Symud i'r prif gynnwys
Cuddio Rhestr Erthyglau

9 erthygl ar y dudalen hon



Weeds: [Being a paper read before the members of the Aberystwyth Paxton Society by Mr D. D. Williams Of the U.C.W.] As a rule every one grows definite crops upon his land, whether farm or garden. The crop produced is composed of plants desired and presaut by special invitation, as well as of other plants not specially invited and not specially sown. These uninvited guests constitute the weed part of the crop, chiefly wild plants and it may be even cultiv- ated plants. Potatoes left unintentionally in the soil may spring up in the succeeding crop, and being uninvited guests there, constitute weeds. In the same way any other plants springing up in a field growing another crop are weeds. Writers on weeds define them variously thus:—"Every plant different from the crop and growing with the crop to its hindrance." Any plant when it is not wanted." "A useless plant "etc. Weeds have been the natural produce of the ground since Adam delved. They are a curse, and their hardihood,powers of propaga- tion, persistence and ubiquity are universally re- cognised. That they can be Eradicated there is no donbf,but only by continuous labour, and the moment the effort is relaxed the small seedlings pop up their heads. The gardener must always be more suc- cessful than the farmer in combating weeds. be- cause his cultivation is more intense and his area smaller. Few gardens are without a weed and cer- tainly no farm, and not only is there no clean garden or farm, but any land would soon become foul if it were not for the free expenditure of the sweat of the brow which is the oldest weed killer. To the culti- vators oflthe soil, leae of life is one of the most im- portant features in the natural history of any weed and a point too often overlooked s ince methods of eradication depend thereon. Weeds may conveni- ently be divided into three classes, viz., annuals, biennials and perennials. Annual weeds are those which finish their business in a single season, abundant flower and seed production is the coo- spicuous feature of these, they grow from seed, flower and produce seeds in one-season-this is the end of one generation of them, e.g., charlock and chiclvwseds. Biennial weeds like annuals yield one crop of seeds, and one only. The business of life is however not confined to one, but distributed over two seasons. During the first year they de- vote themselves to vegetative processes i.e. to the manufacture of seedmaking materials which are stored away in the fleshy tap-root which is always in these, and during the second year this stored-up food together with all the available material within the plant is used up in the produc- tion of seed. Then the plant dies. It is easy to distinguish between the scoring biennial and the annual which lives from hand to mouth, so to speak: only in the former is the tap root especially thickened and fleshy, examples of these are seen in burdock and in our cultivated roots turnips &c. Perennial weeds,-Tlie-e like biennials, make neither flower nor seed during the first season; unlike biennials however they yield repeated crops of seed during succeeding seasons. To accomplish this, they must be provided with a perpetuating and persistent apparatus furnished with buds and called for convenience root stock." The presence of this, is, indeed, a most important botanical peculiarity. From this, new roots, new shoots and seed parts are produced, within it is contained a store of root, stem, leaf. flower, and seed-making foods, and by its activity the plant is propagated and multiplied. Perennials then can multiply in two ways by root- stock and by seed, so that it is most important to be able to distinguish the root-stock and avoid confounding it with the root, e.g. the "creeping root of couch grass and strawberry is not root but root- stock, and the bulbs or knots of oat grass or twitch are root-stocks. Docks, coltsfoot and thistles are all familiar example? of this class of plants. An- other point of importance is the relative amount of seed produced by these three classes of plants. The perennials must not exhaust themselves in seed production, if they do, perennial character is lost. Thus it happens that most pronounced perennial character is always associated with comparatively scant seed production, whereas annuals and biennials waste all their energy in seed production and then die. The behaviour of weeds when cut should be carefully studied in our efforts to eradicate them. If the stem of an annual is severed from the root the plant is killed because the root left behind in the g:ound has neither buds nor apparatus capable of producing them. A biennial may be cut in two ways:-(l). Below the j unction of the "crown" with the tap-root. (2). Above the junction of crown and tap-root. In the first cisea