Everything you need to know about pigeonpea cultivation, harvest and growth. Learn about:- 1. Introduction to Pigeonpea 2. Botany of Pigeonpea 3. Origin and History 4. Classification 5. Geographic Distribution 6. Climate 7. Soil 8. Field Preparation 9. Sowing Time 10. Manures and Fertilizers 11. Water Management 12. Weed Management 13. Cropping Systems 14. Harvesting and Threshing.
Contents:
- Introduction to Pigeonpea
- Botany of Pigeonpea
- Origin and History of Pigeonpea
- Classification of Pigeonpea
- Geographic Distribution of Pigeonpea
- Climate Required for Cultivating Pigeonpea
- Soil Required for Cultivating Pigeonpea
- Field Preparation of Pigeonpea
- Sowing Time of Pigeonpea
- Manures and Fertilizers of Pigeonpea
- Water Management of Pigeonpea
- Weed Management of Pigeonpea
- Cropping Systems of Pigeonpea
- Harvesting and Threshing of Pigeonpea
1. Introduction to Pigeonpea:
Pigeonpea [Cajanus cajan (L.) Millsp.] belongs to the genus Cajanus, subtribe Cajaninae, tribe Phaseoleae, and family fabaceae. It is commonly known as redgram, tur, arhar, no eye pea, etc. The word Cajanus is derived from a Malay sword ‘katschang’ or ‘katjang’ meaning pod or bean. Many species of the closely related genus Atylosia successfully cross with pigeonpea. Pigeonpea seeds used as dal are rich in protein (21%), iron and iodine.
They are also rich in essential amino acids like lycine, tyrocene, cystine and arginine. The green pods are used as vegetable. The pod husk and leaves after threshing serve as a valuable fodder for cattle. Woody plant stems are used as fuel.
Pigeonpea being a legume possesses valuable property as restorer of nitrogen in soil. Pigeonpea plants are also used to culture the lac producing insect in China. It is grown on mountain slopes to arrest soil erosion. The perennial pigeonpea is also useful in agroforestry systems.
2. Botany of Pigeonpea:
Seedling:
When sown under optimal moisture and temperature (29°C-36°C), the seed testa splits open near the micropyle on the 2nd day. The tip of the radical elongates and emerges from the seed coat. On the 3rd day the hypocotyl appears as an arch and continues to grow upward. The hypocotyl turns light purple. The seedling epicotyl elongates 3-7 cm before the first trifoliate leaf emerges.
Root:
Pigeonpea has a taproot system. The root growth, under ideal conditions, begins on the 2nd day after sowing of the seed. The testa splits open near the micropyle. The radical elongates and emerges from the seed coat. The primary structure of the root is tetrarch. Secondary thickening takes place as a result of cambial activity. The main root of older plants becomes thick and woody.
Pigeonpea roots are deep and wide spreading in the soil, with well- developed lateral roots. They may extend down more than 2 m, but extensive development takes place in the upper 60 cm of the soil profile. Short-duration genotypes develop a smaller root system than long-duration genotypes. Lateral roots were found much longer in spreading types than in the erect types.
Nodule:
Pigeonpea is nodulated by the cowpea group of rhizobia, mainly on the upper 30 cm of the root system. Nodulation starts approximately 15 days after sowing (DAS) and continues up to 120 days. It declines towards pod filling. The nodule development is through the meristematic zone, arching around the apical end and the medulla contains many bacteroid- filled cells. Sometimes the latter are highly vacuolated. The nodules differ in size from 2-4 mm. They may be spherical, oval, elongate, or branched.
Stem:
The pigeonpea has a strong woody stem. The primary vascular tissue of the stem is organized into strands connecting the nodes; each strand is associated with a ridge on the stem. Collenchymatous bundle caps underlie the epidermis of the ridges. During the vegetative phase, the xylem parenchyma, and the medullary rays contain starch.
This disappears in the reproductive phase, showing that the reserves are mobilized for pod development. There are cells within the phloem region and the outer part of the pith containing densely staining material. These cells are joined end to end, forming ducts. Such secondary ducts differentiate at an early stage in the primary tissue and are also formed within the secondary phloem. They occur in the stem, pods, and roots.
