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.
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 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.
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.
In desert areas of Rajasthan, Neem has been planted along with canal area and watered for the first 5-7 years. Under Saudy-Arabian Arid condition, Neem is usually watered for the first 10-12 years, after which it taps ground water.
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. Highest oil content has been reported from Banswara region of Rajasthan (43.2%), while the lowest oil yield of 32.4% has been reported from Jaisalmer region. It has been observed that as rainfall in an area increases oil content also increases. Among the International provenances tested, Bangladesh provenance has yielded maximum oil content (48.6%). However we presume a conservative yield of 5,7,10,15, 20 kg/tree respectively from 5th year onwards. Yield generally stabilises from 9th year. Sale price of the seed may be considered @ Rs.3/kg.
Irrigating the young stock, keeping the field clear from competing weeds & soil loosening have been reported to produce good results in neem.
Neem seed price is projected to be Rs.10000 / ton in the near future. So, it is high time to exploit the potential of this hitherto neglected tree & to manage neem for higher economic returns to farmers. It has been estimated that 10 yr old tree can yield a timber of 5-6 c.ft / tree.
Neem extracts as insecticides. Neem products are unique in that they are not outright killers. Instead, they alter an insects behaviour or life processes in ways that can be extremely subtle. Eventually, however, the insect can no longer feed or breed or metamorphose & can cause no further damage.
- Azadirachtin : One of the first active ingredients isolated from neem, Azadirachtin has proved to be the trees main agent for battling insects. It appears to cause some 90% of the effect on most pests.
- Fungicides : Neem has proved effective against certain fungi that infect the human body. Such fungi are an increasing problems & have been difficult to control by synthetic fungicides.
- Antibacterials : In trials neem oil has suppressed several species of pathogenic bacteria including Staphylococcus & Salmonella spp.
- Antiviral agents : In India, there is much interesting, but anecdotal information attributing antiviral activity of Neem. Its efficacy particularly against pox viruses is strongly believed, even among those of advanced medical training. Small pox, chicken pox have traditionally been treated with a paste of neem leaves – usually rubbed directly on to the infected skin.
- Dermatological Insects : In India, villagers apply neem oil to the hair to kill head lice, reportedly with great success. Neem seed oil and leaf extracts may be the wonder cure for psoriasis. It relieves the itching and pain while reducing the scale and redness of the patchy lesions.
- 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.
- Malaria : Practitioners of the Indian Ayurvedic Medicine system have been preparing neem in oral doses for malarial patients for centuries. Neem’s antimalarial activity was reported in Ayurveda books as far back as 2000 BC (by Charaka) & 1500 BC (by Sushruta).
- Pain Relief & Fever Reduction : Neem may also be a ready source of low cost analgesic (pain relieving), or antipyretic (fever reducing) compounds. In trials, positive results have been obtained for significant analgesic, antipyretic & anti-inflammatory effects.
- Contraceptive Agents : Indian scientists from the Defence Institute of Physiology & Allied Sciences (DIPAS) have applied for patents on chemicals isolated from the neem oil which have proved to be promising contraceptive agents which are DK-1 & DNM-5. A third active agent coded as DNM-7 acts as an abortifacient causing abortion if administered orally after implantation has already occurred. A Neem oil formulation called “Sensal” is now sold in India for contraceptive purposes.
- Veterinary Medicine : Ancient practice & initial testing of neem derivatives against various livestock pests indicated that this is an area of particular promise for the future. Insects of veterinary importance are obvious targets for neem products.
- Cosmetics : Neem is perceived in India as a beauty aid. Powdered leaves are a major component of atleast one widely used facial cream. Purified neem oil is also used in nail polish & other cosmetics.
- Lubricants : Neem oil is non drying and it resists degradation better than most vegetable oils. In rural India, it is commonly used to grease cart wheels.
- Fertilizers : Neem has demonstrated considerable potential as a fertilizer. Neem cake is widely used to fertilize cash crops particularly sugarcane & vegetables. Ploughed into the soil, it protects plant roots from nematodes & white ants, probably due to its contents of the residual limonoids. In Karnataka, people grow the tree mainly for its green leaves & twigs, which they puddle into flooded rice fields before the rice seedlings are transplanted.
- Other products
- Resin : An exudate can be tapped from the trunk by woundings the bark. This high protein material is not a substitute for polysaccharide gum, such as gum arabic. It may however, have a potential as a food additive, and it is widely used in South Asia as “Neem glue”.
- Bark : Neem bark contains 14% tannins, an amount similar to that in conventional tannin yieldings tree (such as Acacia decurrens). Moreover, it yields a strong, coarse fibre commonly woven into ropes in the villages of India.
- Honey : In parts of Asia neem honey commands premium prices & people promote apiculture / apiary by planting neem trees.
- 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.
- Soap : India’s supply of neem oil is now used mostly by soap manufacturers. Although much of it goes to small scale speciality soaps, large scale producers also use it, mainly because it is cheap. Generally, the crude oil is used to produce coarse laundry soaps.
- Neem Leaf Tea : Several companies have started processing neem leaves for Tea production and selling as neem leaf Tea. Although it tastes bitter, in the long run it may catch up with the masses especially to the health concious people.