Diversity weed rather large, and it is necessary to classify them in order to study them successfully, as well as to develop measures to combat them. In agricultural practice, two main classification schemes are widely used — agrobiological (the most important biological features of weeds are taken into account: the mode of feeding and reproduction, life expectancy) and the botanical (class, family, species, plant genus) classification of weeds is determined. In this article we will analyze in detail the biological classification of weeds.
- Non-parasitic plants
- Young weeds
- Perennial weeds
- Parasitic plants
- Root
- Stem
Non-parasitic plants
This is a small group of autotrophic weed plants that synthesize organic substances from inorganic in the process of photosynthesis. They have a well-developed aerial part and root system. The classification of non-parasitic weed plants by life expectancy is as follows: juvenile (one- and two-year-old) and perennial.
Young weeds
Young weeds are plants that only breed by seeds, live for no more than two years and die after the formation of seeds. On the basis of life expectancy, they are divided into annuals (according to the characteristics of the life cycle, annual weeds are divided into ephemera, spring, wintering and winter crops) and two-year plants (two vegetation periods are required for full development of the plant from seedling to seed ripening, are divided into real and optional ).
The classification of young weeds is presented in the table:
| Young weeds | |
| Annuals | Biennial |
| Ephemera - plants with a very short growing season (1.5-2 months) can produce several generations in one season. A typical representative of ephemeral weeds is star sprout. Developed in well-treated, moist areas. Its stems are branching, almost creeping, can give adventitious roots. One plant is able to reproduce from 15 to 25 thousand seeds and bears fruit twice a year. | Real - these weed plants are developed strictly according to the cycle peculiar to them: in the first year of life they only accumulate nutrients in the roots, form rosettes and stems, but do not bloom and do not bear fruit,and in the second (after overwintering), fruit-bearing organs are formed (stems with flowers and seeds). Reproduction in the first year of life is seed, and in the second - vegetative. They can overwinter twice and only after that they bloom and bear fruit, but only if the seedlings appear at the end of summer or in the fall and there is not enough nutrient supply in the roots. This type of weed is represented by the following species: жев лип, лекар, clover of medicinal, henbane black. |
| Early spring - sprout in early spring and finish to develop to the collection of cultivated plants or simultaneously with their maturation. Propagated by seeds. This development of weed plants leads to the fact that the soil and seed material is heavily clogged. Representatives of the early spring are the common cockle, wild oats, grunta mountaineer, bird mountaineer, wild radish, white mary, pharmacy smoke and others. | Optional - weeds that can develop both as real biennial weeds, and as annual wintering weeds. It all depends on the specific environmental conditions of growth. |
| Spring late - these weeds germinate with sufficient warming up of the soil, they develop slowly and give seeds together with late spring cultivated plants,their seeds are harvested. Spring late weed plants are propagated by seeds, and their typical representatives are shchirina otkinirovannaya, hedgehog cockerel millet, kurai, ambrosia polynnolistnaya, bristle gray and green, amaranth tilted back. | |
| Winter crops - these weed plants need a dormant period with low temperatures (overwintering), without them their further development is simply impossible. Overwinding occurs in the tillering or rosette phase. The shoots of winter crops appear at the end of summer - in the fall. Grow, as a rule, in crops of perennial and winter grasses. They multiply only by seed. Representatives of winter crops - broomstick, rye fire, shepherd's purse, blue cornflower. | |
| Wintering - they can sprout at the end of the summer and then develop as winter crops, or sprout in early spring and develop as spring. Spring shoots do not form a basal rosette of leaves, and they ripen a little later or simultaneously with grain crops. Late shoots overwinter in any phase of growth. After wintering, they form a rosette of basal leaves, the fast-growing stem and the growing season finish early. Typical representatives are chamomile, odorless, larkspur, common warthoon, field violet, trash can. | |
Perennial weeds
These are plants that have a lifespan of more than two years, they multiply both vegetatively and by seed, and bear fruit many times during life. After the seeds have ripened, in perennial weeds only the above-ground organs die off, and the underground (bulbs, tubers, roots, rhizomes) retain their viability. From the underground organs every year grow new shoots, forming stems, flowers and seeds. If we talk about the method of reproduction, the perennial weeds are divided into two subgroups - poorly propagating vegetatively or not growing at all vegetatively, and propagating mainly vegetatively. Typical representatives of perennial weeds are field bindweed, field mint, garden billow, creeping wheat grass, horsetail, bitter wormwood, dandelion, coltsfoot.