The plant’s damaged tissues secrete droplets of a clear fluid exudate from the secondary ducts on to the cut surface. This turns red on exposure to air and covers the wound with a reddish varnish-like material. This exudate has a stringent taste and may have a role in protection against pests.
Branches:
The branching pattern in pigeonpea depends on genotype and spacing between rows and plants. At a wide spacing, it may form a bush and at narrow spacing it may remain compact and upright. For agronomic purposes pigeonpea plants can be grouped as compact (erect), semi-spreading (semi-erect), and spreading types. Based on the flowering pattern pigeonpea plants may be determinate, semi-determinate or non-determinate.
The determinate type completes the vegetative phase and then enters into the reproductive phase. In this type, the apical bud of the main shoot develops into an inflorescence, and the sequence of inflorescence production is basipetal (i.e. developing in the direction of base). The non- determinate type shows continuous vegetative and reproductive phases.
In this type, the flowering starts at nodes behind the apex and proceeds both acropetally and basipetally. Another group is semi-determinate between the determinate and non-determinate types. It includes late-maturing genotypes where branching starts from different angles, but most of the pods are at the upper region of the plant.
Leaves:
The first two leaves in the seedling called primary leaves, are simple, opposite, and caduceus. The later leaves are pinnately trifoliate with lanceolate to elliptical leaflets that are acute at both ends and are spirally arranged. The leaflets are borne on a rachis, which is swollen at the base (pulvinus).
The leaf size varies from 6-17 cm in length and are about the same width. The rachis varies from 2-4 cm and the terminal leaflets are 4-8 cm by 2-3.5 cm. The lateral leaflets are slightly smaller. There is genetic variability in the size, shape, and color of leaves.
The leaves are pubescent with more on the lower than the upper surface. The hair types are simple or glandular. The latter are spherical and contain a yellow oily material, probably responsible for the fragrance of pigeonpea plants.
The leaves are pubescent with more on the lower than the upper surface. The hair types are simple or glandular. The latter are spherical and contain a yellow oily material, probably responsible for the fragrance of pigeonpea plants.
Inflorescence:
In most cultivars, flowers are borne on terminal or auxiliary racemes (4-12 cm) and are carried on a long peduncle. The raceme inflorescence form a terminal panicle in non-determinate types and a somewhat corymb-shape bunch in the determinate types.
These are grouped together at the end of branches in late types and distributed along the branches in early, medium, and indeterminate types. The number of racemes plant 1 in the pigeonpea world collections ranged from 6 to 915. Flowering proceeds acropetally (in the direction of apex) both within the raceme and on the branch.
Flowering and Pollination:
Pigeonpea is a short-day plant, though a combination of photoperiod and temperature can affect the time of flowering and maturity of pigeonpea genotypes is according to date of sowing. In a fully developed bud, anthers surround the stigma and dehisce a day before the flower opens. Anthesis in pigeonpea starts from 6.00 hrs and continues till 4.00 pm.
The duration of flower opening depends on the climate and environment. This varies from 6 to 36 hrs. Fertilization occurs on the day of pollination. Pigeonpea is an often cross-pollinated crop. The extent of crosspollination ranges from 3 to 40%, with an average of 20%. A plant produces many flowers of which only 10% set pods.
Pod Development:
The pedicel of the flower contains small vascular bundles surrounded by a ring of fibers. During the 1st week of anthesis, the endosperm undergoes rapid development. The nuclei take up a parietal position, forming a large vacuole in the center of the embryo sac.
The embryo sac elongates at the chalazal region and forms a haustorium. The haustorium penetrates into the nucellar tissue. This is instrumental in absorbing food material that is used by the developing embryo.
By the end of the 2nd week there are still large amounts of endospermous tissues and within the embryo, distinct cotyledons are seen. Further development of the seed involves rapid growth of the cotyledons, and almost complete degeneration of the endosperm. In the cotyledons, synthesis of starch and protein starts about 17 days after pollination and continues for 14 days. In each raceme 1 to 5 pods (rarely upto 10) may mature.
Pods are of various color; green, purple, dark purple, or mixed green and purple. Pods with deep constrictions in shape are beaded, while others are somewhat flat. The seeds per pod range from two to seven, and sometimes up to nine. The seeds are in separate locules and the cross walls develop during the 1st week after fertilization.
