Everything you need to know about beet leaf cultivation, production and growth. Learn about:- 1. Introduction to Beet Leaf 2. Origin and Distribution of Beet Leaf 3. Composition and Uses 4. Climate Required for Cultivation 5. Soil Required for Cultivation 6. Sowing Time 7. Manurial Requirement for Cultivation 8. Irrigation Requirement for Cultivation 9. Intercultural Operations and Few Others.
Contents:
- Introduction to Beet Leaf
- Origin and Distribution of Beet Leaf
- Composition and Uses of Beet Leaf
- Climate Required for Cultivating Beet Leaf
- Soil Required for Cultivating Beet Leaf
- Sowing Time of Beet Leaf
- Manurial Requirement for Beet Leaf Cultivation
- Irrigation Requirement for Beet Leaf Cultivation
- Intercultural Operations of Beet Leaf
- Harvesting and Yielding of Beet Leaf
- Cultivated Varieties of Beet Leaf
1. Introduction
to Beet Leaf:
Beet leaf also known as palak is the most important member of the leafy group vegetable crops grown in tropical and sub-tropical regions of India during winter season. It is an herbaceous annual for the production of edible leaf but biennial for seed production.
In early stages of crop growth (at vegetative phase), the plant has very succulent leaves with thick small petiole and rosette in growth habit, however, the vegetative phase about 75 days after sowing is changed into reproductive phase since the stem starts elongating, which is known as bolting.
It is popularly grown in Uttar Pradesh, West Bengal, Punjab, Haryana, Delhi, Madhya Pradesh, Bihar, Maharashtra, and Gujarat states, however, in southern India, it is less poplar and grown only on a limited area, especially in hilly tracts. It is though cultivated widely in India, the information on the area, production, and productivity is not so far available in literature.
Beet leaf is also known as silver chard, seakale beet, silver beet, perpetual spinach, Indian spinach, and spinach beet, which is a close relative of other forms of Beta vulgaris, i.e., beetroot (sugar beet) and Swiss chard since they all have the same chromosome number, 2n = 18, which indicates their close relationship.
All these forms are crossable to each other but do not cross with spinach (Spinacia oleracea L.) due to its different chromosome number. Beet leaf in plant characteristic’s, life cycle, and agro-techniques required for its cultivation is similar to spinach, thus, creates confusion to the common consumer of it, however, botanically these two crops are entirely different, and the points that clearly differentiate these crops are as under –
2. Origin and Distribution of Beet Leaf:
Beet leaf is most probably the native of Indo-Chinese region and was known in China as early as 647 A.D. Use of Beta species as a potherb has been reported since 2000 B.C., whereas, the use of beet leaf has been reported probably dates back to pre-historic times when the leaves were used as potherb.
The tropicalization of Beta genus, which includes beet leaf, temperate sugar beet (beetroot) and garden red beet, might have started first time in Bengal, which is the probable reason for the designation of beet leaf as B. vulgaris L. var. bengalensis, whereas, Choudhury (1967) is of the opinion that this particular beet leaf might have been first time used in Bengal that’s why it is also known as a var. bengalensis.
3. Composition and Uses of Beet Leaf:
Composition:
Amongst vegetables, beet leaf is regarded as the richest source of vitamin A. It is particularly valued for its high calcium, iron, B group vitamins especially riboflavin, ascorbic acid, and vitamin K content since green leafy vegetables are the excellent sources of vitamin K1 (5-16 μg/g) as reported by Ferland and Sadowaski (1992). The beet leaf leaves also supply a sufficient amount of iron, manganese, zinc, and copper.
As the plant matures from 15 to 30 days, the content of iron and manganese is increased, while the content of zinc and copper is reduced. It contains appreciable quantity of protein, which is rich in essential amino acids, especially in Lysine. According to Nath and Subramanyam (1972), the 100 g of green fresh leaves supply as much essential amino acids as 100 g of any non-vegetarian food like meat and fish. The nutritive value of beet leaf per 100 g edible portion is given in Table 20.2.
Uses:
The succulent leaves of beet leaf along with their tender petioles are fried alone or cooked with other vegetables like potato, peas, onion, brinjal, and cheese and cooked with rice and pulses to add flavor and zest. Its leaves and petioles are also used in other preparations like soups, chutney, snacks, and pakaura.
The combination of beet leaf with chickpea in the form of curry is very popular among all age group. In spite of being highly nutritious, it is available in the market at cheaper rate as compared to other vegetables. The nutrition experts have recommended 116 g of leafy vegetables per day per adult for a balanced diet.
