- Mineral fertilizers
- Mineral fertilizers
Lithium is a biologically important element in plant life and influences the content and heterogeneous composition of proteins and nucleic acids, enzymatic activity of enzymes associated with protein-nucleic acid metabolism.
There is data on the role of lithium in the carbohydrate metabolism of plants, an increase in the intensity of photosynthesis during the reproductive period, an influence on the rate of photorespiration and grain productivity of winter wheat. Specific role in alkaloid metabolism is marked. Influence on ascorbic acid accumulation in plants and positive action in the fight against viral infections were established.
The necessity of lithium for humans and animals was proved. The effectiveness of lithium in various diseases depends on its effect on neuroreflex activity as well as adrenolytic, noradrenolytic, antihistamine, antiserotonin action and regulating effect on hormonal activity of endocrine glands, especially cortical layer of adrenal glands. In hypertension of different origin, lithium has anti-stress and sedative effect. Positive effect in some pathological processes is determined by a stimulating effect on the immune system and on nonspecific protective reactions of the body.
When lithium is in excess in human body, it has toxic effect. Symptoms of poisoning indicate a neurotoxic effect of lithium. Increased content in feed leads to decalcification of bone tissue and morphogenic changes in animals. Correction of human and animal intake with agricultural products enriched with lithium is promising.
At present, there is no information on the necessity of lithium for agricultural plants: the reaction to lithium fertilizer application depends on habitat conditions, age and systematic position. Positive effects of lithium fertilizers on tobacco, cotton, sugar beets, tomato, sweet peppers, and potatoes have been noted.
On the other hand, the use of lithium fertilizers as a microfertilizer requires taking into account its possible toxicity. An excess of lithium salts leads to morphological changes in plants – disruption of mitosis. Cypresses, crucifers, honeysuckles, lilies, irises, grasses are very sensitive to lithium.
The intake into plants depends on the content of mobile forms in the soil. Lithium content in soils increases from north to south – from 10-25 mg / kg for sod-podzolic soils to 65-90 mg / kg for ordinary chernozems. The amount of the element depends on the content of lithium in soil-forming rocks, granulometric composition (more lithium in heavy soils), on the amount of organic matter and degree of leaching. The concentration of exchangeable lithium decreases along the soil profile, and it is least mobile in the horizons with maximum accumulation of calcium carbonates. Soil salinization reduces mobility. In addition, there is a relationship between lithium and potassium content in the soil.
In plants, lithium content depends on the systematics and nutritional conditions. Among plants that concentrate in all conditions and prefer its high content in the soil – nightshade, violets, buttercups. Their lithium content is about 60 mg / kg of dry matter. Malvae and Marecae accumulate it only when it is high in the soil. Plants indifferent to lithium – long-leaf mint, camel’s-thorn – contain 20-45 mg/kg of dry matter. Legumes consume small amounts of 4.8-7.9 mg/kg dry matter, but do not avoid land enriched with it. Cereals and bentgrasses consume small amounts and avoid soils high in lithium.
The accumulation of lithium in plants is influenced by soil and climatic conditions. Distribution by plant organs has the following pattern: leaves > roots > stems > fruits. Therefore, leafy vegetables and root crops are the main source of lithium in the diet of animals and humans.
The application of lithium fertilizers for various crops gives mainly positive results, which depend on the method of application and doses. For this purpose, lithium chloride, sulfate and carbonate are used. For pre-sowing soaking (moistening) of potato seeds or tubers, lithium solutions of 0.001 to 0.05% are used, depending on culture. For foliar feeding – solutions from 0.005% for grapes and potatoes, to 0.1% for tobacco. In the soil apply in doses of 0.1-40.0 mg/kg soil, depending on the crop and salt.
Yagodin B.A., Zhukov Y.P., Kobzarenko V.I. Agrochemistry/Under ed. B.A. Yagodin. – M.: Kolos, 2002. – 584 p.: ill.