INTRODUCTIONSilicon, whose content in soil is rather high (50–400 g/kg soil), plays a significant role in soil formationand fertility [1, 2]. Back in 1813, Davy established thatsilicon is concentrated in the epidermal tissues of plants,creating a barrier that protects plants from insect pests.This was the first work on the importance of silicon inplant physiology.Today, we know a lot about the role of silicon in plantlife (Fig. 1). In particular, silicon content determinesthe level of natural protection against biotic and abioticstresses [2–8]. Silicon nutrition for plants increases leafarea and creates favorable conditions for photosynthesis[7, 9]. When added to the soil, readily-soluble silicaimproves the metabolism of nitrogen and phosphorusin tissues, increases the content of phosphates, andfacilitates the consumption of boron and other elements.In addition, it reduces the toxicity of excessive heavymetals, neutralizes the negative effects of excessivenitrogen fertilizers, increases the population ofammonifiers, improves nitrification, and helps the soil toabsorb mobile forms of nitrogen [10–14].Silicon fertilizers are increasingly being used inagriculture across the world (the USA, China, India,Brazil, Japan, South Korea, Mexico, Australia, andother countries). Their production increases by 20–30%annually. An ecological alternative to pesticides, theyalso increase plants’ resistance to stress.Russia-produced silicon fertilizers include naturalsilicon materials (Diatomite, BIO COMPLEX;Promzeolit, PROMZEOLIT), concentrated monosilicicacid with active colloidal silicon (Akkor, MoscowRegion), as well as physiologically active organosiliconbiostimulants (FLORA-SI, Moscow). Among them is aunique fertilizer – NanoKremny (NANOCREMNY) –crystalline silicon with a particle size under 0.5 μm,which has no analogues in Russia or other countries.Silicon fertilizers have a proven positive effecton different soils for the Leguminosae, Gramineae,Solanaceae, Citrinae, and Cruciferae families, as wellas other agricultural crops. However, few studies havelooked into tank mixtures of pesticides and bioactivesubstances in relation to Vitis vinifera. In practice,using scientifically unfounded tank compositionsoften leads to negative phytosanitary and economicconsequences [15].The quantity and quality of grape and wine yieldcan be increased by using foliar dressing with macroandmicroelements. Grape quality is determinedprimarily by sugar content and acidity of the berryjuice. According to State Standard 31782-2012 “Freshgrape of combine and hand harvesting for industrialprocessing. Specifications”, the concentration of sugarsin grapes for winemaking must be at least 160 g/L forwhite varieties and 170 g/L for red varieties. To ensuresuch high concentrations of sugars and stable grapeyield, the grapevine must be provided with sources ofmicroelements [16, 17].In recent years, scientists have been interested in therole of bioorganic additives in winemaking technology.Silicon-containing preparations, in particular, have abeneficial effect on yeast metabolism and functionalactivity. They intensify alcoholic fermentation, enrichthe wine with volatile components and, therefore,improve its aroma [18–20].We aimed to substantiate the use of the NanoKremnymineral fertilizer in the Crimean vineyards and to studyits effect on crop efficiency, the quality and quantity ofgrape, as well as the chemical composition and sensoryindicators of dry table wines.STUDY OBJECTS AND METHODSOur study objects were the grapes of white (Aligoté,Chardonnay) and red (Cabernet Sauvignon) varieties,as well as respective dry wines produced in 2017–2018 in the western piedmont-coastal area of the mainviticulture zones of Crimea, namely the South-WesternZone (S. Perovskoy; SVZ-AGRO, Sevastopol), theCentral Steppe Zone (Legenda Kryma, Geroyskoyevillage), and the South Coast zone (Livadiya branch ofMassandra Winery, Yalta). Grape cultivation was in linewith the technological maps adopted for each variety ineach zone.The technology for dry white table wines(Chardonnay and Aligoté) included the following stages:– crushing grapes on a manual roll-mill crusher;– destemming;– pressing the pulp on a manual basket-type press;– sulfitating the must with sulfur dioxide (75–80 mg/L)and stirring;– clarifying the must at 14–16°С for 18–20 h;– decanting the clarified must;– introducing a pure culture of the Saccharomycescerevisiae yeast from the Magarach