Weeds -- Guardians of the Soil

by Joseph A. Cocannouer

2. Weeds and Weeds

"WEED: any plant growing out of place." But who or what is going to decide when a plant is out of place? Mustard going to seed in a field of ripening wheat is certainly out of place, as are weeds that shoot up like a magic green carpet in a field of young sugar beets. But if a plant is strengthening the soil in a given location, according to the laws of Nature, it is not out of place as a fundamental in maintaining land productiveness.

Some plants always seem to be harmful: poison ivy, for instance, and puncture weed and dodder -- and many others. Some can be harmful under certain conditions: pigweeds growing so thickly that they smother both themselves and the domestic crop. Yet, there are situations a plenty where the wild plant is beneficial both to the soil and the domestic crop with which it may be growing. An example of this is pigweeds in a heavy-soil potato field, the weeds spaced far enough apart to permit strong root development without crowding the potatoes; or a combination of pigweeds and lamb's quarter and sow thistles, scattered thinly in a tomato garden or an onion patch -- or even in a cornfield. In such cases the weeds can become valuable "mother weeds" instead of pests.

In southeast Asia there is a wild plant that spreads in tangled growth along the edges of the fields of the native farmers, often creeping far out into the fields. No other wild plants in that region equal this one in spreading vigor. Though the Malays relish the young pods, farmers insist that it is a bad weed, since they must labor to keep it from growing too near their rice and vegetables. That bad weed in Malaya is the fore-parent of our American cowpeas. When I questioned the Malay farmers, they admitted they usually harvested their best crops near where the payaap was growing. Even so, in their estimation it was a harmful weed.

Nature may at times compel us to discover the value of her wild plants; her weeds. In pre-colonial times a group of explorers, after navigating the Amazon for a lengthy period, decided to strike overland to a point towards which they were heading, hoping thereby to save weeks of time. The little band became lost in the jungles.

After many days of wandering, the men finally came upon a seemingly endless growth of vines bearing great quantities of pods filled with plump seeds that looked temptingly edible. But the explorers had already learned jungle caution. After considerable mental struggle, they decided to cast lots in order to choose a victim, who should risk his life by eating these habichuelas. Thus were our most popular beans discovered. Not only are these beans a staple article of food in many parts of the world; they are soil improvers wherever grown.

I call to mind an old woman in south China whom I saw gathering herbaceous wild plants from an almost barren hillside. She was creeping over the rocks and along the steep banks in search of a few wretched weeds that would help make her tiny plots a bit more productive. My guide explained that the old woman was looking for particular kinds of weeds, though he did not know in what way they were particular. I examined the plants after the Chinese woman had brought them to her field. They or their relatives are common in many parts of the world: two or three varieties of thistle, a poppylike plant, a milkweed and a spurge. There were others I did not recognize. The important thing was that those wild plants -- those weeds -- were treasures in that Chinese woman's desperate economy. They fed the soil that must feed her.

Once, while in Europe, traveling through rural Bavaria, I came upon a man who was cutting green weeds from the roadside, apparently to mix with the manure sweepings which he was also gathering from the road. Among his weeds were nettles, lamb's quarter, thistles, mallow, and bindweed. Immediately I wanted to ask questions, but soon found that my college German was of little use. I did manage to get an invitation from the man to visit his neat farm, where I was introduced to a daughter who spoke English.

The German farmer did not consider many of our common weeds harmful in themselves. According to him the harm came from the farmer's failure to control the weeds while they were growing in his fields. The German had a most efficient, simple method of handling barnyard manure. The manure pile was under continuous construction, and as the manure came from the barn or corral or roadway, it was stacked with layers of manure or litter alternating with layers of weeds. By this method of manure-pile building, the farmer explained, the amount of the final fertilizer was markedly increased through the addition of the food-filled weeds; and firefanging of the manure was prevented because the weed layers permitted proper aeration.

I examined one pile of this fertilizer that had already gone through the processing. The stac on the outside looked like any typical manure pile now and then seen in American barnlots. Inside, the pile resembled true compost somewhat, but was really just mellow, well-rotted manure of a superior quality. I have since wondered if this German farmer could not have been employing a fertilizer-making process handed down from the Romans. The Catholic monks in Europe a few centuries back were known to have employed in their very efficient agriculture some of the teachings of Cato, who had lots to say on this subject.

While weed prowling in one of our midwestern states, I came upon a farm woman who had discovered that dry weeds were a real asset in successful gardening. When I first saw the woman she was collecting the weeds in a thick patch near her garden, and then carrying them to her vegetable plot where she had already made a sizable pile.

I crawled through the road fence and introduced myself. "Tell me," I said, "but aren't folks supposed to carry the weeds away from their gardens instead of onto them?"