we-ti.1 is killed, but in the second an increased number of stems is devel- oped from the cut crown left in the ground. Special cere is accordingly necessary when cutting is re- sorted to for destruction of biennial weeds. Cutting the perennials does not destroy and kill but serves rather to propagate. Complete removal is the only effectual killer in these cases. When connection between weed and soil is severed, food within the pfcint may be applied to seed maturation hence a»nuals tending naturally to seed, especially if somewhat fleshy," such as common chickweed should be weeded as early as possible. If they have flowered and are allowed to lie on the land or on the dung heap some seed is matured and shed. Though uprooted, biennials and perennials may also mature seed when left lying on the. land or thrown on the dung-heap, Part stored with food should always be specially noticed and specially destroyed; such are usually characterised by thickness and fleshness. A food storing organ • other than seed indicates a lasting plant, thus, spear-thistle is a biennial and has a storing tap root. Dandelions and docks have a storing tap root and root stock (perennials) while couch-grass and coltsfoot have a storing root-stock but no tap root (perennials). The habits of growth of the aerial part of weeds must be mentioned as it has mpqh to do with the resultant injury to crop. This dfiends chiefly upon the length of the stem and the amount of fibrous skeleton contained therein. An elongated stem with abundance of skeleton gives a plant of erect lia-oit. When skeleton is defective the stem either trails along the ground- tb rate habit-as in duckweed and spurrey, or rises to light and air by using a crop plant as a support. The part of the weed which attaches io the support may be, 1 The leaf bearing stem twiners," e.g. small bindweed. 2 Hooked hairs. hook climbers," e.g. cleavers. 3 The teoniwls of the leaves, leaf climbers," e,g. hairy vfpcp.j When the stem does not elongate, the leaves are aggregated together and form a rosette apparently springing from the ground; this con- tracted habit is exemplified by coltsfoot, dandelion and daisies. Erect weans occupy little space and shade crop plants comparatively little. Prostrate and contracted weeds take up much surface room. trl tend to choke the crop plants used for support; removal by weeding can only be accomplished, if at all, at a very early stage. Climbers affect the support plant in much the SaMi fcay as twiners; union between weed and crop plant is however less intimate. The habit of grow h the root-stockshould be well under- stood a"?' it affords an important clue to the extriparion of such weeds. Root-stock gives perennial characters and is accordingly the part to ii1Iy destroyed. Habit, here depends chiefly np^ position with regard to the ground, length ancr nvTection of root-stock. Running habit is possesssf^ifoy weeds with the root-stock on the surface of^the ground, elongated and horizontal, e.g^sil^r^eed and running buttercup. Growing lt«»rm«^ ^rops to overshadow and starve these out is the best remedy as they are always bottom plants. Cteeping habit is possessed by weeds having root-stock under ground and elongated e.g. 4istle, corn-horsetail, coltsfoot and couch grass. These are more difficult to eradicate. Earlv refabVal of the leaves and growing luxuriant rtvershadw and weaken these will be the Bulbous habit means that the root- stock1'is1 spdeiaily short and thick, e.g. bulbous battwcip.. Removal of buibs by mechanical ggqpesges will be effective in these case. Other weeds possess deep rooted habits with the root- stack contracted into a crown at the apex of the fleshy" tap root, (the tap roo-, dies away in the prevail* three) examples of these— docks, ribgrass, anc^Anfl&Itons. The removal of the root*-stock is not sufficient in these cases, for the tap-root will throw up fresh shoots, as commonly seen in dqcks. Weeds may interfere with the crops in gjgj&tsS —1 They diminish Jhe cropped area, imerteiii with 3rnp feeding by utilising the fOOti¡ p;mterial-o,fthe soil and preventing access of ligllt to •ire crop. 3 They interfere with root jjreajthim* ^fjd^prevent access of air to the crop- roots. <.1J)ri: 4 they interfere with crop development by^wniog, climbing, etc. The methods by which weeds are multiplied should not be overlooked and this mav take pkie in two ways :— (1) By propaga- (2)!bv.^eproduction. It is not the root winch i the great propagator, but the stem with its buds or root stock, and occasionally the root it- in f\os. The chief method, however, is -i.e., by means of seed or seed apparatus, and this is the only way by which an- biennials ean'muUiply, A red poppy, for instance, produces 25 flowers, and each flower about 50 seeds. Jfhese, then, should be taken in hand before flowering in a I! f ases, and especially if at all flfshv. ffize of seed is uf considerable im- poj-taace aj!