Biochemical composition and nutritional value of pome fruits

Consumer qualities and chemical composition of apples

The market quality of fruits and the demand for them directly depend on the accumulation of sugars, acids, and vitamins. When planning sales and processing, it is important for an agronomist to consider the biochemical profile of the grown cultivars. The main part of the dry matter of fruits consists of carbohydrates, pectins, and organic acids, which determine the taste and storage life of apples.

Component	Content, % of raw mass
Sugars	5—15
Fiber	0.6
Starch	0.8
Pectin substances	0.27
Organic acids	0.3—0.89

Among organic acids in apples, malic (0.37%) and citric (0.11%) predominate; tartaric and chlorogenic acids are also present. Flavonoids are localized mainly in the fruit peel. The apple peel contains a large amount of the antioxidant quercetin, which, together with vitamin C, prevents free radicals from causing harmful effects on the body.

Vitamin	Content per 100 g of fruit
Vitamin P	60—400 mg
Vitamin C	8—22.4 mg
Vitamin B1	0.8—2.3 mg
Vitamin B2	0.05 mg
Vitamin B6	0.08 mg
Carotene	0.02—0.03 mg

Green apple cultivars are distinguished by a specific chemical composition. They contain the substance Bis in the amount of 0.07 mg%, vitamin E (0.63 mg%), and biotin (0.30 mcg%). The mineral complex of apples includes potassium, phosphorus, magnesium, sodium, sulfur, aluminum, boron, vanadium, iron, iodine, copper, molybdenum, nickel, fluorine, chromium, and zinc.

• Fiber in a fruit with peel — up to 3.5 g
• Fiber in a fruit without peel — up to 2.7 g
• Share of the daily fiber requirement in one apple — more than 10 %
• Chlorogenic acid content — from 5 to 50 mg%

Dietary fiber and pectin in apples normalize the functioning of the gastrointestinal tract, improve digestion, help prevent constipation, and increase appetite. Insoluble fiber binds cholesterol, reducing the risk of vascular occlusion and the development of colon cancer. Pectins help remove excess cholesterol produced by the liver, and also bind heavy metals — lead and arsenic. Chlorogenic acid supports liver function and accelerates the excretion of oxalic acid.

Biological activity and medicinal properties of pear

The pear is in demand in the fresh produce market and for dietary nutrition due to its balanced composition. Sugars, enzymes, organic acids, nitrogenous, tannin, and pectin substances accumulate in the fruits. The crop is also valued for its high content of vitamins C, B1, P, PP, carotene (provitamin A), flavonoids, and phytoncides.

Pears contain fewer sugars compared to apples but seem sweeter due to low acidity. Pear fruits and leaves are rich in microelements, including iodine. The crop is also a source of folic acid, which is necessary for hematopoiesis processes.

Unique essential oils and biologically active substances in pear fruits increase the body's defenses, help resist infections, and have an anti-inflammatory effect. Both fresh or dried fruits and leaves are used as medicinal raw materials. The fruits are effective in dietary nutrition for diseases of the heart, liver, kidneys, diabetes mellitus, and capillary permeability disorders.

Decoctions of dried fruits and leaves, as well as pear juice, are indicated for inflammatory diseases of the urinary tract — cystitis and pyelonephritis. It is useful for obese patients to consume pear compote without added sugar. Ripe, juicy, and sweet pears help digest food and are useful for intestinal disorders.

The high potassium content makes the pear useful for the heart and for heart rhythm disorders. In folk medicine, the fruits have long been used as an effective remedy for prostatitis. Additionally, a decoction of dried pears has analgesic, antiseptic, and diuretic effects, while boiled and baked fruits are used for severe coughing, asthma, and pulmonary tuberculosis.

It is recommended to consume pears if the following symptoms are present:

• rapid fatigue;
• dizziness;
• loss of appetite;
• poor wound healing.

Pear seeds also possess pronounced anthelmintic properties.

