3. Weeds and the Soil World
TO THOROUGHLY understand what those wild plants listed in the last chapter can do in building and maintaining the fertility of land, one must know a good deal about the surface sheet of our planet that supports vegetation, and which I call the soil world. For many it is not easy to grasp the fact that the soil world is the absolute dictator of organic life, and that includes human life.
A farm -- or a nation -- blest with unlimited fertile soil is resting on the strongest possible foundation. A nation of fertile soils has little to fear from within or without; for such land breeds national contentment. No such nation exists today -- not excepting our own America. And one of the major causes for the weakened condition of the food-producing lands in the United States has been the wanton destruction of Nature's soil-building plants; her valuable weeds.
A soil world at its best is made up of many active factors, all working harmoniously to maintain the soil's richness. These many factors make up the soil-fertility chain, every link of which has its own indispensable job to perform. This chain is Nature in constructive manifestation.
And wonderful is that soil world, small though it may be, that has no missing links in its fertility chain! One does occasionally run onto such a soil world, even today; an area of land under cultivation where the soil is palpitating with life. It is not difficult to recognize such dirt, through touch and sight and smell: the mellow feel, the odor of mold such as one gets when digging into the virgin organic earth on an undisturbed forest floor. Such earth is usually black, and filled with tiny pieces of broken sticks and leaves in various stages of decay.
I had reached the period of older boyhood when I first explored to my complete satisfaction a soil world like that. We were digging a well in a field containing soil about as rich as Nature could make it. This land had been under cultivation only a few years, and the soil, formed and established strictly according to Nature's laws, had not yet been impaired by man.
Three of us were working, but the other two did most of the digging. I was kept busy catching and penning up the interesting bugs and worms we routed out. That soil was so alive I soon had a menagerie. As we drove the circular hole down into the earth, every layer of soil came out clearly. Before long I lost interest in my bug specimens. That dirt had me.
At that time I had already attended college some and had done considerable reading about soil and land management in general -- anything I could get hold of, which wasn't much, compared with today -- but that first layer of soil showed up much more than I had ever found in books. It actually seemed to be in constant motion. It was inert as a whole, yet there were so many individual moving agents in it that the entire surface layer seemed to be shifting about. The surface soil was two-feet deep or thereabouts, and scattered through it and clearly visible were fat earthworms protruding from all parts of the wall -- a sure sign of the soil's richness. Then there were beetles and grubs galore, and millipedes and ants. Other insects were there, too, perpetually on the move, either in earthworm passages or in roadways of their own. It seemed to me that every conceivable size of soil life was in that dirt, from those so small they were almost invisible, up to the large bugs and worms.
And, of course, there was much more in that soil -- much which the boy was not yet able to interpret: the countless millions of bacteria that were playing such a large part in bringing about the normal decay of the organic materials. Valuable molds, too, were certainly there; and minute insects and worms. But all of this had to await later discovery. In those youthful days of adventure and thrilling expectancy, it was still part of the unknown.
To my hands that surface soil was like the softest velvet. Its mellowness was due chiefly to the great abundance of organic matter, of course; to plant materials in many stages of decay, from the threads weaving around and among the soil particles to broken leaves and stems that had been carried into the ground by ants and other insects. Though disturbed, many insects could be seen keeping right on with their work.
But it was in the subsoil where I met my greatest surprises. Since the land was still almost primeval, the well diggers had not expected to encounter a compact region until we had gone down several feet. This field, however, had formerly been a lush meadow that had possessed few weeds to fiberize the lower soil regions. I still remember that original grass area very well -- it had contained dense grass. Consequently we ran into a stiff subsoil around three feet below the surface. The lower soil contained very little fiber -- except in two or three spots which were very conspicuous.
After examining, those spots for a few minutes, I put a stop to all well digging. How well I recall that discovery! The men wanted to know if I had found gold, and I assured them that I had. I had discovered deep-diving weeds actually at work. Despite my limited scientific knowledge, it was a simple matter to explain to the men just what those weed roots were doing. The deep-foraging weeds of course had moved in after the land had been brought under cultivation; they were a part of the new landscape.