-rega^s ease of extermination. Small small seedlings burial at a moderate depUi secures destruction because the seedlings cannot reach the light and must die from starvation, i,e.. chickweed. Many weeds are sown by means of the seed apparatus which is the seed enabled,~iiv » eel-box. The seed box affords the seeds. Such .weed seeds req uire much water for germination and are more suited to wet and heavy soils, e.g., docks and silver weed. The of composite plants, like dancteljoQj$tc., are provided with feathery ii.u.pqp wjffth /fesna^le them to get blown by the wind to distant areas. Horsetail and ferns are reproduced by :p()re. A field or garden may be- come contaminated .with weeds in several ways, and fyfc r>egreliable, filrnei.- and gardeners clo ¥! 'J!L:rr' not take more precaution against them by exercis- ing greater discrimination in selecting :pure and strong seeds and using clean dung and composts, More contamination is due to these causes than any other, although it is true that many seed are blbwn with the wind and some seeds are sown before the leaves appear, of which coltsfoot is a familiar ex- ample. The system of throwing all sorts of rubbish into the dung heap has gone on long enough and with our improved system of education it is to be hoped that these little matters, which may appear trifling—will receive closer attention; These seeds, etc., pass through the animals indi- gested and get there while others are put there with the rubbish usually piled on. They consti- tute dung impurities and are only of use to the land when thoroughly decayed, then and then only are they dung. That "dung impurities" are stern realities is patent to anyone -the rank: vegeta- tion growing on the heap itself affords conclusivc evidence. It is, therefore, no wonder that weed- ing is ever doing and yet never done." Road scrap- ings again contain the seeds of hedge and road side weeds, e.g., couch, docks and ribgrass. Crops may be seriously damaged by the prematured use of such a manure. In his war against weeds the cultivator of the soil—whether farmer or gardener has to make his land clean and keep it clean. In this he is aided by natural agencies such as frost. which kills tender weeds, and by starving birds whichf devour* many seeds in winter as food Special means are also necessary to get rid of weeds' These in practice as just mentioned are reduced to' 1, Method of making the land clean, 2, Method of keeping the land clean. Land can be made clean by preventing the growth of weeds, and bv the mechanical destruction of those that have grown. Plants vary in hardihood. Environment favourablel to one may be unsuitable to the others. According to the great natural law of "the survival of the fittest weeds may be impeded in their growth and ultimately succumb if the land is so cropped and so treated that the weeds cannot hold their own. Thus many weeds disappear by draining, tilling, manuring, liming, and depasturing. Artificial manures always tend to destroy weeds by producing luxuriant crops which smother them; but nitrate of soda is said to encourage chickweed. Annuals cannot stand depast- uring, which is equivalent to cutting down or leaf removal. Again it is very prejudicial to those perennial weeds with underground root-stocks like couch grass by making the soil too compact. Various mechanical processes again lead to weed destruction, ploughing and digging cut, and bury weeds. The cutting destroys annuals and biennials but not perennials. At the same time seeds are buried, some too deep for germination, other too deep for the seedlings to reach the surface. Hoeing cultivating, rolling and harrowing, all tend to destroy weeds. Cutting leaf, removal, land pulling and gathering are also effective methods. There are two methods of keeping land clean, viz, by prevention of reproduction by seeds or spores and by prevention of multiplication by root stocks. Weeds are prevented from seeding by taking in hand before flowering. A cut or pulled weed may produce seed, if at all fleshy. A fact never to be forgotten when land is to be kept clean. Every- thing put upon the field must be pure, i.e., free from living seeds of weeds the dung, roadscrapings, the compost and the seeds should all be pure. Propagation by root-stock is only to be prevented by its complete removal. Time will not allow us to take any of the weeds separately. So in summing up he should like to impress upon the minds of his hearers the importance of carefully studying the special characters of all weeds, and their duration in determining methods of eradication, and to be alive to the fact that a great many weeds are put in the soil by the cultivator's own hands by- using impure seeds, dung and compost.

Gardening for the Month.

"Lewys Glyndyfi."

1L!<[j A Merionethshire Document<