Food Security What will limit crop yields in the future? Availability and costs of: Nitrogen (N = energy) Phosphorus (P) P...
Mineral N-fertiliser, energy use and  carbon footprint of food production <ul><li>1 kg Nitrogen-fertiliser = 36,000kJ = 1 ...
Why and when will Phosphorus  become a  bottleneck  for crop yield?   <ul><li>Phosphorus fertiliser is a mined mineral </l...
Nutrients limiting wheat yield in 1900 and 2000  and predicted 2100 yields without P-fertilisation Estimated wheat yield p...
Are we using Phosphorus and other mineral fertilisers efficiently?   <ul><li>Agricultural intensification over the last 40...
What is the solution/way forward? <ul><li>The main approaches available are: </li></ul><ul><li>More efficient   recycling ...
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Carlo Leifert S Aconf2010

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Presentation from Carlo Leifert (Newcastle University) at the Soil Association annual conference 4 February 2010, The Custard Factory, Birmingham

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Carlo Leifert S Aconf2010

  1. 1. Food Security What will limit crop yields in the future? Availability and costs of: Nitrogen (N = energy) Phosphorus (P) Potassium (K) COMMUNITY RESEARCH
  2. 2. Mineral N-fertiliser, energy use and carbon footprint of food production <ul><li>1 kg Nitrogen-fertiliser = 36,000kJ = 1 L fuel </li></ul><ul><li>1 kg nitrogen fertiliser ( NH 3 NO 3 ) fertiliser </li></ul><ul><li>= 2.38 kg CO 2 (equivalents of CO 2 , CH 4 and N 2 O) </li></ul><ul><li>Nafferton Farm = 100 ha cereals x 200 kg N/ha/annum </li></ul><ul><li>= 20,000 Liter fuel </li></ul><ul><li>= 47,600 kg CO 2 into the atmosphere per annum for just the wheat crop on one English farm </li></ul>
  3. 3. Why and when will Phosphorus become a bottleneck for crop yield? <ul><li>Phosphorus fertiliser is a mined mineral </li></ul><ul><li>World reserves* are estimated at: 4 - 8 B t </li></ul><ul><li>Annual extraction rates are approx.: 125 M t </li></ul><ul><li>Period of time that currently known world deposits are estimated to last for 1 : </li></ul><ul><ul><li>Pessimistic: 30-40 years </li></ul></ul><ul><ul><li>Optimistic: 60-90 years </li></ul></ul><ul><li>* Based on estimated P-rock deposits with a minimum of 10% P </li></ul>1 Fantel et al. (1985) Natural resources forum 9 :5-24
  4. 4. Nutrients limiting wheat yield in 1900 and 2000 and predicted 2100 yields without P-fertilisation Estimated wheat yield potential (t ha-1) 3 t ha -1 9 t ha -1 4 t ha -1 Yield potential associated with different nutrients:
  5. 5. Are we using Phosphorus and other mineral fertilisers efficiently? <ul><li>Agricultural intensification over the last 40 years is estimated to have resulted in: </li></ul><ul><ul><li>a 2 fold increase in global food production 1 </li></ul></ul><ul><ul><li>a 5-7 fold increase in mineral NPK use 1 </li></ul></ul><ul><ul><li>resulting in a 2-3 fold reduction in nutrient use efficiency of crop production </li></ul></ul><ul><ul><li>2-3 times as much NPK is needed to produce a kg of food than 40 years ago </li></ul></ul>1 Hirel et al. (2007) Journal of Experimental Botany 58: 2369-2387
  6. 6. What is the solution/way forward? <ul><li>The main approaches available are: </li></ul><ul><li>More efficient recycling of Nitrogen, Phosphorus and other mineral via </li></ul><ul><ul><li>animal and green manures, </li></ul></ul><ul><ul><li>crop residues, food processing waste </li></ul></ul><ul><ul><li>communal and domestic organic waste </li></ul></ul><ul><ul><li>human toilet waste/sewage </li></ul></ul><ul><li>Reduction of losses of N,P and K from soils </li></ul><ul><li>Breeding of nutrient (NPK) use efficient crop varieties </li></ul><ul><ul><li>EU NUE-CROPS project </li></ul></ul>
  7. 7. Thank you

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