carried out, but failure often results from negligence during the latter part of the season. Of course, it is possible that seeds may be lying dormant in the soil and make their appearance the next season, but it is taken for granted that all measures to eradicate the plant by preventing the production of seed have been used.

Treatment for Meadows.-The treatment of a meadow necessarily varies according to conditions. If the pasture is very weedy, it is probably due, partly, to overgrazing. In such cases, some of the stock should be removed and the perennial grasses allowed a chance to form a turf. Mowing the weeds once or twice before the seeds are allowed to mature is an excellent plan. Sheep are better weed exterminators than most other animals and will keep many of the noxious weeds down. For some weeds such as buckhorn and wild carrot it may be wise to practice rotation.

Treatment for Grain Fields.-In order that fields be free from weeds, the first essential is to sow clean seed, which will do much to aid in keeping weeds down. Early fall plowing will do much to remove many annual weeds. The common custom in a corn country of sowing wheat on corn stubble, where disking alone is resorted to, is poor practice, because in many cases the corn fields are not clean. It is far better to cut the corn, shock it and then plow. It is not a bad practice in the fall to turn sheep into a corn field to pick out the weeds.

Treatment for Corn Fields.-There is no danger of introducing bad weeds into the soil with seed corn; but bad perennials are scattered by the cultivator, such being the case with quack grass and Johnson grass. Cultivation aggravates the trouble. Where these weeds occur the hoe must follow the cultivator, and this must be kept up during the entire season, hoeing at least once a week. The ground of a corn field should be clean and should be plowed in the fall and again in the spring, being both

disked and harrowed. It will then be ready to be planted in corn, which should be followed by harrowing, and cultivation should then begin as soon as possible. This will keep all of the annual weeds down. By the time the corn is ready to be put by, there will be no weeds. Where quack grass occurs, plowing in the fall should be at least nine or ten inches deep.

Treatment for Garden Weeds.-The annual weeds are easily destroyed by giving thorough cultivation; the perennial are less readily subdued. In the case of nimble will, the "roots" should be exposed to the sun, being killed after a few days of drying. Where quack grass appears, the roots should be removed and the ground given shallow cultivation. As roots appear they should be cut off each week until the close of the season. Occasionally this method is not sufficient; then it is advisable to cover the patch with tarred paper allowing it to remain for six months.

Weeds of the Roadsides.-Many of these weeds are annuals, and by mowing them at the beginning of the flowering season, may be destroyed. If they reappear they should be mowed again, and, if possible, clover and grass should be induced to grow in place of the weeds, where they will undoubtedly thrive. The roadsides on the clay soil of northeastern Iowa contain comparatively few weeds, clover and blue grass occupying the vacant places. The same conditions may be brought about in many other sections of the country. Some states, notably Iowa, have passed a law that roadside weeds must be cut early in the summer, but the law is often violated.

Treatment for Weeds in Yards.-These weeds in most cases are annuals and can easily be destroyed by cutting them off at the time of flowering. Generally, this will suffice. In many cases the seeds are allowed to mature. This should be prevented. Use iron sulphate as a spray. Summer Fallow. The summer fallow is much em

ployed to destroy noxious weeds, especially where

is

difficult to remove them by ordinary cultivation. In the summer fallow the annual weeds will spring up and soon cover the ground. These weeds should be turned under when green, as they will add much to the fertility of the soil. In the case of perennial weeds, it may be necessary to cultivate the field frequently every week, especially in the case of quack grass and horse nettle. It is certain that the summer fallow, with frequent cultivation, will do much to destroy quack grass.

Destruction of Weeds by Chemicals or Herbicides.— For many years, both in this country and in Europe, experiments have been made with various substances looking toward the destruction of fungi by chemical means. For nearly a century, blue vitriol has been used to destroy the spores of smut. It has been known also for many years that certain chemicals, known as herbicides, are valuable for the destruction of weeds. While certain substances, as copper sulphate, for example, are generally recommended for the destruction of fungi, some persons hold that copper, in some of its forms, is injurious to vegetation.

