In this article we will discuss about:- 1. Origin and Distribution of Greengram 2. Climate and Soils of Greengram 3. Growth and Development 4. Varieties and Seasons 5. Tillage, Seeding and Plant Population 6. Nutrient Management 7. Water Management 8. Weed Management 9. Harvesting and Storage 10. Quality Considerations.
Contents:
- Origin and Distribution of Greengram
- Climate and Soils of Greengram
- Growth and Development of Greengram
- Varieties and Seasons of Greengram
- Tillage, Seeding and Plant Population of Greengram
- Nutrient Management for Greengram
- Water Management for Greengram
- Weed Management for Greengram
- Harvesting and Storage of Greengram
- Quality Considerations of Greengram
1. Origin and Distribution of Greengram:
Greengram (Phaseolus aureus), known as mung or mungbean in India, is the third important pulse crop of India after chickpea and pigeonpea. It is considered as wholesome among pulses, free from heaviness and flatulence. Besides its utilisation as food in many forms, haulms are used as fodder and green manure.
Due to its shorter duration, it can be fitted in several multiple cropping systems. Just like other pulse crops, inclusion of greengram in cropping systems improves soil health and fertility.
Greengram is primarily a native of India and central Asia may be a secondary canter. Carbonised grains of greengram are found in archaeological sites of Navadatoli-Maheshwar in Madhya Pradesh dating between 1440 and 1660 BC. Despite its cultivation since prehistoric times, greengram has never been found growing in the wild.
Greengram is cultivated throughout southern Asia. Myanmar, Pakistan, Thailand, Sri Lanka, Indonesia and China are the principal countries of greengram cultivation. It is also cultivated in parts of Africa to a smaller extent. About 45 per cent of global production is in India.
From the available information, the global production of greengram is around 2.5 M t from about 5 M ha with productivity around 500 kg ha-1. In India, the area under greengram is 3.8 M ha with an annual production of 1.56 M t. Average productivity is 413 kg ha-1.
In India, major greengram producing states are Andhra Pradesh, Orissa, Maharashtra, Madhya Pradesh, Rajasthan, Bihar and Tamil Nadu. Andhra Pradesh, Orissa and Maharashtra accounts for about 70 per cent of the area and 75 per cent of production in the country.
Rajasthan ranks first both in area (0.38 M ha) and production (1.56 M t) of greengram followed by Maharashtra with an area of 0.62 M ha and production 0.37 M t. Productivity is highest in Punjab (667 kg ha-1) followed by Jharkhand (600 kg ha–1).
2. Climate and Soils of Greengram:
Greengram is a tropical pulse crop largely grown under semiarid and subtropical environment. It comes up well in regions with 600 to 1000 mm rainfall. In India, it is grown from sea level to 2000 m above mean sea level. Thought, it can be grown in temperature regime of 20° to 40°C, optimum mean temperature is 28° to 32°C. The crop is sensitive to low temperature. Critical temperature is 15°C and at 10°C, germination does not take place.
Greengram is a short day plant and most cultivars flower in 12-13 hrs photoperiod. Flowering gets delayed with extended photoperiod but hastened with a rise in temperature. As elevation increases, flowering is delayed due to low ambient temperature.
Greengram is cultivated on a wide range of soils from sandy loams to black cotton soils. However, it does best on deep loams with good internal drainage. It does not stand waterlogging. Optimum soil pH is 6.5-7.5. It is fairly tolerant to soil salinity.
The land is ploughed once or twice followed by harrowing to obtain a rough seedbed. For a sequence crop after kharif rice, minimum tillage is ideal. Summer crop after a rabi crop usually receive normal tillage. In north India, summer crop is sown dry in furrows between rows of previous crop followed by irrigation.
3. Growth and Development of Greengram:
Soil moisture is the major factor influencing germination. Greengram seed has the remarkable capacity for absorption of water and germination is relatively earlier compared with other major pulses. Leaf area development in greengram is relatively very slow for the first 3-4 weeks, after which it picks up very fast.
Almost two-thirds of the total dry matter accumulation takes place during one-third of the total life span of greengram. The NAR is maximum before flowering and gradually declines afterwards due to dropping of lower leaves. The RGR is maximum in the initial stage of growth but continue to decline with advancement in growth.
Duration of vegetative phase increases with increase in photoperiod from 12 to 16 hrs. The increase will be about a week when the photoperiod extends from 12 to 14 hrs but increase in duration will be substantial when the photoperiod extends beyond 14 hrs.
Under 14 hrs photoperiod, almost all the cultivars flower within 40 days of planting Major yield components are pods per plant, seeds per pod and test weight. Soil moisture deficit hastens flowering and reduces flowering and pod filling period leading to reduced pod number and yield. However, seed size may increase following reduced seeds per pod.
4. Varieties and Seasons of Greengram:
As a result of breeding in different states, a number of improved varieties, suitable for different seasons and agroecological situations have been developed as given in Table 8.16.
Availability of short duration varieties (60 to 65) days revolutionised the greengram cultivation in the country.
As many as four crop can be grown in a year as indicated below:
Kharif:
Mid-June to first week of July. It is grown as mixed or intercrop. It is also grown as sole crop.
Rabi:
Usually as an unirrigated crop on monsoon fallows or after the harvest of kharif, crop on stored soil moisture. Second fortnight of October to first week of November is the optimum sowing time. Usually grown as sole crop.
Late rabi:
Relay crop in kharif standing crop of rice in Peninsular India. Sowing time is from December to end of January or even early February. The crop comes up with the residual soil moisture. It is grown as sole crop.
