Dangerous phenomenon of the cold season
The success of cultivation of agricultural plants is determined by the agrometeorological and agroclimatic conditions not only of the growing season, but also the conditions that develop during wintering.
In the winter period in Russia, various dangerous phenomena for winter, perennial herbs and tree plants are observed. In one area or another with significant intensity, they damage plants or even destroy them.
The agroclimatic study of the winter period gives an idea of what dangerous phenomena are observed in this area, what is their frequency and intensity. This information is used to solve problems of rational placement of plants in the territory when developing methods of protecting plants from these phenomena.
The degree of damage to wintering crops with dangerous phenomena and, most importantly, low temperatures is different in different years and in different winter periods of the year. This is due to the condition of the plants and their hardiness, which vary greatly during the winter and from year to year. Therefore, before it dissects the dangerous phenomena itself, it is necessary to consider at least briefly the physical and biological basis of winter hardiness of plants.
Hardiness of Plants
Hardiness of plants is a biological property of wintering plants to withstand the complex of undesirable weather conditions in cold weather. II Tumanov emphasizes that hardiness is mobile, unstable and not always characteristic, even for the same plant trait. It is due to the direction of the physiological and biochemical processes that occur in plants during the cold season. Hardiness as a quality develops in plants as a result of the hardening process in late autumn.
According to the theory of I.I. The Tumanov process of hardening of plants requires a certain complex of external conditions and takes place in two stages, which precede a slowdown in growth and the transition of plants to a state of dormancy. Continuation of growth and transition to a state of dormancy – the necessary conditions for the passage of the first phase of hardening. Favorable conditions for passing the first phase of hardening of winter plants are sunny and cool weather (daily temperature 10. 15 ° C, at night – about 2 ° C). Under such conditions, sugar forms are formed due to photosynthesis, and the temperature at night significantly reduces their respiratory consumption and growth processes. As a result, inhibits the formation of intracellular ice. Under natural conditions, the optimal period of the first phase of hardening of winter cereals is up to 12-14 days. (According to other sources – 5. 9 days), wood – 30 days. During this period, the number of sugars in plants increases to 70% per dry matter or up to 22% per wet mass, i.e. close to the content of sugars in root crops of the best varieties of sugar beet. After the first phase of hardening, the winter plants easily withstood a decrease in the temperature of the soil in the depths of the node of the node t o-12 ° C.
The second phase of plant hardening leads successfully at an average daily air temperatur e-2. -5 ° C with a gradual acceptance i n-10 ° C and lower dry weather and with a little soil ceck. It can also take place in the absence of light if snow cover is installed in the fields.
During the second phase of hardening, the winter hardness of plants takes on the bound to the tissue due to the dehydration of fabrics, the transition of free water to bound, which reduces the risk of intracellular ice formation and an increase in the concentration of the cell juice. Strength in plant cells is partly transformed into sugar, their reserves increase. According to Tumanov, the duration of the second phase is small – 3rd 5 days. The largest amount of sugar in plants is determined during the second phase of hardening.
It should be noted that the literature indicates that wood plants with a sufficient amount of sugar in the tissues occur immediately.
The hardening effect cannot appear for any reason (drought, late sowing, plants, etc.), a delay in plant development has occurred. So if the growth processes in fruit plants had no time in summer due to the summer village, this can lead to the death of plants in winter. The fact is that the drought that suspends growth in summer does not allow them to complete it by autumn. At the same time, a discharge of different substances from the abov e-ground organs to underground wintering (root systems, rhizomes, onions, tubers) should occur during hardening. For the same reason, the hardening of herbaceous and woody plants deteriorates excessive nitrogen nutrition and extends the growth period until late autumn. As a result, plants cannot be able to undergo hardening processes and to die with small frosts themselves.
The winter hardness of cultures also depends on the humidity of the soil in the autumn period of the vegetation period. The winter cultures therefore receive greater frost resistance if the soil moisture is 50% during hardening. 70% complete moisture. Excessive moisture (more than 80% of the full moisture capacity) has a negative impact on the hardening of the winter in winter. And the winter hardness of fruit trees also depends on factors such as the amount of harvesting, the time of maturation of the fruits, the time of the falling leaves, the autumn frosts. For example, the leaves that are not fully protected by early autumn frosts can accumulate so that plants cannot develop sufficient winter hardening and are also damaged by weak frosts.