There were, needless to say, working roots in the surface soil -- crop roots and weed roots, too. There was a crop of milo on the land at the time. Weeds were few and scattered, for in those pioneer days all weeds were outlaws. But these were a few that had escaped the hoe, and those weeds had all the room they needed for perfect root development.
Immediately I saw what the weed roots were doing in that stiff subsoil, I scrambled up the ladder in order to identify the weeds, and then try to find out which root systems were doing the best job. I remember that I found two or three pigweeds, some nightshades, and a cocklebur or two. It seems there were other weeds there, but I can't now recall what they were. However, the foraging roots of all the weeds were so intermingled I wasn't able to make out which were which. Most of the lateral roots, whether pigweeds or nightshades or cockleburs, were reaching deep into the subsoil. I could distinguish the roots of the milo, many of them accompanying the weed roots right down. For the earthworms and bugs too the weeds had enlarged the feeding zone. And, interestingly, in the areas where there were no weed roots functioning there were only a few milo roots working below the surface soil.
That display of Nature at work was more than just a thriller to me, though I could understand only a part of what I had discovered. It was a whole book of rich knowledge. Here were weeds -- three very common weeds -- enlarging the root zone for cultivated plants, and that in land where there was an abundance of food in the surface soil. That was what seemed most amazing to me: those wild plants didn't need to reach down into those lower soils for their food! Even the well diggers could see that much. Those weeds were feeding deeply because it is natural for many weeds to feed deeply. I did not need further evidence to convince me once and for all that Sol Benson had been right about that pusley up there in his Kansas cornfield. Weeds could enlarge the feeding zone for a cultivated crop!
Years later I was again standing there on that well ladder -- in memory. With more years of study behind me now, I was reading in the well picture what the boy had not been able to grasp: I could see what those deep-diving roots could do in re-establishing a lost surface soil. I could now see deep-diving weeds as the natural agents of soil construction. I had reached the point where I was thoroughly convinced that, without the soil-improving weed link, the soil world would in time lose its normal balance. And at this much later date -- well, our food-producing soils in the United States are woefully out of balance! We are living on unbalanced food products. I am certain that correct weed utilization will go far in re-establishing balance in both situations.
For convenience of study, we usually separate the soil world into two divisions, the surface soil and subsoil, though the demarcation between the two is not always so clear as what we found at the well. The top layer, in which most crops feed, is commonly considered by agriculturists as the whole soil. Such a concept is all right so long as this surface soil is deep, well balanced -- with no links missing from the soil-fertility chain.
It must not be forgotten that an ideal soil is one where there is no gap in the fertility chain. In the surface soil at the well, and in the subsoil where the weeds were operating, fiber was there in abundance and working according to Nature's laws. So was every earthworm, every beetle, down to the tiniest ant. When the laws of Nature operate without hindrance, as they must to construct a balanced soil, the mineral elements are held in the root zone in the organic materials, and then released as the plants need them. Consequently, there is no better evidence that the laws are working efficiently than when there is an abundance of organic matter representing all stages of decay; when the sponge structure is strongly in evidence.
And everyone can learn to be a reliable judge of his own soil. One should form the habit of studying it as one would any other important problem. Look first for the fiber. Pick up a handful of dirt and examine it closely. Fiber must be there to guarantee the sponge structure. The earthworms, healthy and numerous, will also be conspicuous everywhere, as will other worms and insects -- if the fiber content is right. If all these agents are there and healthily at work, your soil world is probably functioning as it should.
