Influence of fertilizers on indicators of the agro-ecological condition of the soil

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Vinnytsia National Agrarian University

INFLUENCE OF FERTILIZERS ON INDICATORS OF THE AGRO-ECOLOGICAL CONDITION OF THE SOIL

Tkachuk O.P. - Doctor of Agricultural Sciences, Professor,

Head of Department of Ecology and Environmental Protection,

Verhelis V.I. - Assistant at the Department

of Ecology and Environmental Protection

Annotation

siderate carrion soil corn

The work is devoted to the study of the expediency of using carrion siderates for indicators of the agro-ecological condition of the soil. The research was intended to study the influence of carrion siderates, which spontaneously sprouted after the loss of crop yields and disking of the field, on indicators of productivity, product quality and its ecological safety of corn and sunflower, as the next crops in the crop rotation, as well as on indicators of fertility and agro-ecological condition of soils. Experimental research was carried out in the conditions of EG “Zorya Vasylivka” of the Tyvriv district of the Vinnytsia region on gray podzolized soils.

Provision of favorable agrotechnical conditions for the growth of fallow siderates of winter wheat, spring barley, peas and winter rape can provide them with a biological mass of23.1 -33.0 t/ha at a height of22-64 cm during the 63-91 days of their vegetation. The most productive can to be ciders of winter rapeseed and peas.

It was established that the biological mass of carrion siderates worked into the soil helps to increase the content of humus by 0.11-0.14 %, alkaline hydrolyzed nitrogen - by 1.7-7.1 %, exchangeable potassium - by 27.4-32.2 %>. The highest content of humus in the soil is provided by siderates of peas and winter rapeseed - 2.44 % each, alkaline hydrolyzed nitrogen - 127 mg/kg - peas, mobile phosphorus - 520 mg/kg - winter wheat, exchangeable potassium - 230 mg/kg - winter rapeseed, the largest number of absorbed bases - 16.8 mg-eq./100 g - peas, the lowest hydrolytic acidity - 1.60 mg-eq./100 g - winter wheat, the highest pH value 5.85 - spring barley.

It was determined that the cultivation of siderates leads to an increase in the content of mobile heavy metals in the soil by 17.2-24.3 %, cadmium - by 10.0-14.3 %, copper - by 17.6-22.2 %>, zinc - by 34.7-39.9 %, compared to the version without siderates. Among the studied siderates, the lowest content of lead in the soil - 1.28 mg/kg and cadmium - 0.20 mg/kg is provided by winter rapeseed; copper - 0.51 mg/kg - peas and winter rapeseed; zinc - 1.73 mg/kg - spring barley.

Key words: siderates, agroecological condition of the soil, nutrients.

Анотація

Ткачук О.П., Вергеліс В.І. Вплив добрив на показники агроекологічного стану ґрунту

Робота присвячена вивченню доцільності використання падалишних сидератів для поліпшення агроекологічного стану ґрунту. Метою досліджень було вивчити вплив падалишних сидератів, що спонтанно проросли після втрати врожаю та дискування поля, на показники врожайності, якості продукції та екологічної безпеки кукурудзи та соняшнику, як наступних культур у сівозміні, а також за показниками родючості та агроекологічного стану ґрунтів. Експериментальні дослідження проводили в умовах ФГ «Зоря Василівка» Тиврівського району Вінницької області на сірих опідзолених ґрунтах.

Забезпечення сприятливих агротехнічних умов для росту сидератів озимої пшениці, ярого ячменю, гороху та ріпаку озимого може забезпечити їх біологічну масу 23,1-33,0 т/га при висоті 22-64 см протягом 63-91 дня їх вегетації. Найбільш продуктивними можуть бути сидерати озимого ріпаку та гороху.

Встановлено, що внесена в ґрунт біологічна маса падалишних сидератів сприяє збільшенню вмісту гумусу на 0,11-0,14 %, гідролізованого азоту - на 1,7-7,1 %, обмінного калію - на 27,4-32,2 %. Найбільший вміст гумусу в ґрунті забезпечують сидерати гороху та озимого ріпаку - по 2,44 %, азоту лужного гідролізованого - 127 мг/кг - гороху, рухомого фосфору - 520 мг/кг - озимої пшениці, обмінного калію - 230 мг/кг - озимий ріпак, найбільша кількість увібраних основ - 16,8 мг-екв./100 г - горох, найменша гідролітична кислотність - 1,60 мг-екв./100 г - озима пшениця, найбільше значення рН 5,85 - ярий ячмінь.

