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Martinsville, Ohio | After much consternation, I finally got it to work half way or better.
It's a good concern. Growing a new business or webiste is not easy, I have learned.
Let's get to the Magnesium, something that has always concerned me, since my soil is over rich in it.
http://fhrfarms1.com/blog/wp-content/uploads/2012/11/2012-05-insert...
It's a PDF because of the graph.
I find it to be pretty true on my farm.
Here are some of those truths:
"What Do The Weeds Really Tell Us?
Weeds shouldn't be a plague or a market to eradicate. They should be viewed as what they are meant to be, an indicator of your soil conditions. Weeds can tell you more about your soil fertility than most standard soil analysis, if you know how to read them. Thes e unwanted guests have many benefits, foremost is to rearrange the soil to allow other plant and soil microbial life to repopulate and restore nature's balance.
Low calcium levels tend to favor many weed types, mostly the grasses like foxtail and quackgrass. Broadleaf weeds are an indicator of a phosphorous to potassium imbalance. They also act as a detoxifier of chemicals in the soil. Theoretically, the more toxic chemicals you apply, the more broadleaf weeds you will be favoring. Succulents are an indicator of poor drainage (anaerobic conditions) and low carbonate ions.
Certain weeds obtain specific nutrients from the soil at various depths . And in various circumstances, e.g., compacted soil, water logged soil, chemically contaminated soil, and high-salt soil. In turn, they manufacture certain metabolites, which they excrete into the soil rhizosphere to be processed by specific microbes. Likewise, these microbes uniquely obtain and metabolize certain nutrients from the soil, which they, in turn, alter and re-excrete into the rhizosphere for use by plants and other microbes. Left to operate naturally, this process regenerates a "sterile" or "toxic" soil to the point where the plant and microbe populations change again and again, eventually to support whatever crop and microbe group we desire. An organism will survive and thrive only if the proper conditions have been established for it to do so. (From Science in Agriculture, Arden Andersen).
Calcium & Magnesium
An imbalance of magnesium to calcium can lead to tight soils and anaerobic conditions. Calcium causes soil particles to move apart and provides good drainage and oxygen movement. Magnesium allows soil particles to stick together, limiting oxygen, which does not permit beneficial microorganisms to flourish. This does not allow organic matter to decompose properly and promotes fermentation that favors by products like alcohol and formaldehyde. These conditions also favor soil diseases such as pythium and phytophora. An ideal Ca:Mg ratio would be 7:1. Weeds that indicate a Ca:Mg imbalance leading to a tight and poorly drained soil would be: Creeping buttercup, curled dock, giant sorrel, broad-leaved meadowsweet, field bindweed, and quackgrass.
Phosphorous and Potassium
Phosphorous is important to the manufacture of sugars and is a key factor in the transport and translocation of nutrients and metabolites within the plant. Too much potassium will have a tendency to replace calcium in the cell resulting in weak cells and black spots on the leaves. An improper phosphorous (P) to potassium (K) ratio will favor the broadleaf weeds like: ragweed, eastern bracken, yarrow, velvet leaf, and lamb's quarter. A proper P:K ratio is 2:1 for most row crops and 4:1 for alfalfa and grasses.
Succulent weeds (purslane) indicate that the soil is deficient in biological carbons (Andersen). This can be attributed to poor drainage where the oxygen is not capable of moving into the soil, creating an anaerobic atmosphere. Most beneficial microorganisms do not prefer this condition, will not grow, therefore the lack of biological carbons.
Control
There are many theories and practical methods to control weeds without using chemical herbicides. The first hurdle that must be overcome is the weed free field. Weeds are not just indicators of fertility imbalances but also can be instrumental in breaking up hard pans and loosing tight soil through their extensive root systems. Weeds are the natural result of defying natures' preference for high species diversity and covered ground. Weeds are natures' struggle to bring about ecological succession. When we clear native vegetation and establish annual crops, we are holding back natural plant succession. Nature abhors a vacuum, and can't stand bare ground either.
