Turnip
Turnip (Brassica rapa L. ssp. rapifera).
Turnip (Brassica rapa L. ssp. rapifera), or fodder turnip, is a fodder agricultural crop belonging to the group of fodder root crops.
Economic importance
Turnip is a high-yielding, early-maturing, cold-resistant crop; it is less demanding of soil fertility than other root crops. It has a milk-stimulating effect. It can be grown as an aftercut or stubble crop after early-harvested grain crops. It is promising for use in a green fodder conveyor, with sowing carried out at several dates.
The tops are also used for feed, in fresh, dried, or ensiled form; they contain a sufficient amount of protein, minerals, ascorbic acid, and carotene.
History of cultivation
Turnip was used as a vegetable crop in Ancient Greece and Rome. It originates from wild turnip, which is widespread in Eurasia.
In Russia, this crop began to be cultivated in the 19th century. It was especially widely grown in the pre-war period. Small, flattened roots were used for food, and large ones for fodder.
Cultivation areas
Due to its undemanding nature, it can be cultivated in regions where other root crops grow poorly, including beyond the Arctic Circle.
Currently in Russia it is grown on small areas and in private household plots.
Growing turnip is promising in the southern taiga-forest and forest-steppe zones with sufficient moisture as an aftercut and stubble crop.
Yield
Under favorable conditions (cool and wet summer), turnip yield reaches 40–50 t/ha.
Under irrigation, yield increases by 1.5–2 times.
Botanical description
Turnip (Brassica rapa L. ssp. rapifera Metzg.) is a biennial plant of the family Brassicaceae (Brassicaceae).
In the first year it forms a raised or semi-raised rosette of large leaves.
During germination, the seeds bring cotyledons to the surface; at this stage they are difficult to distinguish from rutabaga.
The root crop is formed as a result of development of the hypocotyl, and to a lesser extent of the root itself. The shape depends on varietal characteristics; it may be flattened, oval, oval-round, elongated elliptical, elongated spindle-shaped, or irregularly cylindrical. The flesh is loose. The color of the upper part is green, gray-green, brown, red-purple, or purple; of the lower part, white, grayish, or yellow. The flesh color is white, yellowish, or pinkish-yellow.
The root system penetrates to a depth of 1–1.5 m and a width of 40–50 cm. Its absorbing capacity is low.
True leaves are simple, lyre-shaped, dissected, pubescent to varying degrees, glossy, up to 50 cm long, without a waxy coating.
In the second year of life, flowering stems up to 80–150 cm tall appear from buds on the root head. The leaves on them are sessile, lanceolate, light green.
The inflorescence is a corymb (simple raceme). The flowers are yellow, lemon-yellow, or cream; the corolla is four-petaled, with 6 stamens and a pistil. Pollination is cross. It can cross-pollinate with cabbage and radish.
The fruit is a long multilocular silique with a large beak. Seeds are spherical, small, brown, dark brown, or black. The weight of 1000 seeds is 1.5–3.5 g.
Biological characteristics
Temperature requirements
The cold hardiness of turnip exceeds that of rutabaga. Seeds germinate at 2–3 °C. At a soil temperature of 8–10 °C at sowing depth, seedlings emerge after 4–5 days. Seedlings can withstand frosts down to -3…-5 °C, and mature plants down to -6…-9 °C.
A prolonged cold spring promotes bolting in plants.
It tolerates heat and lack of moisture poorly. Like rutabaga, under hot conditions it is more severely damaged by pests, especially flea beetles.
Moisture requirements
Turnip is a moisture-loving crop. The greatest demand is noted during germination in the first year of life and during rooting of stock roots.
It does not tolerate droughts. Lack of moisture leads to the formation of very small root crops.
Light requirements
Turnip is a long-day crop and prefers intense lighting.
However, when used as an undersown crop under winter rye for silage or green fodder, it yields 15–16 t/ha; when undersown under winter rye for grain, 12 t/ha (Belarusian SRI of Agriculture).
Soil requirements
Turnip is less demanding of soils than rutabaga. It grows well on light-textured soils; heavy soils are unsuitable for cultivation. Soil acidity — pH 6–6.5; up to pH 4.3 is acceptable.