The pod wall develops more rapidly than the young seeds. Seed development is visible 7 days after pollination. A pod is formed 15-20 days after fertilization. Seeds reach physiological maturity in 30 days and are ready for harvest at lower moisture content in 40 days. There is little or no shattering of mature pods in the field.
Seed and its Germination:
The color of the seed ranges from silver, white, cream, fawn, black, pink, or red to purple. They are blotched or speckled. Pigeonpea 100-seed mass ranges from 2.8 to 22.4 g with the cultivated varieties ranging from 7.0 to 9.5 g. Seed shapes are oval, pea-shaped, square, or elongate. The most common is a pea-shaped seed found in large seeded late varieties. The number of seeds-pod ranges from 2 to 8.
The cultivated genotypes possess 3-4 seeds-pods. The cotyledons are yellow. Germination is hypogeal and there is no known dormancy. The seedlings emerge from depths of up to 5 cm.
3. Origin and History of Pigeonpea:
The pigeonpea name was first reported from plants used in Barbados. Based on the range of genetic diversity of the crops in India, Vavilov (1951) concluded that pigeonpea originated in India. The theory of its African origin has not been accepted owing to lack of diversity in the region.
Van der Maesen (1980) also concluded that India was the primary center or origin and Africa was the secondary center of origin of pigeonpea. The true wild relatives of pigeonpea are not seen. The closest wild relative of pigeonpea Atylosia canifolia has been found in some localities in east India and many species of the closely related genus Atylosia successfully cross with pigeonpea.
4. Classification of Pigeonpea:
Pigeonpea (Cajanus cajan (L.) Millsp.) belongs to the genus Cajanus, subtribe Cajaninae, tribe Phaseoleae, and family fabaceae. It is also known as redgram, tur, arhar in Hindi and congo bean in English. Cajanus is derived from a Malay word ‘katschang’ or ‘katjang’ meaning pod or bean.
Based on maturity, floral and seed characteristics, the cultivated Cajanus are classified into 2 groups as below:
(i) Cajanus indicus var. bicolor:
Also known as arhar comprises most of the perennial types that are long duration, late-maturing, tall and bushy. This is more prevalent in northern India. Rowers are yellow with purple streak. The standard petal, which is the largest of the 5 petals in the flower, possesses red veins on the dorsal side. Pods are dark coloured and each pod has 4 to 5 seeds. Pods are synchronous in maturity. Arhar yield well in the first season and production decline in the later year.
(ii) Cajanus indicus var. flavus:
Also known as tur comprises the commonly cultivated varieties. These are grown as field crop in southern India. This includes short duration early maturing annuals having smaller plants and bear yellow flowers coupled with fewer plain pods with 2-3 seeds. Pods do not mature at a time and picking is done at an interval of 15-16 days.
Pigeonpea is a perennial woody shrub mostly grown as annual for the seeds. Plants are freely branched and can grow up to 4 m height. It has very strong, profused and deep tap root extending up to 3 m below soil. Leaves are alternate and pinnately trifoliate. Inflorescence will be in terminal or axillary racemes in the upper branches of the bush.
Flowers are multi-coloured with yellow being predominant. Flowers are zygomorphic and often cross pollinating in nature. Pods are compressed, bear 2-9 seeds and un-shattering in nature after maturity. Seeds are lenticular to ovoid, measuring up to 8 mm in diameter and weigh about 10 seeds/gram. Germination is hypogeal.
5. Geographic Distribution of Pigeonpea:
Pigeonpea occurs throughout tropical and sub-tropical regions and in the warmer temperate regions from 30°N to 30°S. It is grown in over 50 tropical countries of the world especially in more arid regions of Africa, Asia and the Americas. In India, it is cultivated as an annual crop, but in other countries, it is grown as perennial crop, where pods are harvested at regular intervals. In some countries, it is mostly grown as a kitchen garden crop for vegetable purpose.
Pigeonpea is next only to chickpea in area and production among all the pulse crops grown in India. India ranks first with about over 3/4 of acreage and production of the globe. The crop is extensively grown in Maharashtra, Andhra Pradesh and Gujarat. In India, pigeonpea occupies an area of about 3.73 million ha with a total production of 3.08 tonnes and average productivity of 826 kg/ha. It is mostly grown as a rainfed crop in dryland areas.
