To successfully combat weeds, it is necessary to have a good knowledge of their biological characteristics, to be able to determine the number and species composition, on the basis of which to develop a set of measures to clean up fields: agrotechnical, chemical, biological and preventive. The classification of weeds is presented in Table 21.
Young weeds. These include the following biological groups: ephemeral, spring, wintering, winter and biannual. All types of young weeds reproduce by seeds, have a life cycle of no more than two years and die off after the seeds ripen.
Ephemera(short-term) - annual weeds with a very short growing season, capable of producing several generations per season. Their lifespan is 35-45 days. In such a short period they manage to produce mature seeds. The seeds fall off and, under favorable conditions (sufficient moisture and heat), germinate again. This can happen two or three times, that is, two or three generations will occur during the warm period of the year.
A typical representative of the group is woodlice, chickweed (Stellaria media) from the carnation family (Carvophyllaceae) (Fig. 10). This is an annual plant with a creeping, highly branched stem. The leaves are opposite, ovate, the lower ones are petiolate, the upper ones are sessile. The flowers are white, small, the fruit is a capsule. Propagated by seeds and vegetatively. One plant produces up to 15-25 thousand. small, with tubercles on the surface, brown or light brown seeds. Seeds germinate well from a depth of up to 1 cm, from a depth of 5 cm they almost do not germinate, but can remain viable in the soil for 30 years. Seed germination in spring begins at a temperature of 5-7°C, seedlings appear in the second half of May, plants develop quickly and after 35-45 days form mature seeds, which; Once in the soil, they germinate and produce 2-3 generations during the warm period of the year. In the second half of summer, development accelerates. Plants branch strongly in all directions. The stems sprinkled with soil form adventitious roots from the nodes, which, when the internodes break, continue to nourish the severed part, which develops into an independent plant. In September, well-grown plants cover the soil with a continuous carpet. Woodlice is a malicious weed, especially in vegetable crops in gardens and vegetable gardens. The plant is moisture-loving; with prolonged moisture it grows on any soil.
Spring weeds are divided into early and late. The former germinate in early spring and complete development before the maturation of cultivated plants or simultaneously with them, the latter grow when the soil is sufficiently warmed and ripen in the post-harvest period. Spring weeds reproduce only by seeds and produce only one generation per year. Seedlings that appear in autumn die when low temperatures set in.
Spring early– young weeds whose seeds germinate in the spring. The plants bear fruit and die the same year. Their seeds germinate at a depth of 0-5cm, at a soil temperature of 2-3°C. The most widespread representatives are common wild oat, convolvulus buckwheat (povetel), Tatarian buckwheat, gillweed, wild hemp (weed), white pigweed (quinoa) and others.
Common wild oat (Avena fatua) is an annual weed from the Poa (grass) family (Fig. 11). The stems are erect, glabrous or sparsely pubescent, the leaves are lanceolate, pointed, glabrous or ciliated at the base along the edges. The plant has increased bushiness and can form from 3 to 30 fruiting stems. The inflorescence is a spreading panicle that can produce 40-50 seeds, and one bushy plant can produce up to 1000 seeds. The fruit is a membranous caryopsis, enclosed in floral scales, with a long, geniculate at the bottom, strongly twisted awn. The seeds at the base have an angled, twisted spine, which unwinds when soaked and facilitates the penetration of the seed to a considerable depth. At the base of the scales there are also thickenings (callus) with a rim of hairs and a rounded joint in the form of a horseshoe.
Oats have different quality grains (heterocarpy or polymorphism). Depending on their location in the spikelet and panicle, the grains differ from each other in biological characteristics (germination, dormancy period) and external characteristics (size, color, size of awns). There are three tiers in the panicle: upper, middle and lower. Flowering occurs from top to bottom, and the ripening and shedding of grains occurs in the same order. The lower grains, the largest in the spikelet, are harvested along with the grain crops. The middle ones, as well as the small ones, the uppermost ones, crumble and serve as a source of annual renewal of wild oats. The grains of the upper and middle tiers are larger than the grains of the lower ones and have better germination. In the spikelet there is a decrease in germination from large grains (lower flower) to small ones (upper flower).
Figure 10 – Chickweed Figure 11 – Oat
medium (woodlice) ordinary
Wild oats have periods of post-harvest ripening (physiological maturation) and biological dormancy. In this regard, it is necessary to distinguish between the ripeness of seeds and their maturity, i.e. readiness for germination. In some groups of weeds (ephemeral, wintering) both periods coincide, and the seeds are able to germinate immediately after shedding. In wild oats, the caryopses may be ripe in the general sense, but immature biologically; a period of dormancy must be overcome before they germinate. During post-harvest ripening, when wild oat seeds become physiologically mature, they enter a state of deep biological dormancy, which requires time and appropriate conditions to overcome.
Dormancy in wild oats is manifested in the inability of freshly shed grains to germinate, which is due to the peculiarity of the seed coats. The membranes are the flower scales, the fruit-sperm membranes and the insulating layer around the embryo. They have density, hydrophobic properties, and affect the state of rest. The dormant period of wild oats depends on the time of destruction of the seed integument (hulls), usually this process occurs within 5-7 months.
Low (freezing) and high temperatures, soil moisture, and various chemicals that destroy the shell have a great stimulating effect on the emergence of wild oats from dormancy.
Wild oat grains can enter a state of secondary dormancy, which is a protective reaction. If, after undergoing primary dormancy, wild oat grains are in unfavorable conditions (the shells are not destroyed, there is not enough moisture in the soil), then they again go into a dormant state, from which it is difficult to remove them even after creating normal conditions for germination. During secondary dormancy, the grains become viable by the following spring.
Oats are ubiquitous, infest all spring crops and are a virulent weed.
Wild or weed hemp (Cannabis ruderalis) belongs to the hemp family (Fig. 12). An annual plant with a tall branching stem, highly frost and drought resistant. The leaves are large, dissected, with jagged edges. In the upper part of the stem there are paniculate male inflorescences called poskonyu. Female flowers are collected in large spike-shaped inflorescences (maters), located in the axils of the leaves. Ripe
seeds (nuts) easily fall off, ripen earlier than grain crops and clog the soil. The maximum number of seeds germinates in early spring from a depth of up to 5 cm. Seeds that do not germinate in the spring go into deep dormancy and can remain in the soil for several years without losing their germination. Germination is maintained even after passing through the digestive tract of animals. The number of seeds from one plant can reach 2000 pieces. Hemp is widespread and infests all spring crops.
The bifid or gillweed (Galeopsis bifida Boenn), belongs to the family Lamiaceae (Laciaceae). An annual plant with a straight branching stem. The leaves are opposite, rhombic in shape, serrated at the edges. The stem, leaves, and inflorescences are covered with short, stiff hairs. The flowers are collected in whorls of light purple or reddish-violet color. The obovate-shaped nut-shaped fruits easily spill out of the bolls and litter the soil; they germinate only after overwintering in early spring from a depth of up to 5 cm. One plant can produce up to 9 thousand. seeds that remain viable in the soil for up to 7 years. The first gill shoots appear at the end of April. Flowering and ripening occurs from bottom to top
the plant not at the same time, which leads to clogging of the soil and grain during harvesting.
The beautiful pikulnik or gillweed (Galeopsis speciosa) differs from the gillweed in its thinner stem and small flowers. Cistus rosemary or honeydew (Galeopsis ladanum) (Fig. 13), it can be recognized by its pink-red corolla. The seeds of all types of pikulnik are poisonous, but contain a lot of oil suitable for technical purposes. Pikulniki are common in forest-steppe, taiga and sub-taiga zones. They infest spring crops, one of the worst weeds in the region.
Convolvulus knotweed or bindweed buckwheat (Polygonum convolvulus) belongs to the buckwheat family (Fig. 14). This is an annual weed with a curly thin stem that twines around the stems of other plants in the direction from right to left. The leaves are heart-shaped and arrow-shaped, the flowers are small, white, arranged in small bunches of several pieces in the axils of the leaves and at the top of the stem. The inflorescence is an elongated raceme, the fruit-acene is triangular, black, very similar in shape to the fruits of buckwheat. One adult plant under favorable conditions can produce up to 65 thousand. achenes that remain viable in the soil for up to 10 years. Fruiting of the weed is extended and continues until the onset of low temperatures. In autumn, freshly ripened seeds do not germinate; seedlings appear in early spring, from a depth of 5 to 10 cm. From a depth of more than 10-12 cm, a small number of seeds germinate. The root is taproot, with long lateral roots located in the arable soil layer.
Knotweed is widespread everywhere and infests crops of all crops, but especially spring grains. By entwining the stems of cultivated plants, it causes lodging and makes harvesting difficult.