collectionof winemaking microorganisms (strain I-271 forChardonnay, I-187 and I-525 for Aligoté) and stirring;– fermenting the must until dry at 20 ± 2°С withstirring 2–3 times a day;– clarifying the wine; and– decanting the wine.The technology for dry red table wines (CabernetSauvignon) consisted of the following stages:– crushing grapes on a manual roll-mill crusher;– destemming;– sulfitating the pulp with sulfur dioxide (75–80 mg/L)and stirring;– introducing a pure culture of the S. cerevisiaeyeast from the Magarach collection of winemakingmicroorganisms (strains I-652 and I-250) and mixing;– fermenting the pulp with a floating cap at 24 ± 2°С,with mixing 7–8 times a day, up to 1/3 of residualsugars;– pressing the pulp on a manual basket-type press;– fermenting the must until dry;– self-clarifying; and– decanting.Fieldworks were conducted with common methods ofviticulture and plant protection [21, 22]. Foliar dressingwas introduced in a tank mixture with pesticides.Experimental treatment schemes are presentedin Table 1.The chemical composition of grapes, must,and wines was analyzed with standard oenologicalmethods [23–25].The phenolic ripeness of grapes was assessedaccording to Glories et al. [24]. Their methoddetermines the potential amount of anthocyanins thatgrapes can produce (ApH1.0) and the amount of easilyextractable anthocyanins (ApH3.2). The ratio betweenthese amounts shows the percentage of easily extractableanthocyanins in the grape berry (Ea, %).The concentration of organic acids was determinedin freshly squeezed, centrifuged must (OPN-8centrifuge, Kyrgyzstan) by HPLC (Shimadzu LC20ADProminence chromatograph, Japan). The methodrequired preliminary calibration with standardsolutions of pure substances on the spectrophotometricdetector, taking into account their retention time.Individual components of the organic acid profile weredetermined at 210 nm. The sample was separated on aSupelcogel C610H column (Supelco0.000.040.080.120.16Chardonnay,LegendaKrymaChardonnay,S. Perovskoyc.u.in an isocratic mode of eluent supply (0.1% aqueoussolution of phosphoric acid, flow rate 0.5 mL/min). Therefractometric detector was additionally calibratedusing solutions of carbohydrate standards with thesame retention time as organic acids, taking intoaccount their analytical characteristics during analysis.The concentration of organic acids in the sample wascalculated mathematically, using the data obtained onthe UV and refractometric detectors.Volatile components were determined by gaschromatography (Agilent Technology 6890, USA) atan evaporator temperature of 220°С and a thermostattemperature of 50–240°С programmed at 4°С/min. Thecomponents were extracted with methylene chloride.The experimental samples were separated on an HPINNOWAXcolumn (Carbowax 20M or PE-FFAP; 30 mlong, 0.25 mm inner diameter). The NIST 2007 databasewas used to identify the substances.Experimental data were processed by variationalstatistical methods using Excel and SPSS Statistica17 (arithmetic mean, root-mean-square deviation, anderror mean square of a singular result). The tables andfigures show the mean values of the indicators (standarddeviation under 5% at P ≤ 0.005).RESULTS AND DISCUSSIONSilicon fertilizers are an innovation in modernintensive agriculture worldwide. NanoKremny is aunique fertilizer that contributes to high-yielding andecological crops. Its main component is a biologicallyand chemically active silicon in a chelated form.Our field experiments showed that NanoKremnyproduced the best results when applied threefold in theperiods of active growth and formation of vegetative andgenerative organs in grape plants: bud pushing, beforeflorification, after florification, and at the beginningof bunch formation (Table 1). This treatment led toincreased stress resistance and yield, as well as reducedfungal diseases. In particular, it contributed to:– higher productivity of grape plants: for example, thefirst three spray treatments of Cabernet Sauvignon(Livadiya, Massandra) improved the water balanceof grape plants and increased the leaf area (by 13.9%),growth and ripening parameters (by 11.3 and 12.2%),and crop quantity (by 14.7%);– lower risk of downy mildew disease (1.2–3.6 times,depending on variety) and oidium (protection improvedby 10–12%) with threefold spraying during blossomclustering, before florification, and after florification;– higher crop yield: for example, by 5, 45, and 49% forAligoté (SVZ-AGRO), Chardonnay (S. Perovskoy), andCabernet Sauvignon (SVZ-AGRO), respectively [26, 27].The quality of grapes and young wines was assessedon the basis of their chemical composition and sensorycharacteristics. The grape batches under study met therequirements of State Standard 31782. The optimalcontents of titratable acids are 6–9 and 5–8 g/L andthose of sugar are 170–200 and 180–220 g/L for whiteand red varieties, respectively [28]. These contents arenot standardized and recommended for table wines inscientific literature. We compared the carbohydrateacidcomposition of the experimental grape batchesagainst the controls and found an up to 5% increase insugars for Legenda Kryma’s Chardonnay and a 5%decrease in sugars for S. Perovskoy’s Chardonnay andSVZ-AGRO’s Cabernet Sauvignon (Table 2). Thismight be associated with a significant (by 45–49%)yield growth. The experimental batches of Aligotéand Livadiya’s Cabernet Sauvignon had a similarcomposition to that of the controls.The concentration of titratable acids in theexperimental samples increased by 7 and 9% for Aligoté and Livadiya’s Cabernet Sauvignon, respectively.NanoKremny significantly reduced active acidity(by 0.20) only in the Cabernet Sauvignon samples,compared to the controls. Thus, we did not identify anychanges in the carbohydrate-acid complex that would becommon for all the experimental samples, regardless ofvariety or place of growth.Silicon makes plant more stress-resistant bystimulating the synthesis of phenolic metabolites andthe activity of protective enzymes, such as monophenolmonooxygenase(MPMO), peroxidase, and others [29–31]. Important technological characteristics of grapesfor winemaking are the content of phenolic compounds,including anthocyanins, phenolic ripeness, and theactivity of grape oxidases at the time of their technicalripeness [32].The experimental treatments increased thetechnological reserve of phenolic compounds in theexperimental samples by 82–170 and 71–82 mg/Lfor white and red varieties, respectively, comparedto the control. We found that the phenolic reserve inthe Cabernet Sauvignon and Aligoté samples, bothcontrol and experimental, corresponded to the valuesrecommended for table wine production: at least2000 mg/L for red grapes and under 1000 mg/L forwhite grapes [28, 32].We did not find a single trend in the effect ofNanoKremny on the accumulation of monomericanthocyanins in grapes at that stage. For example,Livadiya’s Cabernet Sauvignon showed a 3% increasein monomeric anthocyanins, whereas the same varietyfrom SVZ-AGRO had an 8% decrease. CabernetSauvignon growing on the South Coast reaches phenolicripeness when it has at least 45% of easily extractableanthocyanins [32]. We only used phenolically ripesamples of Cabernet Sauvignon (both control andexperimental), with 44–56% of easily extractableanthocyanins. The experimental treatment did not have asignificant effect on this indicator.We found that the effect of NanoKremny on theMPMO activity of the must depended largely on thegrape variety (Fig. 2). For example, Chardonnay showeda decreasing trend, regardless of the place of its growth,which is a favorable factor for white table wines.Cabernet Sauvignon showed the opposite trend, whilethe Aligoté samples were not affected at all. However,we registered a correlation between the MPMO activityand the place of growth. For example, Chardonnayshowed a decrease in the MPMO activity by 24 and33% for Legenda Kryma and S. Perovskoy, respectively,while Cabernet Sauvignon had an increase by91 and 61% for SVZ-AGRO and Livadiya, respectively,compared to the control.Organic acids determine the sensory characteristicsof wines and the intensity of redox processes, as well asprotect them from harmful bacterial microflora [33, 34].Recent studies have proved the relationship betweenthe metabolism of organic acids and plant resistanceto stress [35]. Organic acids are produced duringplant respiration due to the incomplete oxidation ofcarbohydrates, as well as during photosynthesis (mainlyin leaves, with further transportation to grape berries).Since silicon fertilizers create favorable conditionsfor photosynthesis, we can assume that they have anindirect effect on the metabolism of organic acids inthe grapevine. As we can see in Fig. 3, NanoKremnycontributed to a 9–12% increase in tartaric acid in thegrapes, regardless of their variety and growth area. Asimilar trend was observed with malic acid (especiallyin Chardonnay), whose