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Andrew McGuire

@agronomistag.bsky.social
5.6K followers 292 following 511 posts

Views of an agronomist on soil, farming, and science. Evidence-based agriculture. Washington State University Extension. t.co/RZ11P3ozYm Same @ on X.

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Reposted by Andrew McGuire
Joe Janzen @jjanzen.bsky.social · 25/09/2026
Who owns US farmland? Farmdoc has a new tool to visualize foreign interest in US farmland, created by my colleagues Bruce Sherrick and Juo-Han Tsay at the TIAA Center for Farmland Research. Doing this isn't easy, because the numbers are actually very small.
farmdocdaily.illinois.edu
Foreign Ownership of U.S. Agricultural Land - farmdoc daily
Bruce Sherrick and Juo-Han Tsay - Using US land in Farms as the reference, foreign ownership interests amount to 0.67% of the total, and the remaining 99.33% is US owned. Forestland accounts for…
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Andrew McGuire @agronomistag.bsky.social · 21/09/2026
"Cover crop composition, NOT diversity, was the strongest driver of changes to, and legacy effects on, soil microbial communities, agroecosystem multifunctionality and wheat yield." This is consistent across studies. Open access. besjournals.onlinelibrary.wiley.com/doi/full/10....
besjournals.onlinelibrary.wiley.com
Cover crop composition, not diversity, drives agroecosystem multifunctionality and wheat yield
Cover crop composition, not diversity, was the strongest driver of changes to, and legacy effects on, soil microbial communities, agroecosystem multifunctionality and wheat yield. Our results highlig...
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Andrew McGuire @agronomistag.bsky.social · 13/09/2026
"A scientist who wants to change the world in a particular direction is no longer beholden to the truth. They are beholden to a cause...This is why I have come to believe that science and activism cannot mix. It is a plain conflict of interest." www.chronicle.com/article/when...
chronicle.com
Opinion | When Bad Research Feels Good
My work advanced social-justice causes I believed in. There was just one problem.
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Andrew McGuire @agronomistag.bsky.social · 13/09/2026
Montgomery with new book; the geomorphologist takes on farm policy. Regenerative ag, "properly understood," is guided by "minimizing or avoiding both physical and chemical disturbance." And then he claims that glyphosate degrades soil health, and loses me. civileats.com/2026/09/09/o...
civileats.com
Op-ed: Five Policy Changes to Save Agriculture from Itself
From reforming subsidies to treating ag policy as public health policy, here is roadmap for a regenerative, soil-health revolution.
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Andrew McGuire @agronomistag.bsky.social · 09/09/2026
Recent paper: "There is now overwhelming evidence for the destructive effects of the industrial model of agriculture on Earth’s life-support systems." The fact is that ALL models of crop production that will actually feed us have these destructive effects - it's how crops are grown.
photo showing bulldozer clearing forest land in preparation for farming.
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Andrew McGuire @agronomistag.bsky.social · 08/09/2026
Here's why it's easier to be sustainable/regenerative if you only raise livestock: the exports of nutrients are much lower. And this doesn't show N or C. www.sciencedirect.com/science/arti...
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Andrew McGuire @agronomistag.bsky.social · 08/09/2026
"We need to understand nature is always self-organizing, self-regulating, self-healing." - Gabe Brown Pop ecology is the bread and butter of regenerative agriculture. Don't fall for it. yonearth.org/podcast/epis... csanr.wsu.edu/pop-ecology/
csanr.wsu.edu
How Pop Ecology Misleads Agriculture
Romanticized “pop ecology” oversimplifies nature and leads to costly mistakes in real-world crop management.
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WSU Center for Sustaining Agriculture & Natural Resources @wsucsanr.bsky.social · 27/08/2026
Can high Brix make a crop insect-proof? CSANR’s Andrew McGuire examined the claim that virtually no insects will feed on plants at 12 Brix or above. He found little research supporting it. 🔗 csanr.wsu.edu/brix-insect #WSU #PestManagement
Graphic with image of aphids says: Perspectives. Unraveling the Brix-Insect Story.