Figure 12 – Hemp Figure 13 – Pikulnik
weed (wild) cistus (lungwort)
Spreading or rough knotweed (Polygonum lapatifolium) is an annual weed with a straight branched stem, leaves are lanceolate, pointed, short-petioled, whitish-tomentose. The flowers are collected in dense clusters at the ends of the branches. The fruit is an achene. The seeds ripen gradually, fall off easily and clog the soil, where they remain for up to 5-6 years. They remain viable after passing through the digestive tract of animals and can therefore be spread in manure. One plant produces up to 7 thousand. seeds with an extended germination period. The seeds germinate in the spring of next year from a depth of 3-4 cm, and die at a depth of 8-10 cm.
The weed is widespread, prefers damp places, and infests all cultivated plants, especially vegetables.
Field mustard (Sinapis arvensis) belongs to the cabbage (cruciferous) family (Brassicaceae) (Fig. 15). The stem is branched, height 30-120cm. The leaves are short with stiff hairs. The fruit is a pod containing up to 20 seeds. The plant can produce up to 32 thousand. seeds that ripen before harvesting fall off and clog the soil, germinate slowly. The optimal seeding depth is 1-3cm. Seeds remain viable in the soil for up to 11 years, and after passing through the digestive tract of animals, they germinate from 5 to 30%. The plant is found in crops of various crops.
Figure 14 – Convolvulus knotweed Figure 15 – Mustard
(buckwheat bindweed) field
White pigweed (Chenopodium album) is a spring annual weed from the goosefoot family (Chenopodiaceae) (Fig. 16). The stem is straight, branched, the leaves are petiolate, ovate-rhombic in shape. The leaves and stems have a characteristic powdery coating, although there are varieties that do not have such a coating. This upper tier weed reaches a height of 150cm. The flowers are small, inconspicuous, collected in paniculate inflorescences. The seeds are round, shiny, and come in three types. Large ones are brown, flat-round, and germinate 2-3 months after ripening. Medium ones – greenish-blackish – germinate in a year to a year and a half. Small - black ones germinate only in the third year after ripening (seed polymorphism).
White pigweed has high seed fertility. A well-developed plant produces up to 7 thousand. seeds In soil, seeds remain viable for up to 38 years. The action of variable temperatures (heat and cold) greatly increases germination.
Seeds that have overwintered on the soil surface germinate in the spring. When planted to a depth of 10 cm or more, they almost do not sprout. Goosefoot seeds have a hard shell and retain high germination rate (up to 55%), even after passing through the gastrointestinal tract of animals. Therefore, in large quantities they end up in manure, with which they can be carried into the field. White pigweed is a distributor of harmful insects - honey beet fly, beet fly, etc. It is widespread everywhere, infesting grains, row crops and vegetables.
In Eastern Siberia, in addition to white goosefoot, there are green, red, spinous, gray, and creeping goosefoot. All these plants are annual weeds, the biology of their development is similar.
Spring late weeds. Late weeds include young plants whose seeds germinate when the soil warms up steadily. The plants bear fruit and die the same year. They are represented by a small group (6-7 species). The main ones are two types of bristlecones (mice), two types of acorn grass, millet, and kurai.
Blue bristle grass (grass grass, millet grass, sable) (Setaria glauca) is a representative of the Poa family (grass) - a late annual spring weed (Fig. 17). The plant of the lower tier is highly bushy, the stems are single or in bunches, rough, up to 60 cm high. Leaves are linear-lanceolate. The root system is fibrous, powerful, deepening up to 1.5 m. The inflorescence is a cylindrical plume, thick, 3 to 12 cm long, spikelets on short stalks. The fruit is a grain. The plant bears fruit in the second half of summer and reproduces by seeds. One well-developed plant can produce up to 14 thousand. seeds Seeds germinate the next year, when the soil warms up to 6-20°C (in the third decade of May), from a depth of 3-18 cm, germination remains up to 30 years. Germination is protracted, and the bristles develop slowly. First, the plant creates a powerful root system, then a vegetative mass. Covering the entire top layer of soil, the root system dries it out. Gray bristlecone has great vitality. Plants that are torn out and thrown onto moist soil are able to take root. The plant infests row crops and spring crops, especially millet and sudanese, and it is impossible to weed out bristleweed in either millet or sudanese, since it is very difficult to distinguish it from these crops by its shoots. Bristlegrass seeds are difficult to separate from small millet grains. Distributed everywhere.
Figure 16 – White pigweed Figure 17 – Gray bristlecone
Green bristle grass (green mice, millet grass) (Setaria viridis L.) belongs to the bluegrass family (Fig. 18). This is a late annual spring weed. The stems, leaves and inflorescences are like those of the gray bristlecone, only the awns of the sultan are green, not gray.
In general, its biology is very similar to the biology of the gray bristlecone, it has greater fertility (up to 7 thousand seeds), the seeds are small, they are better separated from the millet grain, but are almost inseparable from the mogar seeds. They remain viable for more than 4 years.
The common or upturned amaranth (Amarantus retroflexus) belongs to the amaranth family (Amaranthaceae) (Fig. 19). Annual late spring weed. The stem is straight, thick, branched, pubescent, up to half a meter high. The leaves are on long petioles, rhombic-oval in shape, slightly wavy along the edges. The upper leaves are green, the lower ones are reddish in color. The inflorescence is very dense, spike-shaped, with a large number of flowers. Shchiritsa is very prolific; one well-developed plant can produce 1 million. seeds Reproduces only by seeds. They are black, shiny, flat-round, covered with a waterproof shell, and can remain viable in the soil for up to 40 years. Ripening begins in the second half of summer and continues until frost. The plant is thermophilic. In autumn, in the year of ripening, the seeds almost do not germinate; seedlings appear in the spring, in the first or second decade of June, at an air temperature of 23-25°C, from a shallow depth (1-2cm). When seeds are planted to a depth of 5 cm, seedlings do not form. Immature seeds germinate better. The seedlings are red-pink in color, flowering is extended, and the plant can withstand autumn frosts down to -4°C.
Figure 18 – Bristlegrass Figure 19 – Shchiritsa
green ordinary (upturned)
The weed is common in all agricultural zones. It most heavily infests crops of corn, potatoes, and fodder root crops.
Chicken millet or barnyardgrass (Echinochloa crus-galli) is a late spring weed from the Poa family (Fig. 20). The stem is a straw, bare. Leaves are linear. The inflorescence is a panicle. The fruit is a membranous grain. Caryopsis seeds remain viable in the soil for up to 13 years. The fertility of one plant is up to 60 thousand. seeds The seeds in the panicle do not ripen at the same time. Shoots appear in spring, when the soil warms up to 15-16°C. Seeds germinate from a depth of up to 14 cm.
It is found quite widely. Contaminates crops of spring crops.
The main methods of controlling spring weeds (early and late) include:
– cleaning of seed material;
– soil fallowing;
– thorough pre-sowing tillage;
– thickened sowing of winter and spring crops;
– timely care (harrowing of winter and spring crops, inter-row cultivation of row crops);
– stubble peeling of stubble with mandatory autumn tillage after weed germination;
– use of herbicides.
Overwintering weeds. Young weeds end the growing season with early spring shoots in the same year, and with late spring shoots they are able to overwinter in any growth phase. Weeds of this group are few in number, which is explained by the harsh winter in Eastern Siberia. This group of weeds includes blue cornflower, odorless three-fin grass, shepherd's purse, field grass, roofing grass, etc.
Field grass (Thlaspi arvensis L.) is an annual wintering weed from the cabbage family (Brassicaceae) (Fig. 21). The stem is straight, branched, glabrous. Leaves: lower – basal, petiolate, obovate; the upper ones are oblong, sessile. The inflorescence is a raceme. The flowers are small and white. The fruit is a two-locular pod, the seeds are small, ovoid, dark brown in color, furrowed. One plant produces up to 50 thousand. seeds They ripen relatively early and can germinate in spring and autumn, the most vigorous germination is observed from a depth of up to 3 cm. Seeds remain viable in the soil for up to 10 years. The weed has polymorphism; spring and winter forms are found. If the seeds germinate in the spring, the plant develops like a spring crop; if in the fall, it develops like a winter crop. During the autumn period, the seeds go through the stage of vernalization and hardening. The next year, flowering occurs, and then the seeds ripen. In the region, the wintering form is found mainly. The plant overwinters in the rosette stage.
The whole plant, especially the seeds, has an unpleasant garlicky odor, so it is not recommended for feeding to dairy cows, as milk and dairy products acquire this odor.
Figure 20 – Chicken millet Figure 21 – Yarutka
(barnyard grass) field
Shepherd's purse (Capsella bursa-pastoris (L.)) belongs to the cabbage (cruciferous) family. An annual wintering weed with a straight, branched or simple glabrous stem. Leaves: basal – pinnately dissected; the upper ones are stem, whole or serrated; the lower ones are sessile, covered with hairs. The flowers are small, inconspicuous, white or pale pink in color, collected in an inflorescence - a loose raceme. The fruit is a triangular-obverse-heart-shaped pod, flat. The seeds are very small, oval-shaped, flattened, brown or dark yellow. One adult plant can produce up to 270 thousand. seeds that, when shed, fall into the soil and remain viable for up to 35 years. There are spring and wintering forms. Their development cycle is similar to that of the field grass.