Визначено, що вирощування сидератів призводить до збільшення вмісту в ґрунті рухомих форм важких металів на 17,2-24,3 %, кадмію - на 10,0-14,3 %, міді - на 17,6-22,2 %, цинку - на 34,7-39,9 %>, порівняно з варіантом без сидератів. Серед досліджуваних сидератів найменший вміст у ґрунті свинцю - 1,28 мг/кг та кадмію - 0,20 мг/кг забезпечує озимий ріпак; міді - 0,51 мг/кг - горох та озимий ріпак; цинк - 1,73 мг/кг - ячмінь ярий.

Ключові слова: сидерати, агроекологічний стан ґрунту, елементи живлення.

Problem statement

Soil, as a natural resource, is constantly subject to natural and anthropogenic influences. The influence of natural factors occurs continuously, but mineral and organic substances are in balance, thanks to which the natural course of geological processes is not disturbed.

Anthropogenic influence on soils causes their degradation, leads to a decrease in the productivity of agricultural lands. In Ukraine, the ecological consequences of soil degradation and deterioration of their quality have become particularly acute in the modern period due to the use of land as the only means of subsistence in conditions of survival at the expense of natural soil fertility, without compensation for its costs. High productivity of land in this case is ensured by applying high rates of mineral fertilizers and pesticides [1].

This leads to a merciless depletion of the natural fertility of soils, which is called degradation. Soil degradation leads to the deterioration of soil properties, fertility and quality, its contamination with chemical toxic substances, which is caused by a change in the conditions of soil formation due to the influence of natural or anthropogenic factors. Degradation of soils, and often their complete exclusion from agricultural use, occurs as a result of the processes of water and wind erosion, dehumification, decalcification, over-compaction by agricultural machinery, irrational operation of irrigation systems, which leads to flooding and waterlogging, secondary salinization and salinization of soils; due to violations of agricultural technology, overgrowth with weeds and shrubs, unbalanced application of mineral fertilizers, pollution with toxic substances, radionuclides, unregulated livestock grazing, etc [2].

As a result of such anthropogenic intervention, soils lose their natural stability, which leads not only to a decrease in their productivity, but also to a complete loss of soils and their removal from cultivation. The consequence of this can be not only a decrease in the productivity of crops, but also a significant deterioration in the quality of the grown products, which not only reduces their nutrition, but also accumulates toxic substances: heavy metals, pesticides, radionuclides, salts and acids, oil products [3].

The degree of soil resistance to chemical pollution is characterized by such indicators as the humus composition of the soil, acid-base properties, oxidation-reduction properties, cation-exchange properties, biological activity, the level of groundwater, the proportion of substances in a dissolved state, etc [4].

A situation has arisen where the intensive use of heavy machinery in soil cultivation, the application of pesticides and mineral fertilizers, and chemical preparations violate the natural laws of evolution. Self-regulation in living nature was broken, which weakened the self-defense of plants, animals, and humans.

For a long time, the application of organic fertilizers in the form of manure was a factor in restoring and stabilizing the agro-ecological condition of soils, and therefore a factor in improving the quality of products grown on them. In modern conditions, due to the lack of animal husbandry, it is impossible to solve this problem by adding manure. Therefore, one of the most important ways to restore such soils can be the maximum return to the soil of the plant mass of crops that are not used for economic production and their waste. Such substances can be siderates, as well as by-products of crop production in the form of stubble, straw, stalks, tops, etc. The question of the influence of these organic substances on the productivity of crops of the following crops in crop rotation has been studied at a sufficient level by V. Artemenko (2003), O.M. Berdnikov. (2004), G.A. Makarova (2008), H.M. Gospodarenko (2012-2016), S.F. Razanov (2020) and others [5].

At the same time, the change in indicators of the agro-ecological state of the soil, in particular the content of nutrients, acidity, heavy metals and other toxicants in it, as well as the influence of siderates and crop production waste on the quality and ecological safety of the grown products, has not been studied enough, which determines the relevance of the chosen topic [6].

Analysis of recent research

The relevance and significance of the problem of reproduction of soil fertility in agricultural production is due to the sharp contradiction between the need to ensure the sustainable development of the agricultural sector of the economy and the intensive development of soil degradation processes that make it impossible to sustainably reproduce soil fertility. The main reason for this situation is the dominance of an unbalanced deficit system of agriculture in Ukraine, due to which the most fertile chernozems in the world have turned into soils with an average level of fertility and continue to deteriorate, and the harvests of recent years are mostly the result of a decrease in natural fertility and the impoverishment of its potential part [7].

In the agriculture of Ukraine, 79 % of profit is obtained due to natural fertility and only 21 % is the result of the introduction of technologies. At the same time, there is an “ecological eating away” of profit, since the losses from the decrease in soil fertility are close to, and in some years higher than, the profit from the sale of products by agricultural enterprises of Ukraine. Thus, in 2010, from 18.5 million hectares of arable land, on which the main groups of crops were grown, 2.38 million tons of nitrogen, phosphorus and potassium were irretrievably lost, amounting to more than UAH 16.3 billion. However, this is only the cost of fertilizers, and the costs of their application are not taken into account. According to other data, the annual economic costs from the shortage of products due to soil erosion in Ukraine in general are estimated at 1.5 billion US dollars, and together with the incurred costs - about 2 billion dollars [8].