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Andrew McGuire @agronomistag.bsky.social · 27/08/2026
Do high Brix levels in leaf sap prevent insects from feeding? I looked into the claims. Insects aren't reading your refractometer. My latest, csanr.wsu.edu/unraveling-t...
csanr.wsu.edu
Unraveling the Brix-Insect Story
Andrew McGuire examines the limited evidence behind claims that high leaf-sap Brix protects crops from insect pests.
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Andrew McGuire @agronomistag.bsky.social · 19/08/2026
"Everything is connected" is true is the most trivial sense, but not in ways that matter. It's a romanticized nature-slogan that doesn't identify mechanisms or magnitudes of effects. Which connections matter for your field? Pop ecology won't tell you. csanr.wsu.edu/pop-ecology/
csanr.wsu.edu
How Pop Ecology Misleads Agriculture
Romanticized “pop ecology” oversimplifies nature and leads to costly mistakes in real-world crop management.
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Andrew Kniss @wyoweeds.bsky.social · 07/08/2026
There are a LOT of products out there being marketed to farmers. Many of these products have little to no independent testing to evaluate whether they work. A couple years ago, we tested two products marketed as "soil detoxifiers" - and we found they didn't seem to do anything.
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Andrew McGuire @agronomistag.bsky.social · 27/07/2026
"A scientist who wants to change the world in a particular direction is no longer beholden to the truth. They are beholden to a cause...This is why I have come to believe that science and activism cannot mix. It is a plain conflict of interest." Agroecology, take note.
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Nome @nome.bsky.social · 27/07/2026
Cosmic Crisp has solved most of the problems of the honeycrisp.
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Matthias C. Rillig @mrillig.bsky.social · 27/07/2026
Reading in journal club Roots navigate around decay regions by sensing local pH gradients www.science.org/doi/10.1126/...
science.org
Roots navigate around decay regions by sensing local pH gradients
Plant tropisms enable roots to navigate complex soils by responding to directional environmental cues. Biological decay, although central to nutrient cycling, also creates microbially active and poten...
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Alexander J. Stein @ajstein.bsky.social · 15/07/2026
The EU depends on imported #fertiliser, as shown again by the war in Iran. But manure—suggested by some as solution—cannot replace mineral fertiliser because the #livestock sector itself is a net consumer of it. Scaling up #manure “production” would increase fertiliser use: doi.org/10.1111/1746... +
Figure 2: Balance of nitrogen (N) flows from mineral fertiliser into animal production and from manure out of it (EU27, 2017/18). An illustrated bar chart shows that 5.1 million tonnes of N from mineral fertiliser are used to produce animal feed, but only 2.5 million tonnes of N from manure are provided to the rest of agriculture -- meaning animal production is a net consumer of 2.6 million tonnes of N from mineral fertiliser.
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Andrew McGuire @agronomistag.bsky.social · 08/07/2026
Which is better for marketing?
Susainable ag vs Regenerative ag compared.
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Andrew McGuire @agronomistag.bsky.social · 24/06/2026
While we may never achieve the goal of complete neutrality in science, it is an essential goal. Science will be worse off if we abandon it. Science: an attempt at neutral disinterest in the results with the goal of finding the truth. Activist science: a motivated effort to prove something is so.
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Andrew McGuire @agronomistag.bsky.social · 23/06/2026
Henbit as an easy cover crop: "This common plant is an opportunity for regenerative farming progress. The cost for seed and management once henbit populations establish will be less than the cost for other cover crops..." What do you think? acsess.onlinelibrary.wiley.com/doi/full/10....
acsess.onlinelibrary.wiley.com
Henbit is an attainable cover crop
Henbit is a short-season plant that grows through the winter. It seeds itself in the spring with seeds that stay dormant through the summer and germinate in the fall. Winter growth makes henbit a goo...
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Andrew McGuire @agronomistag.bsky.social · 22/06/2026
If, like me, you wonder about the soil health of the field/pitch while watching World Cup games, here is a fresh paper on the topic. onlinelibrary.wiley.com/doi/full/10....
onlinelibrary.wiley.com
A Comparative Evaluation of Soil Health in American Sports Fields
Sports fields are among the most intensively managed soils, raising concerns about their soil health. The primary objective of this study was to compare soil health in sports field soils with other l...
