In article there is a speech about what harm put the severe winters to long-term plantings.
Also the technique of definition of a damage rate is given in article by a frost of fruit and berry crops. The recommendations promoting restoration of plants after frosts are besides made.
Development of highly effective gardening often becomes complicated a number of natural factors among which the most serious are periodically repeating severe winters doing big harm to gardens, to fruit nurseries, and also plantings of berry cultures.
Frost resistance of fruit-trees depends on age, conditions of cultivation and a physiological condition of plants. It is changeable during the different periods of vegetation and rest. In most cases trees are damaged by frosts partially, the full death of an elevated part of plants to the line of snow cover is quite often observed. The most dangerous is damage of cages of a cambial zone of a trunk, branches and roots.
At negative temperatures water from cages passes in mezhkletnik where turns into ice. Because of dehydration and folding of colloids of protoplasm there is a dying off of cages. Frost resistance of plants of subjects is higher, than more water-retaining ability of protoplasm which depends on thickness and water penetration of covers, quantity of gidrofilny colloids, concentration of cellular juice and existence in a cage of so-called protective substances. At slow thawing dying off can not come, since water manages to be absorbed gradually from mezhkletnik back in a cage.
1. Nature of damages of fruit and berry crops
Degree of frost resistance of an elevated part of plants is subject to seasonal changes. Since autumn degree of frost resistance of fruit-trees raises, and by the end of winter decreases. Critical temperatures of death of different breeds fluctuate from-24 to – 42°S, and below. The steadiest grades of an apple-tree in deep rest are damaged at temperature – 41-42°C, grades of a pear, plum and a cherry – 35-Zb°s, sweet cherries – 30-32°C, an apricot-24-28°C ipersika-24-26°C. Sharp fluctuations of temperature in the second half of winter or sudden frosts lead in the autumn to damage of fruit-trees and even their death at temperature – 16-25°C.
The fabrics damaged by a frost get the brown or brown coloring, the intact core, wood, the cambium is kept by white or light gray color, and a bark – greenish.
Plants are damaged when snow drops out on not frozen damp soil, the root system doesn’t stop growth and in an elevated part water continues to arrive.
Morozoboina arise after long impact of low temperatures on a tree, a consequence of that are bark and wood damages in the form of longitudinal cracks reaching sometimes to the tree center. The bark along cracks, as a rule, lags behind wood, increasing these the size of a wound. Such damages are observed in hard frosts, especially at sharp fluctuations of temperature during day and night time. The damage rate morozoboinami depends on duration of rostovy processes and a wood maturity. Trees with the growth tightened in the autumn are damaged more strongly, than what finished growth in time.
Trees of summer grades of an apple-tree are damaged more poorly, than autumn and especially winter, younger trees – are stronger, than entered fructification, high-standard – is stronger, than low-standard. On the rehumidified sites strongly are damaged not only young, but also fructifying trees of an apple-tree, a pear, sweet cherry, plum, a cherry and an apricot.
Fruit kidneys of kostochkovy cultures and autumn and winter grades of a pear are injured almost annually, and in severe winters and especially in winters with sharp fluctuations of temperature the death makes them from 5-15 to 98-100 %. The damage rate depends on duration of the frosty period. Strongly injured fruit kidneys don’t reveal in the spring. More often fruit kidneys are injured by frosts at the end of winter – the beginning of spring since after end by plants of the period of deep rest even a short-term drowning can cause the beginning of their active activity.
Fruit kidneys of different grades of one breed are injured unequally. The most appreciable distinctions are observed at a cherry, sweet cherry, it is slightly less – at an apricot and plum. Rostovye kidneys at the majority of fruit breeds are steadier against low temperatures and less often freeze, than fruit. But at a peach fruit kidneys often happen are steadier, than rostovy. The injured, fruit kidneys bureyut, without revealing, dry up and fall down. In later phases of development of fruit kidneys frosts damage more often pestles – the most not cold-resistant part of a flower. Death of pestles – one their reasons of decrease in a crop in gardens in frosts.
