ARECANUT AGRONOMY PRACTICE

Introduction

Arecanut highly profitable commercial palm, it produces the common chewing nut, popularly known as betel nut or supari. These nuts are consumed at large and in so have a great demand. The arecanut has got religious significance as well, especially in Indian subcontinent. India is the largest producer of arecanut in the world. The areca nut is not true nut per se, but rather a fruit categorized as a drupe. It is commercially available in dried, cured and fresh forms

Climate and soil

Arecanut requires abundant and well distributed rainfall. It grows well within the temperature range of 14-36 0C. It can be cultivated up to an altitude of 1000 m in deep and well drained soils with low water table. Laterite, red loam and alluvial soils are most suited.

Raising planting material

Mother palm should be more than ten years old with early bearing nature with good fruit set. Fully ripe nuts weighing more than 35g should be selected from mother palms. Selected seed nuts are sown 5cm apart in sand beds with their stalk ends pointing upwards. Beds are to be watered daily. Three month old sprouts can be transplanted in secondary nursery beds of 150cm width and convenient length. Apply basal dose of well decomposed cattle manure@ 5 tonnes per ha. Transplant the sprouts at a spacing of 30x30cm with the onset of monsoon, provide partial shade, irrigate during December to May and provide drainage during rainy season. Periodical weeding and mulching are required. Polythene bags (25x15cm, 150 gauge) with a potting mixture (top soil: farm yard manure: sand 7:3:2) can also be used to raise secondary nursery.

Seedling selection

Twelve to eighteen month old seedlings with more than five leaves and minimum height should be used for transplanting to the main field

Planting time

Planting should be done in May-June in well drained soils. In clay soils prone to water logging, planting may be postponed to August-September

Spacing and alignment

Planting is to be done at a spacing of 2.7m x 2.7 m. The rows may be aligned in north-south direction by deflecting the north-south line at an angle of 350 towards west to minimize sun scorching. Protect outer row of plants on South – West and Southern sides from sun scorching by covering the stem with areca leaves or leaf sheaths or by growing tall and quick growing shade trees.

Planting

Pits of 60x60x60cm should be dug and filled with top soil, cow dung and sand up to 50cm. Seedling should be planted at the centre of the pit and soil should be put to cover up to the collar region of the seedling. Banana can be raised as a shade crop in the inter-spaces.

Fertilizer application

A fertilizer dose of 100g N, 40g P2O2 and 140g K2O (200g of urea; 200g of rock phosphate and 230 g of muriate of Potash) per palm per year is recommended. 12kg of green leaf and 12kg compost or cattle manure should be applied every year. While the full dose of organic manure is to be applied every year, it should be enough if we apply 1/3 of the chemical fertilizers during the first year; 2/3 of the recommended fertilizer during the second year and full dose of fertilizer from third year onwards. Under rainfed conditions, 1/3 of the recommended dose in April-May and 2/3 in September-October should be applied. Under irrigated conditions, the April-May dose can be applied in February. During February or April-May, broadcast the fertilizer around the base of each palm after weeding and mix with the soil by light forking. During September-October open the basin to radius of 75-100cm and to a depth of 15-20cm, apply the fertilizer and cover with dug soil.

Organic matter recycling

On an average, 5.5-6 tones of organic wastes/ha/year will be available in arecanut garden. Direct recycling of these waste do not meet the crop demand immediately. Vermiculture technique is proved to be an efficient method in composting. To prepare vermicompost, areca wastes are chopped into small pieces of 10cm and heaped. The heap is sprinkled with water daily and maintained for two weeks. Then the chopped material is arranged in beds of one meter width and convenient length. For this, cement tanks and trenches can be used. A layer of 10-15cm waste material is alternated with 2cm layer of little cow dung over which earthworms are released at the rate of 1000 no. per square meter. The wastes are converted into fine granular, odourless vermicompost within 60 days. During this period the earthworm population is doubled. About 8kg/palm/year of vermicompost meets the crop nutrient demand. The two cultured species of earthworms. Eudrilus eugeniae and Eisenia foetida can be used.

