Biology Of Turnip Development And Its Relation To Environmental Conditions

2024 Author: Sebastian Paterson | [email protected]. Last modified: 2023-12-16 13:47

Read the previous part - Growing turnips: agricultural technology, seed preparation, sowing, care

The turnip (Brassica rapa L.) belongs to the cabbage family (Brassicaceae).

It is a biennial plant. In the first year of life, forms a rosette of leaves and a root crop. The root vegetable is fleshy, of various shapes. It distinguishes between the head, the neck and the root itself. The color of the bark in the underground part of the root crop is white or yellow, sometimes purple, in the aboveground part it is sometimes the same or green, purple, bronze. The pulp of the root vegetable is white or yellow, sometimes with crimson-red foci, juicy, tender, sweetish, with a specific "turnip" aftertaste: with a lack of moisture and mineral nutrition it becomes bitter.

The leaves are mostly dissected, of various shapes. Their color varies from light green to dark green. The leaves have a wrinkled surface, pubescent, without wax bloom.

Turnip seedlings appear under favorable soil and climatic conditions 5-6 days after sowing. 22-24 days after germination, the turnip begins to noticeably thicken the root crop. On the 65-70th day after sowing, early ripening varieties begin to die off leaves, the diameter of the root crop reaches 9-11 cm, the largest of them weigh 400-500 g. In plants left in the garden, the formation of new leaves and the death of old ones continues, increases weight of root vegetables, but their pulp loses its juiciness, and the core becomes flabby with voids.

In the second year, seed plants reach a height of 35 to 135 cm. Flowers are yellow, of various shades. At the end of flowering, an elongated pod is formed, which opens when ripe. Seeds are round, shiny, red-brown or brown, darken with long-term storage. The mass of 1000 seeds is 1.5-3.8 g.

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Requirements for growing conditions of turnips

The growth and development of turnips is influenced by the main external factors: temperature, light, moisture, soil nutrition.

Turnip heat requirements

Turnip is a cold-resistant plant. Its seeds begin to germinate at + 1 … + 3 ° С. The emergence of seedlings is accelerated with increasing temperature. The optimum temperature for seed germination is + 8 … + 10 ° С. Turnip grows well and forms roots with a high sugar content at a temperature of + 12 … + 20 ° C. Higher temperatures inhibit root crop growth.

Turnip plants react more strongly to sudden and sudden cold snap than to a gradual decrease in temperature. In autumn, when it drops to + 5 … + 6 ° C, the growth of root crops is significantly reduced. Under the influence of low temperatures, flowering plants appear, forming a rough, woody root crop. Turnip seedlings can withstand short-term frosts up to - 5 … - 6 ° С, adult plants - up to - 8 ° С. At the same time, early ripening varieties are less resistant to negative temperatures.

Turnip light requirements

Turnip is a light-loving culture, especially in the first time after germination. In low light, plant growth and development are severely retarded. Therefore, with a thickened sowing, it needs thinning, with which one cannot be late.

Turnip is a long day plant. With a reduction in the length of the day, the growing season is sharply reduced, and the accumulation of dry matter is accelerated. Most of the domestic varieties are well adapted to growing in the northern regions, and in a long day with good light they give a high yield of root crops.

Turnip moisture requirements

If you want large turnip roots with good pulp quality, provide moderately moist soil and sufficiently high air humidity throughout the growing season. At low air humidity without watering, it forms small roots with coarse bitter pulp. An excessively high soil moisture also adversely affects plants, since stagnation of water in the upper layers makes it difficult for air to reach the roots, causing various diseases.

There are two critical periods in the development of plants, when the turnip especially needs watering: the first is the moment of emergence of seedlings and the beginning of the formation of the first true leaves, when the roots are not yet sufficiently developed; the second is the last month before harvesting.

Replenishing the moisture deficit during these periods significantly increases the yield and improves its taste. On turnips, due to their greater early maturity, the lack of moisture affects more strongly than on rutabagas.

The negative effect of drought can be avoided by choosing a sowing time such that the most critical period of turnip growth coincides with the period of precipitation.

Turnip soil requirements

The best for turnips are humus-rich, light loamy and sandy loam soils. It also grows well in cultivated peaty areas. Turnip is relatively resistant to increased soil acidity. Turnip varieties with flat and rounded-flat root crops can be grown in areas with a shallow arable horizon (15-18 cm), however, a high yield of turnip root crops gives only with sufficient supply of nutrients.

