Cajanus cajan (L.) Millsp.

Home

Leguminosae

Synonyms

  • Cajanus indicus Spreng.
  • Cajanus  flavus DC.
  • Cytisus cajanus L.
  • Cajanus cajan (L.) Druce.
Author: Le Houérou
 

Common names

Guandul, poroto guandul, poroto paraguayo, sachacafé, falso café, arveja (Argentina), guando (Brazil), quinchoncho (Venezuela), frijol de árbol (Mexico), Cumandái (Paraguay), red gram, tur, arhar, dahl (India), catjang, kachang (Asia), pigeon pea (Australia), pigeon pea, angola pea (United Kingdom), pois d'angole (French-speaking West Africa), Puerto Rican bean, pigeon pea (Hawaii).

Description

Annual, or more usually short-term perennial shrub that may reach 4-5 m in height, but usually 1-2 m only, woody at the base, with a variable habit, but usually erect. Deep and quick growing tap root. Angular stem resulting from three ribs starting from the base of each petiole. Leaves trifoliate, alternate set in a spiral along the stem. Leaflets oblong, lanceolate 5-10 cm long x 2-4 cm wide, pubescent likewise the stem. Lateral petioles, 2-3 mm the terminal one reaching 10-20 mm. Stipules linear 2-3 mm long, stipulets filiform 1-2 mm long. Flowers usually yellow but they may also be striated with purple streaks or plain red. Corolla 20-25 mm, with the flag 18-20 mm wide. Calyx 10-12 mm long, with 5 linear teeth. Inflorescence composed of racemes having 5-10 flowers on top of an axillary, little divided peduncle. Pods flat, with an acuminate tip, pubescent and of variable colour, 5-9 cm long x 12-13 mm wide, containing 2-9 seeds in shades of brown, red or black. Husks bearing deep, oblique furrows underlining the septa between the seeds. Life span, up to 5 years. Pigeon pea is extremely variable from the genetic view point hence the very many cultivars. Reproduction system is ca 60 % autogamous, the chromosomic number is 2n = 22. There are 16,000-18,000 seeds per kg and some 10 % hard seeds. 

It is a short-day plant. Gooding (1962) reported two groups of plants in Trinidad one group spans 60 to 106 days in the time taken from sowing to podding, the other up to 237 days. It flowers over about two months as days become shorter, and has flowers and ripe pods on the plant at the same time. It flowers in 98 days in the Kimberley district in northern Australia (lat. 15°S) with pods maturing in 178 days. It flowers in eight months in the Bombay district in India (lat. 20°N). Too much shading causes the plant to make spindly growth and to bear thin, pale green foliage and few pods (Krause, 1932). The growing period lasts from 60 to 235 days, depending on cultivar and latitude.

Temperature

Cajanus cajan is very heat-tolerant. Prefers hot moist conditions. Under Hawaiian conditions grows between 18 and 30°C. Will grow at temperatures above 35°C under adequate soil conditions of moisture and fertility. Does not tolerate frost, but will grow in temperatures to just above frost level. Will seed as a perennial at 1840 m down to a minimum night temperature of 10°C (Krause, 1932). Subject to frost damage (Schofield, 1945). Tall plants may escape light frosts because of the height of the foliage.

Water

Cajanus cajan is one of the most drought tolerant legume crops, with a wide range of rainfall tolerance, but prefers more than 625 mm and in elevated areas exceeding 2 000 m cold nights and cloudy weather interfere with fertilization of flowers. Flowers well where rainfall is 1 500 to 2 000 mm. On deep, well-structured soil will grow where rainfall is 250 to 375 mm (Krause, 1932).

Soil

Tolerates a wide range of soils, from sands to heavy black clays. Tolerates a wide range of pH, but the most favourable range is pH 5.0 to 7.0. It is sensitive to salt spray, high salinity and to water logging. Will grow in sand provided it does not contain more than 0.0005 g of sodium chloride per gram of soil (Krause, 1932).

Distribution

Of unknown origin, probably Indian and African. Cultivated in ancient Egypt, Africa and Asia since prehistoric times, later introduced to America. Now acclimatized in several tropical countries. The major producer is India with over 100 cultivars, 2.4 million ha cultivated and 90% of world production. Its altitude range is 1250 m in Hawaii (Ripperton and Hosaka, 1942), at heights of 1230 to 1500 m it fails to set seed; 0 to 3000 m in India (Krause, 1932) and Colombia (Crowder, 1960). Essentially a plant of the semi-dry lowlands but has wide adaptability. Generally should not be planted above 770 m. Latitudinal limit is 30° N and S, the optimal being 15-20° for most cultivars.