Irrigation and drainage

Under Dakshina Kannada conditions, palms are irrigated once in 7 days during November-December, every 6 days during February and every 4 days during March-May. At each irrigation, 175 litres of water should be applied per palm. In drip irrigation, only 16-20 litre of water per day per palm is sufficient resulting in saving of 44 per cent of water over hose method. 2-3 microtubes/drippers should be placed in the basin opposite to each other or in a triangle. Adequate drainage with 75cm deep drainage channels should be provided during rainy season

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Cultural operations

Soil should be loosened with light digging in October-November. Terracing should be provided in undulated lands to prevent soil erosion

Cover cropping

Mimosa invisa, Stylosanthes gracilis, Calapogonium muconoides and pueraruia Javanica are suitable cover crops. The seed rate requirement per hectare for Mimosa, Stylosanthes, Calapogonium and Pueraria is 15kg, 9kg, 11kg and 11kg, respectively. Sowing of these crops may be done during May-June. The crops can be cut and incorporated during October.

High density multispecies cropping system

The long pre-bearing period, high investment and low returns in initial period are the main reasons which make it essential to take up inter/mixed cropping in arecanut plantation. Banana, Pepper and Cocoa can be grown in areca inter-spaces in coastal Karnataka and Kerala. In addition, acid lime and betelvine can also be grown with arecanut in West Bengal and Maidan parts of Karnataka. Banana can be planted simultaneously with arecanut in the centre of four palms. Besides main crop, two ratoon crops can be taken up and after three years, entire crop is to be replanted. When areca palms attain the age of 6-8 years, two rooted cuttings of pepper are to be planted on the northern side of the palm at 75cm distance. Cocoa is to be planted in 4 year old arecanut garden.

Harvesting and processing

Harvesting of nuts at correct stages is very important for obtaining the produce of better quality. In chali preparation, only ripe nuts are harvested. It should be ensured that fully ripe nuts alone are harvested for preparation of chali. The out-turn of Patora and Koka will be more if unripe or under-ripe nuts are harvested, which fetches only lower price in the market. After harvesting, the ripe nuts will have to be sun-dried for about 45 days. It is essential to spread the nuts uniformly in a single layer for drying. Proper drying of the nuts is important to prevent fungal infection of the nuts in the drying yard. Turning of nuts once a week may be attended for ensuring uniform drying and better quality of produce.

Tender nut processing

If the market requirement is for the processed tender nuts, harvesting green fruits at an appropriate stage of about 6 months maturity is essential since produce prepared out of over mature fruits fetches lower price in the market. The tender nut processing consists of dehusking, cutting the soft nuts into pieces, boiling cut pieces with water or dilute extract from a previous boiling and drying. After boiling, the arecanut pieces are given a coating with kali (a concentrated, thick extract obtained after boiling 3-4 batches of arecanut) to get a good glossy appearance. Both sun and oven drying can be adopted..

Alternative uses of Arecanut

Many studies have been conducted to find out the alternate use of the crop. The main constituents of arecanut are polyphenols, fat polysaccharides, fibre and protein. Besides these, nuts contain alkaloids viz. arecoline (0.1 – 0.7%) and others in trace amounts such as arecadine, guvacoline and guvacine. It was found that tannins, a by-product from the processing of immature nuts find use in dyeing clothes, tanning leather, as a food colour, as mordant in producing variety of shades with metallic salts etc. The nuts contain 8-12% of fat, which can be extracted and used for confectionery purposes. The refined fat is harder than cocoa butter and can be used for blending. The medicinal properties were described by Vagbhata (in 4th Century AD) as effective against leucoderma, leprosy, cough, fits, worms anemia, obesity. Recent studies have shown that arecanut has pharmacological uses viz. Hypoglycemeic effect, mitotic activity, antihelminthic activity, cholinomimetic activity etc. However, several studies have also implicated arecanut to cause carcinogenesis. Further, arecanut also shows medicinal value in the following lines however these values are yet to be exploited for commercial use.

• In the metabolic system as a digestive and carminative
• Anti-diabetic (Research from Hyderabad Medical College)
• Used against certain skin diseases
• Used as aphrodisiac
• Improves eyesight when used as Thamboola seva
• Helps in relieving asthma
• CFTRI Mysore has developed a soft drink concentrate called Pan Supari Nectar
• For Low Blood Pressure (Old Arecanut)

Arecanut husk finds use in preparations of hard boards, paperboards, cushions and non-woven fabrics besides being a good source of furfural. But all these are not commercially exploited due to the cost factors. The arecanut leaf sheath could be used for preparation of throwaway cups, plates, plyboards, tea chest, packing cases and suitcases and these are commercially exploited to some extent.