In the conditions of Eastern Siberia, the shepherd's purse gives two generations. Seeds of the first generation ripen in July, the second - in early September. The weed overwinters as a rosette or adult plant. Seeds begin to germinate at soil temperatures of 9-14°C, from a depth of up to 3 cm. In the year of ripening, up to 58% of the fallen seeds can germinate; seedlings appear extended, throughout the entire growing season.
Found everywhere. Contaminates grains, vegetables and row crops.
Roofing skerda (Crepis tectorum L.) from the Asteraceae (Asteraceae) family (Fig. 22). The stem is straight, slightly branched. The basal leaves are notched-lobed, and the stem leaves are sessile. The fruit is an achene. The seeds are small, seedlings appear in early September, the plant develops a rosette of 5-10 leaves. The plant overwinters in the rosette phase. It grows from mid-May, blooms from late June to mid-July. Seeds germinate from a depth of up to 4 cm. One plant can produce up to 40 thousand. achenes.
Skerda is found in crops of long-term perennial grasses and spring crops.
Overwintering weeds infest mainly winter and spring crops.
Measures to control wintering weeds:
– timely peeling of stubble followed by autumn plowing;
– spring harrowing of winter and spring crops;
– use of herbicides.
Winter weeds. These are young weeds that require low temperatures of the winter season for their development, regardless of the germination period. In the first year of life, winter dicotyledonous weeds form rosettes of leaves, and cereals bush and in this form overwinter. The following year, after exposure to negative temperatures, the plants shoot out their stems, bear fruit and die.
Rye brome (Bromus secalinus L.) is from the bluegrass family (Fig. 23). The stems are bushy, straight, glabrous, up to 100-120 cm high. Leaves are multi-flowered, glabrous. The fruit, a grain, is tightly enclosed in flower scales. The plant reproduces only by seeds. One plant can produce up to 5 thousand. grains that sprout in 6-10 days. Seeds remain viable for up to 3 years. The grains germinate quickly and amicably from a depth of 3-5cm. Shoots usually appear in the fall along with winter rye, overwinter in the tillering stage and form flowering stems the following summer. The plant matures by the time winter rye is harvested. Rye grains are very similar in shape and size to rye grains and it is not always possible to distinguish them. Rye brome is a specialized weed of winter rye and wheat crops. It reduces grain yields and deteriorates grain quality. A large admixture of it to the grain makes the bread darker, the moisture content of the flour increases, which leads to its mustiness and spoilage.
Figure 22 – Skerda Figure 23 – Bonfire
roofing rye
Great borer (Androsace maxima L.) from the carnation family. Plant up to 15cm high. The stem is arrow-shaped, straight, bare. The leaves are sessile, the basal ones are serrated. The flowers are small, white, collected in inflorescences - a simple umbrella. The fruit is a capsule, the seeds are small. Shoots appear in August. In the summer-autumn period, the plant forms a rosette and a tap root system. The weed overwinters in the form of a rosette. Regrowth begins in spring, at the end of April. Flowering occurs in mid-June, and the seeds ripen in early July. The borer clogs perennial leguminous grasses of long-term use and fallow lands.
Winter weeds most heavily clog winter crops.
Measures to control winter weeds:
– grain cleaning;
– combating excess moisture;
– careful spring care of winter crops (harrowing, fertilizing);
– use of herbicides.
Biennial weeds. Biennial weeds in the first year of life form a rosette of leaves, develop a root system and accumulate reserve nutrients in the roots. In the second year, stems develop, bear fruit and die. If fruiting is disrupted in biennials, they can overwinter a second winter in order to bear fruit normally. Biennial weeds are represented by a large group.
Yellow clover (Melilotus officinalis) belongs to the legume family (Leguminosae) (Fig. 24). The stem is straight, bare, branched, 100-150 cm high. Leaves are alternate, trifoliate, petiolate, with stipules. Flowers are collected in a brush. The fruit is a transversely wrinkled bean that contains one, rarely two, seeds. The weed reproduces by seeds. One plant can produce up to 33 thousand. seeds Seeds require high soil moisture (50-60% of HB) and germination temperature (13-17°C). Seeds remain viable for 20 years. Unlike other biennial weeds, the plant does not form a rosette of leaves in the first year, rather than a flowering stem. In winter it dies off, leaving only the root and a small number of buds on the root collar to overwinter. In the spring, the buds grow, form new stems, which bloom and bear fruit, and die after fruiting.
Sweet clover contaminates spring and winter crops. The weed is very drought-resistant and can grow in saline soils. Seeds remain viable for decades. The plant contains coumarin, which causes illness in animals and gives milk an unpleasant taste.
White sweet clover (Melilotus album) differs from yellow sweet clover in the color of the corolla and the shape of the convolutions on the surface of the bean. Plants infest grain and row crops. Found everywhere.
Common Velcro (Lappula myosotis Moench) from the borage family (Borraginaceae). The stem is straight, branched, 30-60 cm high. Stem leaves are sessile, oblong-linear or lanceolate, basal leaves are oblong-elliptic. The leaves and stems are covered with grayish bristles. The inflorescence is a loose raceme. The flowers are dark blue. The fruit is a nut. The seeds are attached and do not fall off. Once in the soil, they germinate in spring and summer. In the year of germination they form a rosette and a taproot system. The weed overwinters in the form of a rosette. The seeds, after ripening in August, germinate well (up to 75%) from a depth of up to 5 cm. It infests perennial grasses and spring grain crops.
Measures to control biennial weeds:
– cutting the root system with moldboard hoeing machines or plows with flat cutters during fall cultivation;
– systematic mowing of non-arable land.
Perennial weeds. Perennial weeds differ from annual weeds in that they bear fruit several times during their life. They reproduce not only by seeds, but also vegetatively - from the underground parts of the plant: roots, rhizomes, bulbs, etc. Particularly malicious and difficult to eradicate are rhizomatous and root-sucking weeds, which produce shoots and shoots from the underground part of the plant.
Rhizomatous weeds They reproduce by seeds, but mainly vegetatively, that is, by underground stems (rhizomes) covered with modified leaves in the form of scales, under which there are buds in the form of eyes. This group of weeds is quite numerous.
Creeping wheatgrass (Agropyrum repens) belongs to the Poa family (Fig. 25). A herbaceous plant with an erect, smooth, hollow stem up to 100-120 cm high. Leaves are linear. The inflorescence is a two-row spike. The fruit is a grain fused with floral scales. One plant, together with shoots from rhizomes, produces up to 19 thousand. grain Seeds germinate in 10-20 days at a temperature of 20-25°C. They germinate well from a depth of 1cm, but do not germinate from a depth of 7cm. In soil, seeds remain viable for 4-5 years.
Shoots appear throughout the growing season. The plant does not form fruiting stems from seeds; they develop only in the second year. In the first year of life, in the phase of formation of 4-5 true leaves, rhizomes begin to form. They branch strongly, with their ends coming to the surface, forming a stem with reproductive organs. The rhizomes (young ones are white, old ones are yellowish-brown) bear rudimentary leaves and buds that do not have a dormant period. They germinate in the second half of summer, when the best conditions are created for this - an abundance of moisture, heat, food.
Creeping wheatgrass reproduces mainly by rhizomes, which are located horizontally in the soil. A small piece of rhizome with one or more living buds can form a plant with several rhizomes within one season. Even three- to five-centimeter sections of rhizomes bearing 1-2 buds can take root in the soil and produce a new plant.
Thus, the presence of buds located throughout the rhizome makes it possible to preserve the reproductive ability of the vegetative reproduction organs. The bulk of the rhizomes lies at a depth of 10-12 cm. Young and old rhizomes overwinter in the soil. Regrowth is observed in the first ten days of May, the growing season of the weed continues until late autumn. Wheatgrass rhizomes place increased demands on the air content in the soil. Studies have shown that the rhizomes lie deeper the lighter and looser the soil and, conversely, the closer they are to the surface the denser and heavier it is. Whole rhizomes live for 12-13 months and die off after the formation of young rhizomes from them. Unsprouted buds last no more than one year, but germinate intensively when the shoot is damaged. The buds germinate well when the rhizomes are cut into pieces. The smaller the sections of rhizomes formed during soil cultivation, the more fully the buds sprout on them. On sections with two and three buds, about 58% of all buds germinate, with four buds - 44%, and with five - 38%. Double tillage of the soil with disc harrows with well-sharpened discs produces up to 50-60% of wheatgrass rhizome segments from 1 to 10 cm in length and 80% from 1 to 15 cm in length. The deeper the rhizome segments are embedded in the soil, the weaker and more depleted the shoots (awls) appear on the soil surface. The rhizomes of creeping wheatgrass are resistant to temperature influences. Creeping wheatgrass promotes the spread of diseases (rust, ergot) and pests (wireworms, grain fly larvae, grain cutworm).