However this may be, it is also true that copper sulphate in various forms, chiefly in the preparation known as bordeaux mixture, is one of the most valuable means that the horticulturist has for combating fungous diseases. It is likewise true that copper sulphate, in some of its forms, when used to kill the smut spores in corn, is more or less injurious to the young plantlet. The injury here retards somewhat the development of the oat or wheat plant, but the plant recovers completely later.

The discovery was made in France about a dozen years. ago that copper sulphate destroyed charlock and mustard. The discovery was accidental, but it led M. Aimé Girard to experiment with various materials in the same line, and since then many experiments with these

herbicides have been made, both in this country and in Europe.

The substances experimented with by M. Girard, were common salt (NaCl), copper sulphate or blue vitriol (CuSO4), iron sulphate (FeSO4), sulphuric acid (H2SO4), sodium nitrate (NaNO3), ammonium sulphate, (NH4)2SO4, potassium sulphide (K2S), basic slag (a mixture of lime phosphate, lime sulphate and some other substances), carbolic acid (C6H5OH), slaked lime, and formaldehyde (CH2O).

Very successful results from the treatment of weeds have been reported by Sommerville, Foulkes, and Voelcker of England, Steglich, Aderhold, Frank, and Heinrich of Germany, and by Girard, Dusserre, Marre, and Heuse of France. In this country, some of the earliest experiments were made in 1897 by Jones and his co-workers, Orton, Morse, and Edson, of the Vermont Agricultural Experiment Station by destroying the hawkweed with common salt. In 1898, an experiment was reported with salt, copper sulphate, kerosene, potassium sulphide, white arsenate of soda, and commercial weed killers.

In 1900, Professor Bolley reported the successful treatment of weeds with copper sulphate and later reported the treatment with equal success of Canada thistle, dandelion, mustard, false flax, worm-seed mustard, corn cockle, shepherd's purse, bindweed, pigweed, kinghead, red river-weed, ragweed, and cocklebur. The rose was not destroyed and leaves of wheat were injured but slightly. The chemicals used were common salt, iron sulphate, and corrosive sublimate. I reported on the effect of carbolic acid on the Canada thistle and of copper sulphate and bordeaux mixture upon two types of mustard. Professor Shutt and Fletcher of the Canada station also reported the successful killing of weeds by herbicides. Wilson of Minnesota reported on the use of some chemicals with quack grass and found kerosene ineffectual; salt, how

ever, being effectual where a sufficient quantity was used. Stone of Cornell University Experiment Station also reported on the successful treatment of certain weeds with copper sulphate, and Moore of Wisconsin reported on the successful treatment of mustard with iron sulphate.

The above gives an idea of the activity along this line. Perhaps we can do no better than to discuss the different chemicals and their action on weeds separately.

Copper Sulphate.-This well-known fungicide has been found effective for the destruction of certain weeds. At the Iowa station it has been found that it destroyed the leaves of burdock, prickly lettuce, common mustard, prostrate pigweed, and goosefoot. It was ineffectual on the leaves of morning glory, and was only slightly effectual on knotgrass. It did not seriously affect the leaves of the foxtails. The copper sulphate, to be effectual, should be applied according to the following formula: 12 lbs. copper sulphate to 52 gallons of water. Spraying should be done in dry weather If it rains immediately after spraying, the spraying should be repeated. Prof. Bolley finds this strength solution is as effective for weeds as 100 pounds of iron sulphate. Professor Howitt of Guelph tells me it is not as effective on mustard as iron sulphate.

Sodium Chlorid.-Salt with some of the weeds experimented on by Bolley gave good results, using it at the rate of one-third barrel for fifty-two gallons of water. It is certain, however, that in many of the perennial weeds this will not be effective. It is certainly not effective in the case of the Canada thistle, quack grass, morning glory and milkweed. Salt has been repeatedly recommended for Canada thistle, but it is only efficacious where large quantities are used and where cattle are allowed to tramp around or utilize the salt thrown around the roots.

Salt has long been recommended to exterminate certain weeds, but Professor Jones of Vermont has shown that while an application of salt may have killed some weeds