Allelopathy
Allelopathy is the ability of one plant to chemically inhibit the growth of other plants around it. Rye is one of the most useful allelopathic cover crops because it is winter hardy and grows almost anywhere. Rye contains a great deal of allelopathic chemicals. When left undisturbed on the soil surface these chemicals leach out and prevent weed seeds from germinating. This is effective for around 30 to 60 days. Once the rye is tilled in, the allelopathic effect is lost. In one study, a cover crop of rye and one of clovers showed 85 -95% broadleaf control 45 days after planting corn. Other crops that have allelopathic effects are wheat, sunflowers, sorghum, and rapeseed. All members of the mustard family (Brassicaceae) contain oils that inhibit plant growth and seed germination. In general, typical levels of cover crop residues, when left on the soil surface, can be expected to reduce weed emergence by 75-90%. In general, a rye cover crop will decrease weed pressure from 83% of broadleaf weeds to 36% of grasses, with clover cover crops controlling 66-40% of broadleaf weeds to 34% of grasses (Principles of Sustainable Weed Management for Croplands, P.Sullivan, ATTRA, Agronomy System Series, Sept. 2003).
Bio-herbicides
Bio-herbicides are made up of microorganisms that can target very specific weeds. The microbes possess invasive genes that can attack the defense genes of the weeds, thereby killing it. The genes of disease-causing pathogens are very specific. The microbe's genes give it particular techniques to overcome the unique defenses of one type of plant. They instruct the microbe to attack only the one plant species it can successfully infect. The invasion genes of the pathogen have to match the defense genes of the plant. Then the microbe knows it can successfully begin its attack on this one particular type of plant. The matching gene requirement means that a pathogen is harmless to all plants except the one weed identified by the microbe's genetic code.
This selective response makes bio-herbicides very useful because they kill only certain weed plants that interfere with crop productivity without damaging the crop itself. Bio-herbicides can target one weed and leave the rest of the environment unharmed. There are few bio-herbicides on the market today, but since they are very weed specific, more work is destine to produce future bio-herbicides that could be a long lasting control method for production agriculture.
Mulching and Smother Crops
A fast growing crop can smother weeds by out competing them for nutrients and sunlight. An example of a short duration "smother crop" would be oats , buckwheat, and sorghumsudangrass. If possible mulch the soil. It sounds like a lot of work, but in Nebraska wheat straw was applied in early spring at rates from " ton to 3 ton per acre. At the higher rates, weeds were reduced by more than two thirds (Principles of Sustainable Weed Management for Croplands, P.Sullivan, ATTRA, Agronomy System Series, Sept. 2003).
Crop Rotation
Changing crops through rotations limit the buildup of weeds that have a similar growing habit as the crop. Fields of annual crops favor short-lived annual weeds. Rotations change the timing of cultivation, herbicide applications, and fertilizer inputs. This changes the growing conditions from year to year, something that few weed species can easily adapt to.
Intercropping
Intercropping is growing two or more crops together. Having different plant types growing together enhances weed control by increasing competition in tight crop spacing. When one crop is inter-cropped into another standing crop prior to harvest, the planted crop gets off to a weed free start. Intercrop soybeans into standing green wheat, planting date, planting method, and variety must all be well planned in advance. Soybeans can be planted into standing wheat, but less damage occurs to the wheat if the beans are planted in skip rows. You can plug certain drop tubes in the grain drill. Then plant the soybeans with row units spaced at the skip rows in the wheat. The tractor tires will follow the skip rows resulting in little damage to the wheat. Some results indicate that three to six bushels were lost in the beans when intercropped with wheat. This method might be even more risky where growing seasons are shorter, like in the northern mid-west.
Closing Notes
Weeds are a constant problem to agriculture, presented here are a few methods to gain long term control. Balance and re-mineralize the soil. This not only benefits the crops, but also diminishes the weeds. The minerals that they are designed to "pull up" have been added by you! Concentrate on calcium, phosphorous, and sulfur. Try some alternative methods of cover cropping or intercropping, if your program and equipment can be set up for the new method. Alternate your herbicides to avoid developing resistant weeds. Mechanical cultivation with a rotary hoe is effective if conditions are favorable. Try incorporating more than one of these methods to see which system is the most successful at reducing weed pressure. Remember, nature is always trying to overcome everything we do, so we need to out think her and double up on our efforts."
Ed
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magnesium
