Feed-In Tariffs - Making sunlight a cash crop - Philip Wolfe (Ownenergy)
Nitrogen Cycling: Risks and Opportunities - Keith Goulding (Rothamsted Research)
1. Nitrogen cycling:
risks and opportunities
Keith Goulding
Head: Department for Sustainable
Soils and Grassland Systems
Rothamsted Research
2. Driving forces for better N utilisation
Projected population increase requires 50% more
food by 2030; 70% more by 2050.
Royal Society says we need ‘Sustainable
Intensification’. Cultivating more land risks
destruction of forests and large carbon losses.
N is the key to yield in most countries, but making N
fertiliser uses fossil fuels and produces greenhouse
gases.
Must improve NUE to reduce costs, fossil fuel use
and losses to air and water.
NB some room for greater use of legumes but not
wholesale switch.
3. Example: problem of poor NUE of meat
production. Intensive pig production from field to
fork
‘Reactive nitrogen in the environment.’ UNEP 2007
4. Example: N surpluses on some UK farms
N surplus (= N inputs – N in product; kg N/ha)
Fertiliser N input (kg N/ha)
sheep
arable
dairy
pig/arable
organic
dairy (clover)
8. 0
100
200
300
400
500
600
21/10/03 10/11/03 30/11/03 20/12/03 09/01/04 29/01/04 18/02/04 09/03/04 29/03/04 18/04/04
SoilWaterNitrate(ppm)
0
5
Temperature(°C)
Low N Plot
High N Plot
N release very variable through the season:
nitrate in soil on Broadbalk field, Rothamsted
Tony Miller, Rothamsted
10. RB209: The Basis of Good Practice
Reliable information: soil type; regular soil
analysis; cropping fertiliser and manure history;
nutrient balances; winter rainfall.
Realistic estimate of crop yields and fertiliser
needs; take account of fertiliser prices.
Estimate SNS: RB209; PLANET, ‘Tried and
Tested’
Utilise available nutrients in organic manures.
Careful selection of fertilisers – price and
quality.
Correct rate, method and timing of fertiliser
and manure applications; accuracy.
Good record keeping.
12. Better manure management
Estimate or measure N content
(RB209; MANNER); make allowance
when calculating fertiliser
applications
Recycle effectively – band
spreading; injection
Where possible, apply from late
winter onwards
Measure application rate
Manure Management Plan
13. ‘Tried & Tested’ SNS
calculator
You can use our SNS calculator
to help you determine the Soil
Nitrogen Supply of your soil. You
will need this index number when
using the ‘Fertiliser Manual
(RB209)’ for guidance on
fertiliser application rates.
Tried & Tested SNS Calculator
14. Improving NUE involves assessing risk and
eliminating ‘leaky’ practices
N leached
(kg ha-1
)
15. Could also consider:
Min Till
Precision seeding and fertiliser
application
Fertigation
16. Acknowledgements
Rothamsted Research is an
institute of the UK Biotechnology
and Biological Sciences
Research Council.
The UK Department for
Environment, Food and Rural
Affairs funded some of the
research described in this talk.