In the dissertation, the features of growth, development and formation of yield and quality of green mass of silage corn (Zea Mays) as a bioenergy crop for biogas production are scientifically substantiated, depending on the use of macro- and micro-fertilizers in the conditions of the Right Bank Forest Steppe of Ukraine.
The research on the topic of the dissertation work was carried out during 2019–2021 and is a component of the initiative topic of research of the BilаTserkva National Agrarian University under the task "Scientific substantiation of adaptive and resource-saving technologies for growing agricultural and bioenergy crops in the conditions of the Central Forest Steppe of Ukraine" (state registration number 0118 U004125) .
The influence of macro- and micro-fertilizers on the growth, development and formation of productivity of corn hybrids of different maturity groups was established. The influence of the analyzed factors on the formation of indicators of photosynthetic activity of corn hybrids was revealed. The use of macro- and micro-fertilizers to increase the level of yield of green mass, the output of biogas and methane, and to improve the quality indicators of the green mass of corn hybrids is substantiated. An economic and bioenergetic assessment of the proposed crop cultivation technology was carried out.
The practical significance of the obtained results lies in the development of scientific and practical recommendations for production regarding the use of macro- and micro-fertilizers in the technology of growing corn for silage as a bioenergy crop for biogas production. On the basis of the obtained results, the elements of the technology of growing corn for silage have been developed due to the selection of energy hybrids and the optimization of the plant nutrition system in the conditions of the Right Bank Forest Steppe of Ukraine.
The improved elements of the corn silage growing technology were tested under production conditions in the farms of the Zhytomyr and Vinnytsia regions.
The results of the research were used in the educational process of the Belotserkiv National Agrarian University in the educational disciplines «Bioenergy crops» and «Design of technological processes in crop production» for students of specialty 201 «Agronomy».
The analysis of the scientific sources of domestic and foreign scientists regarding the current state of the biogas industry in the world and Ukraine, the use of substrates of plant origin for obtaining biogas and the influence of macro- and microelements on the productivity of corn and the output of biogas and methane was carried out.
It was established that the use of macrofertilizers extends the vegetation period of corn by 1–2 days, while microfertilizers, on the contrary, shorten it by one day. Close correlations between the duration of the vegetation period of corn hybrids and hydrothermal conditions during the years of research were revealed.
The height of corn plants reached the highest values in the phase of grain wax maturity and was 222,0–249,0 cm in mid-ripe hybrids, and 212,7–236,7 cm in mid-early hybrids. When applying macrofertilizers, the increase in plant height was 3,4–7,6%, and microfertilizers – 1,5–1,8%, compared to options without their application.
The maximum area of the leaf surface was in the flowering phase of the corn hybrid Karifols in the variant with the application of N120Р90К90 and YaraTera Tenso Cocktail + YaraVita Kombiphos – 49.0 thousand m2/ha. In all accounting periods, there was an advantage of options with the use of macro- and micro-fertilizers in terms of leaf surface area, compared to control options.
The increase in the net productivity of photosynthesis when using macrofertilizers was 2,8–11,6%, and microfertilizers – 1,0–3,9%, compared to the control options. In medium-ripe hybrids, the photosynthetic potential of crops was higher by 18,6–36,5% compared to medium-early hybrids. Close correlations were established between leaf surface area, photosynthetic potential and green mass yield of corn hybrids.
With the application of macro- and micro-fertilizers, the weight of the corn plant increases by 12,7–30,8% and 0,7–2,8%, compared to options without their use. Under the influence of macrofertilizers, the share of leaves and stems in the total mass of the plant decreases by 0,3–0,8%, and microfertilizers – by 0,1–0,3%, while the share of grain in the total structure of corn plants increases by 0,3–1,2% and 0,1–0,3%.
The content of dry matter in corn plants was in the range of 31,5–39,9%, in grain – 58,6–63,4%, leaves – 34,8–37,1%, cob wrappers 31,0–34,2 % and corn stalks – 22,9–25,3%. On average, according to the experiment, the hybrid Bogatyr had the highest dry matter content –39,2%. Under the influence of macrofertilizers, the content of dry matter decreased by 0,3–1,3%, compared to the control variants. Application of microfertilizers did not affect the content of dry matter.