Biochemical potential of cherry and plum

Cherry is one of the most valuable fruit crops, second only to garden strawberry in the richness of its chemical composition. Its fruits contain a balanced complex of fructose, glucose, carotene, folic and organic acids, as well as copper, potassium, magnesium, iron, and pectins. The combination of vitamins C, B1, B2, B6, magnesium, cobalt, iron, and folic acid effectively strengthens the walls of small blood vessels and prevents the development of anemia. A high concentration of ascorbic acid stimulates the immune system, helping the body resist viral infections.

Due to the high levels of coumarins in the fruit pulp, cherries improve the rheological properties of blood and reduce the risk of thrombosis. Regular consumption strengthens the heart muscle and accelerates rehabilitation after strokes and heart attacks. Cherry fruits serve as a natural antioxidant, slowing down cell aging, and help in the prevention of rheumatic diseases and atherosclerosis. Cherry juice and the folic acid in its composition normalize the central nervous system and improve cerebral circulation.

Plums accumulate a wide range of mineral substances, proteins, carbohydrates, free organic acids, and dietary fibers. Their fruits contain vitamins A, B1, B2, B6, PP, C, E, as well as potassium, calcium, sodium, phosphorus, magnesium, chromium, zinc, iodine, manganese, copper, and fluorine. A distinctive feature of the plum is the high concentration of vitamin P and P-active compounds, which lower blood pressure and strengthen the walls of blood vessels.

Fresh and dried plum fruits, as well as juices with pulp, have a mild laxative effect for intestinal atony and facilitate the elimination of cholesterol. Coumarins contained in the fruits and leaves of the plum dilate coronary vessels and prevent the formation of blood clots. The leaves also possess medicinal properties: decoctions made from them are used as an effective wound-healing agent. Plum consumption stimulates hematopoiesis, improves liver function, and accelerates the elimination of toxins in cases of gallbladder disease.

Nutrient requirements of fruit and berry crops

Fruit trees and berry shrubs grow in the same place for years; therefore, the fertilizer system is the main factor in maintaining soil fertility. Obtaining stable and high-quality yields is possible only with an uninterrupted supply of macro- and micronutrients to the plantings. The total amount of nutrient uptake depends on the planned yield, plant habit, and the concentration of elements in plant tissues. Among fruit crops, the apple and peach have the highest nutrient requirements, while among berry crops, the strawberry and gooseberry do.

Crop	Yield, kg/100 m²	Nitrogen (N), g/100 m²	Phosphorus (P₂O₅), g/100 m²	Potassium (K₂O), g/100 m²	Calcium (CaO), g/100 m²
Apple (fruiting)	615	668	179	715	734
Pear (young, fruiting)	220	336	81	378	435
Plum (young, fruiting)	99	339	102	435	471
Strawberry	108	1560	346	1844	—
Red currant	201	1330	510	820	1740
Black currant	73	630	250	340	940
Gooseberry	180	790	400	1230	960

• Maximum nitrogen uptake (strawberry) — 1560 g/100 m²
• Maximum potassium uptake (strawberry) — 1844 g/100 m²
• Maximum calcium uptake (red currant) — 1740 g/100 m²

The initiation of fruit buds in perennial plantations occurs in the year preceding fruiting. To build an effective nutritional system, it is necessary to consider two critical periods of active nutrient absorption:

• Spring and early summer — during this time, there is intensive shoot growth and formation of the current fruit and berry harvest.
• End of the growing season (late summer and autumn) — the phase of thickening of the trunk and branches, accumulation of reserve substances, and bud formation for the future harvest.

Fruit and berry crops grow in the same place for decades, so the soil must be prepared before planting nursery plants. One should start with agrochemical analysis to determine the actual soil fertility and bring it to optimal levels. Without this, it is difficult to count on good survival rates and a quick start for a young orchard.

• Organic matter in the soil — at least 7–8 %
• Available phosphorus and potassium — at least 120–150 mg/kg
• Optimal acidity — pH 5.5–6.5
• Liming frequency — once every 5–8 years
• Depth of lime incorporation — 40–50 cm

The reaction of the soil solution directly affects the development of the root system. Each crop has its own optimal acidity range. In relation to pH levels, fruit and berry plants are divided into three main groups:

• Cherry and plum require a neutral or slightly alkaline reaction (pH 6.0–7.5);
• Apple, pear, currant, and gooseberry develop better under a slightly acidic reaction (pH 5.5–6.5);
• Strawberry and raspberry are capable of tolerating a more acidic reaction (pH 5.0–6.0).

