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$100,000,000 annually. All of this could be prevented by applying better methods of cultivation. I have also had a very complete illustration that the removal of weeds. increased the crop greatly in the case of a cornfield which contained a great deal of quack grass. In 1908 this field was cleaned and the present season has been in oats. The treated field contained one-third more oats to the acre than the weedy adjacent fields.

The same has been shown to be true also in some experiments made by Professors Edson and Eaton, for Vermont; they report not only a much larger yield but more fodder. The yield in fodder in some cases was two and one-fourth tons.

Why Weeds Are Injurious.-Weeds are injurious to the farmer because they exhaust the soil of the valuable nutrient material required for the crop. No one succeeds in obtaining a good yield of corn, wheat or other cultivated crop where weeds are allowed undisputed sway. The difference can be noticed at once when one farmer keeps his field clean and his neighbor allows weeds to grow. The one may obtain 60-70 bushels per acre from his field, while the latter has but thirty-five. Surely it does not pay to allow weeds to grow on land worth seventy-five or eighty or one hundred dollars per acre. Prof. H. L. Bolley says: "It is quite evident that if one sows enough seed wheat or other cereal to give a proper planting for the largest possible yield of grain, that it will not be possible to obtain this fullest yield if the ground already contains countless seeds of many sorts of weeds. One of the worst fallacies that is known to farming is indicated at this point. Almost every farmer knows some sort of weed which he thinks, or at least says he thinks, is of no harm to the wheat crop. For example, many persons have said French weed does not hurt the wheat crop, and many persist in saying that common mustard does not reduce the yield of wheat or

oats. One might thus make a list covering practically all kinds of weeds. A peculiar feature is observed, however. It is never said of the weedy plant that it is not injurious to crop yield until it becomes so abundant on the man's farm or in a particular neighborhood that it seems practically impossible for the farmers concerned to get rid of it. It is then tolerated and finally the evil effects condoned in the manner indicated.

"A growing crop or plant gets its food material by absorbing the soil solutions. The excess of water is evaporated by the leaves. No more water is taken up by the crop than is evaporated by the leaves.

"If the leafy growth of a cereal crop is not normal in extent, but weakened and insufficient because of crowding out by other plants which exclude light and proper air supply, then the rate of water evaporation from the leaves, and consequent absorption from the soil, will be greatly diminished. Thus even if there is an abundance of water and food materials, the cereal crop does not get its just supply if it is unduly crowded by other weedy growths. When drouthy times occur the weeds are able to do their greatest destruction."

"We have made many examinations of this question and have almost invariably come to the conclusion from our studies that where a normal stand of grain or other crop is upon the ground the yield of the crop will be found to be reduced in approximately direct proportion to the weeds which are developed on the ground during the growth season. This assumes that the water and soil conditions are normal. If, however, such conditions. are abnormal during the maturing period of the crop, the loss in yield occasioned is often very much greater than that indicated. This is especially true if a drouthy time occurs just while the grain is filling."

A part of the depletion of our soils must be attributed to the growth of weeds on the farms, some weeds being

much more exhaustive than others. We need conservation of the fertility of soil by preventing the growth of weeds.

Another reason why weeds are injurious, especially to young crops, is because they crowd out the useful plants. This is particularly true of such weeds as nut grass in our cornfields, mustard, at times, in oats and flax fields.

Some weeds are injurious because they are poisonous to man and the lower animals. Cowbane and water parsnip are powerfully poisonous; the seed of corn cockle poisons grain; squirrel-tail, wild barley and awned brome grass are injurious because the awns work into the gums, causing serious inflammation and consequent loss of teeth.

Weeds are injurious because, on account of their presence, it is much harder to remove the crop. It is much more difficult to harvest wheat where Russian thistle is present. It is much more difficult to harvest small grain where wild buckwheat and morning glory occur. spines of rose stems often inflict injury to persons obliged to shock and stack grain.

The

Weeds are frequently injurious because they harbor fungi. The well-known club root of cabbage occurs on mustard and on other allied plants; also on common pepper grass, and Dr. Halsted has shown that this is a frequent source of the disease on cabbage. Rust is often found on squirreltail grass. Professor Bolley says: "Weeds, because of their rank foliage, tend to keep the atmosphere cooler and moist, keeping the stems and foliage of the grain plants befogged with dew and other moisture when ordinarily it would remain comparatively dry. This accounts for the rust getting a stronger infection in the wheat fields than upon a clean, open crop. Later, when the grain is strongly attacked by the rust fungus and is in great need of water to keep up the supply which is being evaporated from the straw or stems where the rust has

broken them open, the weeds cause the greatest damage by robbing the soil of the necessary moisture; the grain must, therefore, be shriveled in maturing."

Root rot of cotton is abundant on many plants, but especially so on members of the mallow family, as sida and shoofly. In this way this fungus is transmitted to cotton, sweet potato and the apple tree.

It is not unusual for owners of elevators to dock wheat containing a great deal of any weed seed proving difficult of removal, although the wheat itself might be graded No. 1. The seed of kinghead cannot be taken out by the proper elevator machinery, hence the elevator men at Duluth decided that after August 1, 1910, they would dock wheat that contained a great deal of kinghead. In the grain-growing states of the Dakotas and Minnesota, there is considerable dockage on account of weed seeds and the same is also true of the Canadian Northwest provinces. The loss to the farmers must amount to millions of dollars a year.

Certain weeds are injurious because when they become mixed with small grain, they must be removed before it can be sold as "A" wheat or oats, although all other conditions may be fulfilled. Where there is much mustard in oats, the grain will not bring so good a price as clean oats do, and the same may be said of wheat containing cockle, vetch, cow herb, garlic, sweet clover,

etc.

Some Weeds Are Useful.-Weeds may in some cases serve some useful purpose. Digitalis is obtained from foxglove; hyoscyamine from black henbane; daturin from Jimson weed. Many weeds, like tansy and hemp. have medicinal properties. Others serve culinary purposes, as when the roots of chicory are used as a substitute for coffee. Lamb's quarter, dandelion and the young shoots of pokeweed are used as spring greens. The roots of tanweed or shoestring (Muhlenberg's

smartweed) were formerly used in the process of tanning. The tubers of the cultivated artichoke are used as food, and the Indians used the wild artichoke in the same manner. The meadow sunflower was another plant that furnished food to the Indians. Sweet clover is an excellent bee plant, a good forage plant and a satisfactory soil renovator. Dr. Millspaugh states that many weeds possess good fertilizing properties. Weeds are of value if, when added to the soil, they give looseness and furnish a plant covering. Professor Bolley says: "The plant growths, consisting largely of common weeds and grasses which at once occupy idle land, keep it from becoming a useless dust bed and finally a mass of shifting sand. In shiftless and improper crop rotation the weeds and grasses which intervene may be looked upon as savers of soil quality. Those with tap roots bring up the substances from a greater depth than some of the ordinary crops; and by their varied characters introduce essential elements of proper crop rotation and in other ways reinstate the humus of the soil, which, by poor cropping methods, is often quickly removed. Under certain conditions large crops of weedy growths plowed under by shiftless farmers produce conditions of green manuring which, while not of the best type, are essential in preventing an entire loss of humus."