“There are no substitutes for phosphorus in agriculture,” the United States Geological Survey succinctly warns in a January 2022 market report. Farmers are certainly aware of this–without enough, crop leaves turn purple–and demand is growing rapidly.
How to get phosphorus
The world’s farms get most of their critical supplies of phosphorus (P) from three general sources: soil, organic fertilizer (usually manure), and mined chemical fertilizer. Morocco is famous for its vast reserves of rock phosphorus, and that nation is already the world\’s second-largest producer. China is the world\’s top supplier of mined phosphorus, with the U.S. coming in at number three, according to USGS data. Plans for new and expanded phosphorus mines are in the works since global demand for phosphate fertilizer is rising—worldwide consumption increased by 7% year-over-year by mid-2021, USGS reports. The United Nations Food and Agriculture Organization (FAO) expects agricultural demand for mined phosphorus to rise strongly again this year, especially in Africa and South Asia.
“There are no substitutes for phosphorus in agriculture.”
Commercial farms in the U.S., Brazil, Europe, and China are getting all the phosphorus they need to keep crop yields high, either from well-endowed soil or from fertilizer they can afford. However, a team of researchers from the Netherlands and China says soils in tropical and subtropical climates where smallholder agriculture dominates are badly deficient in phosphorus, harming smallholder farmers’ yields, as they recently reported in the journal Nature Sustainability.
Filling an enormous gap
Holding up Brazil as an example of where farmers have successfully overcome P shortages, the research group argues that the developing world’s farms need to boost their soil P intake rates by anywhere from 8% to 25% to raise farm productivity to Brazilian levels. The scientists estimated that smallholder farms (5 hectares or less) in sub-Saharan African and Southeast Asian nations will need to nearly triple their consumption of phosphorus compared to 2015 levels if they’re to meet a target of doubling smallholder yields and incomes by 2030, one of the U.N.’s Sustainable Development Goals. India would need to almost double soil phosphorus intake to meet the same goal. “On a per-area basis, all regions will have to substantially increase their P input,” the scientists concluded (https://www.nature.com/articles/s41893-021-00794-4).
“All regions will have to substantially increase their P input.”
Where will this extra phosphorus come from? “There are no imminent shortages of phosphate rock,” USGS assures us. Nevertheless, this particular source may not be suitable for budget-strained smallholder farmers. The authors suggest improving soil P retention and better utilizing manure and other organic waste.
Discovering the right formula, they say, will likely require “research, extension services, farmers’ training, demonstration farms, incentives to motivate and support the learning phases, procuring P fertilizers and other necessary inputs at fair prices, and dedicated insurance schemes.” In other words: all hands on deck.
— Grow Further
Photo credit: A phosphate mining operation in Western Sahara. Creative Commons.