For stone fruits, a full dose of lime is applied, calculated as 1.5 times the hydrolytic acidity (Hg x 1.5 in mg-eq/100 g of soil, converted to kg per 10 m²). For apple and currant, the dose is calculated using the formula 1 Hg. For gooseberry, the application rate is reduced by 25–30% and applied in two stages. When planting strawberries, liming is carried out only at pH 5.5 and below, and deacidifying agents should be applied in advance — 2–3 years before planting the nursery plants.

To neutralize acidity, ground limestone, dolomite flour, Gumi-Lime, marl, or defecation lime are used. These materials help balance the elements in the soil solution. Application rates are calculated based on the soil texture.

Soil	pH KCl 4.8–4.9	pH KCl 5.0–5.1	pH KCl 5.2–5.3	pH KCl 5.4–5.5	pH KCl 5.6–5.7
Sandy loam	0.35	0.3*	0.25*	0.0	0.0
Light loamy	0.5	0.45	0.4	0.35	0.3*
Medium loamy	0.55	0.5	0.45	0.35	0.3*
Heavy loamy	0.65	0.6	0.5	0.45	0.4

* — liming is optional. Doses are given in terms of CaCO3, kg/m².

In addition to liming, it is essential to increase soil fertility in low-fertility areas using organic matter. To do this, apply manure or compost at a rate of 4–6 kg/m², or pre-sow green manure crops. Basic mineral nutrition is provided by applying phosphorus-potassium fertilizers at a rate of 50–100 g/m².

1. Perform an agrochemical analysis and determine the soil texture on the plot.
2. Apply liming materials to a depth of 40–50 cm (if deacidification is required).
3. Distribute organic matter (4–6 kg/m²) and phosphorus-potassium fertilizers (50–100 g/m²) over the area, then till the soil.
4. Prepare planting holes by filling them with the top humus layer taken from the row spacings.

At-planting fertilization and young orchard care

If the growth of young trees is noticeably weakened and shoot length does not exceed 30–40 cm, nitrogen application begins 2–3 years after planting. This is done with good aeration and sufficient soil moisture. For top dressing, use urea (15–25 g/m²) or the preparation Gumi-Omi Nitrogen. Nitrogen fertilizers are more effective when applied in split doses: give half the dose in spring during intensive root and shoot growth, and the second half in mid-summer.

In cases where phosphorus and potassium fertilizers were not applied before planting or were applied in insufficient quantities, the doses are increased in the second and third years after planting. Apply 25–30 g of superphosphate and potassium chloride (or Gumi-Omi Phosphorus and Gumi-Omi Potassium preparations) per square meter. This allows the content of available phosphorus and exchangeable potassium in the soil to reach an optimal level.

Basic application rates and fertilization systems in a fruiting orchard

As soon as a young orchard begins fruiting, the nutrient uptake from the soil increases sharply. In the first 4–5 years after planting and the first 2–3 years of fruiting, trees consume relatively few nutrients, with nitrogen predominating in the uptake. However, during the period of mass fruiting, the plants' demand for nutrients increases dramatically. In apple and pear trees, potassium begins to predominate in the uptake, while in sour and sweet cherries, it is potassium and phosphorus.

To maintain the balance of elements in fruiting orchards and berry patches, an organic-mineral fertilization system is used. Specific doses are calculated based on the soil's nutrient supply level. Basic guidelines for annual application per one square meter of the tree trunk circle are as follows:

• Organic fertilizers — 3 kg/m²
• Urea — 35–45 g/m² (or Gumi-Omi Nitrogen — 70–90 g/m²)
• Superphosphate — 10–30 g/m² (or Gumi-Omi Phosphorus — 20–60 g/m²)
• Potassium chloride — 10–45 g/m² (or Gumi-Omi Potassium — 30–120 g/m²)

For precise nutrition management, use the application standards for basic and complex fertilizers. The table below shows recommended doses depending on the soil type and the group of horticultural crops.