Beet leaf is the cheapest and richest source of minerals and vitamins necessary for maintaining good health, thus, it has been put in the category of protective food. Night blindness especially in children, which is mainly due to the deficiency of vitamin A, can be corrected by the consumption of beet leaf. The plant is reputed in Indian medicine as a tonic, and used to treat liver and spleen ailments.
The leaves of beet leaf because of having very high fiber content are laxative, thus, their inclusion in diet prevents constipation and colorectal cancer. They provide roughage, which helps in movements of bowel, thus, they have a significant place in a balanced diet. The dieticians recommend it to the patients having anemia and gynecological problems.
Its leaves and seeds are applied to burns and bruises to impart cooling effect. In general, its intake is good for health but its consumption is taboo to those prone to or suffering from stone formation in kidney and urinary tracts.
4. Climate Required for Cultivating Beet Leaf:
Beet leaf has a much wide range of adaptability, thus, it can be cultivated both in autumn-winter and spring-summer seasons, however, the crop being a cool season vegetable grows best in autumn-winter at a temperature range of 16-18°C without any bolting and can tolerate temperature as minimum as 1.4°C.
It can withstand frost and warm weather better than other winter vegetables but extremes of climatic conditions, especially high temperature (35-40°C) coupled with long days, lead to premature bolting (early bolting) without giving sufficient cuttings and affect the yield adversely by reducing the number of cuttings.
In hot weather, the leaves become stiff due to increased fiber content, as a result, palatability is lost, and the edible stage passes away more quickly. Cool weather (low temperature) coupled with short days is conducive to the development of succulent, tender and mild flavored foliage, and favors rapid growth of leaves.
Under such conditions, the crop gives more number of cuttings. In hot weather, it can be grown with assured irrigation at frequent intervals. In regions with mild climatic conditions, the crop can be grown year the round. However, under tropical conditions it can be grown merely in winter.
5. Soil Required for Cultivating Beet Leaf:
The crop can be grown on any type of soil having proper drainage facilities and sufficiently fertile, however, it performs better in loam or sandy loam soil rich in organic matter.
Working with beet leaf Mishra et al. (1973) reported that the crop is highly tolerant to salts, hence, being tolerant, it can successfully be cultivated in slightly alkaline/saline/sodic soils, and the cultivars Jobner Green and S-23 can endure a soil pH up to 10.5, however, the crop performs better in the neutral soil with pH range from 6.5 to 7.0.
The soil is prepared to fine tilth by ploughing and planking repeatedly for proper seed germination and better stand of crop.
6. Sowing Time of Beet Leaf:
The sowing time of beet leaf varies with the regions and their climatic conditions. In plains, it is sown three times in a year, i.e., in early spring, in the beginning of rainy season and in September as main season crop (Table 20.3), while in areas where the climatic conditions are mild, it can be cultivated round the year.
Seed Rate:
The seed rate depends on its viability and germinability, soil type, soil fertility, irrigation facilities, and growing season. In general, for autumn-winter crop, about 10-15 kg, and for spring-summer crop, 25-30 kg of seed is needed to sow a hectare of land area. The rate of seed may be increased proportionately as the germinability of seed is reduced.
Seeds should be true to type and of good quality to harvest higher yield of good quality fresh green leaves. Seeds should be soaked overnight in water before sowing to improve and to hasten germination.
Seed bed of convenient size and irrigation channels are made in thoroughly prepared soil. Beet leaf is a direct seeded crop because of having strong tap root system and sown either in lines or by broadcasting method, however, sowing in lines is preferred over broadcasting method because it facilitates cultural practices and easy cuttings of the crop. For line sowing, the distance between rows is kept 20 cm and plants are thinned 5 cm apart to maintain optimum plant density per unit area.
Seeds are usually sown 2-3 cm deep, depending upon the type of soil and moisture availability. Chaudhari et al. (2004) obtained highest greens yield from beet leaf cv. Pusa Jyoti spaced at 45×15 cm spacing. Singh and Srivastava (1981) obtained higher net returns from tomato when intercropped with beet leaf.
Gawade et al. (2003) fetched highest monetary returns from beet leaf intercropped with cauliflower, while Patil and Ranpise (2003) obtained maximum monetary returns, highest net profit, and lowest C: B ratio when beet leaf was intercropped with cabbage.
