In article of research associates of the APP Crimean institute the characteristic of a condition and development of crops of winter crops is given, poseyanny on the crop’s eve of the current year and recommendations about leaving depending on their condition in a perezimovka are provided.
FEATURES of DEVELOPMENT of WINTER CROPS DURING the AUTUMN and WINTER PERIOD of 2005-2006
It is known that winter hardiness of the winter depends on many reasons, however production inspections showed that in absolute majority of years the death and an izrezhennost of crops occurs because of agrotechnology violations.
In many respects winter hardiness of the winter defines a right choice of term of sowing. At crops into early terms of a plant before leaving in winter develop, accumulate many auxins and during the winter don’t pass to a condition of relative rest. At such plants higher hydrolytic activity of enzyme invertazy remains that testifies to an intensive expenditure of carbohydrates on activity processes. Rather low activity of proteolytic enzymes the smaller quantity albuminov also is considerable and readily soluble globulins point to internal fiziologo-biochemical instability of plants. At weather fluctuations during the winter period they intensively spend plastic substances, weaken – that by spring can lead to their izrezhivaniye and even death.
Long-term researches of the Crimean institute of agroindustrial production showed that the most productive and rather winter-hardy there are the plants which have reached by the end of autumn vegetation of a phase of a kushcheniye (2-3 escapes).
For achievement by plants of a phase of a kushcheniye in local climatic conditions on the average it is necessary 480°S the sums of positive temperatures.
By long experiences this and work practice it is established that optimum terms of sowing winter for the Crimea, is the period between September 20 and on October 10. According to mean annual data at crops in these terms by the end of autumn vegetation the sum of daily average temperatures, near 500°S is gathered.
However, in the conditions of autumn of 2005 and winter of 2005-2006, winter practically didn’t stop the vegetation because of abnormally warm weather conditions of this period. It is enough to tell that since September 20 till December 10 daily average air temperature didn’t fall below a mark +5,6°S. For this period the sum of daily average temperatures made 7870S that more than in 1,5 times above the necessary sum necessary for achievement by winter of a phase of a kushcheniye.
Such weather conditions are especially undesirable to winter barley at which stages organogeneza pass more intensively, in comparison with winter wheat. These facts also cause expediency of later sowing of winter barley (for 7-10 days).
Therefore, considering abnormally warm weather conditions for vegetation winter, danger of transition from a kushcheniye phase to an exit phase in a tube is possible on irrigated crops of winter barley, vyseyanny at the beginning of optimum term of sowing. The outgrown crops are very unstable to influence of low temperatures, especially on a high background of a nitric food.
It is known that at winter crops life cycle proceeds during 2 periods. The first period passes in the autumn – from crops to the steady frosts, the second – begins in the spring and proceeds before grain maturing. During the autumn period the winter should pass two phases of a hardening. The first phase passes late autumn at temperature from 0 do+6°S on light. In these conditions growth of the winter is slowed down, and photosynthesis still remains. The expense of products of photosynthesis as a result decreases and there is an accumulation of sugars. Before leaving in winter at winter crops about 20-25 % of sugars in terms of solid collect.
The second phase of a hardening proceeds at weak frosts (from-2 to – 5°S). Light existence in this case has no value. When passing the second phase of a hardening there is a continuous outflow of water to intercellular space, the contents it in cages decreases. As a result in mezhkletnik of a plant ice is formed, but in contents of cages crystals are absent. Effective increase of frost resistance of plants is reached only at end of both phases of a hardening.
It is by practical consideration established that by the time of transition of daily average temperatures through +5°S (the termination of the active autumn period of vegetation) frost resistance of winter wheat at their identical development (3 escapes of a kushcheniye) can differ considerably. In warm autumn many grades had average vymerzaniye temperatures – 9,8°S, in cold – 14,50S on a depth of knot of a kushcheniye.
Thus, considering the increased temperature of the autumn period of vegetation winter, their further viability directly depends on a temperature mode of the winter and spring period of vegetation. Under identical conditions of spring negative action of spring frosts (-10-12°C), considerably increases if the autumn was warm. The plants which have grown in the conditions of warm autumn and spring have the lowest frost resistance.
Except a vymerzaniye winter, in the conditions of the Crimea probably also negative influence of a vypiraniye of the plants, accompanied by a rupture of roots, especially at crops to the friable neosat-down soil and neprikatanny after crops. At an exposure of knots of a kushcheniye in the spring, on such fields the prikatyvaniye of crops by annulate skating rinks should be obligatory agroreception.
For successful rewintering of the winter depth of seal of seeds on which depth of a laying of knot of a kushcheniye as deepening of knot of a kushcheniye on 1 centimeter raises its zimoustoychivost on 3°S substantially depends has importance. The great value has also existence of snow cover.
According to determination of this dependence it is established that at daily average air temperature – 14°S on a depth of knot of a kushcheniye the temperature of the soil raises at height of snow cover of 2 cm to – 10,5°S, at 4 cm to – 9,40S. On the average each centimeter of snow cover (to 10 cm) increases soil temperature on 1°S. At bigger size of snow cover the temperature of the soil raises all on 0,2-0,4°C on each centimeter of snow cover.
To reduce dependence of winter frosts on harmful influence it is possible at the expense of spring podkormok nitric fertilizers. Thus, in the conditions of warm spring, the lowered doses of nitrogen in podkormkax, in the conditions of late spring – raised are rather effective.
As a whole it is necessary to note that because of extremely warm autumn weather conditions, winter go to winter with the lowered immunity to low temperatures and their further destiny, and, therefore, destiny of a crop depends on severity of weather conditions of the winter and spring period of vegetation.
For giving to stability plants when rewintering irrespective of the fact which from the reasons of their damages the main is, it is necessary to observe the following requirements:
1) application of the correct system of processing of the soil giving its good physicomechanical condition;
2) crops by seeds of grades of the most adapted for local soil climatic conditions;
3) uniform seal of seeds at crops on depth of 5-6 cm;
4) the creating an enabling environment for good autumn growth of plants so that up the time of approach of winter of a plant had 3-4 stalks;
5) providing healthy nutrition of plants;
6) protection of crops against diseases and wreckers as the sick and damaged plants strongly suffer from adverse conditions of wintering.
L.Radchenko, the deputy director on scientific work, K.Zhenchenko, the manager. laboratory of agriculture, N. Saenko, senior research associate, APP Crimean institute.