Fertilizer	Gray forest soils, leached chernozems			Typical chernozems
	Pome fruits	Stone fruits	Berry shrubs	Pome fruits	Stone fruits	Berry shrubs
Manure (decomposed), compost	20–30	10	6–8	10–12	8	4–6
Ammonium nitrate	0.06	0.04	0.02	0.06	0.04	0.02
Superphosphate	1.0	0.4	0.2	0.5	0.3	0.15
Potassium sulfate	0.15	0.06	0.04	0.08	0.05	0.03
Wood ash	0.8	0.4	0.2	0.4	0.2	0.1
Ground limestone, dolomite	0.6–1.0	0.3–0.4	0.1–0.5	—	—	—
Bionex	1–0.5	0.7	0.5	0.5–0.6	0.4	0.3
Gumi-Omi Phosphorus	1.0–1.6	0.4–0.5	0.3	0.7–1.0	0.3–0.4	0.2
Gumi-Omi Potassium	0.25	0.1	0.06	0.1	0.08	0.05
Gumi-Omi Nitrogen	0.09	0.06	0.04	0.08	0.06	0.03
Gumi-Lime	0.8–1.4	0.5–0.87	0.3–0.7	—	—	—

Fertilization timing and foliar top dressing

The efficiency of nitrogen nutrition directly depends on the correct distribution of the dose throughout the season. At the beginning of the growing season, fruit trees experience maximum nitrogen demand. High yield and active shoot growth can completely deplete soil nitrogen reserves by the end of summer. It is agronomically justified to apply nitrogen in two or three split doses according to a clear schedule.

1. The first application is carried out in early spring, immediately after bud break.
2. The second dose of nitrogen is applied after the mass shedding of excess fruit set.
3. The third part of the dose is distributed in autumn, after the completion of harvesting.

Foliar application of carbamide is indispensable in years with abundant flowering, when the setting of buds for the following year's harvest is under threat. The first spraying is carried out 8–10 days after flowering, and the subsequent 2–3 treatments are repeated at two-week intervals. It is extremely important to strictly maintain a safe concentration of the solution for each type of plant.

Crop	Urea solution concentration for spraying, %
Apple	0.5–0.1
Pear	0.8–1.0
Plum	0.6–0.8
Cherry	0.4–0.8
Berry crops (except strawberry)	0.4–0.6
Strawberry	0.8–1.0
Grape	0.4–0.7

In addition to macronutrients, the garden requires timely provision of micronutrients. Their deficiency is often provoked by soil conditions and imbalances in the main fertilization system. The risks of lacking specific elements are distributed as follows:

• On carbonate and limed soils, plants often experience an acute deficiency of manganese, boron, and zinc.
• When excessive doses of phosphorus fertilizers are applied, the plant uptake of zinc, manganese, and copper is blocked.
• On acidic soils, a molybdenum deficiency occurs most frequently.

To promptly eliminate signs of starvation, foliar micro-nutrient top dressing is used as the fastest way to deliver nutrition. Spraying is carried out according to the developmental stages: in the budding stage before flowering, immediately after it ends, at the stage of fruit swelling, and after the completion of harvesting harvesting.

Foliar top dressing and pre-planting fertilizer rates for berry crops

Berry shrubs grow in the same place for several years. Rapid entry into fruiting and annual high yield determine their increased demand for nutrient conditions. Foliar treatments allow for the prompt correction of micronutrient deficiency during critical developmental stages of the plants.

Nutrient	Fertilizer	Solution concentration, %	Dose per 10 l of water	Timing and method of spraying
Manganese	Manganese sulfate	0.05–0.10	5–10 g	On leaves
Boron	Boric acid	0.10–0.15	10–15 g	1st – after flowering; 2nd – during berry growth
Copper	Copper sulfate	0.02–0.05	2–5 g	On leaves
Zinc	Zinc sulfate	0.05–0.10	5–10 g	On leaves
Molybdenum	Ammonium molybdate	0.01–0.03	1–3 g	On leaves
Cobalt	Cobalt sulfate	0.005–0.01	0.5–1.0 g	On leaves
11 micronutrients	Gumi-K	0.01–0.02	15 ml	On leaves
Boron + 11 micronutrients	BOROGUM-M	1.5	150 ml	On leaves
NPK + 13 micronutrients	BOGATYI	0.2–0.3	20–30 ml	1st – after flowering; 2nd – during berry growth

The foundation for high productivity is laid even before planting nursery plants. Incorporating organic matter and phosphorus-potassium fertilizers during deep tillage brings the content of mobile forms of phosphorus and potassium to optimal values. This provides young plants with nutrition for their first years of development.

