Ground nut or Pea nut

CLASSIFICATION

Kingdom: PlantaeDivision: TracheophytaClass: Magnoliophyta

Order: FabalesFamily: Fabaceae

Subfamily: FaboideaeTribe: Aeschynomeneae

Genus: ArachisSpecies: A. hypogaea

Origin & distribution of ground nut

Ground nut is native to Brazil .It is widely distributed throughout in the south America. At the present ground nut is widely cultivated in almost all tropical and sub tropical countries of the world. India is the largest producer of ground nut followed by China , USA. , Sudan , Senegal , Nigeria , South Africa , Indonesia and Brazil. It also grows in Burma , Argentina and Thailand.

Botanical characters of peanut

Groundnut is herbaceous annual plant, basically interlineate in growth habit. The habits are bunch ( erect) , semi spreading ( ovate) and spreading ( prostate). In spreading forms the axis is very short and erect and primary branches spread horizontally along with ground. In bunchy type main axis is long and erect and primary branches are oblique to the main axis. The intermediate forms between these two are classified as semi spreading.

Botanical charactersThe plant has tap root system consist of numerous lateral roots. Being leguminous crop root nodules are developed on roots that help fix atmospheric nitrogen. An inflorescence products cataphylls at first node that give rise to flower. The flower developed either above or below the ground level. They are sessile orange to yellow in colour complete and papilonaceous in nature. The corolla having five petals i.e a standard two wings and partially united two keels. It is placed in end of the long calyx tube having five sepals in gamosepalous condition with three lobes. The stamens are 8-10 in number and only eight bear anthers. They are in monoadephous condition. The stigma usually protrudes above the anther level.

FloweringGroundnut is self –pollinated crop but out crossing may occur up to 2.5% . It is extremely difficult for crossing. The flower opens early in the morning. i.e. 6-9 a.m. and anther dehisce 1 to 2 hours before opening the flower. Next day all flower parts except small sessile ovary withers. Normally the flowering period last 3 to 6 weeks in case of bunch and 6 to 8 weeks in case of spreading types. After fertilization gynophores i.e. stalk of the ovary, elongate forming peg, curved downward pushing the ovary into the soil where the pod develops.

Area of Cultivation

In India the cultivation of Groundnut is mostly confined to the southern Indian states, viz., Gujarat, Andhra Pradesh, Karnataka, Tamil Nadu and Maharashtra. The other important states where it is grown are Madhya Pradesh, Rajasthan, Uttar Pradesh and Punjab.

SeasonGroundnut is essentially a tropical plant. It requires a long and warm growing season. The most favourable climatic conditions for groundnut are a well distributed rainfall of at least 50 centimetre during growing season, abundance of sunshine and relatively warm temperatures. It seems that plant will grow best when the mean temperature is from 21-26.5 Degree Celsius. Lower temperatures are not suitable for its proper development. During ripening period it requires about a month of warm and dry weather. The rainfed crop should be sown with the advent of monsoon in the last week of June or in the first week of July. The sowing should be completed as early as possible as delayed sowing causes progressive reduction in the yield. Where irrigation facilities are available, groundnut should be sown around 20th June or 10-12 days before the onset of monsoon with a pre-sowing irrigation. This helps in best utilization of monsoon by the crop because all the germination will take place before rains start which ultimately result in a higher yield. It will also help in getting the field vacated in time for the sowing of Rabi crops. In southern part of the country where groundnut is sown in Rabi season also, it should be sown in the month of November and December.

SoilGroundnut thrives best in well-drained sandy and sandy loam soils, as light soil helps in easy penetration of pegs and their development and also harvesting. Clay or heavy soils are not suitable for this crop, as they interfere in penetration of pegs and make harvesting quite difficult. Groundnut gives good yields in the soil with pH between 6.0-6.5.