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Andrew McGuire @agronomistag.bsky.social · 15/06/2026
Decades of research said organic farming builds soil better. A study of 3,000 actual farms says: not so fast. It's not organic vs. conventional — it's about biomass inputs, nitrogen, and tillage. The practices matter, not the label. My latest... csanr.wsu.edu/what-actuall...
csanr.wsu.edu
Dominant Factors: What Actually Builds Soil Organic Matter
Organic and conventional systems can build soil when their practices support the dominant drivers of organic matter.
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Petty Ranch / Chris Sayer @pettyranch.bsky.social · 11/06/2026
Oh, absolutely. Irrigation is probably the biggest driver of increased SOM for an area like ours. And it can contribute to other issues. But I wish people could see that rather than a strict org/conv binary, proper utilization of best practices from both toolkits is likely to deliver best results.
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Andrew McGuire @agronomistag.bsky.social · 11/06/2026
Organic vs. conventional farming, which builds soil better? A new study of 2,900+ real farms found NO difference in soil organic matter. Why? Because the label doesn't matter — plant biomass inputs, nitrogen, rotation & tillage do. Focus on dominant drivers. csanr.wsu.edu/what-actuall...
csanr.wsu.edu
Dominant Factors: What Actually Builds Soil Organic Matter
Organic and conventional systems can build soil when their practices support the dominant drivers of organic matter.
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WSU Extension @wsuextension.bsky.social · 11/06/2026
Up to 12 Extension professionals from across the US will be selected to participate in the upcoming #WSU Specialty Crops Adaptation Course for a week-long mix of farm & research tours, workshops, specialty crop scenario planning & more. #GoCougs To apply: csanr.wsu.edu/resources/cl...
csanr.wsu.edu
Specialty Crops Adaptation Course
Extension professionals can apply for a week-long course on climate adaptation planning for specialty crop systems.
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Noah Fierer @noahfierer.bsky.social · 10/05/2026
The recent NY Times article on Oath (a soil inoculant company) warrants a mini-thread, so here we go: www.nytimes.com/2026/05/01/b... (1/9)
nytimes.com
After Prison, a Financial Titan Plots an Unlikely Comeback
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Jordon Wade @jordonwade.bsky.social · 05/05/2026
One of the most frustrating things I find in the soil health world is the assumption that a management is good/bad rather than evaluating it within a given system/context. Finally some nuance - a great reminder!
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Andrew McGuire @agronomistag.bsky.social · 05/05/2026
"Most field studies that report consistent agronomic benefits use moderate biochar rates, typically about 5 to 15 tons per hectare, rather than the very high rates sometimes used in research trials." OK, what's the cost at moderate rates? sciencesocieties.org/publications...
sciencesocieties.org
Biochar: A promising tool for soil health and nutrient efficiency in sustainable agriculture | Science Societies
Biochar: A promising tool for soil health and nutrient efficiency in sustainable agriculture
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Tuomas Mattila @tuomasjmattila.eurosky.social · 27/04/2026
2020s tech for the tractor, 1800s tech for the tillage. #conservationAgriculture is the way to go.
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Petty Ranch / Chris Sayer @pettyranch.bsky.social · 21/04/2026
Some data from my world: This time last year "Size 60" avocados (most common size) returned about $1.75/ lb to the grower. Today = $1.06. This time last year a gallon of UN32 (conventional nitrogen fertilizer) was about $4.96 Today = $8.54 Not fun.
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Richard Waite @waiterich.bsky.social · 02/04/2026
Just read the underlying study. It 1) does not say “modern agriculture is collapsing,” 2) acknowledges need for 35-56% more food by 2050 without further land clearance, 3) says labor needs in traditional systems are 10x higher, 4) says crop yields in highly agrobiodiverse systems are 20-40% lower.