Wheatgrass is widespread and is a harmful weed of all field crops.
Figure 24 – Yellow clover Figure 25 – Creeping wheatgrass
Chickweed (Agropyrum ramasum Richt) belongs to the bluegrass family and is very similar to wheatgrass. It has a horizontally growing rhizome, from which lateral rhizomes are formed, lying at a depth of 18-22 cm.
Pigweed (finger grass, dog tooth) (Cynodon dactylon Rers) belongs to the Poa family. The stems are geniculate-rising, 40-60 cm long, ending in a palmate inflorescence of 3-8 spikelet branches. The bulk of the rhizomes are located mainly in a layer up to 22 cm. In loose soil, about 40% of rhizomes lie in a layer of 0-10 cm, and in dense soil - about 80%. In the spring, up to 15% of the buds on the rhizomes germinate, and over the entire
growing season – about 35%. When the rhizomes are cut into pieces, up to 90% of all buds become active.
Horsetail (Eguisetum arvense L.) is from the horsetail family (Eguisetaceae). Horsetail is a flowerless plant that reproduces by spores that spill out of sacs that open in the ear and are carried by the wind. The spores ripen in early spring, after which the fruiting stems die. The plant has articulated, hollow stems, with serrated sheaths at the nodes (Fig. 26). Fruiting stems appear early in spring, they are juicy, light brown or reddish, up to 7-25 cm high, have one spikelet at the top, which consists of corymbose leaves sitting on short stalks and carrying sacs with spores on the underside. Barren stems develop later than fruiting stems; they are branched, green, and hard.
Horsetail also reproduces by rhizomes, which from the end of spring produce barren stems that persist until autumn. Rhizomes lie at a depth of up to 1 m. The main number of horizontal rhizomes is located at a depth of 30 to 60 cm. At the nodes of horizontal and vertical rhizomes, nodules with nutrients are formed, ensuring the development of spore-bearing shoots in the spring, and when
When separated from the rhizomes, they can give rise to new plants. Horsetail also develops from sections of horizontal and vertical rhizomes. It grows on moist and acidic soils and is a harmful weed of all agricultural crops.
Measures to combat rhizomatous weeds should be aimed at destroying vegetative reproductive organs.
To combat creeping wheatgrass, the suffocation method is used. This method includes peeling the field with disk implements in a cross direction to the depth of the bulk of the weed rhizomes (10-12 cm) and deep plowing (23-25 cm) with a plow with skimmers after the appearance of wheatgrass seedlings.
On soils infested with deep-rhizomatous weeds, after harvesting, the field is plowed to the depth of the bulk of the underground stems, and then disced and re-plowed with a plow with skimmers to a greater depth. Herbicides are also used.
Root shoot weeds They reproduce by seeds and, mainly, vegetatively, that is, by root shoots from buds located throughout the root system. They are widespread and represented by a large group. The most common weeds in this group include field sow thistle, field thistle, field bindweed, etc. Root shoot weeds reproduce both by suckers (root shoots) and seeds. The roots spread to varying depths up to several meters.
Pink sow thistle or thistle (Cirsium arvense), belongs to the Asteraceae (Asteraceae) family (Fig. 27). The stem is straight, branched, up to 120-130 cm high. The leaves are oblong, with spines along the edges of the leaf blade. The plant is dioecious, that is, on each plant some stems form male inflorescences, others form female ones. The inflorescence is a basket. All flowers are tubular, reddish-purple or pink.
Figure 26 – Horsetail Figure 27 – Sow thistle
field pink (thistle)
The fruit is a whitish or light brown achene with a long stem. One plant produces up to 40 thousand. seeds Seeds in the soil remain viable for up to 7 years. They germinate best at a temperature of 25-30°C.
The plant begins to vegetate from the end of May. Reproductive organs are formed from the buds located on the root collar of the main root. Flowering is observed in the first ten days of July and continues until autumn. Seedlings appear throughout the entire growing season. In the first year of life, the plant develops slowly and forms only a rosette of leaves and a tap root. In the second year, horizontal roots of the first order appear on the vertical root. These roots penetrate vertically into the soil. The plant forms shoots (offshoots) from the thickened parts of the lateral roots and acquires the ability of vegetative propagation. Second-order roots extend from the lateral roots, which again form suckers and new roots. In the first year of life, the main tap root penetrates the soil to a depth of 3.5 m, in the second - 4-5 m, in the third - 7-8 m. A root system of such thickness develops with loose underlying rock.
According to A.I. Maltsev, on 1 m 2 of arable soil layer on the roots of thistle pink, together with the offspring, there can be 17 thousand. vegetative buds. The reproductive power of thistle is so great that even
small parts of its roots with a bud can grow back and produce new plants.
Pink sow thistle removes up to 130-140 kg of nitrogen and 5 times more potassium from the soil than spring grains. It shades cultivated plants, uses soil moisture, and contaminates all agricultural crops.
Yellow sow thistle (field) (Sonchus arvensis L.) belongs to the Asteraceae (Asteraceae) family (Fig. 28). Due to the abundant secretion of milky juice, it is often incorrectly called milkweed. The stem of the plant is straight, hollow, up to 120 cm high. The leaves are entire or pinnately incised, covering the stem. The inflorescence is a basket, the flowers are yellow, ligulate. The fruit is a dark brown achene with a non-shedding pod of silvery-white hairs. Blooms from June to September. Propagated by seeds and root shoots. One plant can form up to 30 thousand. seeds that germinate from a depth of 0–2 cm. From a depth of more than 12 cm, seeds do not germinate, but remain viable for up to 5 years.
Thistle seedlings appear at soil temperatures up to 20°C. In the first year of life, vegetative organs are not formed. The plant forms a rosette of 5–7 leaves and a root system with buds. Regrowth occurs in the spring, at the end of May, and throughout the entire growing season. The emerging seedlings grow very quickly and after 80–90 days they develop long roots with adventitious buds that produce fruiting stems. The root system is less powerful than that of pink thistle and is more superficial in location. The main root deepens to 50cm. Horizontal roots extend from it and lie in the arable layer of soil. Both the main and lateral roots are covered with many buds. From them shoots develop, which form a dense network of roots with vertical roots extending from them. Long horizontal roots are placed at a depth of 8–12 cm. The bulk of the buds (up to 62%) are located on root shoots, at a depth of up to 20 cm. The root suckers are fragile and easily break into pieces, which have greater vitality than that of pink thistle. Even a five-centimeter piece can take root and produce a new plant. Root suckers contain a large amount of lignin, which allows them to overwinter well.
Sow thistle infests all crops, especially spring grain crops. This is a widespread harmful weed in Eastern Siberia.
Field bindweed, or birch (Convolvulus arvensis L.), from the bindweed family (Convolvulacae) is a herbaceous plant with thin climbing stems up to 10 cm long (Fig. 29). The stems twine around the cultivated plant counterclockwise (unlike Convolvulus buckwheat), which leads to severe lodging of grain crops. Leaves are petiolate, alternate, lanceolate or oblong-ovate. The flowers are solitary on long stalks, large, pink or white, with a pleasant scent. The fruit is a two-locular capsule with two valves and contains two seeds in each nest. The seeds are ovoid, triangular, large, rough, dark brown or dark gray. They remain viable in the soil for up to 50 years; they germinate best from a depth of up to 5 cm, but can germinate from a depth of 1 cm. One plant produces up to 1000 seeds. The plant reproduces by seeds and root suckers. The root system is powerful. The main root deepens to 2.5 m. At a depth of 25–40 cm, lateral horizontal roots extend from the main root. The latter, having traveled a certain distance, make an upward bend, where the buds mainly develop, giving rise to new shoots. It is enough to damage or trim the roots of field bindweed so that they produce shoots more abundantly than before.
The seeds have an extended germination period due to the hardness of the shells, which contributes to their long-term preservation in the soil. Germination requires a soil temperature of at least 17°C and soil moisture of 17–18%. The seedlings that appear in May develop quickly and produce taproots and lateral roots. Two-month-old plants are capable of vegetative propagation. By autumn, the roots penetrate to a depth of 150 cm, and generative buds are formed on them. The plant overwinters in the form of a rosette. The resumption of the growing season occurs at the end of May. In the second year of life, lateral horizontal offspring are formed. Flowering occurs in the second year. It is extended and begins in July. The seeds ripen in August – early September. They do not fall off and fall into the harvest mass during harvesting.
Field bindweed infests all agricultural crops.
Figure 28 – Sow thistle Figure 29 – Bindweed
yellow (field) field (birch)
To combat root shoot weeds, the method of depleting the root system is used by systematically cutting off the rosettes that appear on the soil surface. In the fall tillage system, in the fall two plowing operations and deep plowing with a plow with skimmers are carried out. We also apply the depletion method in combination with sowing crops (pea-oat, vetch-oat mixture, mustard, winter rye), which shade the soil and newly regrown plants. Herbicides are used to control root shoot weeds.
