MEDICINAL PLANT- NEEM/ ARYAVEPPU/ MARGOSA

 

Common name: neem, margosa

Scientific name: Azadirachta indica A. JUSS.
Parts used: Leaves, Flower, Oil, Seed.

Commercial importance: It acts as vermifuge, insecticide, astringent, tonic and antiseptic. It possess anti diabetic, anti bacterial and anti viral properties and used successfully in cases of stomach, worms and ulcers. Root barks possess astringent, tonic and antiperiodic properties. It is also useful in malarial fever. The oil is used in making neem-based soaps, shampoos and toothpaste. Leaves are used to cure chicken pox. It is also used in the treatment of acne and has blood purifying property. Neem tea is usually taken to reduce the headache and fever. Its flowers are used to cure intestinal problems. Neem bark acts as an analgesic and can cure high fever as of malaria. Even the skin diseases can be cured from the Neem leaves. Dental Treatments : In India, millions of people use twigs as "tooth brushes" every day. Dentists have endorsed this ancient practice, finding it effective in preventing periodontal disease. Neem fruits : The fruits are recommended for urinary diseases, piles, intestinal worms, leprosy etc. The dry fruits are bruised in water & employed to treat cutaneous diseases.

How to cultivate

It generally performs well on areas with annual rainfall varying from 400 - 1200 mm. It thrives under the hottest conditions where maximum day temperature reaches 50⁰ C. But it cannot withstand freezing or extended cold.

Soil

Neem grows on almost all kinds of soils including clayey, saline and alkaline soils but does well on black cotton soils. It thrives better than most other trees on dry stony saline soils with a waterless sub-soil or in places where there is a hard calcareous or clay pan near the surface. It does not tolerate inundation. It has a unique property of calcium mining which changes the acidic soil into neutral. Neem also grows well on some acidic soil. It is said that the fallen neem leaves which are slightly alkaline are good for neutralising acidity in the soil.

Nursery Practices

Nursery Site : Nursery could be either a temporary or permanent one. Site in either case should have a perennial water source and located on a flat ground with well drained soil. On a hilly site, a moderate slope preferably on the northern aspect has to be chosen.

Seed collection and storage

Only fruits at the yellow green colour stage are pricked from the branches by hand or by using ladder. After collection the fruits are depulped immediately. Soaking in cold water for a few hours helps in removing pulp. Fruits are then rubbed over a coffee weir and floated in water to separate seed from pulp. Storing neem seed for 5 months at 40% natural moisture content at 16 degree centigrade is possible. For short storage the seeds are closed in polythene bags and exposed to air once in a week to keep them viable. Long term storage of Neem seeds for more than 10 years is done at 4% moisture content and -20⁰ Centigrade temperature. For this purpose seeds are dried very quickly i.e. within a few hours after depulping in a mono layer at temperature more than 20 degree centigrade to prevent chilling damage under a fan. Shade drying and storage of seed in cloth bags at a temperature upto 4 ^o Centigrade is also done to improve seed viability. Storage of seed in earthern pot containing wet sand (30% moisture) helps to retain viability upto 60% at the end of 3 months. On an average 5000 seeds weigh one kilogram.

Sowing of Seeds

Germination rate of Neem varies between 15% (stored seeds) and 85% (fresh seeds). Hence, to ensure higher viability of the seeds, their immediate sowing in nursery is recommended. Pre-soaking the seed for 24 hours in cold water and removal of the endocarp or cutting of the seed coat at the round end with a sharp knife also increase its germination capacity. Examination of seeds at the time of sowing is also necessary. Seeds are cut across with sharp blades and the cotyledons are examined. If the cotyledons are found green, seeds are sound and suitable and if they are yellow or brown, then seeds are not suitable for sowing .

Sowing of seeds in nursery beds made up of fine river sand is done in drills 15 c/m apart. Seeds are sown 2.5 cms deep at distance of 2 to 5 cms in the lines and lightly covered with earth to safeguard against birds and insects which often eat radicles of the germinated seeds on the surface. The beds are sparingly watered to prevent caking. Alternatively seeds can be sown directly into pots. Germination occurs in 1/2 weeks time. Once the hypocotyl is erect the seedling is transplanted into the containers. Seeds are sown 3 / 4 months before planting date. Potting mix comprises of 50% sandy loam, 40% river sand and 10% compost by volume.

