Tillage effects on soil demonstrated at PASA conference
(Pennsylvania Association for Sustainable Agriculture)
By Sarah Wharton, Lab Assistant
Nature as Mentor was the theme of this year’s Pennsylvania Association for Sustainable Agriculture (PASA) conference, held at State College, PA. With over 1,000 attendees, 400 were there for the first time (myself included). The focus was creating ecosystems on our farms that more closely mimic those of the wild, in order to decrease our reliance on pesticides, fertilizer, and fossil fuels, and regenerate our farmland.
“You burned the house down to cook a hotdog!” was one of countless memorable quotes from Ray Archuleta, main speaker at the conference and NRCS conservation agronomist. This remark referred to tilling a field in order to release nutrients for that year’s crop—an unsustainable practice that destroys organic matter and soil texture. Ray explained that tilling releases more nutrients than can be taken up by the crop, so much of the fertility is washed away, requiring the application of inorganic fertilizer in the years following tillage. Many of us in the audience were surprised to learn how detrimental tilling is to the soil, after watching Ray perform two illuminating demonstrations.
For the first demonstration, Ray dropped four clods of soil into separate beakers of water. Two of the clods were from organic tilled fields that were recently put into production after years of pasture. The other two clods, same soil series as their tilled cousins, were collected from a no-till portion of the field. The effect of the water on the soil was dramatic. The tilled clods instantly crumbled apart, losing all structure and clouding the water. The no-till clods stayed as is, held together by microbial glues, an essential component of soil structure lacking in tilled soil.
In the second experiment, Ray simulated a rainstorm by pouring water on a piece of no-till soil and organic tilled soil, each atop a sieve. The water ran right through the no-till soil, quickly filling the basin under it. Very little water made it through the tilled soil, instead collecting on top. Ray explained that when the plow pulverizes the soil structure and oxidizes the microbial glues, the soil compacts and greatly inhibits infiltration. Ray argued that we don’t have a “runoff problem” causing our rivers to fill with sediment and phosphorus, but an “infiltration problem.”
Cover crops were also highlighted in many of the workshops. “Treat your cover crop like your cash crop,” said Steve Groff of Cover Crop Solutions. This mantra was repeated the next day by Mary-Howell and Klaas Martens, veteran grain farmers from Penn Yan NY. Both Steve and the Martens highlighted the importance of maintaining healthy, biologically active (and untilled) soil on the farm, and that using cover crops not only sustains soil health, but also builds it. Using cover crops to “grow your own nitrogen” allows farmers to decrease or stop application of inorganic fertilizer. Decreasing inorganic fertilizer use not only has numerous environmental benefits, but saves farmers money as well. Of the cover crops discussed, tillage radish was deemed a “rock star.” This large tuber, with its deep taproot, mines and stores nutrients, increases organic matter, helps manage weeds, and aerates the soil. Tillage radish is also very tasty and can be harvested as a food crop.
Both Steve, Ray, and the Martens discussed the myriad benefits of using cover crop polycultures, which in many documented cases actually have significantly higher yields when grown together, as opposed to when grown in monoculture. A few presenters shared images of monocrops next to polycultures after weeks of no rain. The monocrops were yellow and half-dead while the polycultures were moist and green, a testament that plants often perform better in tandem than they do alone.
The range of different backgrounds and experience among the attendees was tremendous, with both young farmers and veteran growers. All however, gathered at PASA with at least one common thought in mind: it’s time for change. Change our farmland from unsustainable to sustainable, from destructive to restorative, from battling nature to a partnering with nature.