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

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

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 m 3 /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 depletion of 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 persons food. Source: Cordell, Drangert & White (2009a) Water and phosphorus for food security Both are critical to food production, but need to be managed differently

Humanity became addicted to phosphate rock in the 20 th century! 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). Rapid population growth, urbanization, intensive agriculture and the Green Revolution => increased fertilizer production. Recycling organic nutrients dramatically decreases Discovery of phosphate rock. Historical sources of phosphorus ( )

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

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

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

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

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

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

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

A waste management hierarchy for P recovery The extended waste management hierarchy includes both liquid and solid waste in urban sanitation systems and agriculture 1.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

Can we eat climate-smart and phosphorus- smart? Think twice when shopping Dont 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: Swedens National Food Adminstration Report 2008:9

Nutrients in human excreta The Urine Equation: An adult eats 250 kg of cereals per year, which has been grown on less than 250 m 2 and fertilized to more than fifty per cent by the persons urine. Amount of nutrients from an average Swede per year Jan-Olof Drangert, Linköping University, Sweden

Nutrient fertiliser values and CO 2 emissions 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 Million SEK/yr

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

Nutrient flows originating from households Year 2030 River/lake Jan-Olof Drangert, Vatema HH Bio- waste Illegal dumping 2 % P, 5 % N Compost 19 % P, 20 % N Greywater 20 % P, 5 % N WWTP 20 % P 5 % N Effluent 2 % P, 3 % N Sludge 18 % P 2 % N To forest: 18 % P 2 % N Urine 40 % P, 63 % N To farm: 40 % P. 63 % N Faeces 19 % P, 7 % N Dewater 15 % P 4 % N To air: 1 % P, 1 % N Uncontrolled dumping 1 % P, 2 % N Compost 33 % P, 22 % N To air: 1 % P, 8 % N To farm: 32 % P, 14 % N Effluent 3 % P, 2 % N

A pig and its potential impacts Cereals ImportImport 2.5 pigs/yr Greenhouse gases (18%) Eutrophication and dead zones in seas Meat Recycling to farmland Jan-Olof Drangert, Linköping University, Sweden 3.5 m 3 faeces 4/1.6/1 kg/yr 5 m 3 urine 5/0.4/3 kg/yr Can fertilise 1500 m 2 and produce 800 kg of rice

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

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

Why is it so difficult to apply P? Plants need kg/ha, but 0.5 kg/ha/day kg/ha kg/ha kg/ha. Fast (t,d,w) transport Slow (m,y) transport Source:Stoumann Jensen, L. 2010

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

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

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 worlds 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) Epilogue Jan-Olof Drangert, Linköping University, Sweden