Cultivation of Sunn-Hemp (Crotalaria Juncea) in India

June 26, 2021May 2, 2023 Agrovista 0 Comments

Cultivation of Sunn-Hemp (Crotalaria Juncea) in India

Introduction;

Table of Contents

Sunn-Hemp (Crotalaria juncea L.) or Bombay hemp or Banars hemp, belongs to the family Leguminosae. It is an erect annual with few lateral branches, growing to a height of 1.2 to 3.0 meters. It is one of the important fiber crops of India.

Sann-hemp is probably indigenous to India and has been grown in this country from very early times. It is found throughout the plains of India It was introduced to other countries from India.

The important sunn-hemp growing countries of the world are U.S.S.R. Romania, India, China, Hungary, Poland, Turkey, Brazil, Chili, and Bangladesh. In India, it is cultivated on about 1.4 lakh hectares with a total production of about 50,000 tonnes of fiber. It is grown mainly in Uttar Pradesh, Madhya Pradesh, Maharashtra, Rajasthan, and Orissa Uttar Pradesh has the largest area under sunn-hemp cultivation followed by Madhya Pradesh.

Vernaculer Names of Sunn- Hemp;

‘Hindi ; Sonai or San

Bengali; Sanpat

Marathi;, Tag

Malayalam;Vakku

Oriya ; Sanpat

Telgu ; Janumu

Kannada ; Saab

Importance of Sunn-hemp Crop ;

1) It plays an important role in the national economy both as raw material for indigenous industry and also as a foreign exchange earner through export.

2) Recently it has gained additional importance because of the increasing demand for a particular grade of fiber (white) for the manufacture of tissue paper and paper for currency as it contains a high percentage of cellulose and a low amount of lignin.

3) The farmers themselves make use of the fiber for making ropes, twines, nets, matting. etc. It is also used for making rugs, sacks,s, etc.

4) Sunn-hemp is also raised as a green manure crop. When it is grown for green manuring purposes, the crop is turned under with a soil inverting plough when the plants are about six to eight weeks old. It adds about 40-60 kg nitrogen per hectare to the soil after decomposition.

Climatic Requirements for Sunn-Hemp Crop;

1) Sunn-hemp is a warm-season crop and hence grows best in tropical and subtropical regions of the world.

2) In northern India, it is grown in the Kharif season

3) In the southern parts of the country, where the winter is not so pronounced, it is raised in Rabi also.

4) It requires a minimum of 40 cm of well-distributed rainfall during the growing season for its successful cultivation for fiber purposes.

Soil Requirements for Sunn-Hemp Crop;

1) Well-drained loamy soils are best for sann-hemp cultivation.

2) If there is proper management for drainage it can also be grown on heavy soils

3) Acid soils are not at all suitable for this crop.

4) When grown for fiber it is not sown on heavy or waterlogged soils but for green manuring purpose, it can be sown on heavy soils too.

Important Varieties of Sunn- Hemp;

Several varieties released from different states are under cultivation, which differs in their period of maturity, branching habit, and in the quantity and quality of fiber which they yield. Salient features of some of the important varieties are given below:

Verities	Characterstics
K-12	,Black Seed, harvest in 136 days, adds green biomass of 16 – 26 tonnes /ha ,Yield potential 6-10 Q/ha
K-12 Yellow	Yellow seed Coat , superior to K-12 ,Resistant to wilt, Yield potential 14 q/ha
Narendra -Sanai	Harvest in 152 days, seeds are bold and black color, average seed yield of 6-8 qt/ha.
ST-95	Selection from a type introduced from Taiwan ,slight resistant to wilt and top shoot borer
ST-55	Yield potential 14-15 qha’, moderately resistant to wilt
ST-11	Selection from local types, higher fibre yielder than K-12 yellow in Uttar Pradesh
SH-4	Selection from local types, higher yielder than K-12 yellow in Uttar Pradesh, West Bengal, Madhya Pradesh
SNN-53	Selection row local types, suitable for West Bengal and Uttar Pradesh, yield 12 qt/ha
JRJ-610	Yield Potential is about 10 gha’ and suitable for irrigated and rainfed, fiber quality is stronger (13.19g/ tex)
SUN -37	Selection from accession no 037, early maturing (90-100 DAS), resistant to wilt and mosaic, yeild protential is 10-12 q/ha
PAU -1691	Bold Seed With Black Color, Yield Potential 16-18 qt/ha

Rotations and Mixed Cropping in Sunn-Hemp Crop ;

1) Sunn-hemp is usually sown after the harvest of Rabi crops as the main Kharif crop or an early pre-monsoon crop.

