
800
600
500
600
400
400
300
200
200
100
Mar-11
Mar-10
Mar-09
Mar-08
Mar-07
Mar-06
Mar-05
Mar-04
Mar-03
Mar-02
Mar-11
Mar-10
Mar-09
Mar-08
Mar-07
Mar-06
Mar-05
Mar-04
Mar-03
Mar-02
Mar-01
Mar-01
0
0
•Reef Rescue package
•WA Fertiliser Action Plan
•Societal expectations
Australian dairy industry
increasingly reliant on:
– purchased feed
– nitrogen fertiliser
Nutrients in Australian dairy – a paradigm shift
Current and future challenges
Infrastructure and innovation
Farm gate nutrient balance = Inputs minus outputs
Within - Farm
OUTPUTS
INPUTS
Dairy
cows
Feed
Animals
Milk
Animals
Bedding
Seed
Pasture / crops
Manure
Manure
Crops
Silage, hay
Fertilizer
N fixation
Irrigation
Precipitation
Manure
Soil
Leaching
Soil accumulation
LOSSES
Gaseous
Runoff
Farm system nutrient balance
Within - Farm
OUTPUTS
INPUTS
Dairy
cows
Feed
Animals
Milk
Animals
Bedding
Seed
Pasture / crops
Manure
Manure
Crops
Silage, hay
Fertilizer
N fixation
Irrigation
Precipitation
Manure
Soil
Leaching
Soil accumulation
LOSSES
Gaseous
Runoff
Accounting for Nutrients on Australian Dairy Farms
• Improve our understanding of nutrient flows, transformations,
use efficiencies‘, balances, and potential losses on Australian dairy
farms.
• Define standard methodologies and processes for undertaking nutrient
accounting
44 dairy farms reflecting the diversity of production
systems
Quarterly farm visits
• Sampling: feed, milk, manure
• Cows in Space and Time
Farmer diaries
• Feed purchases, fertiliser, etc
• Daily records of cow locations
Special farm visits
• Effluent applications, soil
sampling, legume sampling.
Farm Description
State
Organic (O) or Conventional (C)
Total Land (ha)
Dairy Farm Land (ha)
Contact Land (ha)
Cow Number
Contact Land Stocking Rate
Irrigation Ha
Irrigation %
% Feed imported
Farm 19
Min
Max
Vic
C
67
67
58
167
2.9
55
95
29
67
47
40
51
0.4
0
0
3
1046
612
460
1263
3.7
329
95
66
Whole farm Nitrogen balance - farm # 19
N (kg)
Imports
Silage
Hay
Concentrates/grains
Feed minerals
Byproducts
NPKS blends
Urea/Liquid N
Other fertilisers
Soil ameliorants
Animals
Irrigation
N fixation
Atmospheric deposition
Other
Total Imported
N (kg/ha)
1869
1626
5786
0
0
0
10350
0
0
0
53
441
58
0
32
28
100
0
0
0
180
0
0
0
1
8
1
0
20183
351
5574
222
0
0
0
97
4
0
0
0
Exports
Milk
Animals
Forages
Manure
Other
= 351  101
0
Total exported
BALANCE
Efficiency (%)
5796
101
14387
250
29
29
= 101 ÷ 351
Whole farm Phosphorus balance - farm # 19
P (kg)
Imports
Silage
Hay
Concentrates/grains
Feed minerals
Byproducts
NPKS blends
Urea/Liquid N
Other fertilisers
Soil ameliorants
Animals
Irrigation
N fixation
Atmospheric deposition
Other
Total Imported
P (kg/ha)
326
283
1489
0
0
3925
0
0
0
0
3
0
6
0
6
5
26
0
0
68
0
0
0
0
0
0
0
0
6032
105
1008
57
0
0
0
17
1
0
0
0
Exports
Milk
Animals
Forages
Manure
Other
0
Total exported
1065
18
BALANCE
4967
86
18
18
Efficiency (%)
Variation in balance and efficiency
Nitrogen Surplus/Deficit (kg/ha)
600
500
400
198
300
Whole-farm Nitrogen Use Efficiency
200
50
45
100
0
N Use Efficiency %
Nitrogen (kg/ha)
700
40
24 41 12 37 7 30 14 9 28 25 31 38 27 5 6 21 33 15 8 20 4 44 2 3 13 22 40 19 16 42 10 23 17 39 1 43 32 34 18 11 36
Farm ID
35
25
30
25
20
15
10
5
0
5 1 11 7 2242412137392743443313 8 6 4036 2 4 3228192034 3 38182512151416312317302410 9
Farm ID
Variation in balance and efficiency
Phosphorus Surplus/Deficit (kg/ha)
140
100
80
60
32
Whole-farm P Use Efficiency
40
20
180
0
-10
160
140
15 3 39 9 7 5 24 37 31 12 43 10 33 25 44 40 42 28 23 30 20 21 22 38 8 11 6 17 18 13 41 16 4 1 2 34 32 14 19 27 36
Farm ID
Efficiency %
Phosphorus (kg/ha)
120
120
100
80
60
32
40
20
0
412714 1 19 2 3628212213 6 4 3038 8 37323412114425 5 421620334017183123432410 9 39 7 3 15
Farm ID
Are there particular farm characteristics that influence
nitrogen surpluses and whole-farm efficiency?