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𝙲𝚑𝚊𝚛𝚕𝚎𝚜 𝙲. 𝙼𝚊𝚗𝚗 @charlescmann.bsky.social · 25/03/2026
It's Norman Borlaug's birthday! If you don't know who he was, you should--regardless of what you think about modern ag and the global food system--as NB was, for better and worse, a major part of creating them. Last year, I had a fun talk with Derek Thompson (@dkthomp.bsky.social) about the guy.
podcasts.apple.com
Plain History: How Norman Borlaug Stopped the Apocalypse
Podcast Episode · Plain English with Derek Thompson · May 16, 2025 · 1h 9m
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Andrew McGuire @agronomistag.bsky.social · 24/03/2026
For all you dried okra fans out there. Nutritional Value Score Rates Foods Based on Nutrient Density and Noncommunicable Disease Prevention.
Chart of the value of different foods from high, dried okra, to low, Gatorade.
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Kate Marvel @drkatemarvel.bsky.social · 24/03/2026
I just resigned from NASA. It breaks my heart to leave, but I’ve become convinced the best path forward is to do the best science I can, and that can’t be here anymore. I’m still in love with the promise of those four magic letters. Ad astra per aspera, and remember: Earth is the only good planet.
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Andrew McGuire @agronomistag.bsky.social · 24/03/2026
Yesterday's AP article tells gardeners to apply 3-4" of compost to the soil. Do the math: 3" is about 100 tons/acre with ~2000 lb of total N per acre. !! Any farmers out there doing that? apnews.com/article/heal...
apnews.com
Soil is the foundation of your garden. Keep it healthy!
Healthy soil is the foundation of a thriving garden. Soil is not simply “dirt.” It supplies plants with important nutrients, and is home to billions of organisms that feed plants and fight pests.
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Tuomas Mattila @tuomasjmattila.eurosky.social · 23/03/2026
Not to be petty or mean, but especially in #soilhealth and #regenerative ag: if you have a "researcher" presenting simple truths on complex matters... check the Google Scholar account.
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Jordon Wade @jordonwade.bsky.social · 23/03/2026
One reason soil erosion is so tough is that it occurs over long timescales. In these long term plots in Wooster, OH, you can see that reduced tillage and adding grasses in the rotation has prevented ~4” of topsoil loss in the past decades. This always reminds me of the Wendell Berry quote…
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Andrew McGuire @agronomistag.bsky.social · 19/03/2026
Want to know why these Jena experiment results do not apply to annual cropping systems or cover crops? Read this: csanr.wsu.edu/why-ecologic...
csanr.wsu.edu
Why Ecological Biodiversity Research Results Seldom Apply to Agriculture
Ecological biodiversity results seldom apply to agriculture due to fundamental differences in systems and goals.
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Andrew McGuire @agronomistag.bsky.social · 17/03/2026
There are more soil inoculant products than ever, but research has found most don’t survive long enough to matter. Here’s why: ➡️Tiny cultivable fraction ➡️Fermentation-soil mismatch ➡️Native competition ➡️Soil‑to‑soil variability My latest, csanr.wsu.edu/why-soil-ino...
csanr.wsu.edu
Why Soil Inoculants Fail
Research shows why most soil inoculants struggle to establish in field soils and rarely deliver consistent crop benefits.
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Andrew McGuire @agronomistag.bsky.social · 09/03/2026
Again, plant diversity is not the source of benefits. "The presence of individual species, rather than diversity per se, determined the soil binding capacity of the system." Open access. www.sciencedirect.com/science/arti...
sciencedirect.com
Can increased cover crop diversity increase root-soil binding and reduce soil loss during overland flow?
Although cover crops can potentially improve on-farm soil and water management to reduce erosion, their ability to bind soil and whether multi-species…
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Michael Grunwald @mikegrunwald.bsky.social · 05/03/2026
I don’t have a deeper message other than: Food and farming issues almost always involve tradeoffs. I wish people would grapple with the tradeoffs rather than retreat to vibes and ideology. END
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Andrew McGuire @agronomistag.bsky.social · 05/03/2026
Why do organic, agroecology, and regenerative ag all look so similar? Because they're built on the same foundation: pop ecology; notions about nature that feel intuitive but don't hold up to scrutiny. csanr.wsu.edu/pop-ecology/
Venn diagram showing nearly full overlap between 1) Organic, 2) Agroecology, and 3) Regenerative agriculture.