2) It is grown in rotation with wheat, potato, Rabi oilseeds, etc.

3) A few rows of sann-hemp are sometimes sown as a mixed crop in the fields of ragi, cotton, sesamum, etc., for the purpose of seed production.

4) Some tradition, farmers sow a few lines of sunn hemp on the borders of bajra, ragi, and jowar crops.

Field Preparation for Sunn-Hemp Crop ;

1) The soil should be made friable and weed-free for sowing of sann-hemp.

2) One ploughing followed by two to three cross harrowings is sufficient.

3) In case summer ploughing is done, only two harrowings or ploughings with local plough are needed.

4) After harrowing, the field should be leveled by giving a gentle slope to ease drainage.

5) There should be proper moisture in the soil at the time of sowing for proper germination of seeds.

Seed and Sowing of Sunn-Hemp Crop;

1) Sunn-hemp seed losses its viability quickly, therefore, not older than one year seed should be used for sowing purposes.

2) For fiber crop it should be sown in lines at a distance of 30-centimeter line to line and 7-10 centimeters. plant to plant.

3) About 20-25 kg of seed is required for sowing one hectare.

4) When sown for green manuring it may be sown broadcast and about 55-60 kg seed per hectare is required.

5) The crop is generally sown with the onset of monsoon or in May-June with pre-irrigation in north India.

6) Seed should be sown 3-4 centimeters below the soil surface.

Manures and Fertilizers Requirement in Sunn-Hemp Crop;

1) Sann-hemp being a leguminous crop fulfills its nitrogen requirement through the process of symbiotic nitrogen fixation in nodules on roots

2) However, it requires about 50 kg P205, per hectare for the proper development of roots and nodules and also to stimulate crop growth.

3) Besides phosphorous, calcium is also required in some of the soils.

4) No response in the application of potash has been observed.

5) Traces of boron and molybdenum are required, but these elements are added only after soil testing

6) All the fertilizers are applied at the time of sowing.

Water Management in Sunn-Hemp Crop;

1) Generally, the crop does not require any irrigation during the Kharif season.

2) In case the crop is sown early in the month of May or June, it may require one or two irrigations before rains start.

3) When the crop is grown for fiber one irrigation must be given in drought conditions if rains stop for a long spell.

4) The crop at the same time can not tolerate too much water standing in the field, therefore, for obtaining good yield and quality fiber excess water should be removed from the field after heavy and continuous rain.

Weed Control in Sunn-Hemp Crop;

1) There is not much weed problem in the sann-hemp crop, because seedlings grow very fast and smother all weeds.

2) In problem areas one weeding in the early stage of crop growth is sufficient.

3) Sometimes there is a problem with Ipomoea plants that grow along with crop plants and flowers and fruit at the same time as sann-hemp. The seeds of Ipomoea disseminate along with the sann-hemp seed and create problems in subsequent years also. Therefore, they should be removed manually before flowering.

Diseases and Pest Management in Sunn-Hemp Crop;

Important diseases of sann-hemp are wilt; anthracnose; rust and powdery mildew.
Disease Management;

1) Wilt
It is caused by a fungus known as Fusarium vasinfectums. This disease is sometimes very destructive. Wilt affects both young and old plants, causing them to dry up.
Control Measures
(1) Grow wilt-resistant varieties like K-12, K-12 Yellow etc.

(2) Seed should be treated with Agrosan G.N. before sowing.
2) Anthracnose
The disease is caused by a fungus known as Colletotrichum curvatum. the disease causes considerable damage to seedlings. Usually, the cotyledons, as well as leaves, drop out.
Control Measures

(1) Seed treatment with Agrosan G.N. or Ceresan is effective to some extent

(2) Spray crop with Blitox or Fytolan.
3) Rust
This disease is caused by a fungus known as Uromyces decorarus. It is responsible for considerable damage to the crop in some of the areas where sunn-hemp is grown.
Control Measures
(1) Grow resistant varieties.

