Pasa 2026

I was only able to attend one day this year. Here are the sessions I attended:

• Digging Into Soil Organic Matter: Science & Strategies for Building Organic Matter Over Time

• Plenary

• Regional Breakouts: South Central

Digging Into Soil Organic Matter

This session featured an overview of the science of Soil Organic Matter (SOM), practical examples and outcomes on two farms, and current practical research.

Bonnie McGill (American Farmland Trust) covered SOM science including fractions, formation, and preservation.

SOM formation is heavily influenced by soil structure, also called tilth. Good tilth is something that most farmers know instinctively: "crumbly" soil with a range of aggregate and pore sizes. Soil particles are bound together as aggregates via soil particle size/chemistry (e.g., cation exchange capacity), fungal hyphae, and microbial and plant exudates. Good tilth allows adequate soil air exchange and water infiltration and biological function. The Cornell Assessment of Soil Health provides a framework that captures these factors.

image from Jocelyn Lavalee

SOM is mainly composed of three parts or fractions: dissolved organic matter (DOM), particulate organic matter (POM), and mineral-associated organic matter (MAOM). Of these fractions DOM is the shortest lasting and MAOM is the longest lasting.

POM is formed by larger soil organisms as they shred and move around surface matter such as dead leaves (e.g., beatles, worms, etc.). MAOM is then often formed from POM along with exudates from these or smaller organisms (e.g., protozoa, bacteria). The exudates bind POM to minerals in the soil. Good tilth provides more surfaces/sites for MAOM to form.

The practices for building long-lasting SOM (MAOM) and good tilth are similar (and reinforcing) -- minimizing tillage/disturbance, crop rotation, cover cropping, and soil amendment. Each of these practice areas have a number of variables to consider for each unique situation. For example, selecting cover crops which scavenge phosphorus after a manure application.

Good SOM is important for good soil health, and good soil health is important for the planet (and farmers!). Much SOM (often upwards of 90%) is lost as carbon dioxide, contributing to climate change. Healthy soils retain water, resist flooding, and are resilient to climatic events. Healthy soils are biodiverse, with fewer pathogenic species, produce healthier plants that better resist weed pressure, and produce a better harvest yield.

Amanda Butterfield (Maple Valley Cattle Company) and David Johnson (Provident Farms) provided examples of practices and outcomes on their farms. Maple Valley is a beef farm while Provident produces beef and row crops, also doing seed cleaning (selling seed). Overall these two farms demonstrate how livestock can be used to build and sustain SOM. Maple Valley takes a more hands off approach -- with very little mechanization they have managed to build up their SOM on land which was previously timbered and strip-mined. No tillage, just livestock. Careful rotational grazing is key. Provident has implemented carefully selected crop rotations along with minimal rotational tillage. Provident has established a healthy SOM, which they have been able to maintain through their practices. Some tips from Provident: Shallow tillage is < 2" deep, clover is "leaky" on it's own (best pair with oats) and is frost seeded, buckwheat is used to scavenge ("bring up") phosphorus, avoid tillage on hot/dry days (though of course no tillage or field work when wet), consensus is > 10,000 Lb / axle will cause subsoil compaction which is semi-permanent.

Laura Kaminsky (Pasa) presented the latest findings from the Soil Health Benchmark Study, which provides a analysis of data gathered from participating farmers, mainly on tillage and soil health. This is still a work in progress but the latest findings hint at an inflection point for soil management intervention and SOM formation.

Plenary

The first day's plenary featured awards and aknowledgements followed by the annual speech by Pasa Executive Directory Hannah Kinney Smith. I was surprised to learn that funding to sustainable farms that was canceled by the Trump administration has been restored after a lawsuit. This funding is for projects, administered by Pasa, which address climate challenges facing farmers. Mudcollege Farm had hoped to use some of this funding for implementing agroforesty practices, so it will be interesting to see what comes of it!

Regional Breakout: South Central

This breakout group put Pasa attendees from our region together to discuss issues of mutual interest. It was remarkable how many attendees are involved in agroforestry work. My small breakout group included Katherine and Tim Clymer (Threefold Farm), Harrison Rhodes (Trees for Graziers), and Zach Elfers (Future Forest Plants). Threefold Farm produces kiwi berry, persimmon, fig, and pawpaw. Trees for Graziers consults with livestock farms to add silvopasture production. Future Forest Plants grows native trees for sale, and Elfers is also a founding member of the Keystone Tree Crops Cooperative.

I missed Will Brownback's (Spiral Path Farm) keynote speech, as I was unable to attend Pasa day 2. I appreciated reading a summary in Lancaster Farming. Brownback spoke about the challenges he and his family faced personally, including the death of his brother, and how education (including through Pasa) and improving practices allowed his family and farm to grow from a struggling operation into the successful business they are today.