Taproot weeds They are distinguished by an elongated and thickened taproot, which goes into the soil to a depth of 1.5-2.0 meters. Plants reproduce by seeds and vegetatively. These include dandelion, common gum (Silene inflate), curly dock, wormwood (Artemisia absinthium), etc.
Common dandelion (Taraxacum vulgare L.) from the Asteraceae family. This weed is rare and litters the edges of fields and roadsides.
Curly sorrel (Rumex crispus L.) is from the buckwheat family. The plant has a straight stem, simple or branched, up to 60 cm high. The lower leaves are petiolate, spear-shaped, the upper leaves are sessile, lanceolate. The flowers are unisexual, small, form a loose panicle, green, pink, violet-red. The plant is dioecious. The fruit is an achene. One plant can produce about 8 thousand. seeds that germinate from a depth of 2–3 cm. Seeds do not germinate from a depth of more than 6 cm. In the first year, the seeds form a rosette of leaves and develop tap and lateral roots, where adventitious buds are formed, which produce shoots the next year, and a flowering stem develops from the rosette. As the shoots grow, the number of stems increases more and more, and the lateral roots lengthen, giving rise to new shoots.
Sorrel infests forage crops. This is one of the most harmful impurities in forage grass seeds, from which it is almost not separated.
This group of weeds infests winter and spring grain crops. Found in gardens and meadows.
Fibrous root weeds They are distinguished by developed thread-like roots, the bundles of which extend directly from the root collar. They reproduce mainly by seeds. These include the great plantain and the caustic buttercup (Ranunculus acer), which is a poisonous plant.
Great plantain (Plantago major L.) from the plantain family (Plantaginaceae) is a herbaceous plant with a simple leafless stem in the form of an arrow, bare, up to 30 cm high. The leaves are collected in a basal rosette, ovate, entire, glabrous, on long petioles. The flowers are small, with a brownish corolla. The inflorescence is a cylindrical, long spike. The fruit is a two-locular capsule and contains up to 30 seeds. The seeds are small, wrinkled, almost matte, brown, with a whitish rounded scar. Plantain propagates mainly by seeds. One plant can produce over 320 thousand. seeds that quickly germinate from a depth of no more than 2–3 cm. Seeds remain viable for up to 7 years. The large plantain has a shortened root, from which adventitious roots extend in a bunch in the form of a brush, going deep into the soil up to 20 cm.
When pruned, a short root may grow back weakly, but the plant can withstand the most severe trampling. It grows near roads and in meadows.
Measures to control root weeds:
– systematic shallow pruning and removal of rosettes in combination with deep fall plowing;
– mowing weeds in meadows and along roadsides.
Bulbous weeds They reproduce mainly vegetatively, using bulbs. This group includes round onions, wild garlic and other plants.
Round onion (Allium rotundum L.) from the lily family (Liliaceae). A herbaceous plant with a straight stem, up to 80 cm high. Leaves are alternate, linear. The flowers are pink or purple. The inflorescence is a spherical umbrella. The fruit is a three-lobed capsule. The seeds are triangular, black, rough, capable of falling into the soil. In the first year of life, the seed produces 1–2 leaves and a small bulb; in the second or third year, a flowering stem is formed. Onions reproduce by both seeds and bulbs. There are 15–50 bulbs on one plant. When cultivating the soil, the mother bulbs disintegrate into baby bulbs and clog the soil, germinating in the fall and producing shoots with 2-3 leaves, similar to shoots of winter rye.
Onions contaminate grain crops, especially winter rye.
Tuberous root weeds They reproduce mainly vegetatively and form thickenings on the roots or underground stems.
Swamp chickweed (Slachys palustris L.) from the Lamiaceae family. The stem of the plant is tetrahedral, straight, branched, up to 100 cm high, covered with hairs. Leaves are opposite, sessile, oblong-lanceolate. The flowers are in a spike-shaped inflorescence, arranged in whorls. The corolla of the flower is dark pink, with reddish spots. The fruit is a nut. One plant produces up to 700 nuts, which are well preserved in the soil. The weed reproduces by seeds and vegetatively. Seed germination begins after overwintering in the soil from a depth of up to 6 cm. Seeds remain viable in the soil for several years. In young plants emerging from seeds, a fibrous root develops in the first year. The lower part, extending from the root collar, turns into rhizomes. During the second year, the rhizomes thicken at the ends in the form of elongated tubers with buds. The tubers are easily torn off, especially when cultivating the soil, and produce new plants. Marsh chickweed mainly reproduces by underground shoots or tubers. The tubers are round, consisting of individual segments with two oppositely located buds. After overwintering in the soil, each tuber produces one shoot. When cultivating the soil, the tubers easily break into individual segments. Each segment is capable of sprouting and dies by autumn. Chistets infest grain crops, meadows and pastures.
creeping weeds They reproduce by tendrils and stem shoots that spread along the ground and take root in nodes. These include creeping buttercup (Ranunculus repens) and others.
Control measures:
– peeling of the field followed by autumn plowing;
– inter-row cultivation of row crops.
Figure 30 – Dodder Figure 31 – Broomrape
Weed control should be based on the principle of controlling the number of weeds, i.e. maintaining the population at a level at which they do not cause economic damage. When weeds have a very high reproduction potential or belong to quarantine or potentially dangerous species, control measures are developed taking into account the threshold of harmfulness. The specific value of harmfulness thresholds should be determined for each agricultural landscape based on data on crop loss, the number of weeds and factors influencing their dynamics.
Security questions
1. The concept of “weeds”.
2. Features of weeds.
3. Classification of weeds.
4. Measures to control spring weeds.
5. Measures to combat root shoot weeds.
Brief Explanation
Weeds are plants that are not cultivated by humans, but litter agricultural land. Weeds are found in fields, meadows and other agricultural areas.
Weeds cause great damage to agriculture, reducing the quantity and quality of crops, facilitating the spread of pests and diseases, and reducing the productivity of agricultural machines. When operating tillage and harvesting units on heavily weeded fields, equipment breakdowns and forced downtime are inevitable. All this reduces labor productivity and increases production costs.
High fertility, non-simultaneous and extended germination of seeds, long-term preservation of seed germination and other biological features not only contribute to the spread of weeds, but also enable them to remain in the fields, despite the applied control measures.
The large number of weeds found in Russia (more than 1,500 species) necessitates combining them into groups based on their most important characteristics. These include: the method of plant nutrition, their life expectancy, the method of reproduction (classification of weeds according to A.I. Maltsev, Table 5).
Among the weeds there are poisonous and harmful ones. These include: field thistle, blue cornflower, field bindweed, convolvulus knotweed, field larkspur, creeping buttercup, wild radish, common rapeseed, horsetail, wormwood, blue bristle grass, and field bristle.
Knowing the characteristics of the growth and development of weeds, you can prevent their appearance in the fields or destroy them. The system of weed control measures consists of: preventive and exterminatory.
Table 5 - Classification of weeds
Preventive control measures include: 1) cleaning of seed, 2) mowing of roads, boundaries, irrigation and drainage canals before weeds bloom, 3) proper storage of manure, 4) purification of irrigation water, 5) steaming or grinding feed containing weed seeds , 6) cleaning containers and machines from weeds, 7) observing weed quarantine, 8) installing grain catchers on harvesting machines, 9) timely and high-quality sowing and harvesting of field crops.
Exterminatory weed control measures include: agrotechnical, chemical, biological. Among the agrotechnical control measures, soil cultivation methods can be mentioned (plowing, harrowing, peeling, cultivation, etc.).
Biological control measures include all methods aimed at better development of cultivated plants and suppression of weeds (crop rotation, timing and methods of sowing, use of fertilizers, liming, etc.), as well as the use of various organisms (fungi, insects, nematodes, etc.) , which can have a detrimental effect on weeds.
Chemical control measures include: the use of herbicides and chemicals that attack weeds. In agriculture, herbicides of organic origin (derivatives of various organic acids and other organic compounds) are mainly used. Herbicides used in agriculture have relative selectivity of action, i.e. inhibit and destroy weeds without damaging agricultural crops within the recommended application rates and timing.
But controlling weeds using only agrotechnical or chemical methods alone does not provide the desired effect. Especially when fields are clogged with such malicious weeds as field bindweed, creeping wheatgrass, which belong to the group of perennials and reproduce mainly vegetatively. Complete and quick clearing of fields from weeds with the least amount of labor and money can be achieved by using a set of techniques with mandatory consideration of the biological characteristics of weeds. This is achieved by combining agricultural techniques with the rational use of chemical and biological plant protection products.
Weed control is a truly pressing issue for every summer resident. Therefore, we decided to immediately consider the topic and find the best ways to combat weeds in the garden. So, advice from professional summer residents on this matter.
