Page:Popular Science Monthly Volume 41.djvu/238

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THE POPULAR SCIENCE MONTHLY.

authorized right to the soil. Clover and the best of grasses may be serious weeds, fit subjects to be uprooted by the cultivator or hoe, when growing in a corn-field and injuring the maize crop. If a field is devoted to wheat, it follows that all other plants therein may be weeds, whether it be cockle, red-root, or an oak tree.

There is a possibility of any kind of a plant being a weed, but this thought does not prevent some species always being out of place. For example, there is no function in the economy of the farm garden that the Canada thistle can do as well as many other plants. As a forage plant, or a source of nutritious seeds or beautiful flowers, the pig-weeds are a substantial failure, equaled only by their success in occupying the soil and robbing it of nourishment designed for useful plants. It would puzzle any one to find a proper place for the horse-nettle, now advancing upon the Eastern farmers from the Southwest, and destined to spread its horrid, prickly, worse than worthless branches over our cultured soil. The bur-grass, cockle-burs, burdock, and a long list of congeners are practically universal every-day curses from which all earnest crop-growers wish to be free.

The natural covering of a fertile soil is a growth of vegetation. Upon the broad, open prairie there is a dense coat of grass, while in the Eastern States a heavy growth of trees clothed the virgin soil. So strong is Nature's desire to assert this right that if we allow one of our fields to lie fallow, at the end of the season it will be covered with vegetation. She understands that a bare soil is a wasteful soil, for while it is not producing anything it may lose by leaching much fertility already in its bosom. Every generation of plants inherits the deposits of all previous generations, and in turn should add to the accumulated stock in the soil. By this economical and saving practice of Nature the fertile newly broken grass lands have been made, while the upper soil in the forest has received the enriching accumulations of ages. Man overturns this harmonious system, and by breaking up the sod destroys the very method by which sod is made. He clears away the forest and many of the conditions which favor the growth of trees. It is upon this newly exposed soil that weeds assert their supremacy, and if the hand of man is withheld they will soon weave a garment, in itself unattractive, that clothes the bare earth. Weeds have a thousand ways of doing this to one possessed by cultivated plants. Bring up, if you please, some soil from the bottom of a newly dug well, and if exposed for a season some weeds will have planted colonies upon the bare heaps and vied with each other for the entire possession of the new territory, at the same time gaining in forces for the occupation of any similar place elsewhere.