Soil fertility in biologized crop rotations depends on the saturation of them with legumes and sideral crops, perennial grasses, the involvement of grain crops in the organic matter cycle. The crop rotation was studied: 1) four-field grain and steam: clean steam winter wheat chickpeas spring barley (control); 2) five-field grain and steam: occupied steam (clover green manure) winter wheat chickpeas spring barley mustard + clover; 3) seven-field grain and grass: occupied steam (green manure oats) winter wheat mustard chickpeas safflower dyeing spring barley sainfoin (hatcher field); 4) semi-field grass and grassland: occupied steam (phacelia green manure) winter wheat spring wheat chickpeas grain sorghum spring barley alfalfa (hatchery field). The highest balance of organic matter was ensured in a five-field grain-steam crop rotation with clover for green manure +1.92 t/ha, in this crop rotation the highest balance was observed for nitrogen +23.8 kg/ha and phosphorus +1.3 kg/ha, grain harvest from 1 ha of arable land 0.51 t/ha. The greatest balance of potassium was ensured in the seven-field grain and grass-crop rotation with facet on green manure +8.8 kg/ha. The highest humus balance was observed in a seven-field grain-grass-crop rotation with oats per green manure +0.12 t/ha.

In Greece, agriculture plays a key role in supporting the socio-economic sustainability of rural areas, as this sector is the main user of agricultural land. In Greece, agriculture covers a large part of its territory. It accounts for about 30% of the total area. The total cultivated agricultural land (arable crops, horticultural land, permanent crops) amounts to 3,221,680 hectares compared to the 171,603,000 hectares of the EU-27. In 2018 the main crop groups per year were distributed as follows: 53.4% of cultivated area (1,719,600 hectares) was used for arable crops, 1.9% (61,890 hectares) for horticultural, 33.7% (1,085,100 hectares) for permanent crops and 11.0% (354,760 hectares) of arable land was under set-aside. 56% of arable land is located in lowland areas, while the rest is in mountainous or semi-mountainous areas. An important parameter for crop efficiency is the irrigated agricultural area. One-third of the arable land is irrigated. The highest irrigation rates (97%) are occupied by horticultural crops, 43% by arable land, 38% by tree crops and 36% by viticulture. The average size of agricultural holdings is less than 5.0 hectares and the number of large farms has increased. Thus, 76.0% of rural households have a size of less than 5 hectares, while less than 1% have a size of more than 50 hectares. It is worth noting that agriculture must take care of soil protection, water quality, natural resources because these are vital factors in ensuring the sustainability of humanity. Keywords: Soil resources, Sustainable agriculture, Agricultural production.

With a blocked cutting of closed soil on the vibrating cutting edge of the bit, a deformation cone is formed due to cyclic and transient compression of the gas phase, which becomes a carrier of the kinetic energy transformed in the form of high-frequency supersonic shock waves. The angles of inclination of the cone-forming deformations coincide with the angles of repose of the soil and are equal to approximately 45°, as a result of which the shock waves propagate in the least energy-consuming way. The high-frequency nature of the shock waves leads to the fact that at frequencies of τ < 0.0037 s, the adhesion between solid inclusions is interrupted in the deformation zone, and the internal friction of the soil is essentially leveled out. This process is carried out through chisel-type tillage implements of the original structures considered in the present work.