1. Do farms that have a higher reliance on imported feed have higher
N surpluses?
600
N Surplus (kg/ha)
500
400
300
200
100
0
0
20
40
60
80
Proportion reliance on Imported Feed (%)
100
Are farms that have higher stocking rates more efficient at
using nitrogen?
Whole-Farm Use Efficiency (%)
Nitrogen Use Efficiency (%) and Contact Land
Stocking Rate
100
90
80
70
60
50
40
30
20
10
0
0
1
2
3
Contact Land Stocking Rate (cows/ha)
4
Are farms that have higher production per ha more efficient
at using nitrogen?
Whole-Farm N Efficiency (%)
Nitrogen Use Efficiency (%) and Milk
Production
100
90
80
y = 0.0003x + 24.702
R2 = 0.0554
70
60
50
40
30
20
10
0
0
10000
20000
30000
Milk Production (L/ha)
40000
Nutrient balance and efficiency in
vegetable production systems
N
P
Balance (kg/ha/yr)
N
P
Efficiency (%)
Wells et al. 2000
105-740
130-476
3-31
1-5
Chan et al. 2010
–
143-243
–
6-10
Ovens et al. 2008
~200
~80
~69
~8
Nutrient balance and environmental impact ?
2.0
1.5
40
1.0
0.5
0.0
0
500
1000
P balance (kg/ha)
Nutrient in runoff (kg/ha)
Runoff P (mg/L)
2.5
30
Nitrogen
Phosphorus
20
1500
10
0
0
200
400
600
800
Balance (kg/ha)
Wells et al 2000
Nutrient balances inform management
Lower minerals in feed supplement
Diet additives and manipulation
Animal Selection
Reduce inputs
Milk
Dairy
cows
Crop and pasture
selection
Pasture / crops
Manure deposition:
non- collected,
non-productive areas
High fertility areas
Manure
Manure capture:
Milking, housing,
feeding systems
Modified
fertilisers
Soil
Nitrogen
transformation
inhibitors
Leaching
Soil accumulation
Rates, timing and
placement of
fertilisers & effluent
Gaseous
Runoff
Optimum soil conditions
to reduce nutrient loss
Conclusions
• Nutrient surpluses of N (& P & K & S) are potentially high to
very high on most dairy farms
 Median N surplus is 226, but ranged from 40 – 600 kg N/ha
 1 litre of milk = 14 g of N lost to the broader environment
• Median N use efficiency on Australian dairy farms is 28%,
but ranged from 14 – 50%.
• Modelling of N surpluses suggest that loss pathways are
highly dependant on the mgt system, soil & climate conditions
• Generic opportunities to increase N use efficiency
 Reduce fertiliser N, (P, K, S) inputs
 Rates, timing and placement of fertilisers & effluent
 Greater capture, reuse and redistribution of excreted nutrients
 Reducing feed nutrient intakes, reducing excreta concentrations
Lessons for the vegetable industry
•Need to clearly define objectives
•Nutrient balance provides data/information but not
the answer
•Nutrient balances are not environmental predictors
•Spatial definition is critical
•Temporal definition is important – particularly for P
•Need standard and comprehensive methods
•Need benchmarking data – what is acceptable ?
•Nutrient balances can be powerful source of farm
and industry information