There are many contradictions about preparing the soil for planting various crops, fertilizers and their application rates, harvesting and digging. We have repeatedly raised topics about how, to what depth, and how to remove the roots of weeds from the beds and destroy them outside the dacha. But this spring we talked with several professionals whose combined experience spans decades in the dacha business, and what’s most interesting is that facts emerged that really require discussion. So, we present our arguments, and only you decide whether to act using classical methods or use new ideas to destroy plants we don’t need.
The best way to remove weeds remains physical, by digging up the soil and removing roots, tops, and seed pods. Timely cleaning of the soil from the above-ground parts of plants during the warm season, as well as removal of rhizomes during autumn digging or spring work, allows you to minimize the number of weeds in the future. But not everyone welcomes this opinion.
There is really something to think about here, because when we dig up the soil, we raise seeds from the depths to its surface, which, receiving moisture, being ventilated and illuminated by the sun, germinate very quickly. In just a week you will again have to use the glanders in the garden or palisade. But this fact has the right to life only in the summer cottages of those of us who carry out digging without cleaning, so it’s worth thinking about the correctness of the process.
Killing weeds with chemicals: is it worth it?When preparing a certain area for landscaping work, for laying paths or constructing small country houses, it is quite advisable to use chemicals, since many of them effectively burn out roots, kill seeds, and also fight against soil contamination and insects. But remember that this method kills all living things on the site, and if such preparation precedes planting, then nothing may grow on the site. The introduced chemicals remain in the soil for a long time and have a negative effect on garden crops, flowers, and ornamental plants. Therefore, chemical agents should be used to control weeds only in certain cases.
Practical methods are considered to be recent inventions, as well as classical methods of soil preparation and protection, which make it possible to grow plants in an area that is as clear of weeds as possible.
Here it is worth remembering the cultivation of vegetables, berries and herbs on vertical structures, in boxes, greenhouses, under film, in hydroponics, in separate greenhouses, in well-mulched soil, and so on.
Let's try to optimize the work and make sure that not weeds, but cultivated plants grow in the beds. We begin the struggle for a quality harvest.
Today we decided to make a so-called summary of knowledge, put together the best methods of control, and also recall some preventive measures that will allow you not to fight these plants, but simply help them not to grow.
- Let's start with the controversial opinion that we have already discussed above: should we dig up the beds or not? Here it is worth starting from the purpose of the beds, your requirements, and the selected plants. After all, digging is carried out to increase the soil, so that in winter the earth is “cleansed” of infections and insects, to absorb fertilizers into the fertile layer, and so on. But at the same time, on warm days or closer to spring, such digging may not be beneficial. The choice is yours, but the decision must be informed.
- Next, we would like to point out the opinion of many farmers and summer residents who claim that spot fertilization is correct. That is, it is necessary to fertilize the soil immediately before planting, and precisely in those places where planting occurs. In addition, you can further fertilize throughout the season, but not in advance, so as not to stimulate the growth of weeds.
- We consider the correct opinion to be early spring harvesting of the first weeds, drying them outside the dacha area and burning them. But cleaning alone will not be enough; it must become systematic in order not only to reduce the number of weeds, but also to prevent them from returning the moment you give up. Therefore, a sharp shovel and glanders should always be at the ready; no one has canceled this.
- We have long used soil mulching to conserve moisture, but it is also used against weeds. Therefore, it would be a good idea to lay pine needles or straw on a cleaned bed, in a layer of about 7-10 cm. You can also use sawdust or bark passed through a chopper. It’s okay if you do this before planting, this process works well to stop the development of weeds. By the way, the method can also be used in the garden, filling the tree trunks with high-quality mulch.
- Let's remember the black plastic film that many of us already use in beds with zucchini, paprika, tomatoes, and herbs. The film is spread on the bed and covers its entire surface. Only in places where crops emerge, slits should be made for normal growth.
- You can also use ground-blooded plants to destroy weeds, which, with their root system and thick covering, gradually displace uncultivated guests from the garden bed. They can be planted between bushes, near trees, on slopes of garden beds.
- There is also an opinion that cereal plants help well in the fight if they are planted in rows to compact the main plantings. In some cases, the grown greenery is mowed, but sometimes it is given the opportunity to rise to protect the plantings from the burning sun.
- Sometimes it is necessary to adjust the composition of the soil to remove weeds. For example, to get rid of some mosses, use a mixture of river sand with urea and vitriol, in a ratio of 5:1:1, to get rid of woodlice, and also to normalize the acidity of the soil, a well-known mixture - ash and lime - will help.
- It is important to understand what proper watering of plants is. The main thing here is not only knowledge of agricultural technology, but also the use of modern equipment. Drip irrigation, by the way, will help not only save water and reduce costs, but also supply water only to those plants that need to be watered. Weeds will not receive life-giving moisture.
A small set of tips will help you fight weeds in your dacha more effectively, so we recommend that you listen and draw certain conclusions.
A simple way to control weeds (video) Special control measuresIn addition to classic and new methods of destroying and preventing the appearance of weeds, there are additional measures that will help clean the soil and help us grow a crop of cultivated plants, and not a whole bunch of weed tops.
Soil dressing, burningWe said earlier that we do not have a very positive attitude towards chemical tillage of the soil at the dacha, but sometimes there is simply no other choice, especially when weeds are in full swing occupying the beds, and the cultivated plants have not even sprouted. In this case, many recipes are used, but solutions based on potassium or table salt are considered the most effective. Also, a solution of ammonium nitrate can be used. In this case, it is worth remembering that when working with homemade chemicals, or with stronger substances, you need to use not only your own means of protection, but also the manufacturer’s instructions and expert advice. Never start work without protection, never overdose or change recipes yourself, store chemicals in hard-to-reach places, use them only for their intended purpose.
Always use the beds somehow, because where there are no cultivated plants, nothing prevents weeds from developing. Plant grass or flowers if you don't have time for a garden this season, clean the soil and cover it with film if you don't plan to plant anything in the near future. Remember, it is very important to constantly cultivate the soil and avoid long breaks between preparing the bed and planting crops.
While plant seeds are breaking through the soil, young weeds are already showing off on the surface with might and main, so preference should be given to seedlings rather than planting with seeds. Stronger and more viable seedlings will not be so clogged with weeds, especially if you additionally help them in this difficult fight.
Crop rotation and constant rotationRotation of crops is necessary not only because of their replacement in the garden, but also in order to reduce the concentration of weeds. Thanks to the right schemes, you have a chance to seriously reduce the number of unnecessary plants and increase the yield of tomatoes, potatoes, zucchini, eggplants and other garden plants.
These measures will help not only destroy weeds, but also improve the quality of the soil, position it for planting and harvest, and optimize it for certain plants.
High-quality weed control (video)Preparing the soil and controlling weeds are important points in gardening that will help achieve high results and a good harvest. Try to pay maximum attention to your garden and vegetable garden, because any cultivated plant loves care, and will gladly thank the summer resident with a harvest if it receives high-quality protection and care. But weeds are not only harmful.
Reviews and comments(7 ratings, average: 3.79 out of 5)
Oksana Dmitrievna 10/23/2014
Hello! I share my interesting experience of obtaining a rich harvest. I got it interview with Doctor of Agricultural Sciences Mikhail Chursin and inspired by the article, I decided to use his recommendations, and you know, I was right.. All summer we ate cucumbers and tomatoes from the garden, and also prepared zakat for myself and my family for the winter. For those interested, here it is Sveta 12/19/2015
Once I bought poison for the grass, for targeted control. It was a plastic bottle with liquid. There was a foam cap on its neck. It was necessary to squeeze the liquid onto this pad and lubricate the leaves of the weed. After a few days it began to turn yellow and then withered along with the roots. This made it convenient to destroy dandelions and plantains in the lawn. And I never saw such a product in stores, and I don’t even remember what it was called. Maybe someone knows, tell me :)
Alexander 12/22/2015
Looks like a Roundup.
Olesya 05/29/2017
There is one very good way - animals. on the site of the future garden bed you need to make an aviary, and geese, chickens, ducks or a couple of piglets will cope with the weed in a month maximum. and if you leave them there for a season, then for a long time.
Nadezhda 05/31/2017
Weeds are the scourge of my garden life. I have been fighting them for as long as I can remember. I have a plot in the flooded part and after every flood, very interesting plants are found in the beds that we haven’t had since birth. The river brings the seeds. Therefore, we have not been waging a radical fight (for example, with chemistry) for a long time. Poison the soil so that everything happens again in the spring? No. Only the classics with digging and mulching. And yet, somehow I missed and neglected a couple of beds, so the bed with cucumbers overgrown with weeds had the highest yield. The weeds created shade and turned out to be more useful than harmful during that dry summer. But this is an exception, the “war” continues this year!
Weeds– these are plants that litter agricultural land and harm agricultural crops
These are those plants that are not cultivated by humans, but have adapted to grow together with cultivated ones.