concentration increased by 8% inCabernet Sauvignon and by 25 and 48% in Chardonnayfrom S. Perovskoy and Legenda Kryma, respectively.The quality assessment revealed that all the whiteand red dry table wines produced from the grapestreated in different ways met the requirements of StateStandard 32030-2013 “Table wines and table winestocks.General specifications” (Table 3).The chemical composition of wines and theirquality result from a combination of factors, includingagricultural methods used in the vineyard. To neutralizetechnological influence, we used the same technologyto produce all the wines. The technologically relevantparameters of grape and wine quality were taken fromprevious studies [10, 28, 32].We found that the Chardonnay and Aligotéexperimental wines showed various trends in relation totitratable acids and active acidity. In the Aligoté wines,the concentration of titratable acids was determinedby the yeast strain. For example, strains I-187 andI-525 increased titratable acids by 1.5 and 0.2 g/L,respectively, compared to the control.Just as the experimental batches of Chardonnaygrapes, the experimental wines from them had a highcontent of phenolic compounds – 7% higher than inthe controls. Their technological reserve in the Aligotéwines, however, remained the same. On average,the concentration of phenolic compounds in theexperimental wines amounted to 114–123 mg/L, whichwas 26–29% lower than in the controls (Fig. 4).It was impossible to determine the exact effect ofNanoKremny on the chemical composition of CabernetSauvignon wines at that stage of research. Only 33% ofthe wine samples showed an 0.7 g/L increase in titratableacids. In 33% of the tested wines, the concentration oftitratable acids decreased by 0.9 g/L. In other cases, thisindicator was the same for both the experimental winesand the controls. The profile of organic acids in the “grapes-wine”chain showed the dominance of tartaric acid, whoseconcentration in the control and experimental samplesdid not differ, averaging 1.4 g/L (Fig. 5). Malic acid,however, did not show the same increasing trend inthe wines as it did in the experimental grape samples.Its average concentration in the experimental wineswas 33% lower than in the controls. This might be dueto malolactic fermentation, which also led to higherconcentrations of lactic and succinic acids, mostlyexpressed in the experimental wine samples (Fig. 5).Although NanoKremny contributed to theaccumulation of phenolic compounds in the grapes,their concentration averaged 1446–2427 mg/L in67% of the experimental wines, which was 2–7%lower than in the controls. The only exception was thewines from SVZ-AGRO where the concentration ofphenolic compounds averaged 1593 mg/L – 20% higherthan in the control. This might be due to the initialcomposition of raw materials and the physiological andbiochemical properties of the strains used. Compoundsproduced from fermentation can affect the speed ofredox processes initiated and mediated by phenoliccompounds.The concentration of monomeric anthocyaninswas 301–385 and 314–401 mg/L in the control andexperimental wines, respectively. In Livadiya’s wines,monomeric anthocyanins accounted for 12–17% ofphenolic compounds, only half of their proportionin the grapes. In the wines from SVZ-AGRO, theyamounted to 20–26%, almost the same as in the grapes(21–23%). This might be due to their ability to bindwith other сompounds, form complex structures, andprecipitate [36]. This assumption could be supported bya lower content of acetaldehyde in the wine materials in2017 (8–40 mg/L) compared to 2018 (90–133 mg/L).Aroma is an important characteristic of winequality. According to the chromatographic analysis, theconcentrations of aroma-producing components in theAligoté and Cabernet Sauvignon wines averaged 104–108 and 120–149 mg/L in the controls, and 96–104 and112–141 mg/L in the experimental samples, respectively.Aliphatic and aromatic alcohols were predominantamong aromatic substances, with the same totalconcentrations in the experimental and control samplesaveraging 27–31 and 25–32 mg/L for Aligoté and 35–47and 27–35 mg/L for Cabernet Sauvignon, respectively.All experimental wines from Aligoté grapes,regardless of the yeast strain used, showed an increasein ethyl esters 1.2–1.5 times (Fig. 6). They also hadhigh concentrations of acetic acid esters – 2.2 times and1.6 times higher when treated with the I-187 andI-525 yeast strains, respectively (Fig. 6). The I-525 strainraised the concentration of dioxanes and dioxolans to anaverage of 3.29 mg/L, which was 2.9 times higher thanin the controls.The experimental wines from Cabernet Sauvignongrapes showed lower (1.2–1.5 times) concentrationsof ethyl esters, averaging 7–9 mg/L. As we can see inFig. 