In order to stop these negative processes, it is necessary to make wider use of natural ways of restoring and replenishing the reserves of organic matter in the soil, thanks to which not only the degradation processes in the soil will stop, but also the yield of plants grown on them will increase and the costs of their cultivation will decrease. In conditions of shortage of organic fertilizers in the form of manure, emphasis should be placed on green fertilizers - siderates [9].

Green fertilizers (siderates) are fresh plant mass of specially grown crops, partially or completely worked into the soil to increase its fertility and improve the nutrition of subsequent plants with nitrogen and other elements. These cultures are called siderates, and the practice itself is called sideration, i.e., green manure is understood as the application of not yet dead green juicy biomass of plants, rich in sugars, starch, protein and nitrogen, to the soil, as well as their roots, which were still functioning at the time of tillage. This fundamentally distinguishes green manure from other organic fertilizers, both dry (straw) and partially decomposed (manure), applied to the soil [10].

“Sideration” and “green fertilizer” are rather conventional names; the first of them reflects the role of the sun's rays (sidereus - related to heavenly bodies), and the second - the role of chlorophyll-bearing green organs of plants and the measure of plowing green mass into the soil, which is also called green fertilization [11].

In English-language literature, the term “cover crops” is more common. It is understood as crops that are grown primarily to create a plant cover, regardless of whether the plant mass will be incorporated into the soil in the future as organic green manure or will remain on the soil surface in the form of plant residues. The importance of their application will depend on the correctly defined main task, which must be solved at the expense of the grown cover crops and their justified selection for this purpose. As for the terms “green fertilizer”, “sidereal fertilizer”, which can be used as cover crops, they are interpreted in the same way in our and English-language scientific literature [12].

Also, the use of fodder and siderable crops to create favorable conditions for the development of one or a group of crops in a biological farming system is called “environmental improvement”, and the plants themselves, which are grown for this purpose, are called “environmentally improved fodder crops”, “environmentally improved fodder crops” and “environmentally improved siderable crops” [13].

The production of siderates, like any other organic fertilizers, enriches the soil with organic substances, reduces its acidity, weediness of fields, increases buffering, improves the structure of the soil, and activates the vital activity of soil microorganisms. Their cultivation prevents the loss of nutrients due to erosion and migration along the soil profile. Sideration is used in fields far from farms, where it is economically unprofitable to bring manure, as well as in farms with small production of organic fertilizers, in specialized farms without animal husbandry. Green fertilizers are of great importance during the reclamation of produced quarries of non-metallic minerals and contaminated soils. For example, clover grows well on areas contaminated with motor oils. To detoxify the soil, sow trefoil, burgun and sweet clover [14].

The organic substance of green fertilizer can be considered as a reserve of all nutrients necessary for plants, which are created in the soil and which are not immediately transformed into an assimilated form, but gradually, throughout the growing season, ensuring continuous growth and development of plants. Especially valuable is green manure from leguminous crops, capable of enriching the soil with nitrogen by fixing it from the atmosphere with nodule bacteria. In this sense, the planting of leguminous green-fertilized plants can be called a living factory of nitrogen fertilizers, which without complex machines, but only thanks to the work of nitrogen-fixing microorganisms, bind a large amount of free nitrogen in the air into a useful form of soil organic matter. So, when 10 tons of green mass of lupine is harvested, the soil is enriched with nitrogen by 54-56 kg/ha, clover - by 62, peas and fodder beans - by 52, and cornflower - by 59 kg/ha. It is also important that soil fertilized with nitrogen accumulated by leguminous plants does not require additional costs [15].

Siderates mobilize nutrients from the lower layers of the soil and move them into the arable layer. If the application of manure is the return to the soil of nutrients that have been used by plants to create a crop, the application of green manure is the mobilization of nutrients from solar energy, the atmosphere and the lower layers of the soil, which are not used much [16].

Green fertilizers help restore the normal cycle of organic matter and nitrogen in the soil. The results of research using labeled isotopes showed that when white mustard is used in the form of a harvest siderate, the nitrogen nutrition of barley plants and winter grain crops improved significantly, mainly due to an increase in the nitrogen utilization rate of mineral fertilizers by 40-60 %. Increasing the resources of additional forms of nitrogen not only creates more favorable conditions for the growth and development of agricultural crops, but also reduces the contamination of the soil and plant products with nitrates and other harmful substances that can come with mineral fertilizers [17].