The classification of perennial weeds by biological groups is as follows: root-rootstocks, rhizomatous, root-root, raceme, tuberous and bulbous, urinary follicle and creeping.
Root sprinklers weeds are rather dangerous perennials that are endowed with a pivotal, powerful, deep-rooted root. From the root, the lateral roots, on which there are regeneration buds, diverge radially, mainly growing vegetatively with adventitious buds on the roots and, to a lesser extent, seeds. Representatives of this type of perennials - field sage, field sow thistle, small oxaloaceae, common colza, creeping gorchak.
Rhizomatous Perennial weeds are endowed with underground vegetative reproductive organs (rhizomes), which develop very much, and they are placed in the soil at different depths. The rhizomes are quite tenacious, they contain a supply of nutrients. They reproduce mainly by vegetative adventitious buds on underground stems and, to a lesser extent, by seeds. Representatives are creeping wheatgrass, sage palm, coltsfoot, millennial, alep sorghum.
Rodroot weeds are perennial plants that multiply by seeds and have a tap root system. Sometimes damaged roots can produce vegetative shoots.Root one, thickened, extending deep into the soil, without rudimentary nodes, buds and leaves. The stalks die off annually and are renewed from the buds that are laid on the root collar or in the surface part of the stem. This species of perennial weeds is represented by wormwood, dandelion, curly sorrel, and chicory.
Brushwood - perennial weed plants with a fibrous root system and propagated by seeds. Root powerful wrist. The leaves and stems die off every year, and new ones are born in their place next year. Representatives of the brush root are a caustic buttercup and a large plantain.
Bulbous weeds have a bulb that serves to accumulate organic matter, multiply vegetatively, modified underground thickened stems. The bulb consists of a flat, strongly shortened stem-bottom on which thick scales develop, and in the center of the bulb are kidney-babies. The representative is a round onion.
Tuberous weeds - perennials with tubers, which are the organs of their vegetative propagation. The representative is Chistele marsh.
Creeping - perennial weeds that have above-ground creeping vegetative organs (stems) - something between a flower stem and real underground rhizomes that are intended for vegetative reproduction. In the nodes of the stems there are buds and leaves. Vegetative shoots are formed from the buds, which create their own independent root system. Representatives of creeping weeds are cinquefoil goose, creeping buttercup, ivy-shaped bud.
Parasitic plants
In the process of evolution, parasitic weeds have lost their ability to photosynthesis, and their nutrition occurs at the expense of the host plant by special organs-suckers or hausters. On the stems of plants there are reduced leaves-scales (without chlorophyll), which protect generative shoots in the early stages of their development. Parasitic weeds are propagated by seeds. Parasitic plants are divided into root and stem with respect to the attachment point of the parasite to the host plant.
Root
Parasitic plants with thick simple or branching stems, with scaly leaves of brown color. Flowers are collected in a simple ear. A new young sprout develops from the seeds, it does not immediately rise to the surface of the soil, but remains in it by that time until it finds the necessary root of another host plant into which it is embedded and forms a thickening on it - a growth. Soon the stalks of the parasite make their way from this growth, and the stalks of the cultivated plant gradually dry out. Typical representatives of root parasites are broomrape hemp and sunflower broomrape.
Stem
These are annual and perennial parasitic plants that are completely devoid of their own roots and leaves. Only a filiform stalk ripens from seeds. On the soil surface, he finds the one he needs to feed the host plant and sticks to it until the end of his existence. All parasitic stem plants develop well flowers, fruits and seeds. Representatives of parasitic stem plants - flaxseed dodder, field dodder, clover dodder, and others.
In conclusion, a schematic complete classification of weed plants is presented in the form of a table:
| Weed plants | |||
| Non-parasitic | Parasitic | ||
| Juvenile | Perennial Root sprinklers Rhizomatous Rodroot Brushwood Bulbous Tuberous Creeping | Stem Root | |
| Annuals | Biennial | ||
| Ephemera Early spring Spring late Wintering Winter crops | Real Optional | ||