Frost resistance of a flower isn’t adequate to frost resistance of plants, the Flower of the majority of fruit breeds are damaged during frosts at temperature fall to – 2,2°S, and the stuck fruits – to – 1,1°Si below. At wild strawberry a flower start to be damaged at temperature – 1,5°S. With further fall of temperature the damage rate raises. Damage of a flower and buds of wild strawberry depends on a phase of development of a flower and a structure cvetonosa Therefore various grades are damaged in unequal degree, for example, early more often than average and late.
At buds, as well as at a flower, pestles are most sensitive to low temperature. A wild strawberry flower with completely damaged pestles don’t fasten some berries. At partially damaged a flower (the part of pestles remained) process of fertilisation occurs, but fruits are in most cases formed small, strongly deformed.
3. Technique of definition of a damage rate frost of fruit and berry crops.
With a view of forecasting of productivity, definition of degree and nature of damages winter frosts of fruit plants carry out the analysis of a condition of fruit-trees and yagodnik.
At fructifying trees first of all analyze a damage rate of fruit kidneys on 3-4 summer branches, and at young – on annual escapes.
At definition of a condition of fruit kidneys on the 3rd-5 trees of each grade at the kostochkovy select not less than 100 kidneys from top, the same quantity from average, and also the lower part of krone, and at semechkovy on the cut-off branches there should be not less than 20-30 kidneys. The cut-off branches place in water and maintain at room temperature within 5-7 days. At an apple-tree and a pear analyze kidneys on kolchatka and other fruit educations, and at kostochkovy breeds – on buketny branches and on annual escapes. After thaw and before the beginning of blooming of kidneys the analysis can be carried out without a preliminary otrashchivaniye.
The analysis of kidneys carry out on cross-section cuts (cuts do by a sharp garden knife or a razor edge). At the injured kidneys the central part (flower rudiments) have dark brown coloring, and at healthy – light green, At kostochkovy breeds often kidneys are injured not completely, i.e. a part of rudiments of a flower in one kidney freeze, and the part remains the healthy. In the top part of krone fruit kidneys are injured less, than in average and it is much less, than in bottom.
Results of the account register in the magazine.
The analysis of damage of various fabrics of branches by means of a magnifying glass and a microscope is separately carried out. For this purpose from each branch 1,2, and the 3rd summer age do cross-section cuts and define a damage rate of each fabric, on each branch separately. The damaged fabrics have the brown coloring, intact – light. The assessment of a damage rate is carried out on 6 – a ball scale with the following values of points; 0 – there is no damage; 1-damages of total area of an analyzed fabric make 5-10 %; 2-25 %; 3-40-50 %; 4-to 75 %; and 5 points – complete damage of fabrics.
The analysis of damage of sectional yagodnik is carried out by an otrashchivaniye of the cut-off branches (at the end of winter), and wild strawberry – by an otrashchivaniye of monoliths. By intensity of blooming of kidneys and existence of the dismissed – determine a damage rate.
4. The agrotechnical actions promoting restoration of plants.
Scrap of trees. Degree scraps depends on age of trees, force and nature of damages and pedigree and high-quality features. Thanking a scrap before blooming of kidneys moisture evaporation decreases, the water mode dereza improves. For restoration of the young trees which have been poorly damaged by a frost, thin out krone. At average damage at the same time with a prorezhivaniye of krone rejuvenate skeletal branches. Strongly damaged or lost branches and escapes cut out. Remained cut off to that place where external layers of wood and a cambium healthy or are damaged slightly. The young trees strongly damaged by a frost root out and make reconstruction of plantings. During time strongly damaged skeletal branches cut out scraps of the damaged frost young and fructifying trees of an apple-tree and a pear on a ring. At kostochkovy breeds, especially at a peach, for the best healing of wounds leave a thorn in length 10-12 see. In the spring, for the second year after rejuvenating scraps, carefully thin out and form krone of young and fructifying trees.
