Introduction:

Its actual place of origin is very controversial as some people believe is to orginate in India while others say that red gram was found in the wild estate in Africa in regions of upper Nile and the coastal districts of Angola. From Africa it spread to other parts of the world and to India. Australian people grow it for fodder and vegetable purposes. Now it is being grown in Africa, America, Australia, Hawaii, Ceylon, Netherlands, Malaya, East and West Indies, India, Indo-China, Pakistan, etc.

In India, Arhar is mostly grown in the states of U.P, M.P, Maharashtra, Bihar and Andhra Pradesh, Punjab, Haryana, West Bengal, Assam, Orissa, Rajasthan, H.P., Gujarat, Jammu and Kashmir, Karnataka, Tamil Nadu, Kerala, etc. However, the major area is restricted to north Indian states.

Arhar is grown as annual but tur varieties grow like perennial plants. The plants are bushy, densely branched having a height of about 150 cm to 300 cm depending upon type and management practices. It bears tap root with well developed lateral or secondary roots that consist nodules on them like any other leguminous plants. The stem is strong, woody, round but slightly ridged during active growth period having numerous branches. The leaves are pinnately compound and trifoliate with oblong, lanceolate leaflets. The flowers are arranged in recemose order. They open in the evening and remain open whole night and upto noon time of the next day. The structure of flower, nature of pollination, pod setting and pod characters are similar to that of any other papilionaceous plants.

The Cajinus cajan differs in plant character, pod character and maturity duration, etc. but most of the cultivated types belong to two categories.

1. Cajanus cajan var.bicolor: They are late maturing, plants grow very tall or probably they are tallest of both the types which are freely branched and bear flowers at the end of the branches. The pods are relatively longer and use to contain 4 to 5 seeds in them.
2. Cajanus cajan var.flavus: They have shorter duration and accordingly they fall in early maturing category of plants. Plants are shorter, bushy having flowers at several points along the branches. The pods are also shorter which bear two to three seeds in them.

Climatic and Soil Requirements:

Arhar needs moist and warm weather during germination (30-350C), slightly lower temperature during active vegetative growth (20-25 0 C) but about 15-18 0 C during flowering and pod setting, however, at maturity it needs higher temperature of around 35-40 0C. Water logging, heavy rains, frost are very harmful for the crop. Hailstorm or rain at maturity damages the entire crop.

The crop may be grown on any type of soil but sandy loam to clayey loam soils are supposed to be best. Soil must be very deep, well drained and free from soluble salts in them.

Land preparation:

The land may be prepared as for most of the kharif legumes keeping in view that there are no bigger clods, established weeds and left over stubbles of the previous crop. The field should be thoroughly levelled so that there is no accumulation of water in the field.

Varieties:

Sowing:

Treated seeds of suitable variety having high germination and high real value should be selected for sowing the crop. In irrigated condition the crop should be sown by giving one pre-monsoon irrigation at least a fortnight earlier than the first shower so that plans are well established during rainy season, however, under rainfed conditions the sowing may be done immediately after rains have started. Thus in no case the sowing should be delayed beyond last week of June. In case of diara lands which are prone to flood, the sowing should be done by mid of September.

Line sowing by seed drill or malabasa at a depth of about 7-10 cm using a row to row spacing of 60-75 cm and plant to plant 15-20 cm is always better than broadcasting. About 10-15 kg high quality seed would be sufficient for one hectare area but it depends on variety and sowing time.

Manures and Fertilizers:

As a practice the arhar crop is grown on marginal and sub-marginal lands of poor soil fertility status due to which the yield is found to be so poor that it does not give much profit. The crop is heavy feeder but due to symbiotic bacteria present in the root nodules, most of the required nitrogen is fixed from atmosphere, however, it needs heavy doses of phosphate. The crop grown from inoculated seeds needs lesser quantity of nitrogen as the plants emerged from treated seeds are well nodulated hence they have high nitrogen fixing capacity than the plants grown from untreated seeds.

For raising an ideal crop it is required to apply about 25-30 kg N, 50-75 kg P2O5, 30 kg K2O (if the soil is poor in K) and 10-15 kg ZnSo4 in one hectare area. The entire dose of fertilizer should be basal placed at a depth of 12 to 15 cm or 7 to 10 cm below the seed layer in the same row.

Interculture:

The crop plants grow very slowly during their early growth period of 45-50 days an the crop suffers from a severe weed infestation which causes a drastic reduction in grain yield. Therefore, it is advisable to keep the field free from weeds and a weed free condition may be achieved by giving two hand weedings once about 25-30 days and another about 45-50 days after sowing of the crop. Where hand weeding is not possible use of Lasso (Alachlor) at the rate of 3.0 kg/ha as pre-emergence or Basaline at the rate of 1.0 litre/ha as pre-sown incorporation in soil may be done. By using herbicides the field will be weed free upto 50 days of sowing and least damage to the crop will take place.

Irrigation:

The crop is mostly grown rainfed but one light irrigation between flowering and pod filling stage increases the seed yield. In the event of drought or under aberrant weather condition the crop needs life saving or protective irrigation which is in addition to those mentioned earlier.

Plant protection measures:

The crop mostly suffers from wilt, stem rot and sterility mosaic diseases. The wilt and stem rot may be controlled by using resistant varieties, providing well drained soil conditions and adopting a nice crop rotation. The sterility mosaic may be controlled by using resistant variety and three to four spraying of Metasystox 0.1% solution when the mites (Eriophyid mute) start attacking the crop and first attacked plant is visible in the field.

There are several insects which are found to attack the crop like pod borers, tur pod fly, plume moth, hairy caterpillar, leaf hopper, bean fly, etc., but the pod borers are found to cause a considerable loss to the crop. Most of the insects or almost all of them can be killed by spraying of 0.2 to 0.3 per cent solution of Endosulfan 35 EC or Nuvacrone 40 EC soon after they are visible in the field. The spraying should be repeated for their complete control and if needed a higher concentration of 0.4 or 0.5 per cent may be used for spraying.