"I suppose so," she smiled. "I guess I'm a little contrary. Amyway, I like to burn weeds on my vegetable plots. Am I scientific?"

"Decidedly! That's what interests me. May I ask how you happened to discover that weed ashes are especially good for your vegetables?"

"By experimenting, and through the smattering of science I learned in high school and college. One who has nibbled a bit at biology is likely to wish to try out new things with plants -- don't you think?"

(For a fuller discussion of burning, see Chapter 7.)

We then walked out into the patch from which she had been gathering her weeds. There were horseweeds, a lighter growth of lamb's quarter, annual ragweeds, and thistles: the usual farm weeds for that locality. I moved the dirt with my foot and pulled up several of the weeds, most of which revealed strong root systems. I also crumbled some of the fibrous, mellow soil in my hands, and as I did that I was taken back across the years to some of the weed coves I had known in the Cherokee Strip during my boyhood. "With all of man's knowledge of soil science, he is not able to produce a dirt like this," I told her. "And all built by the weeds themselves -- the very same weeds that give you excellent ashes for your vegetables."

She trickled a handful of the soil through her fingers. I could tell that she knew how to appreciate good dirt. "There's one thing I've found out about the soil in here: for some reason it warms up early in the spring. Even when there is frost in the ground elsewhere, I can get warm soil here for my seed boxes."

Her words brought back days in the Indian country when I often tramped the woods and hills with a hunter-naturalist who used to say to me: "If you wanta scare up deer on a blizzardy day, always make for a weed patch that ain't too close to any house. Weed patches are warm even in coldest weather, and the deer know it."

One spring back there in those boyhood days I decided to explore the soil in one of my favorite weed coves, with the hopes of discovering just why it should be warmer than the surrounding land. My patch consisted mostly of giant ragweeds, or horseweeds, bordered by annual common ragweeds and thistles and mint. Being quite young and unlearned in the science of geology, I at first imagined that Mother Nature was sending the heat from the interior of the earth as a special favor to weed coves -- or to the deer and other wildlife that sought warmth in such coves. But the further I dug into the soil of my cove, the more I came to suspect that the horseweeds themselves were responsible for the warmth. How -- I hadn't the slightest idea then.

It was not until many years later that I learned why the deer could depend on weed coves to supply them with warmth on frigid days. The soil in such a cove is close to being an ideal organic soil, composed mostly of plant materials in various stages of decay. And since the bacteria that are largely responsible for transforming the weeds into humus are very active and persistent workers when conditions are favorable for them, as conditions are in a virgin weed cove, a great amount of heat is being continuously generated. In such situations the bacteria keep up their work to a degree, even in winter. This heat is the heat of decay. The woman had discovered this heat in her weed patch, and by using weed ashes on her vegetable plots, she had discovered something else.

Our common weeds, possessing vigorous root systems, go down into the lower soils for a goodly portion of their mineral foods because the minerals which plants require are usually abundant down there. Being strong feeders, the weed roots take up great quantities of the minerals and then bring them up to be stored in the stems and leaves. So, when the weeds were burned on the garden, those minerals were deposited there in the ashes, ready to be taken up easily by the growing vegetables. In this manner -- and in many other ways -- weeds are Nature's true guardians of the soil. They are the farmer's friends when he uses them intelligently; often his friends though he fights them.

Generally, the "weeds" in this book are the same old enemies of my boyhood. They were enemies then because I had not yet learned their worth. Grass is not included herein since grass does not improve the soil in the same way as do these deep foraging weeds; the deep-rooted herbaceous dicots. They are annuals usually, though a few biennials and fewer perennials are also reliable soil builders.

Near the top of the list I place pigweeds, two or three strains, and lamb's quarter, both familiar throughout the country in garden and field. Under most conditions these weeds are beneficial to the crop with which they may be growing. The same can be said for some of the nightshades, the ground cherry, and succulent purslane. Even some of the noxious weeds, like the cocklebur and bull nettle, are soil improvers where the individual plants have ample room for full root development. Then there is the goldenrod, an attractive weed that can be used in fiberizing gravelly soils, or loose sandy soils. On slopes where water erosion has done its work, the persistent yard purslane along with a few other creeping weeds will do a good job at starting land comeback.

It is possible that no soil-improving weeds in the United States excel the ragweeds, particularly the common annual rag, because the latter will establish itself in practically all types of soil. The giant ragweed, often called the horseweed, is also valuable but is more selective in its habitats. And not far behind the ragweeds are the sunflower, the milkweed, two or three thistles, the annual wild morning glory, stinging nettles, annual smartweeds, wild lettuce, and several wild legumes, including sweet clover, the latter the aristocrat of all weeds. All of these wild plants have root systems that forage deeply into the soil and can be employed as mother weeds, or as green manures in a rotation. All of them are soil builders.

Next: 3. Weeds and the Soil World

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