Fertilization of sugar beets

Sugar beet is a plant that contains many valuable nutrients essential for our body, such as protein, folic acid, sugars, numerous vitamins and minerals. It is a plant with proven comprehensive medicinal properties. Among other things, beets contribute to lowering blood cholesterol levels, prevent atherosclerosis and are widely used in the prevention of many diseases. Currently, in agricultural practice, sugar beets are grown almost 100% for industrial purposes – sugar production. Growing sugar beets requires a systematic supply of essential nutrients – properly balanced fertilization. Sugar and fodder beets are plants with high nutritional requirements. From a field with an area of 1 h, along with the yield of these plants we export about 200-240 kg of nitrogen, 60-90 kg of phosphorus, 260-400 kg of potassium, 160 kg of calcium, 100 kg of sodium, 90 kg of magnesium and about 400 g of boron. The natural nutrient abundance of soils is too low for the requirements of beets. Also, organic fertilizers do not fully cover such a high demand for essential minerals. When growing beets, it is therefore necessary to use mineral fertilizers. The composition of these fertilizers should be carefully selected according to specific soil conditions and the actual nutritional needs of such a demanding plant.

Beets take up nitrogen in amounts proportional to the content of this element in the soil. At high abundance, the uptake is excessive in relation to the actual needs of the plant. Its maturation is then delayed, and root respiration losses in the heaps are increased. In addition, the sugar content in the roots decreases, while the amount of harmful nitrogen and ash (molassigenic substances) increases, making the processing more expensive. The use of excessive amounts of nitrogen, not balanced by an adequate amount of phosphorus fertilizers, causes a marked reduction in root yields and deterioration in root quality. Insufficient nitrogen content in the soil, on the other hand, has negative effect on leaf growth – there are fewer leaves, they are small and pale. Such leaves are not able to produce a sufficiently large amount of assimilates.

Even very large doses of phosphorus fertilizers, exceeding the physiological needs of the beet, have a positive effect on the quality of the roots. They contain more sugar and much less harmful nitrogenous compounds that impede processing. Under such conditions, the resistance of beets to rot in mounds is also improved. On the other hand, phosphorus deficiency, and especially lack of phosphorus, reduces the yield of fresh and dry weight of beet leaves and roots, and deteriorates its technological and biological quality. Plants experiencing phosphorus deficiency have characteristic “stiff” and dark green, dull leaves. Often a rusty-brown coloration appears on the tops and edges of the leaves.

Sugar beets can take up large amounts of potassium from the soil, but this does not significantly deteriorate the technological quality of the roots; on the contrary – it actually improves it. In addition, plants abundantly supplied with potassium are more resistant to drought and disease and accumulate more sugar in their roots. Plants experiencing potassium deficiency have limp, wavy leaves. Older, outer leaves are paler than young leaves, with numerous necrotic spots on their surface. The edges and tops of these leaves dry out.

Sugar beets, fodder beets and other root crops have a high demand for boron, while most soils in Poland currently show a significant deficit of this element. Therefore, mineral fertilizers containing this element in their composition should be used to fertilize beets. Deficiency of the micronutrient causes curling of beet leaves. During the period of full development, the youngest, middle leaves turn yellow, while later they turn brown and die (the so-called heart leaf gangrene). Symptoms of boron deficiency are then seen in the roots in the form of dying and suberization of the parenchyma (known as dry root rot).

Cultivated soils are also significantly deficient in assimilable magnesium, and sugar beets are particularly sensitive to deficiency of this component in the soil. Symptoms of magnesium deficiency are observed on the oldest, outer leaves of beets in the form of light green and then yellowish or orange spots between the innervation (known as leaf marbling). These leaves are severely wavy, wither, dry up and fall off quickly. These symptoms are accompanied by a reduction in the yield not only of the leaves, but also of the roots.

Beet also requires sulfur for proper growth, a deficiency of which is increasingly common in soils not fed with organic fertilizers. The deficiency of this element is evidenced by the light coloration of the edges of the youngest, middle beet leaves. They are pale, upright and stiff. A darker mesh of innervation is visible on them. Sulfur deficiency particularly affects the deterioration of the biological and technological quality of the beet. In addition to the elements described above, copper (Cu), zinc (Zn), manganese (Mn) and sodium (Na) are also essential in beet nutrition, improving the nutritional value of sugar beets while increasing the sugar content in the roots. Multi-nutrient fertilizers containing adequate and biologically justified amounts of nutrients are a prerequisite for abundant sugar beet yields and their good quality.