Fertile floodplain, cultivated sod-podzolic, drained peatlands and marshes (after application of boron and copper micronutrient fertilizers), moderately moist loamy, and organic-matter-rich sandy loam soils are optimally suitable.
Growing season
The growing season in the first year of life is 70–110 days; in the second, 65–90 days.
Crop rotation
Turnip crops are best placed in lower relief areas where moisture conditions are better.
The best predecessors in turnip crop rotation are fertilized winter crops, annual grass-legume mixtures for hay and green fodder, grain legumes, maize, potatoes, fodder beet, perennial leguminous grasses of the first year of use, and silage crops. In vegetable crop rotations, it is not placed after crops of the Brassicaceae family. Fields infested with wireworms are unsuitable for turnip cultivation. It is economically impractical to place its crops far from livestock farms.
It can serve as a good predecessor for grain, grain-legume, and silage crops.
Fertilization
Nutrient removal per 1 tonne of root crops and the corresponding amount of tops for turnip is 2.5 kg N, 1 kg P2O5, 3.8 kg K2O.
If organic fertilizers were not applied to the preceding crop, they are applied for fall tillage at 30–40 t/ha.
To obtain a root crop yield of 40–50 t/ha, P40K60 is also applied for the main plowing.
In spring, N60-90P20K30 is also applied for cultivation.
It is recommended to apply phosphorus fertilizers in rows when sowing turnip, 20–25 kg/ha of granular superphosphate.
Part of the nitrogen fertilizers can be shifted to topdressing at 30 kg/ha, which is carried out after thinning the seedlings.
Soil tillage
In general, soil tillage for turnip is similar to that for rutabaga.
Turnip responds well to early fall tillage, which, depending on the thickness of the arable layer, is carried out to a depth of 20–30 cm with plows with skimmers.
In areas with insufficient moisture in winter, snow retention measures are recommended.
In spring, harrowing and smoothing are carried out to conserve moisture and level the soil surface for uniform sowing. Before sowing, cultivation is recommended. Heavy and slaking soils are plowed with moldboards removed and simultaneously harrowed, or rotary-tilled. Light-textured soils are rolled before sowing.
Sowing
Seed treatment
For treating turnip seeds before sowing against ascochyta, blackleg, downy mildew, phoma, bacteriosis, olive spot, seed molding, and black mold, the preparation TMTD is used. Treatment is carried out 2–15 days before sowing or in advance.
Sowing dates
For summer feeding of turnip, it is sown in early spring. For autumn and winter use, as well as for aftercut or stubble sowings, sowing dates shift to summer.
Sowing methods
Turnip is grown only by sowing seeds, as it tolerates transplanting poorly.
For uniform sowing, it is recommended to mix seeds with granular superphosphate and granulated phosphamide for control of crucifer flea beetle, fraction 2–4 mm, as ballast. Ratio of ballast substances: 2.5 kg phosphamide and 20–25 kg superphosphate per hectare seeding rate. Calcined millet seeds or dried sifted sawdust are also suitable as ballast.
When sowing to a target plant stand density, it is recommended to replace up to 20 seeds per 1 meter of row (Leningrad Agricultural Institute).
Turnip is usually sown by the wide-row method, with row spacing of 45, 60, or 70 cm, or by the two-row method with row spacing of 50 cm and band width of 18–20 cm. Root yield with the latter method is 30% higher (Borets state farm, Dmitrov district, Moscow region).
In regions of excess moisture or with a shallow arable layer, for example in northwestern Russia, sowing is carried out on ridges or beds.
Vegetable seeders are used for sowing seeds, for example, SON-2.8, SKOSSh-2.8, SON-2.8A, SO-4.2, SKON-4.2.
Seeding rates
The seeding rate of turnip is 1–2.5 kg/ha (according to other data, 3–4 kg/ha1), adjusted depending on soil and climatic conditions and field weed infestation.
When using precision sowing with calibrated and pelleted seeds, the seeding rate can be reduced to 0.8 kg/ha (Leningrad Agricultural Institute).
