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“Granular” herbicides are “incorporated” (mixed) into the soil, prior to planting. “Wettable powders” and assorted liquids are applied with sprayers. They are mixed in the sprayer tank, which gives rise to the term “tank mix.” A simple backpack sprayer holds up to about five gallons. “Saddle tanks” mounted on the sides of a tractor can hold hundreds of gallons. Trailer-mounted spray tanks are even bigger. Folding booms on such sprayers can easily be 60 feet wide.
Nozzles or tips are mounted every few feet on sprayer booms. “Flat fan-spray” tips produce an overlapping tapered-edge spray pattern that provides uniform coverage. They work with both pre- and postemergent herbicides. “Flood-type” nozzles are normally reserved for liquid fertilizers. “Full” and “hollow-cone” nozzles deliver circular spray patterns and are most often used with insecticides or fungicides. Sprayer tips come in brass, plastic, ceramic, stainless steel and hardened stainless steel.
All sprayers must deliver just the right amount of “active ingredient.” Too little herbicide means poor weed control and repeat spraying. Too much may be hazardous to the applicator, or “phytotoxic” (injurious) to crop plants and leave excessive residues. That’s why weed scientists remind herbicide applicators to “calibrate” their sprayers by periodically measuring the amount of herbicide they deliver.
And anyone who has ever used a power-sprayer to paint will warn about the ever-present danger of “spray drift.” Even a slight breeze can blow herbicide mist on prize rose bushes and valuable vegetation that you don’t want to zap.
“Resistance” is another term increasingly linked with herbicides. “There are about 250 species of herbicide-resistant weeds in the world,” according to Purdue University. “The highest number is in areas where production row-crop agriculture is most intensive and relies almost exclusively on herbicides for weed control. That would be North America, Australia and Europe.” Nature developed herbicide-resistant “super weeds” around 1960, more than 30 years before genetic engineering gave us a few herbicide-resistant crop plants.
Here are 10 other things you can and should do to help control weeds on your place:
1. Stop Seeds Now – Never let any weed go to seed. “Weed seed populations in the soil should be kept to a minimum by preventing weeds from producing seed in and around vegetable fields. Destroy all weeds immediately after a crop is harvested,” cautions the Commercial Vegetable Production Recommendations from Penn State.
That’s why, no matter how many pressing chores there are to take care of around your property, you should always make time to at least mow your worst weed patches before they set seed and make the problem even worse. “But the days aren’t long enough,” you say. Nonsense! Why do you think tractors have headlights?
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