Summer:
As a sole crop optimum sowing time is from third week of March to second week of April. As a relay crop, it is sown a week before the harvest of wheat (May) followed by irrigation. As a companion crop, it is intersown between sugarcane or cotton crop.
5. Tillage, Seeding and Plant Population of Greengram:
There is no need for a fine seedbed. One or two ploughings followed by harrowing is adequate for a kharif crop. Greengram on deep soils during rabi is usually on kharif fallows that are kept weed free by repeated harrowing. There is no tillage for late rabi (relay crop) as the seed is broadcasted in sanding crop of rice about a week before its harvest.
For a summer crop, tillage depends on the time available between the harvest of the standing crop and seeding of greengram. In highly intensive cropping systems, minimum tillage is practiced. If there is a gap of a month, the land will be prepared as for the kharif crop.
Greengram is sown by broadcast, drilling in rows or in furrows behind a plough. Drill sowing is ideal, as it allows intercultivation for weed control. Dropping the seed in furrows (kera or pora) is equally effective, however, at higher cost. A row spacing of 30 cm with 5 cm between plants in the row (30 x 5 cm) is optimum for irrigated crop. For a rainfed crop, a spacing of 30 x 10 cm is ideal. For spreading types, 45 x 10 cm appears to be adequate. For a relay crop, there is no row spacing since it is sown by broadcast.
In any case, optimum plant stand is 30 plants m-2. A seed rate of 20 kg ha-1 is optimum for an irrigated crop with closer spacing. For wider row spacing, 15 kg ha-1 is adequate. For a relay greengram, relatively higher seed rate of 25-30 kg ha-1 is essential. Optimum depth of sowing is 3-5 cm for irrigated crop and 5-7 cm for a rainfed crop.
6. Nutrient Management for Greengram:
Nearly 40 N, 10 P2O5 and 15 K2O kg ha-1 is removed by 1.0 t of greengram. Rhizobium inoculation considerably minimise the need for nitrogen fertiliser application.
From the available information, the following general fertiliser schedule can be recommended for greengram:
Rainfed crop: 10N and 30 P2O5 kg ha-1. Around 40 kg P2O5 ha-1 is necessary if the soils are deficient in phosphorus.
Irrigated crop: 20 N and 40 P2O5 kg ha-1. About 50 kg P2O5 ha-1 is necessary if the soils are deficient in phosphorous.
Relay greengram crop will not receive any fertiliser. In general, there is no response to application of potassium. If the crop is grown on light and shallow soils deficient in potassium, 25 kg K2O ha-1 may be optimum. Greengram associated with VAM absorbs greater amounts of phosphorus. Greengram has higher Mg requirement than blackgram.
7. Water Management for Greengram:
Rainy season and postrainy season greengram crop is almost rainfed. Relay greengram on rice fallows is grown on stored soils moisture. However, when greengram is relay-cropped with wheat on light soils of north India, it receives two to three irrigations. Summer season greengram is grown with assured irrigation. The daily water requirement varies from 3.0 to 4.5 mm, depending on the season.
Its total water requirement is 300 to 400 mm depending on crop duration. Flower initiation (35 DAS) and pod filling (55 DAS) are the critical stages for soil moisture stress. Scheduling irrigation at 50 per cent DASM or at IW/CPE ratio of 0.4 is adequate for optimum yield and high water use efficiency. Waterlogging should be avoided at flowering and pod filling since the yield reduction could be as high as 75 per cent.
8. Weed Management for Greengram:
Weeds are major problem in rainy and postrainy season greengram compared with summer irrigated crop. First 30 DAS is the critical period for weed competition. Since row seeding with a row spacing of 30 x 5 or 30 x 10 cm is recommended, there is scope for intercultivation using local blade harrows. A single hand weeding around 40 DAS can remove weeds within the row.
Herbicide use may prove uneconomical due to low yield levels of greengram under rainfed situations. If the row spacing or soil condition does not permit intercultivation and hand weeding, use of herbicides is the only option.
Any of the following herbicides can be used against weeds in greengram:
PPI or PRE herbicides:
Pendimethalin (0.75-1.0)
Fluchloralin (0.75-1.0)
PRE herbicides:
Alachlor (1.0-2.0)
Metolachlor (0.5-0.75)
Terbutryn (0.5-0.7
POST herbicide Bentazon (0.75-1.5) applied at two trifoliate leaf stage can control many broad leaf weeds and sedges. In general, one hand weeding at 40 DAS, in addition to herbicide use appears to be ideal for weed management under different situations.
9. Harvesting and Storage of Greengram:
The crop comes to harvest in three months. However, early varies will mature in 60 to 65 days. To prevent shattering of pods, the crop is harvested before it is dead ripe. The plants are uprooted or cut above the ground level with a sickle, dried on a threshing floor for about a week and threshed under the feet of cattle or beating with sticks.
One or two hand pickings of pods are also common. The produce is cleaned and sun dried to about 12 per cent moisture content. Method of storage and control of storage pests are similar to other pulses.
10. Quality Considerations of Greengram:
On an average, greengram contains 24 per cent protein, 1.2 per cent fat and 62 per cent carbohydrates. The lysine, methionine and cystine (mg g-1) are 436, 75 and 55, respectively.
Greengram is primarily consumed in the form of dhal. Green pods are also used as vegetable and haulms as green fodder. It is an excellent green manure crop. Dry seed is boiled and used in soups, made into porridge with rice and wheat. Sprouted seed is consumed as salad. The flour is used in cakes and desserts. Starch is used in making noodles.