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Andrew McGuire @agronomistag.bsky.social · 27/02/2026
This is one of the most clear‑headed soil microbiome papers I’ve read. No hype, just solid science. You might be shocked by how much we still don’t know about soils. By @noahfierer.bsky.social Unfortunately, not open access. www.nature.com/articles/nrm...
nature.com
Embracing the unknown: disentangling the complexities of the soil microbiome - Nature Reviews Microbiology
Soil contains a vast diversity of microorganisms that can directly or indirectly modulate soil processes and terrestrial ecosystems. In this Review, Fierer summarizes the challenges in characterizing ...
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Andrew McGuire @agronomistag.bsky.social · 27/02/2026
Imperfect land sparing, with only 30% of land spared devoted to conservation is still better than land sharing. Why? Because the worst thing ag does to nature is convert it to cropland. Everything after conversion is insignificant in comparison. besjournals.onlinelibrary.wiley.com/doi/10.1111/...
besjournals.onlinelibrary.wiley.com
How imperfect can land sparing be before land sharing is more favourable for wild species?
Our results confirm that real-world difficulties in implementing land sparing will have significant impacts on biodiversity. They also underscore the need for strategies which explicitly link yield i...
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Andrew McGuire @agronomistag.bsky.social · 26/02/2026
"Nature knows best" sounds wise. But we invented farming because nature didn't know best for growing crops. Pop ecology's tradeoff-free farming doesn't hold up to scrutiny. csanr.wsu.edu/pop-ecology/
csanr.wsu.edu
How Pop Ecology Misleads Agriculture
Romanticized “pop ecology” oversimplifies nature and leads to costly mistakes in real-world crop management.
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Andrew McGuire @agronomistag.bsky.social · 25/02/2026
Pop ecology gives us appealing slogans—“nature knows best,” “the balance of nature”—but fails to reflect reality and so misleads agriculture. Here's what the ecology of reality actually tells us. My latest... csanr.wsu.edu/pop-ecology/
csanr.wsu.edu
How Pop Ecology Misleads Agriculture
Romanticized “pop ecology” oversimplifies nature and leads to costly mistakes in real-world crop management.
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Michael Grunwald @mikegrunwald.bsky.social · 23/02/2026
Sorry, but more sustainable farming isn’t more natural farming. It’s farming that doesn’t overrun so much of the earth. That means higher-yield farming that makes more food per acre, so it doesn’t need so many acres to make food.
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Robert "The Bobby Yaga" McNees @mcnees.bsky.social · 22/11/2025
Journalist challenge: Use “Machine Learning” when you mean machine learning and “LLM” when you mean LLM. Ditch “AI” as a catch-all term, it’s not useful for readers and it helps companies trying to confuse the public by obscuring the roles played by different technologies. 🧪
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Andrew McGuire @agronomistag.bsky.social · 06/02/2026
Much of this applies to the nonsense I see about and sometimes within agriculture.
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Andrew McGuire @agronomistag.bsky.social · 16/01/2026
New Extension publication: Cover Crop Mixtures vs. Monocultures: What the Research Shows. pubs.extension.wsu.edu/product/cove...
pubs.extension.wsu.edu
Cover Crop Mixtures vs. Monocultures: What the Research Shows
Meeting future food demand without expanding farmland is a key challenge, and cover crops can help. This publication summarizes research comparing diverse vs. single-species cover crop systems to supp...
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Andrew McGuire @agronomistag.bsky.social · 16/01/2026
What will happen to glyphosate? Nice report. www.breakthroughjournal.org/p/the-clock-...
breakthroughjournal.org
The Clock Is Ticking for Glyphosate
Decisions from Supreme Court, EPA, and State Legislatures Expected in 2026
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Andrew McGuire @agronomistag.bsky.social · 15/01/2026
Why am I skeptical about soil microbiome testing? Microbial communities vary dramatically at tiny scales: root tips, inside aggregates, where plant material decomposes. These microsites host unique communities, yet most tests only give a broad snapshot, missing these critical microsite differences.
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