Crop Comments: Rare weed helps retain soil

On July 23, I was invited by Uri to perform extensive soil sampling on his farm in eastern Chenango County, NY. I’ve been advising Uri in his organic crop program for a couple decades, taking lots of soil samples for him over the years. I met Uri in September 1964 at Cornell University. I was an ag freshman, and he was transitioning from the two-year ag program to the four-year program.

He graduated from Cornell in 1966, then returned to his parents’ family dairy farm in Chenango County. I graduated from Cornell two years after Uri. After some time in graduate school and then military service, I was employed as a dairy/field crops Extension agent in neighboring Otsego County. At some point, Uri and I stumbled into each other again, reviving our friendship, particularly as organic dairy farming gained momentum. My ag sales vocation enabled me to work more with Uri as he became a pillar in the fledgling New York organic dairy farming community.

In my role as an independent cropping consultant, I got Uri to test soils and forages, mostly using the Dairy One Laboratory in Ithaca. Over the last quarter-century, the resulting soil test results have enabled him to optimize crop production as well as maximize soil health.

So, two weeks ago (as I write), he and I hopped into his UTV and sampled 13 fields spread out over Columbus and Sherburne Townships, much of this land being rented.

There are at least two main reasons that I prefer to use this lab: first, its protocol takes into account the structural “personality” of the soil being sampled (shown by soil type). Second, it also makes a recommendation considering base saturation percentages (BSPs). In my modest opinion, determining soil nutrient balance without BSPs is difficult, if not impossible.

In his reader-friendly textbook “Eco-Farm” (1996, Acres USA Press), Charles Walters hints at a soil particle resembling a ball with 100 surfaces. A standard volleyball has eight surfaces – now just imagine one with 100.

In Walters’s text, agronomist William A. Albrecht, Ph.D. (researching at the University of Missouri) “found that for best crop production the soil’s colloid had to be loaded with 65% calcium (Ca), only 15% magnesium (Mg) and that potassium (K) should be in the 2% to 4% range. These values were the saturation figures when nature was at her finest balance, and thus capable of producing healthy crops.”

Without getting any more complicated, let me state that these three soil nutrients are positively charged and are called cations. Because they are negatively charged, phosphates are considered to be anions and don’t occupy any of those surfaces.

This volleyball-type surface of the soil particle is called cation exchange capacity (CEC). Tiny particles, like clays, have bigger CECs, while comparatively huge particles, like sands, have much smaller CECs. Albrecht proposed acceptable BSP ranges of 60% – 70% for Ca and 10% – 20% for Mg (with K, as stated above, in the 2% – 4% range). Add these values up, then subtract that total from 100%, and we see that difference is now absorbed by positively charged hydrogen ions (also cations). Higher hydrogen ion levels correspond to lower pHs (thus higher acidity).

Now back to our soil sampling excursion. One small piece of ground (Uri called it D-7N) that we sampled because of its uniqueness was only about 100 feet by 300 feet. Its most prolific vegetation I sampled separately, then identified as “shaggy soldier.” Its scientific name is Galinsoga parviflora, named for the botanist who discovered it (parviflora is Latin for “small flowers”). According to Wikipedia, “Shaggy soldier is an annual herb about 10 inches tall with opposite leaves. It is so highly branched that it produces two side shoots at just about every node. The stems, leaves and bracts are all sparsely to densely hairy, with a mixture of glandular and simple hairs.” I dug up a specimen of G. parviflora, kept it moist and photographed it against my hat to suggest its relative size.

Further research on my part revealed that the shaggy soldier (also commonly named quickweed) is a highly adaptable annual that thrives in a range of soil types but has certain conditions that encourage its establishment and spread. This species grows in sandy, loamy and clay soils. It can tolerate both fertile garden soils and compacted urban soils, making it common in cultivated beds, lawns and disturbed areas. It adapts to acidic, neutral and basic (alkaline) conditions, so soil pH is not a limiting factor. Apparently, it fits in quite well in circumstances that make regular crops unhappy.

Soil test results for parcel D-7N (a Mardin silt loam) showed a pH of 6.2 (a little low), BSP for K at 1.4% (low), BSP for Ca (very high), BSP for Mg (way low) and phosphorus at 19.6 Mehlich ppm (very low). Shaggy soldier is very content with these numbers while very few cultivated crops are.

It’s pretty evident to Uri and me that G. parviflora is hanging onto soil that might otherwise be lost. G. parviflora belongs to the Asteraceae family. This large plant family includes many familiar species such as sunflowers, daisies and asters. It is characterized by flower heads composed of many small florets arranged in a composite structure.

Shaggy soldier also boasts medicinal uses for treating wounds and cuts. Its fresh juice or crushed plant applied to wounds promotes healing and blood coagulation. For bug bites, stings and nettles, rubbing the plant on the skin helps relieve irritation and swelling.

In terms of edibility, G. parviflora is safe for humans to eat. (Bear in mind that the taste and texture of the plant may not be to everyone’s liking.) Some people describe it as having a slightly bitter or grassy flavor. It can be eaten both raw and cooked, but cooking helps mellow out the taste.

by Paris Reidhead