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Turnip requirements for batteries

Throughout the entire growing period, and especially at the beginning of growth, it needs nitrogenwhich promotes the growth of leaves and roots. With its deficiency, growth retardation is observed, a decrease in the size of the leaf blades, the leaves become yellow-green in color, and the petioles become reddish. Excess nitrogen is harmful, as it lengthens the growing season, reduces the quality and keeping quality of root crops. One of the main reasons for the excessive accumulation of harmful nitrates in vegetables is the application of excessively high doses of nitrogen fertilizers, significantly exceeding the recommended ones. In addition, nitrate fertilizers, compared to ammonia and amide fertilizers, significantly increase the dose of these substances in products. Under unfavorable weather conditions (cold, rainy summers, reduced illumination in cloudy weather), the use of even small doses does not guarantee against an excess of nitrates, which leads to a deterioration in product quality. Late fertilizing with nitrogen fertilizers, especially during the ripening period of products, prolong the vegetation of plants, slow down the biosynthesis of sugars and dry matter, and cause excessive accumulation of nitrates.

Phosphorus is essential primarily in the first phases of turnip growth. It is well retained by the soil, so it can be applied in advance, during the main tillage. Phosphorus accelerates the growth of the root system, increases plant resistance to unfavorable microclimate factors. Insufficient phosphorus nutrition, especially in the initial period of plant development, delays their growth and reduces the yield. Lack of phosphorus leads to weakening of growth, leaves at the edges acquire a purple hue, old leaves become purple. A characteristic feature is a purple tint along the edge of the leaf. Phosphate starvation is most often observed in cold, damp weather and especially on acidic soils with a high content of mobile compounds of aluminum, manganese and iron.

Potassium plays a certain role in plant photosynthesis, affects the water content of cells and the outflow of carbohydrates from the leaves to the root crops. The high potassium content in the soil helps to increase the resistance of the turnip to bacterial diseases. With a lack of potassium, the leaves acquire a pale green color, along the edges they dry out. Acute potassium starvation causes yellowing and browning of the edge of the leaf blade (marginal burn). Lack of potassium affects turnip plants when dry hot weather sets in, as well as in conditions of uneven moisture on peaty soils.

Calcium reduces the acidity of the soil and binds the excess of mobile forms of aluminum, manganese, and ferrous oxide harmful to plants, which greatly reduce the yield. Its deficiency delays the conversion of starch into sugar, reduces the intensity of photosynthesis, and also causes an increase in lateral roots and their thickening, as a result of which the quality of root crops decreases.

Calcium is especially important for root crops, including turnips, in the second half of the growing season, since at this time the processes of sugar formation prevail over the processes of protein synthesis.

The increased acidity of the soil has a negative effect on the yield of turnip. Under conditions of an acid reaction, the supply of nitrogen, phosphorus, potassium, calcium, magnesium, copper and other important elements to plants decreases, the activity of pathogenic microorganisms increases. Turnip in an acidic environment is more strongly affected by keel. The optimal reaction of the soil solution for turnips is considered to be pH 6-6.9.

Turnip is sensitive to micronutrient fertilization. Boron is the most important trace element.… It not only increases the yield of root crops, their sugar content, vitamin content, but also increases resistance to bacterial diseases, as well as keeping quality during long-term storage. With a lack of boron, the pulp of the root vegetables becomes glassy, then brown with an unpleasant taste. Root crops rot. The first signs of boric starvation appear on young plants: the apical points of growth and roots die off, additional rosettes are formed, and leaf blades are bent. The introduction of high doses of basic mineral fertilizers increases the need for turnip in boron. The most critical period here is the start of intensive thickening of the root crop. Boron fertilizers are most effective on limed sod-podzolic soils. In dry, hot weather, boron deficiency is most pronounced.

Copper and magnesium are also important for the growth of turnip, they are involved in the metabolism of plant cells, contribute to an increase in the content of chlorophyll in them. Copper deficiency is often observed in peat-boggy soils.

Turnip responds positively to the introduction of potassium together with sodium. It produces a high yield of root vegetables with a tasty and sweet pulp. Ash has a good effect on its growth and productivity. By neutralizing the acidity of the soil, it protects plants from keel disease and provides them with potassium, and also partially phosphorus, calcium and trace elements.

Read the rest of the article - The use of turnips in medicine

"Round, but not the sun, sweet but not honey …":

Part 1. Cultivation of turnips: agricultural technology, seed preparation, sowing, care

Part 2. Biology of turnip development and its relation to environmental conditions

Part 3. Use of turnip in medicine

Part 4 The use of turnips in cooking