The area of winter wheat cultivation is predominantly in the European part of the country with relatively mild and snowy winters, which allows winter crops to make the best use of autumn and spring moisture to increase yields.
In general, the share of winter wheat in Russian field production is quite significant: it accounts for about 4 percent of all arable land allocated to cereal crops. For example, it is cultivated in the Central Non-Black Earth Region and some regions of the Urals, but the highest yields of winter wheat are obtained in the southern and southwestern regions of the country: Central Black Earth region, Kuban and North Caucasus, Rostov region and Krasnodar Krai, Middle and Lower Volga regions, where relatively dry and hot summer prevents full growth of spring crops, while winter crops due to the use of moisture accumulated in the fall-spring period have time to strengthen and enter into force.
It is in these regions that winter wheat yield is several times higher than spring wheat yield, which makes it expedient to allocate most of the arable land for winter crops. However, since even these regions of Russia are characterized by early frosts and stable minus temperatures, only frost-resistant varieties are suitable for growing winter wheat, and lack of moisture in summer leads to the need to grow short-stemmed wheat varieties.
Since most of the fertile land suitable for growing winter wheat varieties is in the steppe, winter cereal varieties should be characterized by lodging resistance. The use of such varieties under favorable weather conditions allows even in dry summer to obtain a high yield of winter wheat, up to 50-60 c/ha.
As for the zone of Central Russia, the abundance of precipitation in a rather cool summer and severe winter brings a good harvest of winter crops in the Volgo-Vyatsky region, Tatarstan and the regions bordering with the Lower Volga and Black Earth.
Optimal conditions for cultivation of the crop
The heat requirement of winter wheat varies depending on the period of its vegetation. The most favorable temperature for germination of seeds is +15+ 1 °С: this temperature regime with sufficient moisture creates conditions for friendly seed sprouting in 8-10 days after sowing.
About 2 weeks later, if the same temperature is maintained, winter wheat shoots begin to form above-ground shoots, which develop for about 1-1.5 months. The most favorable temperature regime for the development of the above-ground part of the plant – +12-15 ° C; lower temperatures below +10 ° C (but not below +5-6 ° C) leads to slower plant growth, but at the same time increases tillering and helps to form strong low stems resistant to lodging.
Depending on the temperature regime, winter wheat tillering can occur both in autumn and spring; to increase tillering, nitrogen fertilizers are applied to the soil, and the largest seeds are selected for sowing.
In winter, winter wheat varieties require temperature fluctuations depending on the time of day for intensive development. Thus, rather high positive temperatures within 10-12 ° C in the daytime with plenty of sunshine and insignificant minus temperatures at night favorably affects the hardening of wheat shoots and contributes to the active accumulation of plants necessary for growth carbohydrates, and this, in turn, helps them to endure frosts and wintering.
Autumn air temperature drop to +5 ° C leads to a complete stop of plant growth, while modern varieties of wheat are able to tolerate prolonged cold and frosts up to -30 ° C without noticeable consequences for the crop, but only in conditions of sufficient snow cover.
In spring, after the air warms up above +5-6 °C, winter wheat starts to develop again with the formation of new above-ground shoots. It is during this period that sharp temperature spikes between day and night temperatures, which can reach 15-20 °C in the Volga and Black Earth regions, are the most dangerous for plants, as this adversely affects shoot tillering.
Winter wheat is quite resistant to high temperatures and lack of moisture in the soil, but for the best development in the period of ear maturation daytime temperature should not exceed 40 ° C, because too high temperatures lead to metabolic disorders and retard the growth and formation of the ear, reduce the level of gluten in the finished grain. Wheat does not like dry winds – too windy weather can negatively affect the formation of full grain and with lack of moisture in the soil is one of the factors leading to its puniness, so to get a good harvest of winter wheat it is important to carry out moisture protection measures.
Features of winter wheat crop rotation
Winter crops can be sown both on clean fallows and on the fields occupied in the previous year for fodder grasses, corn, rape, barley, leguminous crops with early harvesting date. However, when sowing winter crops on occupied fallows, it should be taken into account that its yield may decrease by 25-50% compared to sowing on clean fallows, but only if in the previous year on clean fallows was carried out the whole complex of measures to retain moisture in the soil, soro-purification and mineral fertilizers.
In addition, the use of large areas under clean fallows in a farm may be economically less feasible than sowing winter crops on occupied fallows.
Thus, the optimal variant of crop rotation should be developed taking into account the specifics of the area, the cost of grain and the yield of a particular variety of seeds to find the most economical variant of crop rotation of all allocated land for crop production.
The occupied fallows, allocated for sowing winter crops after harvesting the preceding crops, are cultivated in the first 4 days after harvesting to a depth of 6-10 cm, otherwise the soil loses moisture and becomes more dense, which leads to increased costs for its subsequent treatment in preparation for sowing seeds. Too deep plowing (to a depth of more than 10 cm) is also undesirable, as it leads to increased clumping of the soil and drying out of its top layer. https://grain.st/
As a result of shallow fallow cultivation, weed vegetation is suppressed, moisture content in the cultivated soil increases, and favorable conditions are created for weed killing and subsequent cultivation of the land for sowing. Whereas the use of uncultivated land for sowing will require mandatory application of general eradicating herbicides into the soil immediately after sowing and before the sprouting of winter crops.
For favorable development of winter crops, the topsoil should contain at least 30 mm of moisture in a form accessible to plant roots; less can lead to the fact that already grown crops may die in the absence of rainfall.
Planting seeds in insufficiently moistened soil is unfavorable for the development of sprouts, especially when sowing occupied fallow, leads to sporadic sprouting of seeds after late autumn precipitation, as a result of which the field with crops quickly overgrows more drought-resistant weeds.
The choice of sowing date of winter crops depends on the region, as winter varieties should have time to gain 3-4 tillering shoots under winter; such development of plants is possible if the average daily air temperature during the sowing period is kept at 15-18 ° C. The average daily air temperature in the period of sowing. In chernozem areas of the right bank zone of the Volga, the optimum regime of moisture and positive temperatures is established by September 8-14, in non-black earth zones and in the Altai, the optimum ratio of moisture in the soil and air temperature may shift to early September.
Too early sowing of winter crops leads to root damage of plants by various types of rots, and their above-ground part is subjected to powdery mildew and brown rust diseases, because the early sprouts in this case will come to the period of maximum development of diseases on the decaying residues of previous crops or grass, procultivated before sowing seeds.
Too late sowing will entail delayed development of plants due to lack of positive temperatures, as a result of which winter crops will not have time to accumulate the required number of lateral shoots and may freeze in case of a strong drop in temperatures during the snowless period. Thus, all sowing of winter crops in the Central Black Earth Region and Volga region should be completed by September 20, as further delay of sowing dates will negatively affect the yield of grain crops and will lead to its reduction by an average of 20-40%.
On chestnut soils, the optimal time for sowing seeds is August 20 – September 1, further delaying the fall sowing becomes the cause of yield by 30-45%.