The effect of mineral fertilizers on the biochemical composition of vegetable crops

Sugar content of vegetables is one of the main indicators of their quality, determining the taste and overall nutritional value of the produce. In the fresh mass of crops, sugars account for 3 to 6%. This carbohydrate complex is 70% represented by glucose, fructose, and sucrose. At the same time, simple monosaccharides predominate in cabbage, tomatoes, peppers, cucumbers, and eggplants, while sucrose accumulates primarily in onions.

• Sugars in vegetables — 3–6% of fresh mass
• Share of glucose, fructose, and sucrose — 70%
• Polyfructosides in garlic — 20–30%
• Cellulose in tomatoes — 0.2%

In addition to easily digestible sugars, crops also accumulate other carbohydrates — starch, polyfructosides, and pectins. Their concentration in the produce varies significantly depending on the plant species. Detailed data on carbohydrate accumulation in different crops are presented in the table.

An important component of cell walls is cellulose, which determines the density of plant tissues. In most vegetables, its level remains within 0.5–1.0%, reaches 1–2% in cabbage, and does not exceed 0.2% in tomatoes. An increase in this indicator reduces the nutritional value of the harvest.

How mineral fertilizers affect the sugar content of vegetables

Optimization of nitrogen nutrition allows for a significant increase in the content of sugars and ascorbic acid in vegetables. Under the influence of nitrogen, plants grow more intensively and form a powerful, physiologically active photosynthetic apparatus. This contributes to a more active accumulation of dry matter and sugars in the tissues. The role of nitrogen fertilizers increases especially significantly under conditions of artificial irrigation.

Phosphate fertilizers, when applied correctly, accelerate the development of crops and stimulate fruit set. They also promote the accumulation of sugars in fruits, but they must be applied taking into account the soil's availability of mobile forms of phosphorus. The effect of potash fertilizers directly depends on the content of exchangeable potassium in a specific area. On potassium-poor soil, potash fertilizers are guaranteed to increase the sugar content of vegetables, whereas in well-supplied fields, this practice has no effect.

Microelements have a significant influence on the carbohydrate metabolism of crops. They activate photosynthesis, stimulate the outflow of carbohydrates within the plant, and accelerate protein synthesis. In addition, micronutrient fertilizers increase plant resistance to diseases and adverse environmental conditions. Due to an increase in the number of buds and the acceleration of flowering, they contribute to an increase in yield, as well as the accumulation of sugars and ascorbic acid.