For smooth germination, the beet leaf seed takes about 10 days under a condition of optimum soil moisture and temperature, however, sometimes, the germination is very poor due to following reasons:
i. Low viability and poor germinability of seed
ii. Lack of moisture in soil
iii. Suboptimal soil temperature
iv. Sowing of seeds deeper into the soil
v. Formation of hard soil curst due to raining soon after sowing
vi. Attack of insect-pests or soil/seed borne diseases.
7. Manurial Requirement for Beet Leaf Cultivation:
Being leafy vegetable beet leaf requires more nitrogen for crown growth, thus, based on different regions and soil conditions numerous recommendations have been made by the scientists working with beet leaf in different institutes.
Incorporation of 35-40 t/ha well composted farmyard manure into soil at the time of land preparation and a top dressing of nitrogen 20 kg/ha after every cutting give quick regeneration of green tender and succulent leaves, however, according to Singh and Joshi (1960), a basal application of farmyard manure 25 t/ha should be followed by 3 top dressings of ammonium sulfate, each being 100 kg/ha.
Singh (1969) recommended nitrogen and phosphorus each 25 kg and potash 50 kg/ha at the time of sowing as basal dose and nitrogen 25 kg/ha as top dressing after every cutting, however, Peter and Devadas (1989) recommended farmyard manure 35-40 t/ha as basal dose, nitrogen 20 kg/ha as topdressing and a foliar application of nitrogen 2-3 kg/ha after every cutting, while Anonymous (1999) recommended farmyard manure 50 t, nitrogen 80 kg and phosphorus 40 kg/ha for a successful crop production of beet leaf in Haryana.
Khandelwal and Nath (1971) recorded the highest yield of beet leaf cv. Jobner Green with foliar application of 1.5% urea 15 days after germination and after each cutting up to the third cutting, however, application of 2.0% urea showed marginal interveinal burning of leaves.
Farmyard manure should be applied and mixed thoroughly into the soil at the time of field preparation, and the whole quantity of phosphorus at the time of sowing, whereas, nitrogen should be applied in 3-4 split doses after each cutting to boost up the crown growth. Soil application of nitrogen 100 kg/ha in combination of two foliar sprays of nitrogen (2-3 kg/ha) gave the best results regarding yield of beet leaf.
The green leaf yield increased with the increasing rates of nitrogen. The highest green leaf yield of beet leaf might be obtained with a combination of nitrogen 150 kg/ha and three cuttings, however, Rajput et al. (1989) obtained the maximum green leaf yield of 14.27 t/ha with nitrogen 120 kg/ha.
8. Irrigation Requirement for Beet Leaf Cultivation:
The irrigation requirement of the crop depends upon type of soil and the growing season. In general, the crop grown in light soils requires irrigations more frequently especially in dry season as compared to the crop raised in heavy soils and in wet season. The field soil at the time of sowing should have enough moisture for assured and good germination of seed, however, if the moisture is scanty in the field, a light irrigation should be given just after sowing, though it is always better to sow seeds after pre-sowing irrigation of the field.
Subsequent irrigations are applied at 6-7 days interval during spring-summer and 10-12 days interval during winter. The rainy season crop is irrigated as and when required because of sufficient moisture in the soil due to rains. Excessive soil moisture and water stagnation affect the yield and quality adversely so light irrigation at short interval is beneficial for good harvest of the crop.
9. Intercultural Operations of Beet Leaf:
Beet leaf is a closely spaced crop, thus, there is not much problem of weeds, even though 2-3 hoeings cum weedings are essential to keep the field weed free especially in early stages of crop growth so that the competition between crop plants and weeds for nutrients, light, moisture and space could be reduced for proper growth of crop plants. Moreover, hoeing in early stages not only destroys the weeds but also improves aeration into the soil and mixes the fertilizers that are top-dressed in the crop.
Usually, hoeing is done after each cutting with Khurpi. Pre-emergence application of Pyrazon @ 1.5-2.0 kg/ha or pendimethalin @ 1.0 kg/ha found effective to control the weeds in beet leaf field. Among the herbicides, Ramana et al. (1994) reported highest weed control efficiency (93.6%) of fluchloration applied at 1.12 kg/ha.
ii. Use of Plant Growth Regulators:
Soil application of triacontanol @ 200-2000 ppm or soaking seeds in its solution of same concentration for five minutes gave the best results with regard to leaf weight. Pandita et al. (1981) obtained the highest green leaf yield of beet leaf per plot (3.6 x 1.2 m) from plants sprayed with 0.05% solution of Atonik (sodium mono-nitroguaicol) five times at weekly interval and seed dipped for 8 hours.
