In our country, the greatest impact on the variability of yields and gross harvests of grain crops is caused by droughts. Thus, in 1946, the USSR managed to collect only 39.6 million tons of grain with an average of 64.8 for the five-year period (1946-1950). million tons. The drought of 1963 covered almost all grain regions: Ukraine, Central Black Earth, Central, Volga, Volga-Vyatka, Ural, West Siberian and Kazakhstan. Severe droughts were in 1927, 1975, 1979, 1981, each of them had its own characteristics.
In the severe drought of 1975 in the USSR, the gross harvest of grain and leguminous crops amounted to only 140 million tons. At the same time, drought paralyzed all the main grain regions of the country and had no analogue in the duration, intensity and coverage of the territory for the entire previous observation period. The average yield of grain crops in 1975 amounted to only 73% of the annual average. A similar situation was also observed in 1979.
If in wet 1978, 237.4 million tons of grain were collected in the country, then in a dry 1979, only 179.2 million tons. For just four years, the difference between the minimum gross yield in 1975 (140 million tons) and the maximum in 1978 (237.4 million tons) was 97 million tons. In many areas, it reached 50% or more, being due primarily to weather conditions. Note that such a variability in gross grain harvests was not observed in any country in the world, including countries located in adverse climatic zones.
Global warming, more frequent droughts and hot weather in the future will only exacerbate the situation.
This problem is solved in two ways:
- Selection of highly productive and drought tolerant plant varieties,
- Improving the agricultural technology of cultivating agricultural crops using an arsenal of agricultural products that increase the resistance of plants to lack of moisture.
According to a number of studies , a valuable sign of drought tolerance is the long photosynthetic activity of the ear itself, whose share in the photosynthetic potential of the plant is about 30% . V.A. Kumakov (1982) refers to the drought tolerance the features of the formation of the leaf surface, namely: a change in the ratio of the sizes of the lower and upper leaves in favor of the upper leaves, the slow death of leaves in the second half of the growing season, which favors a better filling of grain.
Wheat plants have different resistance to insufficient moisture in different phases of their development. A.N. Pavlov (1967) suggested that the decrease in yield occurs due to stress resulting from drought at all stages of plant development, with the exception of the period after the onset of wax ripeness.
In the presence of drought at any period of plant development, a decrease in yield is possible, but a lack of moisture is most pronounced at the beginning of heading.
N.A. Maksimov (1944) considered the main reason for the decline in yield during the drought to be that the growth processes of the vegetative organs develop earlier, when the plant is most demanding for light, and drought at this time leads to a reduction in growth intensity, and a critical period sets in, when the intensity of growth processes decreases due to natural causes and with normal water supply.
Therefore practical interest for agronomists present research results, conducted at the Department of Plant Production of Astrakhan State University. So, when studying the effect of complex organomineral micronutrient fertilizer Gumat + 7 on the biological and economic characteristics of corn, it was found that:
- Presowing seed treatment and foliar feeding of maize plants with complex organomineral micronutrient fertilizer Gumat +7 (produced by Agrarian Technologies LLC, Irkutsk) has a positive effect on its morphological features, stimulating growth processes and increasing the assimilation surface of leaves.
- The complex organo-mineral micronutrient Humate +7 positively affects the biological characteristics of corn, improving the water regime of plants, improving the water regime of plants transpiration rate and water deficit, decreasing transpiration rate at noon when pre-sowing seed treatment by 313 mg / h / 100 cm2, water deficit by 3.0%, and with foliar feeding of plants, by 268 mg / h / 100 cm2 and 2.1%, respectively, compared with the control.
As a result, increased water retention leaf tissue during pre-sowing seed treatment by 3.8% and foliar feeding of plants by 3.2%, which affected on increasing water content in the leaves of corn, which amounted to 465 g during the pre-sowing seed treatment in the upper tier, 54 g in the lower tier per 100 g of dry matter, and when foliar application of 31 and 33 g per 100 g of dry matter is higher than the control. - Complex organomineral microfertilizer Humate +7 in conditions of improved water regime increases the heat resistance of plants during pre-sowing treatment of seeds by 40%, and when foliar feeding of plants by 5% compared to control, which is one of the important conditions for the normal growth and development of corn, especially in conditions of drought and unstable moistening of the Astrakhan region.
- The complex organo-mineral micronutrient fertilizer Humate +7 significantly activates photosynthetic activity of plants, increasing the content of chlorophyll in the leaves, with pre-sowing seed treatment by 0.23 mg / g, and with foliar feeding of plants - by 0.18 mg / g wet weight, increasing the productivity of visible photosynthesis by 98 mg / m2 / h, and 82 mg / m2 / h, compared with the control.
A comparative assessment of the effectiveness of the methods of using complex organomineral micronutrient fertilizer Gumat +7 showed that the best method of application is the treatment of corn seeds before sowing. Although in some cases, the level of effectiveness of the two methods was approximately the same. However, pre-sowing seed treatment was energetically and economically more effective.
These R&D can be found in the library of the Natural Institute of Astrakhan State University at the address: 414000, Astrakhan, pl. Shahumyan, 1.
The article was prepared using the materials of the work of c.x. sciences E.V. Ionova, GNU All-Russian Research Institute of Grain Crops. I.G. Kalinenko.