Manganese in plant life
The presence of manganese in plant organisms was discovered in 1872; for a long time it was considered unnecessary for plant nutrition. K.K. Giedroytz established that manganese acts better on a lime background. The necessity of manganese for plant life was noted by F.V. Chirikov.
Cereals, beets, fodder root crops and potatoes have higher requirements for sufficient content of available forms of manganese in soil. With the harvest of various crops from 1 ha 1000-4500 g of manganese is removed.
Table. Manganese content in plants and its removal with the yield of crops on different soils (by Katalymov)
|Spring vetch (hay)|
Manganese is an essential element for all plants. Its average content in plants is 0.001%, or 10 mg per 1 kg of weight. It is mainly concentrated in leaves and chloroplasts.
Manganese is a metal with high redox potential and can participate in biological oxidation reactions.
The participation of manganese in photosynthesis has been established: after addition of manganese to plants that were deficient in it, restoration of photosynthetic rate was observed after 20 minutes. Manganese is involved in the system of oxygen release during photosynthesis and in reductive reactions of photosynthesis. It increases the content of sugars, chlorophyll and its bonds with protein, improves outflow of sugars, and enhances respiration rate.
Manganese is a member of hydroxylamine reductase, which carries out the reduction of hydroxylamine to ammonia, as well as an assimilation enzyme that reduces carbon dioxide during photosynthesis. It is involved in the activation of many reactions, including the conversion of di- and tricarboxylic acids during respiration. It is assumed that manganese is part of the enzyme that synthesizes ascorbic acid, as well as malate dehydrogenase, isocitrate dehydrogenase, hydroxylamine reductase, glutamintransferase, ferredoxin. About 30 metalloenzyme complexes activated by manganese are currently known.
Manganese is involved in the mechanism of action of indolylacetic acid on cell growth. Manganese has been shown to be necessary as an auxin oxidase cofactor for the enzymatic degradation of indolylacetic acid. Calcium and manganese contribute to the selective absorption of ions from the external environment. With the exclusion of manganese from the nutrient medium in plant tissues, there is an increase in the concentration of the main elements of mineral nutrition, their ratio in the nutrient balance is disturbed. There is evidence of the effect of manganese on the movement of phosphorus from the aging lower leaves to the upper and reproductive organs. It increases water-holding capacity of tissues, reduces transpiration, and affects fructification of plants.
Under acute manganese deficiency, cases of lack of fructification in radish, cabbage, tomato, pea, and other crops have been noted. Manganese promotes and accelerates development of plants. Under deficiency, chlorosis, gray spotting of cereals, and spotting yellowing of sugar beet can be observed.
Manganese fertilizers increase the yield of sugar beet by 0.9-1.6 t/ha on average, increase the sugar content of roots by 0.1-0.6%, the yield of cereal crops – by 0.15-0.35 t/ha on average, silage mass of corn with lactiferous cobs – by 4.0-7.0 t/ha, potatoes – by 2.5-3.5 t/ha, tomatoes – by 3-4 t/ha, as well as cotton, vegetable, fruit and berry crops. The content of protein, sugars, crude protein, gluten, fats and vitamins increases.
Manganese content in soil
There are significant reserves of manganese in soils: in yellow soils – more than 1%, in sod-podzolic and chernozem soils – 0.1-0.2%. However, most of it is in the form of hard-soluble oxides and hydroxides. In soil, manganese is mainly in a divalent form, in silicates and oxides can replace Fe2 + and Mg2 +, which leads to their leaching. In acidic soils, manganese forms ferromanganese nodules with iron hydroxides.
Plants can absorb divalent manganese compounds. Manganese compounds of other valences are unstable, especially the trivalent form. Mn4+ is present in a reducing environment, forming compounds that are hardly soluble. Under conditions of excessive moisture, anaerobic conditions are created, which intensify reducing processes, increasing the content of available manganese. On irrigated lands manganese is not applied. In dry weather, especially on carbonate soils with an alkaline reaction of the environment, divalent manganese transforms into trivalent and quadrivalent forms unavailable for plants. Under these conditions, the effectiveness of manganese fertilizers increases. Manganese mobility increases when ammonia forms of nitrogen fertilizers are applied.
Lime and alkaline forms of fertilizer reduce manganese mobility and its entry into plants. Sod-podzolic soils tend to contain the highest amounts of manganese. Sugar, fodder and table beets, wheat, corn, barley, alfalfa, vegetable and fruit crops especially suffer from manganese deficiency.
As a result of high content of manganese in soil, its amount in the soil solution can reach 2200 μg/l with the formation of complexes with fulvic acids. When the reaction of soil solution is close to neutral, plants may experience a lack of manganese due to transition to hard-soluble compounds. In practice, to prevent the binding of metal ions by soil and improve their availability to plants use chelates of manganese and iron, which are brought with irrigation water and at foliar feedings.