• Organic fertilizers — 6–15 kg/m²
• Bionex fertilizer — 50 g/m²
• P and K for strawberry and raspberry — 60 g/m² each
• P and K for currant and gooseberry — 80 g/m² each

Specifics of berry crop nutrition and the value of black currant

Different types of berry crops have their own mineral nutrition requirements. Strawberry responds with a decrease in yield to an excess of nitrogen in the soil, whereas for raspberry in spring, nitrogen is vital for the formation of replacement shoots. Currant, in turn, is sensitive to chlorine; therefore, it is not recommended to apply chlorine-containing potassium fertilizers to it.

Black currant is valued as a natural source of vitamins and biologically active substances. Its berries contain vitamins of groups B and P, provitamin A (up to 3% mg carotene), pectins, essential oils, phosphoric acid, tannins, potassium salts, iron, and phosphorus. To cover a person's daily need for vitamin C, it is enough to eat just 20 g of fresh berries.

Blackcurrant leaves also possess medicinal potential due to their content of magnesium, manganese, silver, copper, sulfur, phytoncides, and vitamin C (up to 250 mg/kg). Decoctions made from berries and leaves are used for gastritis, gastric ulcers, hypertension, anemia, and bleeding gums, while baths with leaf decoctions help with skin rashes. The complex of anthocyanins and vitamins is preserved during canning, helping to strengthen the immune system and support the cardiovascular system.

Optimum pHKCl	5.5 - 6.5
Liming frequency	once every 5 – 7 years
Application rate	0.4 – 0.6 kg/m 2

Acidic soils are treated by liming with any calcium-containing fertilizer, for example, Izvest-Gumi.

For currants, the nutrition regime is very important during periods of vigorous shoot growth, flowering, fruit set, and berry formation.

At the beginning of the spring growing season, currant plants particularly need a high level of nitrogen, as well as phosphorus nutrition, to activate growth processes and shoot formation. A deficiency of nitrogen at the very beginning of currant growth before bud break, and phosphorus before the onset of flowering, sharply weakens its subsequent growth and leads to:

• a decrease in the setting of fruit buds;
• dropping of fruit set;
• a decrease in berry yield not only in the current but also in the following year.

Intensive potassium nutrition during the berry formation period increases their size and stabilizes yield over the years. If plants are insufficiently supplied with potassium in the first half of the growing season and during an abundant harvest, it becomes necessary to apply potassium fertilizers after harvesting to ensure good overwintering of the wood.

If a sufficient amount of organic and mineral fertilizers was not applied before planting currants, then in the 1st – 3rd years after planting, you should apply:

Fertilizer	Application rate
Phosphorus	up to 100 g/m2
Potassium	up to 70 g/m2

Nitrogen fertilizers are applied annually in early spring – before fruiting and during the period of full fruiting at 10 – 15 g/m2. Annual application of Gumi-Omi UNIVERSAL, Gumi-Omi BERRY at 30 - 40 g of fertilizer per bush or root top dressing with these fertilizers is effective: 0.7 kg of fertilizer in 100 liters of water per 20 bushes.

Gooseberry. Gooseberries contain many B-group vitamins (B2, B1, B9, B6), and the berry is also rich in vitamins A, C, PP, and E. It contains many macro- and microelements: iron, iodine, potassium, manganese, copper, molybdenum, calcium, sodium, nickel, sulfur, magnesium, phosphorus, and fluorine. The berries contain dietary fiber, mono- and disaccharides, and organic acids. The caloric content of gooseberries is approximately 45 kcal on average.