Crop management

  • Land preparation : Thrives best in seed beds prepared by deep ploughing and cultivations to reduce weeds.
  • Rhizobium relationships : Promiscuous and usually not inoculated. The cowpea type of inoculum can be used, the current Australian strain being CB756 and in South America, C95, based on the Australian material (Batthyany, 1970). Oke (1967a) found that nodules appeared on the roots three weeks after seeding, and that young nodules of pigeon pea were the most active in fixing nitrogen.
  • Nutrient requirements : Usually responds to phosphorus, and requires enough calcium, potash, magnesium.
  • Nutrient deficiency symptoms : On old leaves ; Deficiency potassium : Leaf tip yellow or brown. Yellowing spreads from the tip onward along the leaf margin and may coalesce with similar areas at extremities of the lateral veins. Leaf tip becomes scorched as symptoms become more severe. The scorching may spread around the leaf margin but typically there is a yellow band between the scorched area and the healthy green tissue in the early stages. The affected leaves not showing symptoms are generally dark green. Plants stunted. Deficiency magnesium : Mild interveinal chlorosis, veins remain dark green. Interveinal areas become rusty brown or bronzed and may become necrotic so that narrow elongated streaks of dying tissue appear between the veins. The margins of the young leaves frequently inrolled. On young leaves ; Deficiency nitrogen : Leaves uniformly pale green, greenish-yellow, or pale yellow. Oldest leaves show similar symptoms. Deficiency iron : Interveinal areas light green, veins and adjacent tissues remaining dark green. Deficiency calcium : Light green patches, irregular in outline, appear randomly in interveinal areas around the leaf margin. Patches may turn brown, particularly in the youngest and most severely affected leaves. Severely affected young leaves absciss. Stems weak and prostrate. Deficiency phosphorus : No clearly defined symptoms. Plants small and stunted, leaves dark green; no obvious leaf symptoms.
  • Compatibility with grasses and other legumes : Grows well interplanted with Rhodes grass, Cynodon dactylon and molasses grass in Hawaii (Hosaka and Ripperton, 1944), and with pangola grass in Brazil (von Schaaffhausen, 1966).
  • Tolerance to herbicides : It is fairly tolerant of herbicides . (Getner and Danielson, 1965; Kasasion, 1968).
  • Nitrogen-fixing ability : It is regarded as a good plant for restoration of fertility and is used in a rotation such as maize-groundnut-tobacco-pigeon pea for three to four years in Mauritius and Uganda (Stanton, 1966). Hosaka and Ripperton (1944) state that one of the advantages of pigeon pea is the increased growth and palatability of the grass interplanted with it. In Hawaii, a profitable rotation with pineapples, five years for each crop, was developed, to the great benefit of the pineapple crop (Krause, 1932). Oke (1967a) found maximum fixation in pigeon pea of 14.5 mg/day, compared with 10.3 mg for Centrosema pubescens and 4. 6 mg for Stylosanthes guianensis. Eighty-eight percent of the nitrogen fixed was transferred to the tops of the plants.
  • Response to defoliation: It does not persist if heavily grazed (Ripperton and Hosaka, 1942). For cut forage, it should be topped at a height of about 0.8 m. Under grazing conditions, it makes vigorous growth during the first year and then declines and ordinarily requires replanting every four to five years.
  • Grazing management : Allow the plants to develop well before grazing and then lightly graze to a hedge at the desired height. The plant stems are brittle and easily broken, so grazing should not be continuous. In Colombia, where the plants are used for poultry rations, cutting height is 0.5 m in the first year and 1 m in the second year, and cattle are allowed to browse the regrowth. In São Paulo, Brazil, it can be grazed for up to five years if carefully handled.
  • Response to fire : Easily destroyed by fire (Downes, 1966).
  • Seed harvesting methods : Most of the seed pods are picked by hand in the tropics, although mechanical harvesting is done in Hawaii (Krause, 1932). The seed pods ripen irregularly and do not shatter easily. The final drying of the pods may be done after harvest. Threshing the seed from the stem requires a strongly constructed machine such as double-cylinder pea and bean threshers. The seed is then winnowed, graded and stored in airtight containers to prevent insect damage.
  • Seed yield : 900 to 1 150 kg./ha. Akinola and Whiteman (1972) recorded a yield of 7.5 tonnes/ha of shelled seed in experimental plots in Queensland, Australia.
  • Main attributes : It is more adaptable to higher elevations than Leucaena leucocephala, though not to wet conditions; it is palatable forage and there is a high proportion of seed in the forage; it is adaptable to a wide range of soil types. Main deficiencies : Its short life, frost susceptibility and brittleness under grazing.

