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5.1 Phosphorus and f ood security

5.1 Phosphorus and f ood security. Should we worry about P? Are there substitutes for plant nutrients ?. Learning objectives : Phosphorus as a resource, and its links to sanitation and to food security. Our Globe sets the scene.

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5.1 Phosphorus and f ood security

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  1. 5.1 Phosphorus and food security • Should we worry about P? • Are there substitutes for plant nutrients ? Learning objectives: Phosphorus as a resource, and its links to sanitation and to food security

  2. Our Globe sets the scene We are in an era of unprecedented global environmental change Jan-Olof Drangert, Linköping University, Sweden

  3. Water molecules can be made by using a lot of energy Water is renewable (sun-driven cycle) Water is available in soil and replenished annually by rain 70% of global water use is for crop production A balanced diet results in the loan of 1300 m3/yr to each person on the planet based on current practice. This is 70 times greater than the 50 l/d per person for basic water needs. Phosphorus (P) cannot be manufactured or destroyed P is essentially immobile and is mined in only a few countries P is naturally available in soil and depleted by crops 90% of global P extraction is for crop production A balanced diet results in the depletionof 22.5 kg/yr of phosphate rock (=3.2 kg/yr of P) per person based on current practice. 0.5 kg of this reaches the average person’s food. Water and phosphorus for food security Source: Cordell, Drangert & White (2009a) Both are critical to food production, but need to be managed differently

  4. Rapid population growth, urbanization, intensive agriculture and the Green Revolution => increased fertilizer production. Recycling organic nutrients dramatically decreases Most manure was recycled; Human waste recycled in China; No such thing as synthetic or processed fertilizer. Repeated famines and soil degradation in Europe triggered use of other sources of fertilizers (guano, ground bone). Discovery of phosphate rock. Historical sources of phosphorus(1800-2000) Humanity became addicted to phosphate rock in the 20th century!

  5. Phosphorus status in soils in Europe Source: Efma, 2000b

  6. World phosphate rock reserve estimates(’000 tonnes) P scarcity is worse than oil scarcity because P CANNOT be substituted for in food production. So, Source: USGS and ESRI … the linear flow makes countries dependent economically and politically

  7. Food security phosphate rock dependence? Courtesy IFA. Phosphate rock loading in Morocco.

  8. Access to phosphate markets World Bank, 2009 Future fertilizer price spikes are also possible

  9. Peak phosphorus The peak P timeline is disputed, but all agree the quality of reserves is decreasing and production costs are increasing

  10. Phosphorus through the global food system Only 1/5 of the P in mined rock reaches the food on our plates!

  11. Securing a sustainable phosphorus future Business as usual The future is not all dark! Source: Cordell et al., 2009b

  12. A waste management hierarchy for P recovery The extended waste management hierarchy includes both liquid and solid waste in urban sanitation systems and agriculture Reduce (a) waste generation, and (b) harmful contents in products; 2. Reuse the waste more or less as it is; 3. Recycle the waste as input to new products (including biogas); 4. Incinerate to extract the energy content in the remaining waste; 5. Safely landfill residues from the previous steps. Jan-Olof Drangert, Linköping University, Sweden

  13. Can we eat climate-smart and phosphorus-smart? • Think twice when shopping Don’t buy more food than you have time to eat • Eat up the food you cook Serve reasonable portions and use the leftovers • Use your senses Look, smell, taste and feel the food. Most foodstuffs last longer than their indicated ’use-by’ date if they are stored properly • If you want to eat meat Choose local produce and try to eat fish, chicken and no beef • Eat more vegetarian food Especially root crops and legumes • Choose fruits and vegetables of the season Preferably local products Source: Sweden’s National Food Adminstration Report 2008:9

  14. Nutrients in human excreta Amount of nutrients from an average Swede per year The Urine Equation: An adult eats 250 kg of cereals per year, which has been grown on less than 250 m2 and fertilized to more than fifty per cent by the person’s urine. Jan-Olof Drangert, Linköping University, Sweden

  15. Nutrient fertiliser values and CO2 emissions Million SEK/yr Economic value of NPKS in toilet water and sludge, and reduced emissions of GHG compared to use of chemical fertilisers H. Jönsson et al., 2012

  16. To air: 1 % P, 15 % N To air: 1 % P, 40 % N To compost 14 % P, 15 % N Nutrient flows originating from households To farm: 19 % P, 5 % N Compost 20 % P, 20 % N Bio-waste HH Excreta 59 % P, 70 % N Septage 10 % P 10 % N Illegal dumping 4 % P, 5 % N Today Greywater 20 % P, 5 % N Illegal dumping 7 % P, 10 % N Effluent 48 % P, 20 % N River/lake Jan-Olof Drangert, Vatema

  17. Nutrient flows originating from households Year2030 To air: 1 % P, 8 % N To air: 1 % P, 1 % N Compost 33 % P, 22 % N To farm: 32 % P, 14 % N Compost 19 % P, 20 % N Faeces 19 % P, 7 % N HH Dewater 15 % P 4 % N Bio-waste Greywater 20 % P, 5 % N Urine 40 % P, 63 % N Uncontrolled dumping 1 % P, 2 % N Illegal dumping 2 % P, 5 % N WWTP 20 % P 5 % N Effluent 3 % P, 2 % N Sludge 18 % P 2 % N Effluent 2 % P, 3 % N To farm: 40 % P. 63 % N River/lake To forest: 18 % P 2 % N Jan-Olof Drangert, Vatema

  18. A pig and its potential impacts Greenhouse gases (18%) Meat Import Cereals Recycling to farmland 2.5 pigs/yr 3.5 m3 faeces 4/1.6/1 kg/yr 5 m3 urine Can fertilise 1500 m2 and produce 800 kg of rice 5/0.4/3 kg/yr Eutrophication and dead zones in seas Jan-Olof Drangert, Linköping University, Sweden

  19. Loss of food in each step of the food chain Source: FAO, 2011

  20. Plant requirement and nutrient removal Source: Håkan Jönsson, SLU, Sweden

  21. Why is it so difficult to apply P? 1000-2000 kg/ha. 10-100 kg/ha. 0.01-0.1 kg/ha. Plants need 10-30 kg/ha, but 0.5 kg/ha/day Fast (t,d,w) transport Slow (m,y) transport Source:Stoumann Jensen, L. 2010

  22. Exercise: a closer look at phosphorus flows Start from the end! Step 1 Step 2 Step 3 Step 4 Source: Cordell, Drangert & White (2009a) Stay vegetable-based, and return farm waste, your excreta, household and city organic waste tosoil !!!

  23. Was the strong link between the water and sanitation sectors in the 20th century a brief detour in human history? What will come next ? Parenthesis? Most common agriculture + sanitation water + sanitation agriculture + sanitation All rural Essentially urban Jan-Olof Drangert, Linköping University, Sweden

  24. Epilogue The green revolution in the 1950s saved the world from hunger - by using irrigation water, new crop varieties and chemical fertilisers Next revolution must be to recycle the nutrients used in food production ! “Two major opportunities for increasing the life of expectancy of the world’s phosphorus resources lie in recycling by recovery from municipal and other waste products and in the efficient use in agriculture of both phosphatic mineral fertilizer and animal manure” European Fertilizer Manufacturers Association (2006) Jan-Olof Drangert, Linköping University, Sweden

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