However, it is also grown under irrigated condition in about 4.7 % area. Maharashtra leads in both area and production, followed by Andhra Pradesh in area and Uttar Pradesh in production. The productivity of pigeonpea is highest in Gujarat followed by Bihar.
6. Climate Required for Cultivating Pigeonpea:
Pigeonpea is predominantly a crop of arid and semi-arid (tropical) climates grown between 30°N and 35°S. Its drought hardy nature makes it a crop of low rainfall situations; however, it cannot withstand waterlogging and frost. Moist and humid conditions during vegetative phase and dry conditions during reproductive phase are suitable for successful cultivation of pigeonpea. Low temperature at pod filling stage results in delayed maturity. Pigeonpea is quantitatively a short day plant with critical photoperiod of 13 hours. Low light intensity at pod formation is harmful.
It can be grown at a temperature ranging from 26° to 40°C in the rainy season (June to October) and 17° to 22°C in the post-rainy (November to March) season. Pigeonpea is hardy to both low (5°-10°C) and high temperatures up to 40°C. For flowering and pod setting 24°C is the optimum. An amount of daily global solar radiation varies from 400 to 430 cal cm-2 day-1 in the rainy season and 380-430 cal cm-2 day-1 in the post-rainy season.
The plant is sensitive to frost during all stages of its growth. In frost prone area of north India, short duration varieties are grown, as they escape frost. Mean annual rainfall of 600 to 1000 mm, with moist conditions for the first 50-70 days and drier conditions during flowering and pod formation stage will result in successful crop. Rains during flowering stage results in poor pollination and pod development and also invites the attack of pod borer.
The length of growing season extends from 120 to 180 days. Pigeonpea is very sensitive to low radiation at pod development, therefore cloudy weather and excessive rainfall at flowering stage damage the crop to a great extent, which leads to poor pod formation.
7. Soil Required for Cultivating Pigeonpea:
Pigeonpea can be grown on a wide range of soils, however, sandy loam to clay loams are ideal. The soil should be deep, well drained and free from soluble salts. The electrical conductivity of 1.4 dS/m is critical for pigeonpea. It can be grown on soils with a pH range of 5.5-8.0 successfully. The saline-alkaline and water logged soils are unfit for its cultivation, as they adversely affect nodulation.
Well drained, alluvial and loamy soils are good for its cultivation. It is successfully grown in black cotton soils of M.P. and Maharashtra with adequate drainage. It can also be grown in well drained red clay loam soils. It cannot tolerate soil acidity owing to aluminium toxicity.
8. Field Preparation of Pigeonpea:
A weed-free firm seed-bed ensures better plant stand and early vigour to the crop. Pigeonpea requires a clod free seedbed for proper germination and establishment of seedlings. This may be achieved by opening the soil through soil-turning plough or disking, followed by 2-3 cross harrowing or ploughing with desi plough on or before the onset of monsoon. Finally the seed-bed should be planked and leveled. In drylands, a deep summer ploughing is necessary for moisture conservation.
In case of hard pan in the soil, sub-soiling is done. Pigeonpea with its deep root system (>150 cm) can break hard pans in plough layer, and hence called “biological plough”. Thorough leveling of field is essential to allow quick drainage and also to avoid waterlogging. Contour broad-bed and furrows (2.7 m width) or a ridge and furrow planting are preferred to overcome waterlogging. The former land configuration is promising for vertisols.
9. Sowing Time of Pigeonpea:
Pigeonpea sowing in kharif under rainfed condition varies from June-July, depending on onset of monsoon. For sequential cropping of pigeonpea and wheat under irrigated condition, early sowings are preferred. In this cropping system, the crop is sown after a pre-sowing irrigation from late May to 1st week of June, so that the succeeding crop can be sown with the least delay. It is sown in the first week of June in Punjab and Haryana and in the second fortnight of June in Uttar Pradesh and northern Rajasthan.
Late sown crop is more likely to be damaged by frost in northern parts of the country. Early sowing helps in taking a good crop of wheat crop after pigeonpea. Under rainfed conditions sowing could be done with the onset of monsoon in the later part of June or early July. For summer pigeonpea, early May sowing is followed in north India. Time of sowing should be adjusted in such a way to avoid rains and frost at flowering and reproductive stages.