1ФГБОУ ВО Волгоградский государственный аграрный университет пр. Университетский, 26, Волгоград, Россия, 400002 2 Российский университет дружбы народов ул. Миклухо-Маклая 6, Москва, Россия, 117198 В статье представлены опытные данные по комплексному влиянию способов основной обработки почвы и бактериальных удобрений «Азотовит» и «Фосфатовит» на агрофизические, водно-физические показатели почвы и продуктивность ячменя. Установлено, что применение плоскорезных обработок не приводит к уплотнению пахотного слоя выше биологического оптимума и нарушению аэрации почвы, в связи с чем возможно их применение без ущерба для возделывания ярового ячменя. Изучено влияние способов основной обработки почвы и внесения минеральных и бактериальных удобрений на водопотребление ячменя и эффективность использования влаги единицей продукции. Обобщены многолетние данные по урожайности ярового ячменя по изучаемым вариантам. Установлено преимущество двукратного внесения «Азотовит» и «Фосфатовит» на фоне плоскорезной обработки на глубину 0,20-0,22 м. Урожайность по этому варианту составила 1,7 т/га, что выше по сравнению с вариантом, где вносились только минеральные удобрения -0,63 т/га. Представлены расчет прибыли, рентабельность технологии возделывания ярового ячменя и опреде-лен экономически выгодный вариант опыта, включающий двукратное внесение бактериальных удобрений на фоне плоскорезной обработки почвы на глубину 0,20-0,22 м. Рентабельность составила 46,2%. На основании проведенных исследований теоретически обоснованы, эксперимен-тально подтверждены и сделаны выводы, а также даны рекомендации применения технологии в Волгоградской области.Ключевые слова: яровой ячмень, отвальная вспашка, плоскорезная обработка, азотовит, водопотребление ВведениеРоль засушливых районов страны, и в частности Нижнего Поволжья, в про-изводстве зерна исключительно велика. Между тем частые засухи, водная эрозия и дефляция почвы приводят к тому, что урожаи и валовые сборы зерна в подзоне светло-каштановых почв Нижнего Поволжья подвергаются огромным колебаниям, поэтому остро стоит вопрос борьбы с засухой с целью повышения урожаев, обес-печения их устойчивости и преодоления негативного влияния погодных условий.По результатам исследований последних лет в связи с изменением эконо-мических и экологических условий и возможностей сельскохозяйственного про-изводства обоснована необходимость уточнения, а в ряде случаев и пересмотра сложившихся агротехнологических приемов при выращивании ячменя, отвеча-ющих требованиям интенсивной технологии [8][9][10][11].

The influence of sowing methods and irrigation regimes on productivity of extra-early soybean cultivar VNIIOZ 86 has been studied at Russian Research Institute of Irrigated Agriculture. The use of differential irrigation regimes (70-80-70% and 80-80-70% of FMC) resulted in 2.42 ... 2.51 t/ha yield and mid-level profitability of grain production (80.6%), which was 0.25 ... 0.34 t/ha more compared to the control (80-80-80% of FMC), as synchronization of vegetative growth and reproductive development increased grain amount in total biomass up to 36.2%. Differential irrigation regimes restrained an increase in crude protein level in the seeds (at the level of 35.4 ... 41.2%) compared with the control (36.5 ... 41%). However, they increased fat content in the seeds (18.1 ... 21.4%) compared to the control variant (16.1 ... 18.6%). Optimization of irrigation regime increased protein (up to 0.68 ... 0.94 t/ha) and fat (0.37 ... 0.46 t/ha) compared to the control (0.64 ... 0.83 t/ha and 0.29 ... 0.35 t/ha, respectively). The smallest water consumption coefficient was observed in sites with differential irrigation regimes-1,174 ... 1,524 m 3 /t, when in the control site it was 1,651 ... 1,977 m 3 /t. Extra-early VNIIOZ 86 plants require 8 ... 14 irrigations at a rate of 190 ... 230 m 3 /ha. It is enough to perform 8 irrigations in relatively favorable years (2013), and up to 14 irrigations in dry years (2014-2015). To maintain a differential irrigation regime, it is necessary to perform 8 ... 10 irrigations in wet and up to 10 ... 13 irrigations in dry years. The highly profitable cultivation of early soybeans (107.9%) was achieved using drilled sowing (0.30 × 0.042 m) that resulted in significant yield increase (up to 3.02 t/ha) which was 0.41 t/ha higher compared to wide-space sowing technique (0.70 × 0.024 m).