6, the samples treated with the I-652 strain had1.3 and 2.1 times lower concentrations of lactones and acetates than in the controls, averaging 3.14 and3.76 mg/L, respectively. The I-250 strain increasedthe concentration of dioxanes and dioxolans 1.8 timescompared to the control. These compositions of thearoma-producing complex might be determined bythe physiological and biochemical abilities of the yeaststrains used.The assessment of the influence of grape treatmenton the sensory quality of wines showed that young whitetable wines from Chardonnay grapes contained someshades of medicinal herbs, absent in the control samples.The control Aligoté wines were characterized by alight straw color, a floral aroma, with hints of meadowherbs, candy and spicy tones, and a harmonious taste.In contrast, the experimental wines had a straw color, afruity aroma, with herbal, spicy and candy tones, as wellas a fresh, slightly astringent taste. The average tastingscores of Aligoté wines were 7.70 and 7.77 points for theexperimental and control samples, respectively.The control red table wines from CabernetSauvignon grapes had a dark ruby color, a varietalberry aroma with hints of spices, nightshade, moroccoleather, and milk cream, as well as a moderate velvetyflavor with light astringency. Their average tastingscores were 7.69 and 7.82 points for the 2017 and2018 grape harvests, respectively. The experimentalwines (chemical protection + NanoKremny treatment)had a dark ruby color, a berry aroma with light herbaltints, and a somewhat simple palate with moderatetannins. Their average tasting scores were 7.57 and 7.74–7.75 for the 2017 and 2018 grape harvests, respectively.Different yeast strains had no significant effect on thetasting scores of the experimental red wines.Thus, the differences in the sensory scores of thecontrol and experimental wines were statisticallyinsignificant (Р < 0.05).CONCLUSIONOur study showed that the optimal treatment ofgrapevines is a threefold application of NanoKremny(0.15 L/ha) during the periods of active growth andformation of vegetative and generative organs in thegrape plant. This scheme has a positive effect onvegetative development, water balance, grape plantproductivity, as well as yield quality and quantity. Also,it prevents the development of mildew and oidiumdiseases.The NanoKremny treatment of the grapevinepreserves the content of titratable acids during graperipening and accumulates phenolic compounds, tartaricand malic acids in the berries. We found no significantdifferences in the physicochemical parameters of thewines from NanoKremny-treated grapes and the controlwines from grapes that underwent standard chemicalprotection.The sensory evaluation of young wine samplesshowed that the NanoKremny treatment enhanced theexpression of herbal (grassy) shades in the aroma of bothwhite and red wines. Although it somewhat simplifiedtheir taste, NanoKremny did not have a negative effecton the wine quality.CONTRIBUTIONN.V. Aleinikova studied the effect of NanoKremnyon the grape plant and was involved in approving thefinal version of the manuscript. I.V. Peskova processedexperimental data about the effect of NanoKremny onthe quality of grapes and wines, and was involved inwriting the manuscript. E.V. Ostroukhova studied theeffect of NanoKremny on the quality of grapes as rawmaterials for winemaking and on the quality of wines;she was also involved in approving the final version ofthe manuscript. Ye.S. Galkina processed experimentaldata about the effect of NanoKremny on the grape plant.P.A. Didenko conducted fieldworks to identify the effectof foliar dressing on the grape plant. P.A. Probeigolovaand N.Yu. Lutkova analyzed the chemical composition ofgrapes and wines.CONFLICT OF INTERESTThe authors declare that they have no conflict ofinterest.ACKNOWLEDGEMENTSThe authors are grateful to D.Yu. Pogorelov andS.O. Ulyantsev from the Department of Wine Chemistryand Biochemistry at the Magarach All-Russian NationalResearch Institute of Viticulture and Winemaking fortheir help with chromatographic analysis, as well asall our colleagues involved in the preparation of themanuscript.