Propagation

  • Sowing methods : Best sown in rows for interrow cultivation and mechanical harvesting. Can be seeded in holes about 2 m apart or in 35-cm rows for fine stems for silage and mechanical harvesting (van Rensburg, 1967). In India and Uganda, it is usually sown in alternate rows with sesame or Eleusine coracana; in Malawi, with maize; in Hawaii, some sow in double rows 3 m apart from centre to centre and intercrop with forage grasses. Planting is done by maize drill, by broadcasting or by hand. For oversowing into natural pastures, von Schaaffhausen (1966) recommends sowing Cajanus in contour furrows 2 m apart into pangola grass pastures, using 20 to 30 seeds per hole. A large percentage of mature seeds pass undigested into the dung and germinate and many seedlings are established in this way (Krause, 1932). Seed is sown from 2.5 to 10 cm deep, the deeper figure being in hand dibbling. Sow in spring to early summer at 0.5 to 4 kg./ha depending on required density, up to 5 to 7 kg./ha under irrigation.
  • Number of seeds per kg : 16 000. Percentage of hard seed is less than the 10 percent required for commercial sale.
  • Seed treatment before planting : To break dormancy: no treatment is required. Inoculation is usually not necessary. Pelleting is usually not necessary; if to protect Rhizobium, use rock phosphate. For insect and disease control, treat seed with insecticide and fungicide.
  • Seedling is fairly slow to start and weed control for the first two months of growth considerably improves its performance. When established, it makes vigorous growth.
  • Breeding system : Usually self-fertile, but some natural crossing (up to 40 percent) occurs (Khan, 1973). Chromosome number 2n = 22.
  • Minimum germination and quality for commercial sale : Seventy percent minimum germination, with not more than 10 percent hard seed, and a purity of at least 98.8 percent in Queensland. The seed is germinated at 25°C under a cover.

Variability

There are no registered commercial cultivars in Australia, but in India there are numerous varieties. Whyte (1964) reported 86 different types. Commercially there are the late, tall, long-podded, many-grained "arhar" type of north-west and eastern India, and the early, small, few-seeded "tur" type of Madhya Pradesh, western and peninsular India.

Products & uses

Pigeon pea constitutes an important domestic fuel over large areas, albeit its caloric power is low. On certain types of soils such as vertisols the wood production may exceed that of Leucaena. Feed value of the fodder is excellent with 10-15 % CP on the green material DM. But pigeon pea is not always readily accepted by stock that has not acquired a taste for it (Wickens in Litt.,2000). Leaves remain on the plant throughout the dry season. Yields of fodder vary widely with the ecological conditions and the care given to the crop. Tall perennial varieties are amenable to trimming as fodder, but also as green manure (2.6 % nitrogen). The effect of pigeon pea on soil fertility has been studied in detail (Ong & Daniel, 1990). Due to its deep rooting system pigeon pea offers little competition to associated crops and is therefore much used in intercropping systems with cereals such as millet, sorghum and even maize, it also provides a good means to improve fertility in fallows. Fodder yields may reach 25 t DM / ha / yr in close to optimal conditions without fertilization, and 38 t with a 100 kg nitrogen and phosporus applications. Grain yields may vary from 1 to 10 t /ha / yr of shelled grain. Naturally, under the conditions of the South Sahel the expected results are much lower : 2-4 t DM of fodder and stalks plus 600-1,200 kg of clean beans / ha / yr. As a human food, pigeon pea produces, under the Sahel conditions, some 650 kg of beans / ha / yr, having some 25 % crude protein, with a well balanced composition in amino-acids, save for methionine and cystine which are too low for an ideal human food. The pods may be consumed green, used as green peas, or as ripe beans, like cowpea. Nitrogen fixing ability for a density of 7,000-10,000 plants ha is of the order of 100-120 kg N2 / ha / yr (ca 15 mg / pl / yr). The crop has long been used as a windbreak and shade for young coffee trees, forest seedling nurseries and vegetable beds, and is an important honey-producing plant. The canning of green pigeon peas is a major industry in Puerto Rico and Trinidad.