Plants should be sown on green manure in order to obtain as much organic mass as possible. Therefore, they should produce large yields. Green manure is usually used on poor soils, and therefore the plants must be undemanding to soil conditions. It is also important to choose such a sidereal crop that would have a low transpiration coefficient (to save soil moisture), a low seeding rate (to reduce seed costs) and, along with the formation of a high biomass yield, would ensure an early period of earning it in the soil. It is essential that sideral vapors should be used not only on poor sandy and loamy soils in areas with sufficient moisture (in the Ukrainian Polity), but also on soils with a heavy granulometric composition [18].

The diversity and specificity of sidereal crops requires theoretical and technological substantiation of their cultivation and fertilization in order to reduce the anthropogenic load on the surrounding natural environment, increase the productivity of crop rotations with the reproduction of the organic component of soils.

Depending on the amount of heat, precipitation, local conditions, the granulometric composition of the soil, the presence of fertilizers and seeds, the following crops can be sown on siderates: legumes - perennial and annual lupins, white and yellow burdock, seradella, winter vetch and mountain vetch, diaper, peas, etc.; cereals - winter rye, wheat, barley, ryegrass, as well as sown cereal and leguminous perennial grasses, using the first cut for cattle feed, and the fallow - for fertilizer. In the presence of nitrogen fertilizers, it is promising to use cabbage crops (winter and spring rapeseed, winter and spring turnip, oil radish, white mustard, perko), phacelia, fodder peas and other fast-growing crops and their mixtures for sideration. Astragalus, mung bean, quinoa, fenugreek, alfalfa, safflower, lentils, horse beans, gorse, sabdar, bers, soybean, rye, paiza, Sudan grass and many others can be used as side crops [19].

The rapid dynamics of the climate in the direction of warming significantly changes the usual ideas about the diversity of the biological set and the technological capabilities of some long-known cultures. Previously well-known cultures can manifest themselves under these conditions from previously unknown sides and demonstrate excellent productivity. It is advisable to test new crops that tolerate dry periods well, are undemanding to the soil, and are adapted to growing in deserts. These are plants from the leguminous family (woolly astragalus; naked, rough and Ural licorice; small-hairy, mouse and thin-leaved peas; tuberous and meadow plantain; Don and large safflower; large-flowered fenugreek; false or ordinary camel thorn), slender-legged (Karelina reed, multi-stemmed hairy and giant sedge, sedge and Colchis) and many other cultures. The main thing is that the soil is not empty, but is covered with green cover.

Task setting

The research was intended to study the influence of carrion siderates, which spontaneously sprouted after the loss of crop yields and disking of the field, on indicators of productivity, product quality and its ecological safety of corn and sunflower, as the next crops in the crop rotation, as well as on indicators of fertility and agro-ecological condition of soils.

Experimental research was carried out in the conditions of FG “Zorya Vasylivka” of the Tyvriv district of the Vinnytsia region on gray podzolized soils.

The following observations, records and measurements were carried out: determination of soil pollution by mobile forms of heavy metals, indicators of soil fertility, the content of heavy metals in corn and sunflower seeds, the content of protein, starch, fat in sunflower seeds, oil in sunflower seeds, acid number of oil and grain moisture and seeds were carried out in the certified and accredited laboratory of the Zhytomyr branch of the State Institution “State Soil Protection” of the Ministry of Agrarian Policy and Food of Ukraine: soil samples were taken from the 0-20 cm layer in accordance with DSTU ISO 10381-1:2004; determination of the content of humus in the soil - according to the Tyurin method in accordance with DSTU 4289:2004; determination of the content of mobile forms (after extraction with an acetate-ammonium buffer solution pH 4.8) of heavy metals in the soil: lead, cadmium, copper and zinc - by the method of atomic absorption spectrophotometry in accordance with DSTU 4362:2004, DSTU 4770 (2, 3, 9): 2007; determination of soil pH salt reaction - ionometrically in accordance with DSTU ISO 10390-2004; determination of hydrolytic acidity - by the Kappen method in accordance with DSTU 7537:2014; determination of the content of hydrolyzed nitrogen in the soil - by the Kornfield method according to DSTU 7863:2015; determination of the content of mobile forms of phosphorus and potassium in the soil - by Chirykov's methods according to DSTU 4115-2002; determination of the amount of absorbed bases in the soil - according to KappenHilkovits [13].

Presentation of the material of research. Harvesting of the main crops, which occupy the largest cultivated areas under conditions of intensive agriculture and can potentially be siderates: winter wheat, spring barley, peas and winter rape, took place in different periods. Winter rapeseed was harvested at the earliest - July 14, peas - 9 days later - July 23, winter wheat - July 29, and spring barley at the latest - August 6. In general, the period of harvesting crops, which can potentially be used as siderates, stretched for 23 days - from July 14 to August 6 (Table 1).

Table 1

Growth and development of sidereal crops, average 2019-2021, M±m