10. Harvesting and Yielding of Beet Leaf:
The time taken for first cutting depends on growing season, variety, soil fertility, irrigation facilities, and the other management practices followed during cultivation. In general, the crop becomes ready for first cutting in about 3-4 weeks after sowing when the leaves grow to a height of 15-20 cm, and subsequent cuttings are done at 15-20 days interval depending upon crop growth rate of different varieties in different seasons. The succulent leaves are cut about 2 cm above the ground.
Nath and Subramanyam (1972) advised that only well grown succulent and tender leaves should be trimmed or cut. The total number of cuttings depends upon the season and varieties. Winter crop gives more cuttings than spring-summer crop. The cultivar Jobner Green gives more cuttings than cultivar All Green. On an average, the crop gives 4-6 cuttings depending on the cultural practices adopted.
Harvesting of beet leaf in early morning is not at all desirable since the leaves in morning hours keep their turgor very high due to presence of dew, which makes the leaves brittle so during harvesting they break easily, and soon after harvesting start spoiling due to development of enormous decay causing microorganisms.
Since beet leaf produces succulent and tender leaves they may break during post harvest handling, thus, should be handled very carefully. It is a highly perishable vegetable due to very high moisture content, and its leaves after harvesting cannot be kept fresh for longer period, hence, should be sent to the market immediately, however, before marketing, the produce is tied in small bunches with twine.
All the yellow, diseased, and undesirable leaves are trimmed-off before making bunches. Although washing removes the dust particles adhered to the harvested leaves and improves their appearance but not at all desirable because it may cause rotting and yellowing of leaves too soon.
The β -carotene, ascorbic acid, and chlorophyll content of beet leaf cv. Pusa Jyoti grown in two different seasons decreased during storage in both the seasons but these changes were faster in summer as compared to winters. The quality characteristics of beet leaf can be preserved by various methods of dehydration, however, cabinet drying took less time, and the product is found to be excellent in colour and appearance.
Beet leaf because of its highly succulent and perishable nature possesses very short shelf life. The quality of leaves deteriorates with the increase in time after harvesting. The attractive appearance of leaves and their turgidity are lost within 24 h after harvesting. Merely splashing of water is helpful in retaining these qualities of leaves otherwise no use because rotting of leaves starts soon when leaves are heaped. It cannot be stored at room temperature but at low temperature (0°C) and high relative humidity (90 to 95%), leaves can be stored for about 10 to 14 days.
Some studies have been carried out to check the deterioration in quality of leaves. Deore and Bharud (1989) found smallest moisture loss from the leaves 72 h after treatment with GA3 20 ppm and stored under a wet cloth.
Srinivasa and Reddy (1997) noted that the evaporative cool chamber storage of beet leaf, whether packed in polyethylene bags (100-150 gauge with 1 and 0.5% ventilation) or not, slowed down the physiological loss in weight, delayed the symptoms of wilting and rotting, maintained freshness and better colour for longer time and increased the shelf life by 5 days as compared to one day at ambient storage conditions.
Storage life of beet leaf increased from one day (non-packed sample held at room temperature) to 6 days in packed beet leaf in polyethylene bags held in cold storage or cool chamber. Negi and Roy (2000) reported a beet leaf shelf life of 4 days in summer and 6 days in winter.
The yield of the crop depends on the varieties, growing season, irrigation facilities, soil conditions and the package of cultural practices followed during cultivation. The beet leaf greens can be obtained round the year, however, the yield and quality both are always better in autumn-winter season due to short day and low temperature conditions, which favor more number of cuttings. On an average greens yield of beet leaf is about 100-150 quintals per hectare.
11. Cultivated Varieties of Beet Leaf:
In recent years, considerable improvement has been recorded in beet leaf crop. Variability among the indigenous germplasm and its crossability with sugar beet and Swiss chard have helped in developing new improved varieties with extended duration of vegetative phase, increased number of leaves, their size, thickness, and high yield.
This feature of enormous productivity in green leafy vegetables makes them one of the cheapest vegetable marketed in India. Based on midrib and leaf vein pigmentation the varieties may be classified into two major groups, one with reddish midrib and leaf vein, and second with green midrib and leaf vein.
The characteristic features of some improved cultivars developed by various research institutes are as under:
A cultivar developed at Indian Agricultural Research Institute, New Delhi as a pure line produces uniformly green tender leaves. It gives total 6 to 7 cuttings at 15-20 days interval and produces about 125 quintals of green leaves per hectare. In main season (autumn- winter), its plants start developing seed stalks 75 days after sowing.