Pricking :

Seedlings are pricked out at 15 cms x 15 cms when about 2 months old. They do not require any shade. Soil working and weeding are very beneficial. When the seedlings are 7 to 10 cm tall with tap root about 15 cm long, these are transplanted with balls of earth around them. In dry areas, it is necessary to plant larger seedlings of at least 45 cm height since smaller ones are unable to tide over the drought period. This is the reason why seedlings are kept in the nursery beds for another year before planting in the next range.

Planting Techniques :

Neem can be easily raised through direct sowing, entire / polypot seedlings or root-shoot cuttings. For degraded areas direct sowing is more successful and economical provided adequate protection is given during early stages. Entire / polypot seedlings or root-shoot cuttings are more relevant for agro-forestry / silvi pasture and road side avenue plantations. Direct sowing is done either by dibbling in bushes, broadcast sowing, line sowing, sowing on mounds or ridges, sowing in trenches in sunken beds in circular saucers or by aerial sowing. The choice varies with edaphic, climatic, biotic and economic conditions of the site. Planting in pits is carried out by using 20 to 45 cms tall seedlings. Taller ones promise better survival. Planting of stumps prepared from a year old seedlings in crowbar holes also gives good results.

Dibbling in bushes :

Neem seed can be successfully dibbled in Euphoribia bushes. For this purpose, small pits are made and 3 to 5 seeds sown in each pit and covered.

Broadcast sowing :

This is generally done on ploughed land. Very good results are obtained by ploughing of the ground twice. early ploughing during premonsoon showers gives better results than ploughing after monsoon has set in. In arid areas ploughing is done in early spring when the soil is just moist after winter rain.

Sowing in lines :

Neem is grown along with Babool in line sowings in combination with field crops. Here Neem is used as a buffer species to control the insect attack to which Babool is susceptible.

Sowing on mounds and ridges :

This is prescribed for heavy soils. Sowing on mounds (about 70 cm high 60 cm dia. at the top and 2 mtrs dia at the base) in poor soil on trap formation has given satisfactory results. The plants reached 90 cm height 16 months after sowing. Sowing on mounds 3.7 x 1.2 mtr x 46 cm in rows 2.7 mtr apart on black cotton soil has been successful with plant attaining a maximum height of 1.4 mtr in one year after sowing.

Sowing in Trenches : On dry sites for conserving moisture continuous or interrupted trenches are made on which direct sowing is successful. In Tummala method, the trenches are aligned at an angle of 45⁰ to the contours. Similarly, sunken beds and Saucer Method are in vogue.

Entire / polypot planting :

Seedlings which have attained 20-25 cm height by the beginning of the rainy season are planted out in pits of 30 cu. cm at a spacing of 3x3 mtrs. or any other spacing depending on the purpose of plantation. Pruning of leaves except at the tip and roots has been proved successful. Even plants of 45 cm height can be used for this purpose, since smaller plants are found incapable of bearing the stress of drought period. Planting is, however, done during the rainy season.

Planting Root-shoot cuttings :

The stumps are prepared from 12-13 months old seedlings, keeping 2.5 cm of shoot portion and 23 cm of root and are planted in crow bar holes at the break of rains. Stumps from two years old plants have given higher survival and better height growth than one year old root stock. 53% success from root-shoot cuttings has been reported. The success of root-shoot cuttings depends upon rains, prolonged drought may affect survival to a great extent.

Farm forestry plantations :

For raising a block plantation under farm forestry a closer espacement of 5mx5m accomodating 400 trees per ha may be followed. This may vary from field to field and also depending upon the objective. The wider espacement of 7mx7m accomodating about 200 trees per hectare may be on the broader side where Agro-forestry can also be practised.

Care of Young Plantation :

Strip weeding of young plantations has a positive effect on health and survival. Two weedings are sufficient in the first year and one weeding during the second year. First mechanical thinning in the case of transplanted seedlings is done at the age of 5 years. In arid region Neem planted are watered for the first 5-7 years.

Harvesting, Yield & Returns :

Neem starts bearing fruits after 3-5 years and comes to full bearing at the age of 10-12 years. Fruit yield is 10-25 kg per tree per year in the initial years. A mature tree produces 35-50 kg fruit/year. Oil yield varies from 40-43% of seed on dry weight basis. It has been observed that as rainfall in an area increases oil content also increases. Yield generally stabilises from 9th year. Irrigating the young stock, keeping the field clear from competing weeds & soil loosening have been reported to produce good results in neem.