PHOTOSYNTHETIC ACTIVITY OF SEEDLINGS OF WHEAT LINES DEPENDING ON THE PROTECTION AND PROTECTION OF PLANTS IN THE CONDITIONS OF THE SOUTH OF UKRAINE

Abstract

The main cereal crop in the south of Ukraine is winter wheat. According to the size of the sown areas and the volumes of the gross harvest of grain, it significantly dominates other crops. Existing varieties are capable of yielding a yield of 8-9 t/ha or more. However, the imperfection of technologies of its cultivation, adverse climatic conditions, as well as various stressful phenomena does not allow to fully realizing the potential of cultural productivity. Winter disagreements, lack of moisture in the soil and frequent droughts result in significant harvest losses. Therefore, the actual task is to establish the influence of elements of varietal agrotechnics - fertilizer and plant protection systems on seed yield and photosynthetic potential of crops of the studied culture.

The purpose of the research was to study the influence of the mineral nutrition and plant protection on the photosynthetic activity of winter wheat seed crops in the conditions of Southern Ukraine.

The task of the study was to determine the influence of the investigated factors on the dynamics of the formation of the leaf area, the photosynthetic potential, the net productivity of photosynthesis and the parameters of absorption of FAR by winter wheat crops.

The research was conducted during 2004-2010 at the research field of the Institute of Irrigated Agriculture of the National Academy of Sciences of Ukraine. The predecessor was a winter wheat, sown in a pair. A winter wheat cultivar was slaughtered in Odeska 267. The experiment was laid by split plot method. In order to comprehensively study the peculiarities of the influence of fertilizers and plant protection on the growth and development of winter wheat, appropriate observations, measurements, records and analyzes were carried out in accordance with the experimental methodology.

According to the results of our researches, the use of fertilizers significantly increased the area of the leaf surface of winter wheat. The application of plant protection against weeds, diseases and pests also has a positive effect. The best conditions that contribute to the formation of a large area of the leaf surface and its longer functioning are created when introduced from autumn N₃₀-₆₀P₄₀ and N₆₀ in spring nutrition in conjunction with integrated plant protection, when the investigated index increased compared to control at 53.1-58.5%.

The introduction of N₉₀P₄₀ from autumn provided a photosynthetic potential of the same level as with the application of this dose of finely - N₃₀P₄₀ to sow and N₆₀ in spring supplementation - 645 and 647 thousand m²/ha × days, respectively. This indicator has reached the highest level - 1584 thousand m²/ha × days of N₆₀P₄₀ to sowing and N₆₀ in spring nourishment. In addition, a general tendency of photosynthetic potential growth in plant protection variants is established.

Improvement of the mineral nutrient background due to the introduction of mineral fertilizers various phases of plant development led to a decrease in the net productivity of photosynthesis. The growth of this indicator by 12.8-23.3% due to the use of plant protection was noted when fertilizers were introduced in autumn in the dose of N_30-60P₄₀ and N₆₀ in spring supplementation.

The absorption of photosynthetic active radiation by winter wheat crops was influenced by fertilizers and the protection of plants from diseases, weeds and pests. Effective use of PHAR can only be achieved with the integrated application of these factors. The high level of absorption of PHAR in winter wheat crops, more than 75%, was used when applying fertilizers at a dose of N_90-120P₄₀ in combination with integrated protection grew.