Under irrigated conditions, medium- early varieties are sown in the first fortnight of April for double cropping. For early rabi planting in Bihar, eastern Uttar Pradesh, and West Bengal, September to first week of October sowing is ideal. The rabi cultivation of pigeonpea in rice fallows is increasingly popular, and is sown immediately after rice harvest in southern India.
Seed Rate and Spacing:
The row spacing in kharif varies from 40-60 cm in short and medium duration varieties to 60-90 cm in long duration varieties. In rabi season, the crop is grown in 30 cm rows. After germination, the seedlings are thinned to maintain an intra-row spacing of 15-20 cm. The optimum population thus varies from 60,000-1.0 lakh in kharif and 1.5-3.0 lakh/ha in rabi.
The seed rate for early pigeonpea is 15-18 kg/ha, whereas for late varieties it is 10-15 kg/ha. During rabi season, 15-18 kg/ha of seed is needed. In mixed cropping seed rate is adjusted according to the proportion of arhar and companion crops to be grown. In the intercropping seed rate remains same as for pure crop.
Seed Treatment:
Good quality and pure seed (registered or certified) of the selected variety should be used from a reliable source. For obtaining better results and keeping the crop free from seed borne diseases like seed rot and seedling blight, the seed should be treated with thiram @ 1.5 g /kg of seed plus pentachloronitro benzene (PCNB/Brassicol) @ 1.5 g/kg of seed before sowing or seed may also be treated with fungicides like vitavax power 1.5 g or (carbendazim 1.0 g + thiram 1.5 g) per kg of seed.
Bacteria like Rhizobia are found to enhance the fixation of atmospheric N in pulses. Seed treatment with appropriate strains of Rhizobium culture (bacteria culture) before sowing helps in better germination, emergence and nodulation, consequently increasing the availability of more biologically fixed nitrogen.
Inoculation of seeds with Rhizobium culture should invariably be done each and every time of sowing of a legume crop especially when pigeonpea is being taken for the first time in the field or after a long duration. Yield of all the legume plants are directly proportional to the number of nodules.
More the nodules/plant more shall be the yield. Suspend 200g of Rhizobium culture and 250g phosphate solubilizing bacteria (PSB) in 600 ml of water and mix thoroughly. Now pour the slurry on 10 kg of seed drop by drop and mix with the hands till the uniform coating of culture is obtained on all seeds.
Addition of ammonium or sodium molybdate @ 3 g/10kg seeds at the time of seed treatment with Rhizobium culture facilitates better nodulation. Dry the treated seeds in shade on clean cloth, paper or polythene sheet and sow the seeds immediately, preferably in afternoon.
Seed treatment with efficient strains of Rhizobium has been found to improve yields of pulses up to 50 % over the untreated control. In pigeonpea, seed inoculation with Trichoderma harzianum alone or serial inoculation of T. harzianum, followed by Rhizobium may significantly reduce wilt incidence, enhance nodulation and root/shoot growth, but simultaneous inoculation of T. harzianum + Rhizobium was ineffective.
Inoculation of seeds or seedlings with microphos bio-fertilizers can provide 30 kg P2O5/ha equivalent of phosphorus applied as superphosphate by solubilizing the soil phosphorus and also applied phosphorus.
Methods of Sowing:
Three systems are practiced for the sowing of pigeonpea. Flatbed sowing is a common method other than broad-bed-and-furrow method for extra-early group and ridge-and-furrow method for the late maturity group. The latter two methods are useful in fields with poor surface drainage and water logging. The raised beds or ridges also provide better aeration and nodulation in comparison to the flat sown crop.
Experiments at the IARI, New Delhi, have shown that pigeonpea sown on a ridge-and-furrow system in fields prone to water logging gave 30 % more yield compared to flat sowing. At ICRISAT a broad-bed and furrow system is used for sowing extra-early varieties, and ridges-and-furrows are used for medium and late duration varieties. Seed should be sown behind the plough or with the help of seed drill in rows.
In north-eastern plains zone and in vertisols, where excess moisture/water stagnation often causes mortality of plants during early stages, ridge planting of pigeonpea has proved superior over flat planting. This method also minimizes incidence of Phytopthora stem-blight and wilt.
In vertisols, broad-bed and furrow system of planting is preferred. Sow the seeds in lines soon after land preparation and compact the soil by laddering so that the seeds come in intimate contact with soil which will hasten germination. Line sowing facilitates intercultural to kill weeds.