Micronutrient chelates are widely used. For example, in Sweden foliar feedings of sugar beet are carried out with chelate containing 6 % of manganese, EDTA is used as a ligand. In experiments conducted in the UK, treatment of spring wheat crops increased yields from 2.8 to 4.7 t/ha.
Manganese fertilizers are used in Ukraine. A positive effect of their use is noted on chernozem, carbonate, saline and chestnut soils with low content of manganese available for plants. On soils of the Non-Black Earth zone manganese is effective at its content of 25-55 mg / kg soil, Black Earth – 40-60 kg/kg soil, on gray soils – 10-50 mg per 1 kg of soil.
Manganese fertilizers are applied to gray forest soils, weakly leached chernozems, saline and chestnut soils for oats, wheat, fodder crops, potatoes, sugar beets, corn, alfalfa, sunflowers, fruit and berry, citrus and vegetable crops.
Soils that require the use of manganese fertilizers include carbonate black soils, chestnut and brown semi-desert soils of the Volga region, the North Caucasus, the Urals and Western Siberia. On northern sod-podzolic soils these fertilizers most often do not give a positive effect, in some cases have a negative effect on plants.
K.K. Gedroyts and O.K. Kedrov-Zikhman pointed out the positive effect of manganese on calcareous soils. Manganese fertilizers do not always have a positive effect on various soils in the south of European Russia. Probably, the use of these fertilizers should be paid attention to alkaline, neutral and carbonate soils, light on granulometric composition.
On chernozems, an increase in sugar beet yield from the application of manganese fertilizers is 1.0-1.5 t/ha, root sugar content increases by 0.2-0.6%, cereal yield, including winter wheat, increases by 0.15-0.30 t/ha.
Таблица. Effects of manganese on crop yields (by P.A. Vlasyuk), t/ha
|Sugar beet (roots)|
|Winter wheat (grain)|
|Spring wheat (grain)|
As manganese fertilizers are used waste from manganese-ore enterprises, the content of manganese in which is 10-18%. They also contain about 20% of calcium and magnesium, 25-28% of silicon oxide, 8-10% of halides and a small amount of phosphorus.
Table. Assortment of manganese fertilizers
Manganese sulfate because of its high cost is mainly used in greenhouse vegetable production. Given that manganese is effective against phosphate fertilizers, it is advisable to produce superphosphate enriched with manganese.
Marganized superphosphate is a pellet of light gray color containing 1.0-2.0% manganese and 18.7-19.2% P2O5. It is obtained by adding 10-15% manganese sludge to powdered superphosphate during granulation.
Manganese sulfate or manganese sulfate (MnSO4) is a finely crystalline salt, the content of manganese is 32.5%, well soluble in water.
Manganized nitrophoska contains nitrogen, phosphorus, potassium, 0.9% of manganese, well available to plants.
Methods of use
Manganese fertilizers are applied to the soil, used for seed pre-sowing and foliar dressing. Organized superphosphate at a dose of 200-300 kg/ha is used to apply to the soil for sugar beets, cereals, corn, vegetables, oilseeds and other crops with the plow at plowing or pre-sowing cultivation. It is also introduced into the rows during sowing in a dose of 50-100 kg/ha. Superphosphate can be replaced by nitrophosphate, the dose is calculated by the content of nitrogen, phosphorus and potassium. Before sowing it is also possible to apply manganese slime in a dose of 50-200 kg/ha.
When applied to the soil, the dose of manganese per element is 2.5 kg/ha. About a third of manganese fertilizers for agriculture is needed in the form of manganese sulfate for foliar feeding and seed pre-sowing treatment.
To powder the seeds use 50-100 g of manganese sulfate mixed with 300-400 g of talcum powder to process 100 kg of sugar beet, wheat, barley, corn, peas, sunflower seeds. Sprinkling can be combined with seed dressing. For foliar fertilization of field crops, the application rate is 200 g of sulfuric manganese per 1 ha; for spraying of fruit and berry crops, the application rate is 600-1000 g/ha. When aerial spraying, 150-200 grams dissolved in 100 liters of water per 1 ha; when ground spraying, 30-50 grams per 100 liters.
Yagodin B.A., Zhukov Y.P., Kobzarenko V.I. Agrochemistry/Under ed. B.A. Yagodin. – M.: Kolos, 2002. – 584 p.: ill.
Agrochemistry. Textbook / V.G. Mineev, V.G. Sychev, G.P. Gamzikov et al. – M.: Publishing house of the All-Russian Scientific and Research Institute named after D.N. Pryanishnikov, 2017. – 854 с.