After completing the full hardening, the winter hardness of plants and in particular frost resistance increases significantly. Frost resistance understands the ability of plants to resist low negative temperatures in winter. Thus, the critical temperature of the winter wheat from mediu m-sized winter varieties falls t o-18 ° C and clearly visibl e-20 ° C and below. The critical temperature of freezing rye i s-22. -24 ° C and underneath winter barley and Dignul a-13. -16 ° C, Alfalf a-17. -19 ° C. The crowns of many wood plants can tolerate frosts o n-45. -50 ° C, with the exception of a lemon that does not tolerate the air temperatures belo w-8 ° C.
The stability of plants compared to frost changes: at the beginning of winter, the frost resistance of agricultural plants is relatively low, until the middle of winter it increases to maximum values and decreases by spring.
Bod temperatures (at a depth of 3 cm) that damage the winter wheat under different hardening conditions, ° C
This threatens plants in the garden at the end of winter and early spring: 5 driven
Even the most ongoing plants that have survived the long winter cannot withstand insidious harvest weather. Sudden temperatures during the day and at night, bright sun and snow with ice cream can cause great damage. But in order to save the garden and finished with unwanted conditions, it may be enough to know some nuances.
Frost and sun
The most dangerous time for plants from the end of winter to the beginning of spring. The daily air temperature is over zero, which causes the movement of juice in plants, and at night the temperature drops below zero. Due to such differences, the juice, which moved along the plant, freezes the bark of the tree and tears and tears.
Morozoboins stay on it if they are not wrapped in a T time in time to prevent drainage, the tree can die. With the insertion of the thaw, so that the plant does not die from an infection, the damaged place is cleaned in healthy tissue, treated with a 1 %solution of copper sulfate and covered with garden variation. The processed place should be connected to a sack linen or a film.
Such frosts are also dangerous for kidneys and ovaries, which can lead to their death and a complete loss of harvest.
The most endangered plants for such disasters are considered:
- Heat heating plants;
- Young plants with an underdeveloped root system and low immunity;
- Plants transplanted from autumn in which the root system was damaged;
- Plants that grow in places with excessive moisture;
- Plants with fertilizers that have been introduced under them are too late.
To prevent the bark from breaking, you should beat the trees in autumn or cover them with plywood or straw from the south side of light sunlight in spring to slow down the process of juic movement. If there is no snow, it is better to isolate the plants with a clamping binding. And such a problem that the roots should remove after melting snow should be removed and simply sprinkle with the earth.
The most susceptible to this catastrophe are needle plants, as they also evaporate moisture in winter and cannot get them out of frozen soil. This problem can occur with excess soil salinization.
Due to the lack of moisture, the needles become yellow, drill and can even crumble if they do not protect the plant in time.
Combating this problem is worth a ample autumn gas system. In winter you can also water with the watering of the water, only with the condition that the air temperature is above zero.
snow and ice
Beasts of young trees can break under the weight of the wet snow, and if the snow melting is too fast, frozen soil cannot adversely absorb the moisture and the plant is flooded.
If the flood lasts long enough, the plant can die of lack of oxygen, the lawn is particularly susceptible to this phenomenon. It can also die from the ice crust, which is formed when the snow is melted and freezing is sharp. To avoid this, you have to monitor the weather and regularly destroy the ice crust so that the plants do not “suffocate”.
Plants that are exposed to the effects of the north wind, which increases the effect of frost and dries the air, must be planted in quiet areas that are protected from their direct exposure. If you live in the zone of constant winds of this kind, an open fence can serve as protection because it is scattered the power of the wind.
A whole fence will reflect and improve his action in another part of the garden. If you are against the fence, you can plant a hedge of conifers on the east side of the garden.
Few people think that this can harm the plants. But in spring the salt loosens with the melting of snow and penetrates into the ground.
The soil moisture is not only salty and not accessible to plants, salt also acts like poison, poisons and kills plants.
A good gardener monitors the weather and takes measures to protect his garden after the start of negative environmental conditions.