WEEDS. Every plant which grows in a field other than that of which the seed has been sown by the husbandman is a weed, and, inasmuch as it interferes with the intended crop, should be carefully eradicated. One of the principal uses of summer fellows is to destroy the weeds, which come up in spring, and which would shed their seeds in summer, if they were not destroyed before the seeds ripen. When roots are sown in drills, and carefully hoed, they produce the same cleansing effect, and supersede the fallow ; but iu heavy learns which have been neglected and overrun with weeds, a clean fallow is some times indispensable before any improved method can be adopted. When a farmer enters on lands which are in a foul state, it is the cheapest way, in the end, to sacrifice a crop, and thoroughly purge his fields from weeds, especially those which have vivacious roots, and can not be extirpated by simple ploughing. The mode of doing this must depend on the nature and duration of the weeds, whether their roots are perennial or die off after the plant has borne seed. Annual weeds are most readily extirpated by repeated harrowings, by which the seeds are brought within the influence of the atmosphere, and when they have fairly vegetated may be buried or rooted out, and by ex posing their roots to the influence of a hot sun they are effectually destroyed. The seeds of annual weeds are chiefly brought on the land in the manure which is made in the yards, where the cattle fed on hay or straw swallow the seeds, which pass through them undigested. They are also largely sown by the farmer himself in foul seed which he buys of the seedirman.
One of the great advantages of straw, of artificial manures, and of composts made with human excrements mixed with earths and mineral substances, is that they introduce no weeds into the soil. It is re ported that in Chinn, where the dung of cattle is little used, in com parison with human excrements, no weeds are to be found in the fields; and if more attention were paid to the preservation of this highly-enriching manure, and its proper application to the soil, much expense would be saved which is now unavoidably incurred in destroying weeds. Feeding sheep on roots and corn, while they are folded on the Lend, is another mode of manuring a field without introducing weeds, especially if no hay is given them, except clover-hay of the second crop, which is generally most free from the seeds of weeds.
Perennial such as various thistles, docks, &c., are very difficult to eradicate, as the roots strike deep in the ground. and throw up fresh shoots every year. The most effectual mode of destroying them is to draw them whenever the stern is grown sufficiently to give a good hold of the crown of the root.
Besides the common couch grass, Triticum repeat, which is the pest of farmers on light soils, there are a variety of plants which spread both by the roots and by creeping along the surface. Of this kind are the different sorts of quitches, as they are provincially called, which grow in wet soils. The only mode of extirpating these last is draining and careful tillage. The most effectual means of destroying common couch is by the fork. If, after the ground has been once ploughed, it be forked up carefully in dry weather, and the tufts of couch with their roots be exposed to the hot sun, they may be raked off and burnt.
There arc many other weeds, both in arable and pasture land, which indicate slovenly culture, and which disappear on careful cultivation ; such are briars, furze, broom, and rushes ; the last being is welbknown sign of superabundant moisture, and only to be destroyed by under draining. The whole process of cultivation is a continual struggle between the farmer and the weeds natural to the soil he cultivates. Tho sooner he subdues them entirely, the less will be his subsequent trouble ; and the perfection of agriculture is to produce crops of such vegetables as are useful and profitable, and are suited to the soil which is cultivated, while all others are excluded which might interfere with the crops to be raised. The almost universal adoption of the system of drilling and hoeing the crops, tends greatly to the destruction of useless plants on arable land ; much yet may be done by way of improving the produce of meadows and pastures by the destruction of all noxious and useless plants, and the introduction of those which are nutritious and improve the herbage, whether depastured or made into hay ; and nothing is so likely to do so as a good system of alternate husbandry, where the best grasses are cultivated as carefully as the plants which are immediately applied to the food of man.
Annual and biennial weeds are easily got rid of in comparison with those which have perennial roots, and some of which increase the faster the more the roots are divided. It may be proper to observe that too little attention is paid to the weeds in our upland meadows and pastures, many of which are detrimental when they are eaten for want of better food. Of this kind aro batter-cups, which, where the cows are forced by hunger to eat them, may be very injurious to their health and to the production of good milk. As these plants have strong perennial roots, they take possession of rich moist soils to the exclusion of good grasses. When not very abundant the plants may be weeded out by means of a sharp spud or hoe, and the expense will be well repaid in the quality of the hay or pasture.