AS though Filipino farmers and consumers did not already face enough threats to the stability of our agricultural system and food supply, there is growing concern about the global supply of phosphorus, a critical ingredient in fertilizer. With research indicating phosphorous supplies could begin running out as early as next decade, the Philippines will need to work quickly to find alternatives in order to avert a serious food crisis.

The beneficial effects of phosphorus-based fertilizer on crop growth have been known since the 1800s, and the amount the world has used, particularly since the end of World War 2, is astonishing. According to a paper published this month in the journal Nature Geoscience that detailed how much phosphorus 176 countries have used between the years 1950 and 2017, phosphate rock in the form of fertilizers accounts for around 50 percent of the world’s soil productivity. In an article about the study by the magazine Wired, James Elser, an ecologist with Arizona State University and the University of Montana who studies the global phosphorus cycle, said “that we’ve been able to mobilize phosphorus from these ancient geological deposits, and spread it around the world enough so that half of soil phosphorus is now comprised of industrial anthropogenic fertilizer, is pretty stunning.”

The heavy use of phosphorus in agriculture has led to a number of problems. First, even though it is not a rare element, it is non-renewable. Phosphorus used as fertilizer eventually finds its way into freshwater supplies and the oceans through leaching out of the soil or plant, animal and human waste, and cannot be recovered. This also causes a great deal of ecological harm; phosphorus in the water depletes dissolved oxygen, putting fish populations at risk and can cause algae blooms. It is likely that many of the frequent “red tide” events that we experience here in the Philippines are caused or aggravated by the heavy use of pesticides on land.

Another major problem is that phosphate-bearing ores, the only economical source of phosphorus, are concentrated in relatively small parts of the world; about 75 percent of known reserves are in mines in Morocco and the Western Sahara. This drives up prices for phosphorus, as does competition for supplies for the increasing manufacture of lithium iron phosphate batteries. Global phosphorus prices experienced an almost 800-percent spike in 2008, moderated for a time, but then jumped another 400 percent last year due to Covid-related trade bottlenecks.

Scientists are unsure how long the world’s supply of phosphorus will last. Some research indicates that “peak phosphorus,” the point at which production begins to rapidly decrease in successive years, might be reached as early as 2030, although other studies suggest reserves may last for a few decades beyond that. However, it will eventually run out, and some alternative means of fertilizing crops will have to be found.

This puts the Philippines in a bad position, having to compete with larger economies for phosphorus-based fertilizer supplies at ever-increasing prices. Agricultural policymakers and researchers should begin now on the effort to develop alternatives to conventional fertilizer use and make it a top priority.

The study published in Nature Geoscience recommended combining cropland and livestock areas to more easily recycle phosphorus from manure, or planting trees or cover crops, like mustard or barley, that prevent soil erosion in a farm’s off-season to reduce fertilizer pollution in waterways. There are some more technical alternatives that are being researched as well, such as distilling phosphorus from urine, adding magnesium to wastewater to create “struvite,” an alternative fertilizer, or using the solid waste product from biogas production.

None of these promising alternatives to phosphorus dependence will do the Philippines any good, however, unless they are pursued by the government and the agricultural sector. Once one or more effective and economical substitutes for conventional chemical fertilizers are found, the government must overcome a second challenge — getting the nation’s farmers, who have traditionally been slow to embrace innovation, to embrace the alternatives. Doing it now in a manageable way, rather than later when circumstances force a chaotic, rapid change, will be much better for the farm sector, and for the population who relies on it.