The grain is used for human and stock feed. Straw, husks and screenings are useful roughages. Nearly 2 350 000 hectares are grown in India yearly. In one single harvest in Hawaii, the fully podded tops gave 11.2 tonnes of green forage, 4.97 tonnes of dry matter and 400 kg. protein per hectare (Takahashi and Ripperton, 1949). Cattle fed wholly on pigeon-pea pasture have gained in weight from 0.7 to 1.25 kg. per head per day at a carrying capacity of 1 to 3.75 beasts/ha, and liveweight gains of 200 to 500 kg. per hectare per annum have been recorded (Krause, 1932). In Brazil, von Schaaffhausen (1966) found that Zebu bulls grazing a pangola grass/pigeon pea pasture gained an average of 35 kg. in 90 days during a severe drought, while animals on a control pasture lost 6 kg. On rotation pastures of Lablab purpureus, pigeon pea and grasses, 47 bulls gained 40 kg. in 63 days.

Pigeon pea is harvested for hay and for milling for meal in Hawaii when a large percentage of pods are mature probably two-thirds to three quarters of the pods in sight because a large part of the nutritive value of the plant is contained in the seed. Harvest not more than the upper third of the plant to avoid the woody base unless the plant is spindly. Cure on the cut surface of the plant which has just been harvested for six to eight days and then mill into meal. Pigeon-pea hay is an effective substitute for more expensive industrial concentrates. Otero (1952) recorded that in Brazil it made good silage and was very palatable to the animals. If Cajanus is not frosted, it will stand over very well for winter and dry-season feeding.

Nutritional Quality and Animal Production

The plant has a high feeding value for beef and dairy cattle, swine, sheep and goats. The well-leaved and fully podded branches, cut at 0.8 metres, have 40 to 50 percent dry matter, and protein up to 16 percent of the dry matter (Takahashi and Ripperton, 1949). The plant is also a good source of vitamin A. Otero (1952) recorded 11.46 percent crude protein and 22.6 percent crude fibre in the leaves, and 18.36 crude protein and 5.43 percent crude fibre in the seeds. From silage made from the foliage he recorded 15.09 percent crude protein, 26.05 percent crude fibre, and 32.8 percent nitrogen-free extract in the dry matter. The silage had 66.7 percent crude fibre, and 32.8 percent nitrogen-free extract in the dry matter. The silage had 66.7 percent moisture. The forage is not relished by cattle in the immature stage. Grazing should be deferred to the early green-pod stage (Hosaka and Ripperton, 1944). Mature plants may cause irritation of the rumen of cattle (Stanton, 1966).

Dry-matter and green-matter yields

Parbery (1967a) harvested 25.45 tonnes of dry matter in 372 days (unfertilized) and 37.96 tonnes/ha when fertilized with 100 kg. N/ha on Cunnunurra clay but only 1 071 kg./ha, unfertilized, on Cockatoo sand in the Kimberley district of northern Australia. One hundred kg. N/ha depressed its yield on Cockatoo sand. The yield of 37.96 tonnes when fertilized with 100 kg./ha represents 7 704 kg./ha of protein. In Colombia, Herrera and Crowder (1963) obtained 14 000 kg. DM/ha and more than 2 000 kg./ha of crude protein from cutting pigeon pea at ground level or at 15 cm when the plants were 150 cm tall. No regrowth occurred when the plants were cut to ground level.

Pests, diseases & weed

Whyte (1964) records that it is attacked by caterpillars, pod borers, gall fly, wilt (Fusarium udum) and leaf spot. Colbran (1963) found that the roots were attacked by the nematode Helicotylenchus dihystera. In Hawaii it is attacked by the scale insect, Coccus elongatus, a stem borer, termites, a pod borer (Lycaena boetica) and leaf eating caterpillars (Krause, 1932). A 4 percent DDT spray controlled pod borers in Mauritius (Gooding, 1962). The ability to compete with weeds is not high in the seedling stage, but thereafter quickly shades out weeds. Dry season leaf fall also helps suppress weeds (Stanton, 1966). In Puerto Rico it has been affected by spotting of the leaves and pods and seed destruction by Colletotrichum cajani (Krause, 1932). Gooding (1962) reports collar and stem canker caused by Physalaspora and possibly Diplodia, and Hammerton (1975), rust (Uredo cajani).

Links:

References

Gooding 1962 ; Krause 1932 ; Nichols 1964 ; Akinola, Whiteman and Wallis 1975 ; Whyte et al. 1955 ; Berhaut 1975 ; Berhaut 1976 ; NAS 1980 ; Vandenbelt 1988 ; Ong & Daniel 1990 ; Skerman 1977 ; Skerman et al. 1991 ; Dommergues et al. 1999.

It is the opinion of the present writer that pidgeon pea deserves much more attention on the part of agriculture developers in the Sahel than it has received to-date.