Crop Comments: Finger Lakes grower requests fertilizer recommendation
About a month after the Strait of Hormuz blockade began, a farmer named Ken called me, asking me to formulate fertilizers for his small cropping operation in southern Onondaga County.
Ken grows corn for grain, soybeans and mixed mostly grass hay. He sent me soil test results for each of the three fields in question. The fields were small enough that I opted to concoct a blend (a fits-all recommendation). However, the corn piece would receive a top-dress of tamed urea when it was about a foot tall.
Based on the average of three soil test results from samples tested last November at the Dairy One Lab in Ithaca, each acre required a band application delivering 9 lbs. of nitrogen, 40 lbs. of phosphate, 28.3 lbs. of potash, 15 lbs. of sulfur, 3 lbs. of zinc and 1 lb. of boron. (Phosphate is 43% elemental phosphorus, and potash is 83% elemental potassium.)
The ingredients I opted to use (provided by Ken’s fertilizer dealer) were as follows (with N-P-K analysis in parentheses): mono-ammonium phosphate (MAP, 11-52-0); muriate of potash (KCl, 0-0-60); a sulfur product (with 90% S); zinc sulfate (with 35.5% Zn); and a boron product with 14.3% B.
Here’s the formula I came up with (pounds per ton): 1,012 lbs. of MAP, 553 lbs. of KCl, 224 lbs. of sulfur 90, 92 lbs. of sol-u-bor and 119 lbs. of zinc sulfate. This blend would be band-applied at 152 lbs./acre. The tamed urea (46-0-0) would be later broadcast on the foot-tall corn at 100 lbs./acre. Adding up the individual ingredient pounds/acre (listed above), the dosage per acre of this blend is 152 lbs., meaning that a ton would treat 13.2 acres.
Because of Hormuz, the MAP and urea prices are generally at least 50% higher than they were pre-blockade. It’s a painful marketplace quirk of supply/demand economics, since about 20% of our planet’s needs for these two fertilizer ingredients are produced in the Middle East. Mercifully, most of the globe’s potash products (muriate and sulfate) originate in southwest Canada and Russia, thus remaining virtually immune to problems caused by the Hormuz mess.
I was flattered when Ken asked me for help in navigating the ongoing confusing blend of geopolitics and cropsmanship. He made the assignment he gave me much more doable by having performed those soil tests last autumn.
Early in our conversations, Ken mentioned a weed – marestail – which was very prevalent in these fields whose fertility issues he’d sought my help on. I suspected that these soil nutrition problems may have helped make that weed feel welcome. I did some research on that weed, which is also called Canadian fleabane or horseweed. According to Iowa State University Extension, marestail belongs to the Asteraceae family, is native to North America and likes disturbed areas – as well as no-tilled fields.
Quoting those Iowa researchers, “Marestail produces a basal rosette of hairy, irregularly toothed leaves two to three inches long. Stem reaches heights of six feet; the terminal portion is a large panicle of inconspicuous flowers producing numerous wind-dispersed seeds. Pubescent stems are covered with alternately arranged, hairy leaves three to four inches long; lower leaves are irregularly toothed. In typical years, about three-quarters of the population germinates in late summer/fall, the remainder the following spring. Marestail was the first weed to develop resistance to glyphosate in glyphosate-resistant crops. Resistance (to glyphosate) spreads rapidly due to wind-dispersed seed.”
Next, I checked out marestail in my textbook “Weeds: Control Without Poisons” (by Charles Walters, Acres USA Press, 1996). There this subject appears under the name Canada fleabane, a.k.a. marestail, horseweed. Walters wrote that marestail is an “annual that reproduces by seed, usually in grasslands, but also in waste places. This plant can be tiny or grow to six feet or more in height. Simple leaves alternate, are hairy, lanceolate and sessile. The tiny flowers have whitish disks and small white rays. Leaves and flowers contain a terpene that irritates the nostrils of horses. Fruit is an achene, with a parachute of yellowish-brown bristles. This weed takes over abandoned pastures with alacrity, but has a hard time of it when tillage, traffic and moving are involved.”
A little more research on my part dealing with the marestail competing with Ken’s crops showed that it’s a perennial fern that grows wild in northern Europe and North and Central America, as well as in other moist places with temperate climates. It has a long, green, densely branched stem that grows from spring to autumn and the plant contains numerous beneficial compounds that give it multiple health-promoting effects, particularly antioxidants and silica. Antioxidants are molecules that protect one’s body from the effects of free radicals that can cause cell damage. Silica is a compound made up of silicon and oxygen and is believed to be responsible for marestail’s potential benefits for skin, nails, hair and bones.
Marestail is mostly consumed in the form of tea, which is made by steeping the dried herb in hot water. It’s also available in capsule and tincture form.
Despite the human health pluses just cited for this weed, Ken and I are hoping that the proper soil amendment package we’ve adopted will help his corn, soybean and hay crops strongly outperform marestail. It really doesn’t look like glyphosate will be of much help, should the weed become more ornery.
by Paris Reidhead