But don't be dismayed if you find a stiff clay only, or a soil that for various reasons seems unpromising. Don't be deceived by superficial appearances! Such soils may still be rich in plant-food materials. Those materials are just not in a condition to be absorbed by the plant roots. Give that land a good dose of fiber -- and watch the favorable response you get. Decayed barnyard manure, compost built from manure combined with weeds -- or a few well-directed crops of deep-foraging weeds will in time make things right. To conquer and establish balance in heavy, fiberless soils sometimes calls for a real battle. Give weeds a chance to do the fighting. They won't let you down -- if you direct them.
As in my boyhood weed cove, the organic materials provide heat and food for the earthworms and bacteria, and for all other sorts of soil life that play any part in getting the plant's food materials ready for absorption by the feeding roots. With our surface soils largely gone in so many regions of our country, our chief recourse for re-establishing this surface layer is to reach down into the subsoil and rebuild from that; to put a sponge structure into the stiff clays and loose sands, besides bringing to the surface the food materials hidden there beyond the reach of most cultivated crops. Here is where deep-foraging weeds are able to prove their worth. Any of our deep divers can be made to reach down several feet if they are kept on the job long enough. Not only valuable nitrogen is brought up from those lower soils, but also phosphorus and potassium, two other very essential plant foods. It is also probable that the deeper subsoils contain most of the "trace elements" we are now hearing so much about.
In some soils a hard, practically impervious layer, or hardpan, at times develops between the lower soil region and the surface layer, cutting the subsoil off almost entirely as a feeding zone for even the hardiest plants. In the alkali sections of the west and southwest it is known as alkali hardpan, and ranges all the way from a few inches to several feet in depth. In sections where rain is abundant, the hard layer may occasionally be developed by the farmer himself through plowing the same depth year after year. When, for any reason, the fiber has vanished completely, the soil particles are pushed together into a compact mass.
Many years after my discovery at the well, I made use of that weed lesson in improving an area of alkali land in California. The land had a layer of not overly thick yet impervious hardpan lying between the surface soil and the subsoil. (We did not then have machinery for breaking up hardpan.)
I had made a thorough analysis of the soil below the hardpan, securing many samples with my soil auger, and had found that this lower soil contained only a small percentage of the injurious salts. The soil above the hardpan, on the contrary, was strong with alkali that had risen to the surface a long time back -- before the hardpan had developed to shut off the capillary movement of water upward. This surface soil was too strongly impregnated for practically all cultivated crops, as well as most weeds common in that section. Except during the winter and early spring, when surface evaporation was at its minimum, the surface of the land looked as if it were covered with a light fall of snow. But I was convinced, once the hardpan was penetrated in enough places, those surface salts could be distributed throughout the larger soil zone below. Thus diluted they would not be injurious to crops for, as is often the case in such alkali regions, the lower soil was deep and extraordinarily fertile.
So, with white sweet clover mixed with sour clover and bur clover, together with the weed growth that had somehow survived on the land, we started in to break through the hard layer. The weeds were alfilaria, lupines, poppies, carpetweeds, dandelion -- and a few others that seemed to come from nowhere. Among these were a few that did not have to give up immediately the hot days struck. All weeds except the clovers came up of their own accord.
The first trial crop did not seem to get us anywhere, and the second to a casual observer didn't seem to accomplish any more. But it was the second crop which first revealed that something was happening to the hardpan: a spot of vigorous clover here and there; or a clump of other weeds that continued green beyond the time those weeds on such land normally withered and died. It was natural to conclude that these weeds were feeding below the hardpan. The sweet clover had first broken through, then the other weeds followed close behind, enlarging the crevices with their roots.
Then, by planning our operations to fit in with the best growing seasons, we finally had enough breaks in the hardpan so that the concentration in the surface soil could be taken care of by means of the winter rains assisted by flooding. From then on improvement was easy to see. It took us four years to complete the job, but by the time we were through we had turned what the community had looked upon as a stretch of permanent wasteland into productive land. I had a report on this land only a few months ago. It is now ranked as some of the best land in that part of the state. And the rebuilding work was done largely with weeds; weeds had revived a soil world that had long been chained by alkali.
Next: 4. The Fertility Chain and Soil Balance
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