A variety developed at Indian Agricultural Research Institute, New Delhi in 1967 through a selection made from a cross between Swiss chard and Local Palak produces uniform green leaves without any purple pigmentation. It is a late bolting variety.
This cultivar is an induced polyploid (tetraploid) of variety ‘All Green’ and evolved because of treating the seeds of cv. All Green with 2% colchicines solution for 24 hours and selection made from subsequent generations up to 10 years. It is a giant leaved strain and produces large, green, thick, tender, succulent, and crisp leaves of good taste even when eaten raw as salad. They are easily minced and develop pleasant flavor and colour when cooked.
Plants are very vigorous, quick growing and regenerated quickly after each cutting. On an average, it gives fresh green leaves yield of more than 490 q/ha in 6-8 cuttings. It is rich in potash, calcium, sodium, iron, and ascorbic acid. The variety is suitable for growing throughout the year.
A cultivar developed at Indian Agricultural Research Institute, Regional Research Station, (Katrain) Himachal Pradesh through hybridization between sugar beet and local Palak (Gill et al., 1980) is suitable for cultivation in hills throughout the year because of its chilling requirement, which is a character inherited from its sugar beet parent.
Plants are upright, and vigorous with uniformly thick, green, slightly crinkled giant sized leaves. It is a high yielding variety with remarkable ability for regeneration. It has late bolting due to less chilling requirement habit and also has a wide range of adaptability to varying climate. It can also tolerate alkaline soil.
A high yielding variety developed at Indian Agricultural Research Institute, New Delhi produces smooth tender and pure green leaves without any red pigmentation. It has higher vitamin C content of β-carotene than Pusa Jyoti. Its leaves become ready for picking 30-40 days after sowing and may be picked up for 150 days.
In winter and early spring season, it gives green leaves yield of 500 q/ha. It performs best in winter and early-spring season (mid September-March). It is ideally suited for Kharif and summer seasons.
An exceptionally salt tolerant and quick growing variety developed by the Department of Vegetable Science, Haryana Agricultural University, Hisar through a selection produces dark green, large, thick, tender, and juicy leaves. It gives first cutting about 30 days after sowing and a fresh greens yield of about 250-300 q/ha in a total of 6-8 cuttings taken at 15 days interval.
A cultivar with purple pigmentation on stem developed at Punjab Agricultural University, Ludhiana produces light green, thin, narrow, and smooth leaves. On an average, it gives yield of fresh green leaves 275 quintal per hectare.
A variety with mild purple pigment on stem evolved at Punjab Agricultural University, Ludhiana through a selection produces semi-erect plants with shining dark green, thick, long, broad, and succulent leaves. The leaves are succulent and free from sourness. It gives first cutting 30 days after sowing and yields 300 q green fresh leaves per hectare. It is a slow bolter.
A prolific yielder cultivar evolved at Jobner Campus of Sukhadiya University of Udaipur during 1964 as a result of a spontaneous mutation (point mutation) detected from the population of a local collection produces uniform green, large, thick, succulent, tender leaves with strong flavour having entire margin. Leaves are easily cooked and taste is comparable to cultivar All Green. It gives an average yield of fresh green leaves about 300 q/ha.
A high yielding cultivar evolved at G.B. Pant University of Agriculture and Technology, Pantnagar is tolerant to Cercospora leaf spot disease.
A variety developed at Indian Institute of Horticultural Research, Bangalore is tolerant to Cercospora leaf spot disease and produces medium large, dark green, succulent, crinkled, and attractive leaves. It gives first cutting 35 days after sowing and regenerates at a faster rate. Its average yield of green fresh leaves is 410 q/ha from four cuttings. This is a late bolter with vigorous initial growth.
A variety evolved by Dr. S.P. Banerjee through a cross between local Palak and beetroot is very popular in West Bengal. It produces large thick leaves with very succulent stem.
A variety developed by the Department of Agriculture, Maharashtra produces green leaves. On an average, it gives a yield of fresh green leaves about 160 q/ha in several cuttings. It is a late bolting variety.
A variety evolved at Horticultural Research Station, Ooty of Tamil Nadu Agricultural University through a selection from an introduction from Himachal Pradesh produces 15 quintals green succulent leaves per hectare per cutting. Leaves are green with a length of 40-50 cm and breadth of 8-10 cm. It gives first cutting 45 days after sowing and total cuttings four. It produces yield 1.5 tonnes/ha/cutting.