Rainstorms drive nutrient loss in American farmland

Nov 19, 2024
By Farms.com

Phosphorus loss from soil increases with intense rainfall

A study led by Penn State University researchers highlights an alarming trend - essential phosphorus is being washed away from U.S. farmlands due to increasingly intense rainstorms.

Phosphorus, a key nutrient for crops, has been found to be depleting from soil and entering rivers, potentially threatening agricultural productivity and food prices.

The findings, published in the Proceedings of the National Academy of Sciences, reveal that phosphorus levels have dropped in farmland soils over the past 40 years despite efforts to manage nutrient loss.

Analyzing data from 430 rivers, Professor Li and her team discovered that while phosphorus levels in urban areas have decreased due to effective pollution control, levels have increased in rivers near agricultural zones.

This pattern is attributed to the increasing frequency and severity of rainstorms, which erode soil and transport phosphorus into water bodies.

"What we wanted to understand is what happens to the land when these storms pull the subsurface of the soil into rivers and streams. What we found is an alarming loss of this finite element that lets soil sustain life,” Li explained.

This phosphorus runoff not only reduces nutrient levels in farmland but also creates environmental problems in rivers.

Phosphorus in waterways leads to algal blooms that harm water quality, damage ecosystems, and raise water treatment costs. Unlike other soil nutrients, phosphorus does not readily return to soil, making its loss particularly concerning for long-term soil health.

The study calls for innovative solutions, such as improved farming techniques and technologies. For example, Phospholutions, a company founded by a Penn State graduate, is developing a fertilizer that minimizes phosphorus runoff, reducing environmental impacts.

This urgent push for agricultural innovation aims to address the effects of climate change on nutrient loss, ensuring sustainable farming practices that protect soil and crop production in the years ahead.

Video: Spring 2026 weather outlook for Wisconsin; What an early-arriving El Niño could mean

Northeast Wisconsin is a small corner of the world, but our weather is still affected by what happens across the globe.

That includes in the equatorial Pacific, where changes between El Niño and La Niña play a role in the weather here -- and boy, have there been some abrupt changes as of late.

El Niño and La Niña are the two phases of what is collectively known as the El Niño Southern Oscillation, or ENSO for short. These are the swings back and forth from unusually warm to unusually cold sea surface temperatures in the Pacific Ocean along the equator.

Since this past September, we have been in a weak La Niña, which means water temperatures near the Eastern Pacific equator have been cooler than usual. That's where we're at right now.

Even last fall, the long-term outlook suggested a return to neutral conditions by spring and potentially El Niño conditions by summer.

But there are some signs this may be happening faster than usual, which could accelerate the onset of El Niño.

Over the last few weeks, unusually strong bursts of westerly winds farther west in the Pacific -- where sea surface temperatures are warmer than average -- have been observed. There is a chance that this could accelerate the warming of those eastern Pacific waters and potentially push us into El Niño sooner than usual.

If we do enter El Nino by spring -- which we'll define as the period of March, April and May -- there are some long-term correlations with our weather here in Northeast Wisconsin.

Looking at a map of anomalously warm weather, most of the upper Great Lakes doesn't show a strong correlation, but in general, the northern tiers of the United States do tend to lean to that direction.

The stronger correlation is with precipitation. El Niño conditions in spring have historically come with a higher risk of very dry weather over that time frame, so this will definitely be a transition we'll have to watch closely as we move out of winter.