Phosphorus shortage presents a major problem in the future of agriculture and livestock. A scarcity of this chemical element could create shortage in food supply and its complete depletion could spell doom for the human race.
Remember that phosphorus is essential for all forms of life. Inorganic phosphorus in the form of phosphate plays a major role in the structural frame of DNA and RNA. All living organisms also use phosphate to transport cellular energy in the form of adenosine triphosphate or ATP. Furthermore, phosphate is also a component of phospholipids that form a major component of all cell membranes.
The use of phosphorus in modern food production primarily centres on agriculture in which phosphate serves as a limiting nutrient for crops. However, nature cannot easily and directly provide adequate supply of phosphates. Due to greater demand for agricultural outputs, the industry relies on fertilisers containing phosphate to sustain and improve crop production.
It is also important to note that livestock relies on feeds made from agricultural produces. A report from the BBC mentioned that cows and sheep need 8 kilogram of feed grains for every 1 kilogram of meet they produce. Pigs need 4 kilogram. This means that livestock demand indirectly contributes to phosphorus demand.
Importance of phosphorus in agriculture
The agriculture industry recognises the importance of phosphorus in plant life and crop yield. Farmers during the 1800s to early 1900s noticed that using phosphorus-rich bird and excrements called guanos on their fields resulted in higher crop yields. Take note that there are natural levels of phosphates in soils and most plants do just fine with this.
But high yield agriculture would not survive with naturally abundant phosphates alone. Intensive farming quickly drains the soil of phosphorus. And nature cannot quickly replenish the soil with depleted plant nutrients.
Some farmers resort to polyculture and crop rotation. This involves growing different types of crops depending on the season. Take note that different crops have different nutritional requirements. Planting different crops by sequence and based on seasonal condition allows the soil to recover from nutrient loss while also preventing soil erosion.
However, monoculture dominates modern industrial agriculture. This practice of growing a single crop at a time has become popular because it produces more high-demand yields that further translate to better profits for farmers. This practice leaves soils drained of phosphates and the entire farmlands unfertile.
Using animal manure was the most effective workaround. Farmers replenished their fields by using guanos obtained from islands in South America or from animal wastes from livestock. Animal manure contains not only phosphorus but also nitrogen and other plant nutrients. This practice seemed sustainable because it involves salvaging what was initially deemed as an unusable spoil of nature or the livestock industry. Then came the growing demand for agricultural produces due to the ballooning human population. This meant greater demand for phosphorus to increase crop yields. Using manure alone did not suffice. The reserve of guanos was also depleting. This was the first instance of phosphorus shortage. Mining phosphorus became the next solution.
Mining to resolve early phosphorus shortage
Elemental phosphorus exists in several allotropes or forms. The most popular ones are the white phosphorus and red phosphorus allotropes. But this chemical element is highly reactive regardless of form. This is the reason why phosphorus is never found as a free element in nature. Phosphorus-containing minerals instead are usually present in their maximally oxidised state—as phosphate ores or rocks.
Phosphorus mining began in 1850 following the depletion of guanos reserves in South America. The first phosphorus mines opened up in the United States and China. Mineral phosphates soon became the major source of phosphate mining and phosphate fertiliser production greatly increased after the First World War.
It would be safe to say that phosphorus mining greatly improved the outputs of the modern agriculture industry. And it would be safe to say that current food production would not be possible if not for phosphate-based fertilisers.
Growing population and improving socioeconomic conditions drive demand for phosphorus. A report published by the Earth Policy Institute mentioned that the progression of economies from rural societies to urbanised societies resulted in the dependence on fertiliser to maintain land productivity. This essentially means the urbanisation coincides with the growth in fertiliser use.
The growing wealth of developing countries has also driven the demand for fertiliser and phosphorus mining. Higher income allows people to afford meat. But meat has a phosphorus footprint that is about 50 times higher than crops. Livestock animals depend on feeds produced by the agriculture industry. The BBC report illustrates that cows and sheep need 8 kilogram of feed grains for every 1 kilogram of meet they produce.
Understanding the modern phosphorus shortage
Phosphorus is easy and cheap to obtain through mining. This makes fertilisers very accessible to farmers. But phosphate rock is not a renewable resource. Reserves are limited and spread over the globe. Substantial mines are found in limited countries including China, Morocco, Russia, and the United States, among others. Countries in the European Union and some in South America are completely dependent on imported phosphorus for their agriculture.
Report from the U.S. Geological Survey or USGS seems to suggest that a phosphorus shortage is far from happening. There are 300 billion tons of global phosphate reserves according to estimates. Furthermore, phosphate production would incrementally increase from 223 million tons in 2015 to 255 million tons in 2019. Expansion and discovery of phosphate rock mines and development of processing facilities in Africa and the Middle East would drive this trend.
