Rising Fertilizer Prices Shine a Light on the Science of Healthy Soil


Soaring fertilizer prices are renewing attention on other tools that could ultimately improve soil health and boost food production.

Why is this important: Shocks to global agricultural systems – including droughts fueled by climate change, as well as seed and fertilizer shortages due to conflict and natural disasters — are likely to become more frequent.

Driving the news: Fertilizer prices have soared around the world, pushing some farmers to apply less nitrogen, phosphorus and potash to their crops, reports Bloomberg.

What is happening: In the United States, rising fertilizer prices could motivate some farmers to test organic, plant- or microbial-based fertilizers developed by a slew of startups, reports the WSJ.

  • Farmers can also take another look at new digital farming tools to help them use fertilizers and other resources more precisely, says Harold van Es, professor of soil and water management at Cornell University.
  • “One of the things about fertilizers being cheap, easy to apply, and so effective is that they’ve been used inefficiently,” says Jason Kaye, professor of soil biogeochemistry at Penn State University. .

Short term, alternative fertilizers, cover crops and digital tools could be used to reduce and optimize the use of synthetic fertilizers, which lead to environmental costs, including nitrogen runoff into rivers and aquifers.

  • Overtime, they could help build up nutrients in the soil, improve soil health and protect crops from disturbance, Kaye says.

Details: Regenerative and circular agriculture approaches focus on restoring soil health and recycling and reclaiming the resources needed to produce food.

  • The science behind it has progressed over the decades as the tools of genetics, biology and chemistry have become more sophisticated and less expensive – and people have become more interested in the systems that produce their food.

At the University of Minnesota, Researchers led by Donald Wyse are developing more than a dozen cover crops that can be grown when fields in the U.S. Upper Midwest would otherwise remain bare, NYT’s Jonathan Kauffman wrote this week in a Wyse profile. These “evergreen crops” can provide farmers with another source of income and soil with organic matter and carbon.

  • In Uganda and Kenya, smallholder farmers are experimenting with using by-products of rice cultivation – including biochar made from rice husks – to try to improve soil health and crop resistance to disease. .
  • Scientists at Penn State University are investigating whether composted urban food waste combined with animal manure could help reduce the amount of fertilizer needed by crops. Preliminary modeling data from cropland in the Chesapeake Bay region suggests this may be possible without affecting water quality, Kaye says.
  • Washington-based Tidal Vision is experimenting with recycling discarded crab shells to improve agricultural production.

But, but, but… Designing agriculture around ecology brings uncertainties for farmers and the food supply.

  • Nutrients are provided by the decomposition of cover crop plants and manure – a process that depends on microorganisms, available water in the soil, and soil temperature.
  • These processes are harder to predict than taking a known amount of fertilizer and determining how much nitrogen a field will get, Kaye says.
  • He is developing tools to fill this “science gap” by predicting the amount of nutrients a plant or manure will provide, which would help reduce uncertainty for farmers.

A better understanding of soil health is emerging as scientists move from focusing exclusively on chemicals in the soil to also integrating biology and physics, says van Es.

  • He and others are refining assessments of soil indicators that signal its health – a mix of organic matter, its degree of compaction, the soil microbiome and more.
  • In a recent preprint article, van Es and colleagues identified bacterial indicators of soil health, based on genetic sequencing.
  • “It’s still relatively new,” he says, comparing soil health to human health. “Forty years ago, we didn’t measure our good and bad cholesterol regularly.”

The catch: Adopting new tools means taking on new costs. Price levels are important to farmers, especially those who raise food for their own consumption rather than for the market.

  • And, these systems take a long time to set up. Once you do, they’re impact resistant,” Kaye says. “But they won’t help us next year. It takes a decade to build such organic matter in the soil.”

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