Tanins

Tannins are obtained as a by-product from the process of preparing immature betel nuts for masticatory purposes. It was found that tannic acid from the nut, when mixed with ferrous sulphate in warm distilled water gave black writing ink of acceptable quality. He used immature fallen nuts for this purpose. Other uses of tannin are as adhesive in plywood industries and as a textile dye..

Fats

The nuts contain 8-12 per cent fat. Fat from arecanut, can be extracted by solvent extraction using hexane. Areca fat has comparable characteristics with hydrogenated coconut oil. Areca fat can be made edible by refining with an alkali. The fat could be softened by fractional crystallization using hexane (25ºC) and randomization using sodium methoxide, which gave products desirable for use as confectionery fat. Simple blending of areca fat with butter fat and cocoa fat at 3:1 ratio followed by interesterification of areca fat and cocoa fat at 1:1 ratio gave good products acceptable in confectioneries

Arecanut husk

It is the outer cover of areca fruit. It constitutes 60-80 per cent of the total volume and weight of the fruits (fresh weight basis). It is now being largely wasted except for being used as an inferior fuel and mulch. Several processes have been developed for utilization of areca husk for making hard boards, plastic and brown wrapping paper. Areca husk is used as a substrate for mushroom cultivation. Arecanut husk fibre was generally longer than woolenised jute, goat hair or coir fibre. About 50 per cent of arecanut husk fibre was finer than other fibres and the remaining 50 per cent of fibre was coarser than those fibres. The tenacity value of arecanut husk fibre was comparable with that of goat hair and woollenised jute. Wet weight of arecanut husk fibre was comparable with that of other fibres. The weight and thickness of all fibre reinforced plastic sheets were comparable. The proportion of fibre in the fibre reinforced plastic sheets varied between 7.6 and 9.9 per cent. The proportion of arecanut husk fibre was higher (9.12 per cent) in comparison with that of glass fibre (7.9 per cent), though the thickness and water swelling ie, increase in weight of the sheets by immersion in water for 20 days, values were same.

Areca leaf sheath

Leaf sheath is yet another raw material obtained from the arecanut palm. In a year palm sheds 5-6 leaves. A process has been developed for making plyboards from areca leaf sheath. These boards can be used for making suitcases, fileboards, and tea chests. Leaf sheath cup making machine is available in the market for making arecanut leaf sheath cups of different sizes and shape. Arecanut leaf sheath was found suitable for making plyboards. Two plies of processed arecanut leaf sheaths in combination with an ordinary wood veneer as core glued with urea formaldehyde resin are used for making the plyboards. Leaf sheaths obtained from the farm are highly heterogenous having variations in structure, shape and thickness. The rear end is thicker and the two edges are thinner. The thickness at the center ranges from 3.0 8.5 mm (average 5.0 mm). A comparatively homogenous piece of fairly uniform thickness and size 50-65 x 20-25 cm can be obtained if a piece of about 10 cm length from either sides along the grain direction, 5 cm from the distal and 10-15 cm from the end across the grain direction are trimmed out from the sheath. Further, to get a flat sheath of uniform thickness and to remove the buck lings of folds, the sheath is flattened under pressure and heat. For this, the sheaths are soaked in water to about 75 per cent moisture and then pressed for 30 min in a hot Plate press at 4 kg/cm2 pressure and 110ºC temperature. This process gives flat sheaths of 1.0-1.5 mm thickness with about 12 per cent moisture. To prevent fungal growth on the sheath surface, it can be soaked in 1 per cent copper sulphate solution for 24 hr before pressing. The pressed sheaths are then air dried for one hour or longer. The arecanut leaf sheath plyboards made with two veneers of areca sheaths as the faces and one veneer of even an ordinary wood species like Mango as core ply and bonded with Urea formaldehyde resin make commercially acceptable boards with average dry and wet glue shear strengths of 50 kg and 12 kg respectively.

Arecanut stem and leaf

Arecanut stem forms a useful building material in the villages and is widely used in arecanut growing area for a variety of construction purposes. The leaves are good source of organic manure. Their approximate composition is N2 (0.94 %); P2O5 (0.096 %) and K20 (1 %).