Found everywhere - in fields, meadows, pastures (1500 species)
Weeds– these are plants belonging to cultivated species that are not cultivated in this field. For example: rye in wheat, barley in oats, etc.
There are weeds that have adapted to any one crop or group of crops. For example, in winter crops there are mainly cornflower, three-ribs, and rye brome; on millet - mainly bristlecones, chicken millet.
Many weeds infest crops of any crops (wheatgrass, sow thistle, etc.)
Damage from weeds: productivity decreases and product quality deteriorates.
Competition with cultivated plants for light, water, and nutrients.
Worldwide losses from weeds are up to 30-40% of the crop (>100 billion dollars). In heavily weeded areas there may be a 1.5-2 times reduction in yield
The roots of weeds are more developed than those of cultivated plants (in thistle, sweet clover, horsetail, the roots penetrate to a depth of 5.5-7.5 m). Wormwood absorbs water 2 times more than wheat, quinoa - 2-3 times more than barley and corn.
The consumption of nutrients by weeds is much more intense. Pink sow thistle removes 1.5 times more nitrogen from the soil and 2 times more potassium than cereals
Horsetail - consumes NPK 5-7 times more than winter wheat, therefore, with high infestation, most of the fertilizer can be used to “feed” weeds
Field bindweed and bindweed cause lodging of crops.
Pests multiply on weeds and pathogens persist.
Shading from weeds reduces the efficiency of photosynthesis of cultivated plants and reduces the protein content in grain. Product quality is deteriorating. Many weeds and their seeds are poisonous. The seeds of cockle, henbane, and bittergrass make the flour poisonous and unsuitable for food and feed. Horsetail, buttercup, and bittergrass in hay cause poisoning of animals.
Sweet clover and wormwood give an unpleasant taste to milk and butter.
It is difficult to remove clogged crops: the headers break (for example, from coarse sweet clover stems), the threshing drum becomes clogged, threshing becomes difficult, weed stems wrap around the auger, the separating organs of combine harvesters become clogged - breakdowns, increased consumption of fuel and lubricants.
Clogged grain has high humidity, heats up, “burns”, costs for drying and cleaning are required
Up to 30-40% of tillage costs are due to weed control
Some weeds cause allergies (ragwort)
Biological characteristics of weeds
1) Fertility. One cereal plant can produce a maximum of 2000 seeds, while weeds can produce up to 6 million seeds. from 1 plant (white amaranth).
In the arable soil layer there can be up to 3 billion weed seeds/ha.
From 1 m2 of yellow sow thistle there is enough seed to sow 10 hectares
2) Various methods of distribution - by wind, water, animals, with seeds of cultivated plants. The rough surface of weed seeds allows them to attach to the seeds of cultivated plants. Weed seeds are similar in shape and size to seeds of cultivated plants, so they are difficult to separate when sorting.
3) High seed viability. Weed seeds, remaining in the soil, can remain viable for many years.
4) Extended germination. Not all weed seeds germinate in the same year. This makes it difficult to fight them.
5) The ability to reproduce vegetatively. Wheatgrass has rhizomes up to 500 m long per 1 m2, their weight is 2.9 kg/m2; fragments of roots give rise to new plants.
6) Early maturation. The seeds fall off before harvesting begins; unripe seeds remain viable
7) Preservation of seed viability after passing through the intestinal tract of animals. With 20 t/ha of manure, ~350 thousand weed seeds enter the soil
2. Weed classification
a) according to the way of eating
b) by life expectancy
c) according to the method of reproduction
By way of eating:
By life expectancy
Minors :
Ephemera– have a short growing season (45-60 days) and produce several generations per season ( woodlice– in damp areas)
Spring:
A) early– sprout early in the spring, ripen before grain harvesting ( wild oats, white pigweed, wild radish);
b) late– heat-loving, ripen in the post-harvest period ( common aphid, chicken millet, blue and green bristle grass). Late crops (millet, soybeans, corn, sugar beets) become weeded.
Spring weeds germinate in autumn and die in winter.
Wintering– with early germination, the growing season ends (they produce seeds) in the same year; with late shoots. Overwinter in any phase ( shepherd's purse, field grass, blue cornflower, odorless chamomile).
Wintering weeds are more harmful than spring weeds, they are more resistant to herbicides, and their seeds are difficult to separate.
Winter crops– for normal development they need a period of low temperatures ( rye fire, broomstick) – in winter breads
Biennials – development cycle – 2 years ( yellow clover, thistle)
Perennial - living for more than 2 years, reproduce by seeds and vegetatively
Difficult to eradicate, malicious
Pulmonary. They have powerful thread-like roots ( plantain, buttercup) - reproduce by seeds and root segments. Common in gardens, orchards, meadows, near roads and homes.
Creeping. They have creeping and lying stems, reproduce by tendrils and stem shoots ( ivy budra, creeping buttercup).
Tuberous Organs of vegetative reproduction – tubers
(pennyroyal, field mint)
Bulbous. Organ of vegetative reproduction – bulb
(round onion, field onion)
Taproot They reproduce mainly by seeds, but can also be cut from roots ( wormwood, dandelion, horse sorrel, chicory). The roots penetrate up to 2 m, lateral roots extend from them
Rhizomatous– the reproductive organ is underground stems – rhizomes ( creeping wheatgrass, horsetail)
Wheatgrass– rhizomes at a depth of 6-10 cm
Horsetail– rhizomes in several tiers; up to 1 m deep + spores. Rhizomes contain reserve nutrients
The length of wheatgrass rhizomes per 1 hectare can reach several hundred kilometers
The total number of buds on rhizomes is up to 250 million pieces
When the rhizomes are cut into pieces, dormant buds awaken and give rise to new plants.
Root shoots.– The most malicious and difficult to eradicate. Reproduce by seeds and root shoots from buds of the root system
(field or yellow sow thistle, field thistle or pink sow thistle, pink bittersweet (creeping), common cress, field bindweed, common spurge)
Powerful root system with a large supply of nutrients; depth up to 3-5 meters. The bulk of the buds are on roots 6-20 cm deep
3. Weed control measures
1. Agrotechnical
2. Biological
3. Chemical
Agrotechnical control measures:
a) warning;
b) fighter
Preventive measures– aimed at eliminating sources and ways of spreading weeds:
1) cleaning the seed material from weed seeds;
2) cleaning the bunkers of combines, bags, vehicles, grain warehouses, seed cleaning machines;
3) mowing roadsides, ditches, forest belts before weeds bloom, destroying them with herbicides;
4) feeding grain waste to animals, only in steamed or ground form;
5) use only half-rotted manure;
6) compliance with optimal sowing dates and seeding rates (in heavily weeded areas, the seeding rate should be 10-15% higher);
7) timely and high-quality cleaning at a low cut;
8) quarantine for particularly harmful weeds that are absent in the region ( ragwort, pink bitterling, dodder, weedy sunflower)
Destructive agrotechnical measures
Stubble peeling followed by plowing (2-3 weeks) after weed growth;
Harrowing before and after germination;
Inter-row cultivation and hilling;
Vapor treatment;
Combing out wheatgrass rhizomes with spring cultivators (on light soils) - the rhizomes dry out and die
Biological control measures:
Use of specialized insects, fungi, bacteria, viruses
Compliance with crop rotation
Chemical control method
Herbicides(lat.) “ coat of arms" - grass, " cido” – kill
High efficiency and productivity (systemic herbicides - kill roots at a depth of 5-7 m).
Contact herbicides
Continuous herbicides (general exterminators) - destroy all plants. Used on untreated heavily weeded fields or after harvesting (reglon, dalapon, banvel - D)
Herbicides of selective (selective) action. For example: destruction of dicotyledonous weeds in monocotyledonous crops
(2.4 D – amine salt)
Beet herbicides
Anti-oat herbicides
Terms of application of herbicides:
a) Before sowing. Soil herbicides act on weed seedlings (before sowing with incorporation into the soil) by cultivators before emergence
b) After emergence
Processing time
Optimal phase of cultivated plants (specific for each plant).
The temperature should be no more than +25 o C and no less than +15 o C.
During drought, spraying herbicides can harm crops
Integrated weed control system
1) proper soil cultivation
Depletion method (for root suckers)
Strangulation method (for wheatgrass)
2) crop rotation
3) preventive measures
4) timely sowing
5) chemical methods
Weeds include plants that are not cultivated by humans, but infest agricultural land. On the territory of Russia, there are about 2 thousand species of weeds, many of which, in the areas of greatest distribution, cause significant harm to agriculture.
A distinction is made between weeds themselves - wild plants that grow in crops and on uncultivated lands, and weed crops, for example oats in wheat crops, sunflower in grain crops, etc.
