Overview
Cajanus cajan (L.) Millsp., commonly known as pigeon pea, is a perennial legume plant that belongs to the family Fabaceae. It is a tropical and subtropical crop that has been domesticated for centuries and is widely grown in Asia, Africa, and the Americas. Pigeon pea is an important food and medicinal plant that has numerous health benefits.
Appearance
The pigeon pea plant is a short-lived shrub that can grow up to 4 meters tall. It has a deep taproot system that can reach up to 2 meters in length. The leaves are compound with three leaflets that are elliptical, lanceolate, and have a slightly pointed tip. The flowers are yellow, reddish, or purple, and are borne in clusters at the end of the branches. The fruits are elongated pods that contain 3 to 9 seeds that are yellow, brown, or black.
Common Names
Pigeon pea is known by several common names, including red gram, Congo pea, gandule bean, and tropical green pea. In India, it is called arhar dal or tuvar dal, and in Africa, it is known as fio-fio or kandolo.
Uses
Pigeon pea is a versatile plant that has several uses. The dried seeds are used as a protein source in many cuisines, especially in India, where it is a staple food. It is also used to make flour, which is used to make traditional dishes like dosas and idlis. In Africa, the leaves and young pods are used as a vegetable. Pigeon pea is also used as a cover crop to improve soil fertility, prevent soil erosion, and provide nitrogen fixation. Additionally, the plant has several medicinal uses, including as a treatment for coughs, bronchitis, and fever.
Light Requirements
Cajanus cajan (L.) Millsp. grows best in areas with full sun exposure, receiving at least 6 hours of direct sunlight daily. This crop cannot tolerate shade, and insufficient light results in stunted growth and poor yield.
Temperature Requirements
The growth and development of Cajanus cajan (L.) Millsp. are influenced by temperature. Optimum growth temperatures range from 25-35°C. This crop cannot tolerate frost or extreme temperatures, as they affect its physiological processes. Temperatures above 40°C or below 10°C may result in plant death.
Soil Requirements
Cajanus cajan (L.) Millsp. grows best in well-drained soils rich in organic matter. The ideal soil pH ranges from 5.5 to 7.0. The crop can tolerate a wide range of soil textures, from sandy to heavy clay soils. However, it requires a level of soil moisture to grow correctly. The crop is drought tolerant but performs better with adequate soil moisture. Fertile soils with adequate nutrients (nitrogen and phosphorus) produce higher yields of this crop.
Cultivation of Cajanus cajan (L.) Millsp.
Cajanus cajan (L.) Millsp., commonly known as pigeon pea, is a warm-season perennial crop with a deep taproot that is capable of improving soil fertility and structure. The plant requires well-draining soil with a pH range of 6.0-7.5. It can be grown in a wide range of temperatures, from 25°C to 35°C.
Watering Needs for Cajanus cajan (L.) Millsp.
Pigeon pea requires regular watering to achieve maximum yields. Irrigation should be done immediately after planting and continued at intervals of 7 to 10 days during the vegetative growth stages. Once the plant begins to flower, irrigation can be done at intervals of 10 to 14 days. The water requirement is generally 600-700 mm per annum.
Fertilization of Cajanus cajan (L.) Millsp.
For optimum growth and yield, pigeon pea requires adequate nutrients, particularly nitrogen, phosphorous, and potassium. A balanced NPK fertilizer with micronutrients should be applied before planting. In addition, nitrogen fertilizers should be applied at intervals of 4-6 weeks during the vegetative stage. Phosphorus and potassium can be added at regular intervals to maintain soil fertility.
Pruning of Cajanus cajan (L.) Millsp.
Pruning should be done during the dormant phase. This entails cutting back the main stem to a height of 30-40 cm from the ground. This will stimulate the growth of new shoots from the base of the plant, leading to a more compact plant and potentially higher yields. Pruning also helps to keep the plant disease-free by removing any diseased or dead wood.
Propagation of Cajanus cajan (L.) Millsp.
