Thomas Robinson | September 15th, 2020
According to a recent study, global phosphorus levels in soils are declining despite high levels of applied chemical fertilizers and soil erosion is to blame.
Researchers have analyzed global phosphorus levels in soils and found that all continents, except for Asia, Oceania, and Australia, have net negative soil phosphorus balances. Phosphorus loss from soils poses a challenge to the global food supply because without phosphorus, an essential plant nutrient, crops are more susceptible to disease, and are likely to have stunted growth. The most striking finding in the study was that around 50% of phosphorus losses from soils was attributed to soil erosion, a preventable but commonly neglected aspect of agriculture.
Unfortunately, the phosphorus lost because of soil erosion poses another threat in the form of eutrophication. Eutrophication is caused by high levels of nutrients in aquatic ecosystems and is associated with declining water quality. The increased nutrient concentrations promote large populations of algae, which consume large quantities of oxygen when they die and decompose.
Soil erosion in Iowa is a large concern as millions of tons of Iowa’s soil runs off tilled fields and into the rivers across the state each year. Since soil erosion has now been identified as a leading cause for phosphorus losses in soils, Iowa is not only losing tons of topsoil per year, but also losing appreciable amounts of phosphorus as well.