Gooseberries are classified as medicinal food products. This is a unique dietary remedy that is especially valued in case of metabolic disorders (especially in obesity). Gooseberries are of great benefit for diseases of the kidneys, gastrointestinal tract, bladder, gastroenterocolitis, and chronic constipation. Gooseberries are also used as a diuretic and choleretic agent. If hypovitaminosis or a deficiency of copper, iron, or phosphorus in the body is diagnosed, one should eat fresh berries or prepare a decoction from them.

Gooseberries have higher requirements for the level of potassium nutrition than black currants. Gooseberries tolerate increased acidity well and are relatively resistant to chlorosis on carbonate soils (suffering less than raspberries and strawberries in this regard). The optimum pHKCl value ranges from 4.6 to 5.6.

With a medium level of soil nutrient supply, 8 – 10 kg/m2 of manure, no more than 80 g/m2 of phosphorus, and 70 g/m2 of potassium fertilizers are applied during planting. With a high level of soil supply with these elements, the corresponding types of fertilizers are not applied before establishing berry patches.

Against the background of manure (6 kg/m 2 every 3 – 4 years) and a good supply of mobile forms of phosphorus and potassium, nitrogen fertilizers maintain a high effect on gooseberry yield, while phosphorus and potassium fertilizers do not.

In the first two years after planting gooseberries, 10 – 15 g/m2 of nitrogen fertilizers are provided – carbamide or 20-30 g/m 2 of GumiOmi Nitrogen. After the bushes enter intensive fruiting, the dose can be increased by 20%.

Annual application of Gumi-Omi Universal, Gumi-Omi Berry under gooseberries is also effective using the following methods:

• 30 - 40 g of fertilizer per bush;
• root top dressing: 0.7 kg of fertilizer in 100 liters of water per 20 bushes.

Raspberry — a delicious berry, and therefore loved by everyone. But this berry, in addition to its excellent taste, has a number of beneficial properties, thanks to which it is widely used in the treatment and prevention of many diseases.

Garden raspberry berries contain many valuable substances:

Sugars (glucose, fructose, sucrose)	up to 11.5%
Pectin	up to 0.9%
Dietary fiber	46%

The composition also includes organic acids (citric, malic, salicylic), tannins, anthocyanins, flavonoids, mineral substances and microelements (iron, potassium, copper, calcium, magnesium, cobalt, zinc), vitamins C, B1, B2, PP, folic acid, and provitamin A.

Raspberries are low in vitamin C but enriched with iron. Raspberries contain more iron than other fruit crops (2–3.6 mg per 100 g of berries), with the exception of cherries and gooseberries. Its seeds contain fats and beta-sitosterol, which possess anti-atherosclerotic properties. The leaves contain flavonoids and organic acids.

Interestingly, garden raspberries exceed wild ones in salicylic acid content, which is why they are actively used for colds, acute respiratory diseases, flu, radiculitis, febrile conditions, joint pain, and neuralgia. The salicylic acid contained in raspberries reduces high body temperature without side effects, and raspberry berries have a pronounced sudorific effect. If a person regularly drinks raspberry decoction, they get viral diseases less often, and the illness is 2–3 times milder.

Raspberry nutrition: a balance between shoot growth and yield

Raspberry berries and leaves have antitoxic, hemostatic, and diuretic properties, improving kidney function. They are indicated for gastrointestinal diseases, anemia, hypertension, and atherosclerosis, and the copper contained in the fruits helps cope with nervous tension. Organic acids — malic, tartaric, and citric — stimulate digestion and suppress the activity of pathogenic microorganisms, reducing the risk of intestinal infections.

Raspberries are demanding regarding growing conditions and produce the best yield on drained medium and light loams with high humus content. The crop easily tolerates high soil acidity, but on strongly acidic sites, moderate liming will be beneficial as it improves the mobilization of nutrients. Plants consume essential nutrients throughout the entire growing season: phosphorus and potassium are absorbed most intensively during the flowering and fruit set periods, while nitrogen is also consumed after fruit set.

For soils with an average level of soil fertility, 40–60 g of phosphorus, 30–60 g of potassium, and up to 30 g/m² of magnesium fertilizers are applied before plantation establishment. Nitrogen feeding starts only in the 3rd–4th year of fruiting, using mineral fertilizers or organic matter. After planting, organic fertilizers serve mainly as mulch, which retains soil moisture and improves soil structure.