CultivationAlthough groundnut is a deep-rooted crop but looking to its under-ground pod forming habit, deep ploughing should be avoided. Because deep ploughing encourages development of pods in deeper layers of soil which makes harvesting difficult. One ploughing with soil turning plough followed by two harrowings would be sufficient to achieve a good surface tilth up to 12-18 centimetre depth. One or two summer cultivations will minimize weeds and insect pests to a great extent in problem areas. Quality of seeds is of utmost importance for establishing the optimum plant stand. Pods for seed purposes should be stored unshelled in a cool, dry and ventilated place. For seed purposes, pods should be shelled by hand one week before sowing. Hand shelling ensures little damage to seeds. Pods shelled long before sowing time are liable to suffer from loss of viability and storage damages. Discard very small, shriveled and diseases kernels. Only bold seeds should be used for sowing. It is advised to treat the selected kernels with 5 g of Thiram or Captan or Ceresan per kg of kernels so as to check various seed and soil borne diseases. Seed should be inoculated with proper strain of Rhizobium culture particularly in those places where groundnut is to be grown for the first time.

Sowing In bunch types, the row to row distance is kept 30-40 cm and in spreading types 45-60 centimetre. For this, 80-1000 kg of seeds per hectare would be enough for bunch types and 60-80 kg for spreading types. Plant to plant distance would be 15 and 20 centimetre for bunch and spreading types respectively. Sowing should be done about 5 centimetre deep behind the plough or with the help of dibbler or seed planter. On a large scale, seed planter can be used.

Fertilizer and Nutrient ManagementLike the other legumes, groundnut too meets the major part of its nitrogen requirement through nitrogen fixation. However, an application of 20-40 kg nitrogen per hectare as a starter dose should be given to meet the nitrogen requirement of the crop in the initial stage in poor fertility soils. If farm yard manure or compost is available, 10-15 tonnes may be added per hectare about 15-20 days before sowing

Water Management Being a rainy season crop, groundnut does not require irrigation. However, if dry spell occurs, irrigation may become necessary. One irrigation should be given at pod development stage. The field should be well drained. In the southern part of the country where groundnut is grown in Rabi season too, three to four irrigation are necessary. It is advised to give the first irrigation at the start of flowering and the subsequent irrigation whenever required during the fruiting period to encourage peg penetration and pod development. The last irrigation before harvesting will facilitate the full recovery of pods from the soil.

HarvestingIt is necessary to dig the pods at the right time for obtaining higher yields of pods and oil. Nut takes two months to attain full development. A fully mature pod will be difficult to split easily with finger pressure. This stage is achieved when vine begins to turn yellow and leaves start shedding. Harvesting should be done when good percentage of nuts are fully developed and fairly intact. In case of bunch type of groundnut, the plants are harvested by pulling. Harvesting of spreading type of groundnut is done by spade, local plough or with the help of blade harrow or groundnut digger. Leave the harvested crop in small heaps for two three days for curing. After curing, collect the crop at one place and detach the pods either by hand or using groundnut pluckier for separating the pods.

Improved varieties of ground nutT.M.V. 1,2,3,4.

Spanish JSpanish Improved

VR 1-1VR 1-2VR 1-3

SomnathKaushalRS 138

Extraction of oilEdible oil technology can be grouped into two: mechanical pressing and solvent extraction. Sometimes the latter compliments the former. For oilseeds with high oil content such as ground nut, first mechanical pressing will be applied and over 85% of the oil will be extracted. The remaining oil in the expeller cake will then be extracted with solvent. For some other oilseed with low oil content, solvent extraction is generally considered as the best alternative. However, the initial investment cost of solvent extraction is much higher than mechanical pressing. In addition, solvent extraction is more appropriate for large scale processing than small scale edible oil plants.

Traditional method of oil extraction

Oil mill

Properties of peanut oil

Peanut oil, also known as groundnut oil or arachis oil, is a mild tasting vegetable oil derived from peanuts. The oil is available in refined, unrefined, cold pressed, and roasted varieties, the latter with a strong peanut flavor and aroma, analogous to sesame oil.It is often used in Chinese, South Asian and Southeast Asian cuisine, both for general cooking, and in the case of roasted oil, for added flavor. Peanut oil has a high smoke point relative to many other cooking oils, so is commonly used for frying foods. Its major component fatty acids are oleic acid(46.8% as olein), linoleic acid (33.4% as linolein), and palmitic acid (10.0% as palmitin). The oil also contains some stearic acid, arachidic acid,arachidonic acid, behenic acid, lignoceric acid and other fatty acids.Antioxidants such as vitamin E are sometimes added, to improve the shelf life of the oil.

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