Weeds litter fields and natural feeding grounds. Over a long period of existence, some of them have become so adapted to growing among cultivated plants that they are not found outside crops. Such weeds include cockle - a weed of cereal crops, small-fruited camelina, found in flax crops, etc. Other weeds, during their growth in crops, have developed morphological and biological characteristics similar to cultivated plants, such as the shape and size of seeds, timing growth and maturation. They infest crops only of related crops and are called specialized weeds. These, for example, include flax chaff, which infests flax crops, chaff - pea crops, wild oats - oat crops, dodder - clover and alfalfa crops.
4.1. DAMAGE CAUSED BY WEEDS
Weeds, absorbing large amounts of water and nutrients from the soil, inhibit the growth and development of cultivated plants and reduce their productivity. Developing much faster and outpacing cultivated crops in growth, they greatly shade and choke crops, and weeds such as field bindweed and knotweed cause lodging of cultivated plants, weaken the process of photosynthesis and the microbiological activity of the soil. The harmfulness of weeds is determined by their number in crops, as well as their relationship with cultivated plants in the use of environmental factors.
When corn crops are heavily infested with thistle, the crop yield is reduced by 50-72%. When crops are infested with dodder, the yield of alfalfa hay is reduced by 20-30%, and of seeds - by 80-95%.
Weeds also degrade the quality of the crop. In heavily weeded fields, the amount of protein in wheat grain decreases, the amount of oil in oilseed seeds decreases, and the amount of sugar in sugar beet roots decreases.
When harvesting grain crops from weedy fields, the moisture content of the grain increases, which complicates its cleaning and storage. The seeds of many weeds, getting into the grain during threshing and then grinding into flour, deteriorate its quality, and a significant amount of admixture of some weed seeds makes the flour unsuitable for consumption due to the content of organic substances harmful to the human body and animals. Such weeds include cockle, pink mustard, intoxicating chaff, etc. The seeds of the rye brome weed, getting into rye flour, cause rapid hardening of the bread.
Many weeds contribute to the spread of insect pests of agricultural plants, pathogens of fungal diseases (rust, downy mildew, potato cancer).
Weeds make it difficult and complicated to care for crops, harvest crops, and worsen the operating conditions of agricultural machines.
Among weeds there are species that are harmful to humans and animals. Thus, in places where ragweed, ragweed, quinoa, and hemp are widespread, the population often experiences allergic diseases. Poisonous weeds spoil livestock products and cause disease and death in livestock.
A large number of weeds, such as roseate bitterling, caustic buttercup, henbane, horsetail on pasture or in hay, can cause poisoning of animals, and when livestock eats wormwood and tansy along with feed, the milk develops an unpleasant taste.
4.2. BIOLOGICAL FEATURES
To successfully control weeds, it is necessary to know their biological characteristics and methods of spread.
The main features that distinguish weeds from cultivated plants are as follows.
Less demanding in comparison with cultivated plants to environmental conditions. Weeds are more drought-resistant and frost-resistant.
Great fertility. One plant of wild radish produces up to 12 thousand seeds, field sow thistle - up to 19 thousand, field thistle - up to 35 thousand, shepherd's purse - up to 70 thousand, and agaric - up to 500 thousand seeds, while grain bread produces on average about 100 grains per plant.
Ability to reproduce vegetatively. Many perennial weeds reproduce quickly vegetatively. Their underground organs produce a mass of shoots with numerous dormant buds, from which new shoots and independent plants can develop.
Weed seeds can spread over long distances with the help of special devices (floats, clothespins, curls).
The seeds of many weeds remain viable for a long period. There have been cases where the seeds of acorn grass, shepherd's purse, woodlice and some other weeds did not lose their germination for 10-15 years, field mustard - 7 years, grass grass and plantain - 9 years.
Unfriendly weed seedlings. This greatly complicates the fight against them, since germination can take a very long period. For example, one quinoa plant produces three types of seeds. Some germinate in the year of ripening, others - next spring, and others - only in the third year.
Seeds of some types of weeds do not lose their germination when they are in manure, water, silage, or when passing through the intestines of animals and birds. Many weed seeds are brought into fields with melt and irrigation water, when applying fresh manure.
The properties of weeds that make it difficult to control them include the ability to ripen somewhat earlier than the cultivated plants in whose crops they are predominantly found. Thanks to this, by the time crops are harvested, the bulk of weed seeds have time to fall off, and this eliminates the possibility of removing them from the field with the harvest and destroying them when cleaning the seed.
4.3. CLASSIFICATION OF WEEDS
Weeds are classified according to the most important biological characteristics: feeding method, life expectancy, method of reproduction (Table 6).
Young weeds. They reproduce only by seeds, the life cycle is no more than two years, they die off after the seeds ripen. Among them there are several groups.
Ephemeral. During the growing season, with sufficient moisture, plants produce several generations. This group includes the average chickweed (woodlice).
6. Classification of weeds
Spring The growth and development characteristics of these weeds are similar to those of spring crops. They reproduce by seeds. Shoots appear in the spring, the plants produce seeds in the summer or autumn and die in the same year. Depending on the time of germination, spring weeds are divided into early and late.
Early spring. The most numerous group of weeds. They are dangerous for early sowing crops. Weed seeds clog the soil and crops. This group includes: knotweed (convolvulus and birdgrass), field mustard, Tatarian buckwheat, white pigweed, common wild oat, wild radish, barnyard grass (chicken millet), etc.
Late spring. They germinate at temperatures above 10-14 °C. Shoots appear in late spring - early summer. They mainly infest crops that are late in the sowing period and ripen at the same time as them. Late spring weeds include acorn grass, bristle grass, black nightshade, etc.
Overwintering weeds. They finish the growing season with early spring shoots in the same year, and with late shoots they overwinter in any growth phase. This group includes: blue cornflower, field larkspur, shepherd's purse, field grass, tenacious bedstraw, chamomile, field navel, etc.
Winter weeds. For their growth and development they need low winter temperatures. They live in crops of winter crops and perennial grasses. The seeds ripen simultaneously with winter crops. During harvesting, they clog the crop and at the same time fall off onto the soil. This group includes common broom, rye rump, etc.
Biennial weeds. They develop over two growing seasons. When sprouting in spring, in the first year of life they form a rosette of leaves, develop a powerful root system and overwinter in the field. In the spring they quickly begin to grow, bloom, bear fruit and die. This includes omega (hemlock) spotted, henbane, sweet clover, prickly thistle, broadleaf cornflower, etc.
Perennial weeds. The most malicious and difficult to eradicate. After the seeds ripen, the above-ground part dies off, but the organs of vegetative reproduction remain alive in the soil, from which stems, flowers and seeds develop annually.
Fibrous-rooted. Weeds have powerfully developed thread-like roots and reproduce primarily by seeds. They are found in meadows, pastures, along roadsides and in ravines. This group includes buttercup, large plantain, etc.
Taproot. Plants with an elongated and thickened main root and limited vegetative propagation. They reproduce by seeds and partially vegetatively. Distributed everywhere. These include dandelion, wormwood, common chicory, etc.
Creeping. These weeds reproduce primarily by creeping and rooting shoots. They infest grain and industrial crops, forage annual and perennial grasses. The most common are cinquefoil and creeping buttercup.
Rhizomatous. They reproduce primarily vegetatively by underground stems (rhizomes). Large reserves of nutrients are deposited in the rhizome. A small piece of rhizome produces new growth. Weeds grow strongly, forming turf, and choke out cultivated crops.
These include creeping wheatgrass. Distributed everywhere. A very malicious and difficult to eradicate plant. The bulk of the rhizomes (up to 90%) lies in the soil at a depth of 10-12 cm, but the root system is capable of penetrating into the soil in the first year of life by 75 cm, in the second - by 195, in the third - by 250 cm.
Horsetail, etc.
Root shoots. These weeds mainly reproduce by roots that produce offspring. Vertical roots penetrate deep into the soil, horizontal ones extend from them, from the buds of which root shoots are formed. The latter develop most intensively when the root system is cut into pieces and the aboveground organs of plants are destroyed. New growth appears throughout the growing season. These weeds are very difficult to control.
Field thistle. Vertical and horizontal roots bear vegetative buds that grow to a depth of 60-170 cm. In the second and third years of life, the roots, respectively, can reach a length of 4.8 and 7.2 m. The bulk of them (up to 87%) lies in the soil on depth 6-20 cm.
Field sow thistle. Distributed everywhere.
Field bindweed. It is found everywhere (except for the Far North) and infests all crops. A climbing stem up to 2 m long entwines cultivated plants, causing them to lodging. The root system is a powerfully developed, branched vertical and horizontal underground organs, deepening to 4-6 m. The maximum depth of vegetative regeneration is 40 cm. Root segments 1-2 cm long take root in moist soil and produce new shoots.
Creeping bitterweed (pink). Quarantine weed of the southern regions of the country. Seeds and vegetative mass are poisonous to animals. The root system penetrates the soil to a depth of 10 m. The maximum depth of vegetative regeneration is 1.6 m. Sections of roots 10-20 cm long take root in the soil.
