Sneaky Velvetleaf

Sneaky VelvetleafOn June 27, with the help of the landowner, I took four soil samples on a Mohawk Valley farm. The piece being sampled that I found most interesting had been planted to a mix of forage soybeans and brown mid-rib sorghum two weeks earlier. There appeared to be more soybean seeds that were just sprouting, laying on the soil surface, than there were seedling plants with two, three or four leaves. Emerged sorghum plants were few and far between. In the preceding two weeks, local weather conditions had varied all over the board, from the low 40s to the low 90s. Moisture conditions had varied from parched to adequate. The night before last was one of the wetter periods; thus, the four soil samples were air-drying on my porch as I wrote. For soybeans to germinate optimally, soil temperature should consistently exceed 60º F, and sorghum seeds prefer a constant minimum of 65º.

I thought I could see some soybean plants with small, but distinct, true leaves. Examining this foliage closer – even though the leaves were only a half-inch wide – their surfaces felt just a little bit fuzzy, ruling out fledgling soybeans. I had to tell my host that these were weeds, and specifically they were velvetleaf specimens. A little background on velvetleaf (Abutilon theophrasti) is in order. Let me tap into an explanation of this weed which appears in the Acres U.S.A. text titled “Weed Control Without Poison” (1996). Author Charles Walters explained that this annual plant causes trouble in all but the coldest parts of North America. It reproduces by seeds, usually in tilled fields, and, as its common name implies, it has a velvet touch on both sides of the leaves. When crushed, those leaves yield unpleasant odors. Its simple leaves alternate and can be up to 12 inches wide. Flowers, mounted on short stalks, are orange-yellow; the resulting fruit splits open at maturity.

Quoting Walters directly: “It proves troublesome in row crops. The remedy is cultivation, cutting or pulling. Old-timers recommended burning seed pods, even if immature. Poisons are not particularly helpful, because seeds retain their vitality for over 50 years. Only the well-inoculated compost pile will kill them. The appearance of velvetleaf is an early warning system, with specifics attached. It says that decay has gone in the wrong direction, with methane… rather than carbon dioxide… (as) the byproduct. Phosphates in the soil are all complexed. And aerobic microorganisms have gone off duty.”

He stressed that velvetleaf soils have a carbon problem, and that fertilizing with muriate of potash and commercial nitrogen almost guarantees that this unwanted guest will stick around. Herbicides seldom solve the velvetleaf problem, as this weed adeptly develops resistance to many of them. Velvetleaf’s presence is usually proof that calcium and phosphate levels are low or complexed – and that potassium, magnesium and, very likely, selenium are high. Quoting Walters again: “With anaerobes in command, manganese, iron, sulfate, copper, boron and chlorine are cut loose and achieve a high profile. Low humus, low porosity and poor decay translate into high moisture, crusted and sticky soils and aluminum release.”

He pointed out that, counterintuitively, use of herbicides like alachlor and 2,4-D improve the overall vitality of the velvetleaf population. This is mainly through killing the inferior (herbicide-susceptible) specimens, leaving the survivors to reproduce. I say it’s a case where otherwise learned weed scientists continue to fail “Population Genetics 101.”

In addition to velvetleaf’s background, here’s some of its history. This weed originated in either China or India. Its use as a fiber crop in China dates at least as far back as 2000 BCE. It’s still grown there for fiber, which is used to make ropes, coarse cloth, nets, paper and caulk for boats.

Whether as foreign material in crop seed or as an intended fiber crop, velvetleaf arrived in North America most likely before 1700 and became widespread along the East Coast by the early 1700s. Because the colonies desperately needed fiber for rope and cloth, velvetleaf was widely cultivated in the mid-1700s. Although attempts to process velvetleaf fiber never succeeded economically, U.S. farmers continued to cultivate it for more than 100 years. In the minds of most farmers, A. theophrasti’s minuses far outweigh its pluses. Still, here are some of its nutritional benefits: Seeds can be consumed raw or cooked. They can be eaten raw when they are under-ripe. Ripe seed is dried and ground into a powder then used in soups, bread, etc. Seeds contain about 19% of semi-drying oil.

Changing gears some, here’s the June 2022 Dairy One Forage Newsletter, which contained a bulletin that I have summarized: Herewith, the Dairy One team has seen a number of forage pellet, forage cube and chopped hay samples arriving at the lab that contain non-forage supplements and additives. Their workers have tested many of these samples by both wet chemistry and near-infrared spectroscopy (NIR) and found that these sample types are not compatible with their NIR calibrations. The Dairy One hay calibration library contains a wide range of hay species as well as various types of forage pellets and cubes that do not contain additives, supplements or other concentrates. Quoting lab personnel directly: “If your sample does contain hay plus ‘a little something else,’ we recommend one of our wet chemistry packages (rather than NIR packages). If you have any questions regarding which analysis packages are appropriate for your sample, please do not hesitate to contact our Customer Support at forage@dairyone.com.” For folks working with other forage labs, I suggest they contact those labs to determine if they need the “bells and whistles” provided by the wet chemistry (at a little higher price than the NIR version). The extra expense for additional analysis accuracy will be money well spent.

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