Foliar fertilizing is very important to supply apple plants with calcium and micronutrients. The most cost-effective approach to this is the application of the fertilizers in tank mixtures with plant protection chemicals. Plasma-activated water (PAW) has great potential for the use in the agriculture. We used two type of PAWs, PAW1 (made using underwater electrical discharge in an aqueous KNO₃ solution and includes reactive nitrogen species and platinum nanoparticles) and PAW2 (made using a plasma torch with nitrogen gas makeup and contains reactive nitrogen species but not metals). We studied the impact of two PAW types on the contents of Ca, B, Mn, Fe, and Co in leaves and Ca, Mn, Fe, Zn, and Mo in fruits sprayed with tank mixtures containing the fertilizers. We also tested the efficiency of PAW in the control of apple scab when applied as tank mixtures with plant protection chemicals. The application of the PAWs significantly increased foliar Ca when the PAW was mixed with Ca-containing formulations (spraying PAW1 containing Ca increased leaf Ca by up to 21%, and PAW2 up by to 9% compared to Ca spraying without PAW). The largest fruit Ca increase was in the variant treated with PAW1 with a micronutrient spraying program (up to 143%). The PAW treatments enhanced the baseline mineral contents of the plants even when they were not sprayed with the nutrients. PAW1 mainly increased the nutrient contents of the apple fruits. PAWs have proven to be efficient for the control of apple scab, thereby reducing the demand for fungicides. The scab damage to the leaves and fruits was similar in plants treated with PAWs without fungicides (1.7–1.9% on the leaves and 1.6–1.8% on the fruits) compared to the conventional chemical scab control (0.9% leaves and 0.6% fruits) and was significantly lower than in the untreated control (9.3% on leaves and 11.9 on fruits).

The foliar application of micronutrients can improve primary nutrient uptake. As a result, foliar treatments can reduce fertilizer application rates and help to maintain the natural health of soil. Here, we report on the tentative implementation of this approach in an apple orchard located in a temperate climate (JSC “Dubovoye” 52°36′57.1″ N 40°17′04.1″ E; planted in 2002 according to the 6 × 4 m or 417 trees ha^–1 cultivar (cv.) Bogatyr grafted on B118 (Budagovskii 118). Manganese treatments augmented foliar nitrogen content and, in certain seasons, foliar phosphorus, whereas zinc treatments enhanced foliar potassium. Low-rate chemical fertilizers application (once in 5 years) on the background of initial high-rate organic fertilization (60 t ha^–1 manure) allowed us to retain the optimal soil pH in the experimental orchard.

Specific features of the genesis of chernozem-like, solonetzic chernozem-like soils, and hydromorphic chernozem-like solonetzes were investigated on the southern Tambov Plain. Typical chernozems occupy well drained areas. The yield of cereals is limited by the amount of precipitation. On the flat surface of weakly drained watersheds, deeply gleyed chernozem-like soils are formed under the influence of bicarbonate-calcium ground water and water stagnation on the plow sole. In closed depressions with the 1.5- to 2.0-month long stagnation of surface water on the compact lower horizons, podzolized gleyic chernozem-like soils are formed. They have favorable physical properties, weak eluvial differentiation, and rather high acidity. In humid and moderately humid years, the cereals on these soils are waterlogged; in dry years, their yield increases by 20% as compared to that on the typical chernozem. In the low undrained areas of the watersheds, solonetzic chernozem-like soils and hydromorphic chernozem-like solonetzes are formed under the influence of bicarbonate-sodium water. Despite the unfavorable physical properties of the solonetzic horizons, their better supply with moisture determines the possibility to obtain stable high yields of cereals on the solonetzic chernozem-like soils. The productivity of the gleyic chernozem-like solonetzes is low irrespective of the humidity of the year.

A system for the diagnostics of chernozemic soils of the Tambov Lowland based on concretions is proposed for agricultural and reclamation purposes. The relationships between the structure and composition of the carbonate concretions, the long-term water regime of the soils, and the productivity of the crops have been established. The dense concretions in the typical chernozem testify to the depth of the seasonal wetting; the angular-rounded concretions in the deeply gleyed chernozem-like soil, to the upper boundary of the capillary fringe; and the angular concretions with sharp edges and cavities in the gleyic chernozem-like soils, to the groundwater table. In the chernozem-like soils that were waterlogged with bicarbonate-sodium water, the black angular concretions were formed in the solonetzic horizons, while the weakly compacted light-colored ones, in the zone of the capillary fringe. Humic acids were responsible for the color of the dark neoformations, and fulvic acids predominated in the light-colored ones. The appearance of black fine nodules indicated periodic surface water stagnation. Manganese predominantly accumulates in these nodules. The structure of the Mn-Fe concretions in the plow horizon observed at a magnification of 40–50 times has a diagnostic importance. The short-term (2–3 weeks) water stagnation leads to the formation of fine-stratified concretions, and the long-term (up to 1.5 months) stagnation promotes the formation of uniform porous ones. The solonetzic process induced by the bicarbonate-sodium water results in the appearance of mottled concretions.

On dark gray forest and leached chernozem soils of the Tambov region, the effectiveness of using new granular organic fertilizer from poultry excreta was evaluated. After disinfection of the litter by deep drying, the total content of NPK in the fertilizer constitutes 11-12%, the content of trace elements is about 1g/kg. Field experiments conducted in 2019 showed that the yield increase from the introduction of the studied organic fertilizer at a dose of 4-8 t/ha on spring wheat was 25-30%, on spring barley - 20-23%, on sugar beets from the introduction of 8 t/ha - 10-12%, on potatoes - 40-50%, on tomatoes from 6 t/ha - 30-32% Profitability from the use of this fertilizer on cereals is 130-145%, on technical crops - 140-150%, on vegetables - 230-250%. Optimal fertilizer doses contribute to increasing protein in wheat grains by 1.5%, sugar content in sugar beets by 8-9%, starch content in potatoes by 3-4%, and sugar, dry substances and vitamin C content in tomatoes by 1-2%. The introduction of fertilizer in doses higher than optimal contributes to the increase of basic nutrients and micronutrients content in the soil.

Molybdenum (Mo) is an important nutrient participating in nitrogen, sulfur, iron, and copper metabolism, as well as a cofactor in the biosynthesis of auxin and abscisic acid. Apple leaf Mo seasonality and periods of apple tree demand remain unclear due to insufficient data. This study aimed to identify peak leaf Mo levels throughout the growing season to distinguish when apple trees require the most Mo. To analyze seasonal patterns, we determined the leaf Mo contents 11–12 times per season on untreated and Mo-treated apple trees over four seasons in 2020–2023. Foliar fertilizing stimulated a significant increase in leaf Mo status. The Mo contents in untreated tree leaves were significantly lower than in trees after foliar fertilizing. However, in fertilized trees, nutrient contents were low after ten-day periods of heavy precipitation. High leaf Mo levels coincided with periods of intense apple shoot and fruit growth (average Mo level of 0.305 mg kg⁻¹ in untreated trees and 0.386 mg kg⁻¹ in fertilized ones) and apple fruit development and ripening (average Mo level of 0.754 mg kg⁻¹ in untreated tree leaves and 1.069 mg kg⁻¹ in fertilized ones). Mo application via foliar fertilizing in July’s heat is essential for apple tree fruit growth and development to counter negative weather effects. Foliar fertilizing significantly increased tree yields in 2020, 2022, and 2023, resulting in substantially higher overall productivity (169.7 kg/tree⁻¹ without vs. 215.6 kg/tree⁻¹ with fertilizer).