10. Manures and Fertilizers of Pigeonpea:
The crop removes substantial quantity of nutrients. Intensively managed short duration Pusa agati producing 2 t of grains/ha and 6 t stalks/ha removed 132 kg N, 20 kg P, and 53 kgK/ha. Being a legume, it can meet 60-80% of its own N requirement from symbiosis.
Estimates of fixed N in pigeonpea genotypes of different maturity ranged from 6 to 69 kg N/ ha. A long duration pigeonpea grown in north India could fix up to 200 kg N/ha. Pigeonpea seedlings depend on soil-nitrogen in its early stage. Incorporation of FYM @ 5-10 t/ha at the time of final field preparation is beneficial.
A starter dose of 15-20 kg N/ha is applied at the time of sowing. In the later stages of plant growth, most of the N required by plants is derived from fixation in nodules. At times of waterlogging for quick recovery immediately after drainage, 50 kg N/ha as top-dressing is applied to alleviate adverse effects of waterlogging. Besides N, phosphorus is the most frequently limiting nutrient and application of 40-60 kg P2O5 as basal resulted higher yield than no application.
Conveniently, 100 kg diammonium phosphate may be applied. Placement of fertilizers at a depth of 10 or 15 cm increased yield by 35 % over broadcast application. The response to K fertilization is rarely noticed. Inoculation of seed with effective strains of Rhizobium is desirable for symbiotic N fixation.
Use of phosphate solubilizing bacteria along with lower doses of phosphorus is promising to higher P doses. The roots by way of secreting organic acid (piscidic acid) improve solubility of Fe- phosphates. Thus the crop effectively utilizes soil P reserves.
There has been increasing response to S fertilization in pigeonpea grown under intensive cropping systems and in light textured soils. Similarly, the crop responds to zinc fertilization in alkali soils. Pulses are known to be very susceptible to zinc deficiency and zinc deficient plants show stunted growth, reduced leaf size, yellowing and development of brown spot on the leaves.
In addition to N and P, application of 20 kg sulphur/ha, 15 kg ZnSO4/ha, 10 kg borax/ha, 1 kg sodium molybdate, and 1 kg Fe/ha is also recommended for getting higher yields of pigeonpea. Zinc deficiency in the standing crop can be rectified by spraying 5 kg zinc sulphate and 2.5 kg lime dissolved in 800-1000 litres of water per hectare.
11. Water Management of Pigeonpea:
Pigeonpea is largely grown as a rainfed crop, however, it is well established that flower initiation and pod setting stages are most critical for moisture stress. Therefore, irrigation at these stages usually helps the crop. The drought-stress symptoms on pigeonpea are indicated by the leaves pointing towards the sun at noon. Long duration pigeonpea with deep root system and flushes of flowering can withstand drought.
The short duration cultivars, however, are grown with irrigation only. Post-rainy season crop responds better to irrigation. The critical stages for irrigation are branching, flowering and pod filling. Pigeonpea uses about 20-25 cm water to produce about 1 tonne of grain/ha under traditional production systems.
The water requirement and consumptive use of pigeonpea varies from 30-50 cm and 40-50 cm, respectively. At times of prolonged drought, irrigation at flowering and pod filling stages is highly rewarding in kharif. Irrigation of after cessation of rains at 0.4-0.6 IW/CPE ratio has been found ideal in north India.
Drainage is equally important in pigeonpea. Excessive moisture at any growth stage is detrimental to pigeonpea. It promotes vegetative growth and enhances the incidence of Phytophthora and Alternaria blight. Thus, irrigation should be given only when the crop experiences drought stress after flowering and at the pod filling stage. To overcome ill-effects of waterlogging, ridge and furrow planting (with seeding on ridge) is followed in heavy soils.
12. Weed Management of Pigeonpea:
Pigeonpea is infested by several grassy and broad-leaved weeds. Some of the common weeds associated with pigoenpea are – Cyperus rotundus L., Commelina bengalensis L.Phyllanthus niruri, Euphorbia parviflora L., Celosia argentena L., Amaranthus viridis L., Amaranthus spinosus L., Echinochloa colona (L.) Link, Digitaria sanguinalis, Dactyloctenium aegyptium (L.), Ageratum conyzoides L., Eclipta alba L., Portulaca oleracea L.(Common purslane), Trianthema portulacastrum L. etc.