Propagation of Cajanus cajan (L.) Millsp. is essential for increasing the plant population. The plant can be propagated through various means, including:
Seed Propagation
The most common method of propagating Cajanus cajan (L.) Millsp. is through seed. The seeds of this plant are easy to collect, store, and germinate. The ideal time for collecting the seeds is when the pods have turned brown. After collecting the seeds, they should be dried in the sun to remove any moisture. The dried seeds can be stored in a cool and dry place for up to six months. Before sowing, the seeds can be soaked overnight for better germination. The seeds can be directly sown in the field or in nursery beds, depending on the plantation method.
Cutting Propagation
Cutting propagation of Cajanus cajan (L.) Millsp. is also possible and is a faster method of producing new plants. Stem cuttings of about 12-15 cm in length can be collected from the parent plant. The cutting should have at least three to four nodes. The cuttings should be treated with a rooting hormone and planted in soil or sand. The ideal time for taking cuttings is during the rainy season, which provides favorable conditions for rooting.
Layering Propagation
Layering propagation of Cajanus cajan (L.) Millsp. involves bending the low hanging branches of the plant to the ground and covering them with soil. The nodes of the buried part of the branch will produce roots, and the branch can be detached from the parent plant and transplanted to a new location. Layering is a simple and effective method of propagation and can be done during any season.
Grafting Propagation
Grafting propagation of Cajanus cajan (L.) Millsp. involves fusing a scion of the desired plant onto the rootstock of another compatible plant. Grafting is a relatively complex and specialized method of propagation. The use of grafting is still limited in Cajanus cajan (L.) Millsp. and is mainly used for research purposes.
Disease and Pest Management for Cajanus cajan (L.) Millsp.
Cajanus cajan, commonly known as pigeon pea, is a nutritious and important crop grown in tropical and subtropical regions of the world. However, like all other crops, pigeon pea is susceptible to various diseases and pests that can negatively impact its growth and yield. Effective disease and pest management practices are essential to reduce crop losses and ensure a healthy harvest.
Common Diseases
Pigeon pea is prone to several diseases caused by fungi, bacteria, and viruses. Some of the common diseases that affect pigeon pea include:
- Wilt: Caused by Fusarium udum fungus, this disease affects the roots and stem of the plant, leading to wilting and death of the plant. Crop rotation, soil solarization, and use of resistant cultivars are effective management strategies.
- Pod borer: Helicoverpa armigera is a major pest that infests pigeon pea and causes damage to developing pods. Cultural practices and biological control with parasitoids and predators can help manage this pest.
- Sterility mosaic: This viral disease causes chlorotic mottling on the leaves, stunted growth, and reduction in yield. Management strategies include the use of disease-free seeds, early detection, and removal of infected plants.
- Leaf spot: Caused by the fungus Phyllosticta cajani, this disease results in small, dark spots on the leaves that can coalesce and lead to defoliation. Fungicide applications, crop rotation, and removal of infected plant debris can help manage this disease.
- Powdery mildew: Widespread in humid regions, this fungal disease causes a white, powdery coating on the leaves, stems, and pods, leading to decreased photosynthesis and yield. Regular application of fungicides and proper irrigation management can help manage this disease.
Common Pests
In addition to diseases, various insect pests can cause damage to pigeon pea crops. Some of the common pests that affect pigeon pea include:
- Pod fly: Melanagromyza obtusa is a major pest that lays eggs in developing pods, leading to stunted growth and reduced yield. Spraying of insecticides combined with timely harvesting can help manage this pest.
- Aphids: These tiny insects suck sap from the plant, leading to distortion and curling of leaves, and can transmit viruses. The use of resistant cultivars and biological control with natural enemies can help manage this pest.
- Termites: These soil-dwelling insects can cause significant damage to roots and lower stem of the plant, leading to stunted growth and yellowing. Use of termite-resistant cultivars, soil treatment with insecticides, and regular monitoring can help manage this pest.
- Thrips: These tiny insects feed on developing flowers and pods, leading to deformation of the plant and reduced yield. Use of insecticidal sprays and monitoring of weather conditions can help manage this pest.
- Caterpillars: Several species of caterpillars, such as Spodoptera spp. and Euproctis spp. can cause defoliation and damage to developing pods. Biological control and use of insecticidal sprays can help manage this pest.
In conclusion, a combination of integrated pest management strategies, including the use of resistant cultivars, cultural practices, biological control, and chemical control with pesticides, can help manage the various diseases and pests that affect pigeon pea.