There are many contentions against the estimates of phosphate rock reserve. A review study by J. D. Edixhoven, J. Gupta, and H. H. G. Savenije concluded that the estimates done by International Fertiliser Development Centre or IFDC in 2010 presented an inflated picture of global reserves made by mere inferences. The IFDC accordingly lacked clear definitions for reserves and resources and this may allow deposits to be regarded as reserves and resources—a practice unrecognised by leading mineral resource classification.
An investigative report by Natasha Gilbert also mentioned that the estimates lack reliable basis. There is a close link between mining companies and fertiliser producers. Some organisations also have members from fertiliser industry. The often-quoted figures from USGS actually came from foreign governments. This means that there could be connivance and misrepresentation from industry players and the government. The lack of independent data collection makes the estimates unreliable.
Determining whether or not there is a phosphorus shortage is nonetheless challenging. The accurate determination of this shortage depends on pinpointing and comparing the global phosphate reserves, future demand for rock phosphates, and food demand based on population trajectories and socioeconomic trends.
Food security and the environment
The world will need 70 percent more food than what it produces today by 2050 to feed a projected population of 9 billion. Socioeconomic progress in developing countries will also drive meat and dairy consumption. Agriculture will need to be more resilient and phosphorus supply will remain crucial to global food security.
But the issue of phosphorus use in food production goes beyond shortage. The agriculture industry accounts for 80 to 90 percent of phosphate demand. A report from Greenpeace International mentioned that farmers usually apply phosphate in excess but only small amounts are absorbed by crops. Humans consume only about one tenth of the phosphorus entering the agriculture system.
The rest remains in the soil and most ends up washed in water systems resulting in widespread pollution. Excreted phosphates from animal and human manure and urine also end in sewage system and further into bodies of water. An excess of phosphates in bodies of water results in cultural eutrophication. This process leaves rives and coastal areas inhabitable.
Mining and processing phosphorus also require energy. The process involved in extracting phosphate from deposits and ores also result in the production of heavy metals and other toxins. Furthermore, transporting phosphates from mines and processing facilities to farmlands requires the consumption of energy.
What all of these mean is that human activities tamper the natural phosphorus cycle and phosphorus ends up displaced. The global and natural distribution of this chemical element becomes out of balance. Each step involved in the mine-fork interplay—or activities starting from phosphorus mining and agriculture to food production and consumption—involves losses.
In addition, the activities involving the extraction and use of phosphates also result in a myriad of ecological problems. Inefficiency due to unsustainable use of phosphates persists and this immediately affects the environment as well as the future of food production.
There is no actual phosphorus shortage based from the aforementioned. The probable shortage would come from the displacement of this chemical element. Experts have proposed several workarounds nonetheless.
Integrating agriculture and livestock is the most feasible solution. This involves using animal manure as fertiliser. There are also proposals and even attempts to use human urine as fertiliser. All of these suggestions centre on phosphorus recovery.
Food wastage is also directly responsible for phosphorus overuse. A report published by the Plant Research International revealed that 60 percent of discarded food in developed countries is edible. This translates to discarding the resources and all other inputs used in the production of food.
Other workarounds include improving agricultural practices by preventing runoffs and soil erosion through no-till farming or crop rotation. Systematic use of phosphate fertiliser is also another suggestion. There is also a proposal for improving phosphate mining by reducing mining losses and increasing recovery
The proposed solutions, of course, would require financial and technological investments. There are also policy implications in order to implement these workarounds. These include regulatory measures, agriculture reform, institutional changes, and waste management initiatives.
Further details of the BBC report are in the article “Meat in a low-carbon world” authored by Tom Heap and published in 2008. Details of the Earth Policy Institute report are in the article “Data Highlights: Many Countries Reaching Diminishing Returns in Fertiliser Use” by Lester R Brown and published in 2014.
Further details of the U.S. Geological Survey report are in the webpage “Phosphate Rock Statistics and Information” maintained and updated by the US government. Details of the study of Edixhoven, Gupta, and Savenije are in the article “Recent Revisions of Phosphorus Rock Reserves and Resources: A Critique” published in December 2014 in the journal Earth Science Dynamics. Details of the report of Gilbert are in the article “Environment: The Disappearing Nutrient” published in October 2009 in the journal Nature.
Further details of the Green Peace report are in “Phosphorus in Agriculture: Problems and Solutions” published in 2012 by Greenpeace International. Details of the Plant Research Institute report are in “Sustainable Use of Phosphorus” published in 2010 and presented in the European Union.