Production Functions
Jack Hannam
2 March 2015 Dirt Science Course
Food and biomass production
http://www.newenergyfarms.com/
• Growing medium for
plant growth (crops,
grass, timber,
medicinal plants)
70% agricultural land
CEH, 2011
water
nutrients
Physical media
• Water availability
• Nutrient provision and cycling
• Physical properties (influencing above)
• Biological properties (influencing above)
• Anchorage for roots
• Water and nutrient inputs augmented by management
Agricultural Land Classification
• Based on various agricultural limitations:
• Soil
– Texture and structure
– Depth and stoniness
– Chemical properties
• Climate
– Rainfall and temp
• Landscape
– Relief & slope gradient
– flooding
• Interacting factors
– Soil wetness/drought
– Soil erosion
Keay et al., 2012
a) £ 2.6 billion
b) £ 3.6 billion
c) £ 4.6 billion
d) £ 5.6 billion
What was the total income from
farming in the UK in 2013?
What was the total income from
farming in the UK in 2013?
a) £ 2.6 billion
b) £ 3.6 billion
c) £ 4.6 billion
d) £ 5.6 billion
Defra, 2014 Defra, 2014
GLC-SHARE, FAO, FAOSTAT (2014)
Land surface under agriculture = 38.5%
Global yield trends
Ray et al. Nature Comms. 2012; doi:10.1038/ncomms2296
Need for increased crop production...
Patrick Gerland et al. Science 2014;346:234-237
9 billion 2050
Will crop production keep up? –
requirement to double yield by 2050
Ray et al, (2013) PLoS ONE 8(6): e66428
Major challenges, I mean,
REALLY big....
1. Bring marginal land into production
2. Increase productivity on agricultural land
3. Improve yields through crop improvement
(e.g. GM) and management (e.g. pest
control)
4. Reduce food “demand” by managing waste
within the supply chain and dietary change
Environmen
57 % of the overall Utilized Agricultural Area in the EU is classified as LFA [LFA criteria are currently under review]
Yield gaps (Maize +Wheat + Rice)
Mueller et al. Nature 490, 254-257 (2013) doi:10.1038/nature11420
How to do it?
• Sustainable intensification
– Increase productivity whilst minimising
environmental impact
– Launch of Defra SI platform in 2014 (£4.5
million over 3 years)
• Yes, but how to do it? – any suggestions?
Soil focused approaches
• Agroecology – using less external inputs (eg
pest control products, nutrients) – soil
management central to this
• Agri-technology (precision farming)
• Whole farm management
• Balancing soil functions and services!
water
nutrients
Physical media
• SMART targeting
of inputs (at
different scales)
• Promoting water
and nutrient
balances – good
soil structure,
encouraging
nutrient cycling etc
Soil focused
approaches
Potential SOC changes with
conversion from full till to no till
Ogle et al., Agriculture, Ecosystems and Environment 149 (2012) 37– 49
Corn residue C
SOC stocks
Precision farming
Electrical conductivity
Hannam et al, 2014 Hunt et al., Remote Sens. 2010, 2(1), 290-305;
GNDVI
GNDVI = 0.50 + 0.16 LAI, r2= 0.85
Additional pressures
• Climate change
• Water & nutrient scarcity (e.g peak phosphorus)
• Competing land uses (energy crops, urbanisation)
• Land degradation
• Trade-offs with other soil functions and services
• Up-scaling interventions
• Barriers to the implementation of approaches (socio-economic and political)
+2 deg C increase
1981-2010 – ensemble model
Asseng et al., 2014 Nature Climate Change
Yield responses to climate change
water
nutrients
Physical media
Soil responses to
climate change
Soil carbon - decreasing?
Soil biology - temperature responses and knock-on effects for nutrient cycling
Water regime – too much & too little
Phosphorous scarcity
Cordell et al. 2011, Chemosphere, 84, 6, 747 - 758
Energy crops
http://www.newenergyfarms.com/
Rowe et al., 2009 Renewable and Sustainable Energy Reviews
Bob Palmer Bob Palmer
Final thoughts
• Closing yield gaps is challenged by the potential increase in
environmental degradation
• Land suitability/ environmental constraints
• Production responses are spatially variable
• Uncertainly in impacts of soil management interventions
(also linked to point above)
• Balancing other functions and services is required (systems
approaches) to ensure holistic ecosystem service provision
– “multifunctional agriculture”
• You are already contributing to solutions through your
research!