(2) Spray the crop with Dithane Z-78 or Dithane M-45 at the rate of
2 kg in 800-1000 liters of water per hectare.
Insect Pests Management;

Sannchemp crop is attacked by a number of insect pests. The important pests are given below:
1) Sunn-Hemp Moth;
The caterpillars of this pest feed on the leaves and also bore into the seed pods. The caterpillars are about 3-4 centimeters long and spotted with red, dark, and white markings. The caterpillars sometimes damage the crop seriously.
Control Measures

(1) Spray the crop with Endosulfan 35 EC at the rate of 1.5 liters in 1000 liters of water per hectare.

(2) Collect and destroy the eggs.
2) Stem Borer
They bore into the stem near the nodes, causing characteristic swellings and thus affecting the fiber quality. They also bore into the top shoot of the plant resulting in the formation of galls. The affected plants become stunted and the fiber obtained is short, coarse, and specky.
Control Measures
To reduce the incidence of stem borer, three to four sprayings of prophylactic with 0.4% Diazinon (20 milliliters in 10 liters of water) reduce the incidence to a great extent.
3) Green Bug
These green bugs appear in swarms and suck the sap from leaves
Control Measures
Spray the crop with Metasystox 25 EC at the rate of 1 liter in 1000 of water per hectare.

Harvesting of Sunn-Hemp Crop ;

1) The harvesting of sunn-hemp is best done at the pod formation stage for good quality fiber. Such fibers have a good color and luster.

2) Sometimes the plants are allowed to remain in the field until they are dead ripe The fiber obtained from such plants is of very poor quality. Too early as well as too late harvesting spoils the fiber quality.
3) A crop of sunn-hemp grown for the purpose of green manure becomes ready for incorporation in the soil within two to three months of sowing. At this time, the stalks will be tender with very little fiber formation and will take less time for decomposition in the soil.
4) Harvesting of fiber crop is done by cutting the plants close to the ground with a sickle. The leafy top portions of the plants may be chopped off and used either as fodder or may be ploughed down to add organic matter to the soil.

5) After two to three days when most of the leaves get dried up, these plants are shaken to shed the leaves.

6) The plants are then tied into bundles of convenient sizes having 50 to 100 plants in each bundle.

Steeping, Retting, and Extraction of Sunn- Hemp Crop ;

1) The bundles are brought to the nearest ponds, ditches, pools, or streams, and arranged side by side to form a platform in-water for steeping.

2) In some states, the bundles are covered with hyacinth, grass, etc., and the ‘jak’ is weighed down 10-15 centimeters below the surface of the water by stone blocks, concrete slabs, or seasoned logs.

3) Substances rich in tannin like freshly cut logs or clods should not be used as weighing materials, because it will turn the color of the fiber dark.

4) Care should also be taken to see that while weighing down the ‘jak’, the bundles do not touch the bottom of the retting tank.

5) Retting in slow running water is better than retting in stagnant water. This process is complete when the fiber is loose enough for extraction and is easily separated from the sticks. This can be determined by examining one or two plants from the bundle after two or three days of getting.

6) The period of retting may vary from 3 to 15 days depending upon the temperature of retting water and the month of harvesting. In September, retting takes place generally within three to seven days while in December this period may range from 12-15 days. The optimum temperature for retting is 21 to 27°C.
7) The extraction of the fiber of sann-hemp is more difficult than jute.
8) The beat-and-jerk method is unsuitable in the case of sann-hemp as the ney of fiber to stick to the wood is more and the fiber gets entangled in broken twigs. Therefore, fiber is extracted single plant-wise by break the lower ends of the plants and then stripping upwards from the bottom.

9) After extraction, the peeled fiber should be washed thoroughly in clear water to remove the dirt and other adhering plant materials.

10) The fibre needs to be squeezed to remove excess water and spread on bamboo rafts to dry in the mild sun for two to three days.

11) After drying the fiber is graded and bundled into small ‘moras’ for marketing.