These weeds rob the crop of precious nutrients and moisture and also give shelter to insect pests. Pigeonpea has slow initial growth rate. This makes pegeonpea less competitive with weeds. The period of first 60 days is very critical in the life cycle of pigeonpea. If weeds are not controlled in time, they can cause up to 90 % reduction in seed yield.
The crop suffers from early weed infestation. Therefore, it is necessary to keep the crop weed-free during the early growth period (4-6 weeks). The initial 7-8 weeks period of crop i.e. from sowing to branching stage is critical period of crop-weed competition in medium and long duration varieties.
In short duration varieties initial 4-6 weeks from sowing is critical. Thus, control of weeds within 2-4 weeks not only prevents the withdrawal of nutrients from the soil by weeds but also conserve moisture and helps in quick growth and development of crop. Two hand-weedings or mechanical interculture at 25-30 DAS and 45-60 DAS would take care of most of weeds.
Prometryne was quite effective in controlling broadleaved weeds and fluchloralin in controlling grass weeds. Application of any of the above herbicides integrated with one hand- weeding or mechanical hoeing at 6-8 weeks after sowing is more effective to either of the methods alone.
The thick canopy would further suppress weed growth at later stages. Intercropping of pigeonpea with jowar, maize suppresses weeds for longer time. Short duration pigeonpea cultivars take advantage of high plant density to suppress weed competition.
13. Cropping Systems of Pigeonpea:
Pigeonpea is cultivated under varied cropping systems. It can be intercropped or sown mixed with a number of other crops like sorghum, maize, rice, groundnut, sesame, urdbean, greengram, cowpea, ragi, sawan and soybean, and an additional yield may be obtained. These crops do not adversely affect the pigeonpea crop, because by that time pigeonpea starts growing (end of September), the intercrops are ready for harvesting.
There is a possibility of raising early maturing pigeonpea as a summer crop with intercrop of greengram (mung). In this cropping system, pigeonpea may be sown in mid-April keeping a row-to-row distance of 90 cm, intercropped with 2-3 rows of greengram.
Greengram becomes ready for harvest by the end of June. Immediately in the space vacated by greengram, interplanting of blackgram can be done between pigeonpea rows. While blackgram will be ready for harvest by the end of September, pigeonpea matures by mid-November.
The wheat crop may be sown immediately after the harvest of pigeonpea. Short-duration pigeonpea fits well in Pigeonpea-wheat-greengram, Pigeonpea-wheat, Pigeonpea-lentil, Pigeonpea-late potato, Pigeonpea-sugarcane, etc., rotations.
14. Harvesting and Threshing of Pigeonpea:
Pigeonpea should be harvested when 75-80% of the pods are at physiological maturity. Harvesting of pigeonpea, about 25 days after anthesis when pods turn brown and are dry have been suggested by many scientists. Delayed harvesting, during bad weather, may increase the risk of damage to mature seed.
However, harvesting after the 42nd day of anthesis when the dry mass of the seed is low and moisture content is between 20 and 24 percent is also reported by other scientists. The mature pods could be identified as they are brown and have a dry testa. Traditionally pigeonpea plants are harvested by cutting the stem at the base, with an axe or sickle.
The harvested plants are tied in bundles and transported to a threshing floor. These are stacked in upright bundles to dry. The pod s and grain are separated by beating the dry plants with sticks or by using Pullman thresher. Another way to harvest pigeonpea is by hand picking the mature pods. This allows the crop to flower and pod for a second or sometimes a third harvest. Hand picking may not be economical beyond a second flush.
When hand picking of pods is not feasible, the upper branches with mature pods are cut (good for determinate types). Care should be taken in leaving as much of the foliage as possible while removing the pods and allowing the plant to regrow and promote another flush of posa.
However, this method delays the second harvest and usually results in a lower yield than hand picking. The proportion of seeds to pod is generally 50-60%. Threshed and cleaned produce should be further sun dried to reduce the moisture content to 10-11%.
By adopting improved technology, pigeonpea (red gram) may yield 2.0-2.5 tonnes (kharif), 3.0-3.5 tonnes (rabi) of grain/ha, 5.0-6.0 tonnes sticks, 0.8-1.0 tonnes of dry leaves and 0.2-0.3 tonnes of pod husk/ha.