Strong rejuvenating a scrap negatively influences frost resistance of fruit-trees. After it the bark which on skeletal branches and trunks lags behind wood fissures and hangs down in flakes, near a place of cuts and is as though pressed inside. Live cages of a bark die off, then wood is damaged also. Often after strong rejuvenating scraps trees completely freeze. This results from the fact that at such a scrap amplify growth and the period of the active involvement of a cambium that detains increases and worsens preparation for winter. Than earlier the active involvement of a cambium and growth of escapes at length comes to an end, frost resistance is higher than subjects. Moderated a scrap, providing a normal gain of annual escapes and the timely completion of rostovy processes, makes positive impact on frost resistance of fruit-trees.
Care of the soil. Row-spacings are necessary for containing in young and fructifying gardens under black steam that will provide big accumulation and moisture preservation in the soil, and also will promote the best restoration of the damaged plants. It is necessary to give special attention to care of pristvolny strips and circles, systematically throughout all summer to destroy weeds and to loosen the soil, without allowing crops of long-term herbs, in the conditions of optimum and superfluous moistening in the second half of summer it is necessary to sow sideralny cultures with simultaneous introduction of phosphoric and potash fertilizers on 45 kg/hectares of active ingredient.
Garden irrigation. In droughty areas it is necessary to irrigate the trees damaged by a frost for restoration of their activity. Early-spring and summer waterings have great value. The irrigation is necessary for carrying out so that in a zone of bulk of roots humidity of the soil made 70-80 % of the smallest moisture capacity.
Leaving for the shtamby. With deep morozoboinami and considerable damages of a bark on shtambe it is possible to revitalize trees with an inoculation way the bridge for which use root young growth. If it isn’t present, it is possible to impart shanks or specially placed from both parties of a tree saplings or seyanets. The trunks of trees young and entering fructification damaged by frosts are necessary for treating. For this purpose in the early spring it is necessary to clear a dead bark, oprysnut a trunk of 0,1 % solution fufanona and to cover with the garden thief.
Lateness with harvesting, especially winter grades of an apple-tree since it leads to decrease in frost resistance of trees is inadmissible. Collecting fruits is necessary for carrying out in due time. At the trees overloaded with a crop, winter hardiness goes down. The overload of the trees which have been earlier damaged by a frost as it not only worsens process of recovery of these trees is especially dangerous, but also reduces the subsequent winter hardiness and can lead to their death,
5. It is sewn up gardens from spring frosts. Control of the beginning of vegetation with the help:
- early-spring waterings (a delay for 5-8 days);
- sprayings of trees by inhibitors – the preparations detaining blooming of kidneys (sodium salt of maleic acid, sorbinovy and salicylic acids, etrel, Alor);
- sprayings of kroner of 7-10 % by lime solution at the beginning of winter;
- summer scraps of kostochkovy cultures (the laying of floral kidneys occurs on the second wave of growth where these kidneys are differentiated in later terms in this connection there are more cold-resistant and later blossom in the spring);
- creations of smoke screens at frosts to – 2°S (100-150 smoke heaps on 1 hectare. Width of smoke heaps of 1,3-1,5 m, m height-0,8-1,0. Heaps cover with a thin layer of the earth. Dymleniye begin at temperature +1,5-+1i finish in 1-1,5 hours after sunrise;
- than waterings on furrows at fall of air temperature is lower 0°S;
- sprayings of kroner by water (overhead irrigation) prior to the beginning of flower freezing. Spraying stop after ice on trees will thaw. Overhead irrigation gives good effect at frosts to – 5-6°S;
- spraying of kroner by solutions of antifreezes;
- air hashing by means of fans;
- selection of grades pozdnotsvetushchy and steady against frosts.
M. Borisenko, the candidate of agricultural sciences, the deputy director general on agricultural industry of GO agrarian and industrial complex "Krymsovkhozvinprom", L. PALEXA, chief of agricultural department of GO agrarian and industrial complex "Krymsovkhozvinropm", G. Bashta, main agriculturist-gardener of GO agrarian and industrial complex "Krymsovkhozvinprom", Y.Voinov, Candidate of Biology, senior research associate GPKTI "Plodmashproyekt".