The seeding rate is increased in the case of aftercut or stubble sowing of turnip, since the period of nutrient uptake by plants is shortened.
Sowing depth
Sowing depth is 1–3 cm.
Crop care
After sowing, rolling is carried out. When the topsoil dries out, harrowing with light tine or mesh harrows is performed; then treatments with rotary hoes or ribbed rollers when a soil crust forms.
In crop care, shallow harrowing to a depth of 4–6 cm is performed. During the growing season, 2–3 inter-row cultivations to a depth of 8–12 cm are done.
The plant stand density of turnip is 70,000–100,000 plants/ha. To form stand density depending on uniformity of seedlings, the following are used:
- at plant density above 30 per 1 m — cross harrowing in the 3–4 leaf stage using a mesh or light tine harrow;
- at density of 20–30 plants per 1 m — bunching according to the scheme: cut-out 40 cm, bunch 20 cm, followed by manual sorting of bunches.
Harrowing over turnip seedlings and bunches is carried out with caution; in dry weather, one should limit it to bunching only. On uniform, non-thickened seedlings in fields free of weeds, along-row thinners can be used.
To control weeds in turnip crops, pre-sowing treatment with the herbicide Ramrod at 4–6 kg/ha a.i. or pre-emergence treatment with Butizan (against annual grass and dicotyledonous weeds) is carried out.
To control flea beetles and horseradish leaf beetle, spraying with Actellic is carried out during the growing season.
Harvesting
Harvesting is usually carried out by the separate method. For cutting leaves, top-removing machines UBD-3A and KIR-1.5B are used. Then root crops are dug up with potato diggers, converted potato harvesters, or the KKG-1.4 machine.
Turnip can be harvested together with tops and ensiled after preliminary chopping and mixing with grain crop chaff.
Storage
It stores poorly because of the loose flesh and watery root, so it is fed to livestock at the beginning of the stall period.
Turnip roots are stored in above-ground clamps, trenches, or storages. Storage temperature is 1–2 °C at relative humidity 85–95%.
Growing turnip for seed
When growing stock crops of turnip, they are thickened so that 80,000–90,000 stock roots are obtained from 1 ha of sowing, corresponding to 3–4 ha of seed plants. Stock roots should be protected from wilting during harvesting, storage, and planting.
Planting scheme is 70×35 cm. Elongated turnip roots are planted using VPG-4 or VPG-4B; round varieties under a plow or cultivator. The planting depth should ensure that the root head is covered with soil by 2–3 cm.
Turnip seed plants are spaced in the fields at least 2 km from rutabaga seed plantings and other Brassicaceae plants to prevent cross-pollination.
Seed plants are harvested manually or with reapers (depending on plot size) by a two-phase method. Harvesting begins when seeds in 25–30% of siliques acquire a light brown color, and the siliques themselves become yellow-green or light yellow. During ripening, seed plants are protected from birds.
Turnip for seed begins to be harvested in late June–July. Threshing is carried out using combines or threshers. With good agricultural practices, seed yield is 1–1.5 t/ha.
After harvesting turnip seed plants, it is possible to sow stubble fodder crops or winter cereals of group I.
In southern regions, for example in Georgia or Armenia, a non-transplant method of growing turnip for seed is possible. Stock crops are left in the field over winter, necessary care measures are carried out in spring, and the seed harvest is collected in summer. This approach substantially reduces the cost of seeds.
Varieties
In the USSR, 5 turnip varieties were zoned.
Varieties: Esti Naeris, Osterzundomsky, Skorospelyi VIK, Moskovsky, Volynsky ranniy. The first two were the most widespread.
Sources
- Vavilov P. P., Gritsenko V. V., Kuznetsov V. S. et al. (1986). Crop Production. Ed. by Vavilov P. P. 5th ed., revised and enlarged. Moscow: Agropromizdat.
- Kolomeichenko V. V. (2007). Crop Production/Textbook. Moscow: Agrobiznescentr.
- Niklyaev V. S. (2000). Fundamentals of Agricultural Production Technology. Agriculture and Crop Production. Moscow: Bylina.
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