A properly selected application rate of fertilizers should stimulate the growth of weak shoots and simultaneously promote the formation of flower buds on well-developed stems. The harvest of the following year directly depends on the number of replacement shoots and their development. It is important for an agronomist to maintain a balance, as excessive nutrition is harmful to plants.

• Manure before planting — 4–6 kg/m²
• Gumi-Omi Universal / Berry — 0.7 kg per 10 m²
• Nitrogen fertilizers (from the 3rd–4th year) — 10–15 g/m²
• Gumi-Omi Spring (from the 3rd–4th year) — 20–25 g/m²
• Borax or boric acid concentration — 0.05–0.1%
• BOROGUM-M application rate — 20 ml / 2 l of water per 40 m²

On limed soils, raspberries often face a boron deficiency. This manifests as the dieback of stem tips and a delay in bud burst. Boron starvation is corrected by foliar applications, which additionally increase the productivity of the plantings and the sugar content of the berries.

Biochemical composition and dietary value of strawberries

Strawberries are valued as an early dessert berry and a valuable raw material for therapeutic and preventive nutrition. Their fruits improve appetite, normalize metabolism, and beneficially affect thyroid gland function due to the regulation of iodine metabolism. Regular consumption of berries strengthens blood vessels, reduces their permeability and fragility, and also helps clear the walls of cholesterol plaques.

Strawberry berries have a mild diuretic and sudorific effect. This allows for gentle cleansing of the kidneys, activation of bile flow, and prevention of urolithiasis and cholelithiasis. Also, the consumption of fresh berries is indicated for anemia and heart diseases.

Component	Content and biologically active substances
Carbohydrates (glucose, fructose, sucrose)	5–12%
Proteins	1 g per 100 g of berries
Vitamins	C, P (flavonoids), group B, beta-carotene (provitamin A)
Minerals	Potassium, calcium, phosphorus, magnesium, manganese, iodine, iron, sodium, silicon, copper
Organic acids	Citric, malic, salicylic
Other nutrients	Pectins, fiber, phenolic compounds

Garden strawberries have specific requirements for soil fertility. At the same time, they are significantly less responsive to a high level of mineral nutrition compared to other berry crops. Since the root system of strawberries is located in the surface layer, the plants are extremely sensitive to high concentrations of salts in the soil solution.

• Manure application rate before planting — 6–8 kg/m²
• Phosphorus-potassium fertilizer dose at planting — 15–20 g/m² of each
• Depth of localized fertilizer application — 10–15 cm
• Optimal soil acidity level pH(KCl) — 5–6

When planning a strawberry nutrition system on light and medium-textured soil, it is important to follow safety rules to avoid damaging the root system and hindering its development.

• Do not over-fertilize the soil, especially that of a light granular texture (this also applies to pre-planting application).
• Completely exclude the use of chlorine-containing potassium fertilizers.
• Calculate mineral fertilizer doses strictly based on soil analysis, with mandatory consideration of the organic matter already applied.
• Apply dry mineral fertilizers locally on both sides of the row at a depth of 10–15 cm.

Top dressing regulations by plantation exploitation years

1. First year (non-fruiting plantings): for spring planting, apply nitrogen top dressing at the end of summer. Use 5–10 g/m² of urea, or 10–15 g/m² of "Gumi-Omi Nitrogen", or 1 kg per 10 m² of "Gumi-Omi Berry" or "Gumi-Omi Spring". For autumn planting, postpone this task until the following spring.
2. Second year: apply nitrogen fertilizers in similar doses strictly after harvesting.
3. Third and subsequent years: divide the annual nitrogen rate in half. Apply the first part in spring at the beginning of the growing season, and the second — after harvesting.
4. Later plantings (after harvest): additionally apply phosphorus (up to 15 g/m² of superphosphate or 0.5 kg per 10 m² of "Gumi-Omi Phosphorus") and potassium fertilizers (15–20 g/m² of potassium sulfate or 0.5 kg per 10–20 m² of "Gumi-Omi Potassium").