Envis Centre, Ministry of Environment & Forest, Govt. of India

Printed Date: Sunday, December 4, 2022

Green Manure Crops of Kerala

 

 

 

Crotalaria juncea (Brown Hemp, Indian Hemp, Madras Hemp, Sunn Hemp): It is a tropical Asian plant of the legume family Fabaceae. It is generally considered to have originated in India. It is now widely grown throughout the tropics and subtropics as a source of green manure, fodder and lignified fiber obtained from its stem. Sunn hemp is also being looked at as a possible bio-fuel. Its resistance  to root-knot nematodes and is also a soil improving crop via nitrogen fixation The quantity of nitrogen fixed by the crop is 75-80 kg/ha.

 

Sesbania aculeate (Dhaincha): It  is a small tree in the genus Sesbania belongs to the family Fabaceae. It can grow on saline soil. The plant has a great number of uses, including as green manure, rice straw, wood and fodder. It can be used like industrial hemp for rope, fish nets, sackcloth and sailcloth. Its fibers are similar to those of birch trees and show promise as a source of paper fiber. Like other legumes, it can be planted to improve the soil via nitrogen fixation. The quantity of nitrogen fixed is 75 to 80 kg per ha.

 

Sesbania rostrata (New Dhaincha): This is a small semi-aquatic leguminous tree, in the genus Sesbania. It forms a symbiotic relationship with Gram-negative Rhizobia which leads to the formation of nitrogen fixing nodules on both stem and roots. It is mainly used as green manure to improve soil fertility due to its fast growth, high biomass production and ability to convert large amounts of atmospheric nitrogen into a usable form for plants. Other applications include production of high quality forage for livestock and it is a source of fuel-wood. The quantity of nitrogen fixed is 150 to 180 kg per ha.

 

Tephrosia purpurea (Wild indigo or Kolingi): This species of flowering plant in the pea family, Fabaceae that has a pantropical distribution. It is a common wasteland weed. In many parts it is under cultivation as green manure crop. Used as a fish poison. The leaves and seeds contain tephrosin, which paralyzes fish. Larger doses are lethal to fish, but mammals and amphibians are unaffected. It is also used traditionally as folk medicine. It resists drought but does not withstand water stagnation. The seed have a waxy, impermeable hard seed coat and do not quickly germinate. To hasten germination, the seeds are to be abraded with sand or steeped in hot water at 55°C for two to three minutes.

 

 Indigofera tinctoria: This plant is also called true indigo, is a species of plant from the bean family that was one of the original sources of indigo dye. True indigo is a shrub one to two meters high. It may be an annual, biennial, or perennial, depending on the climate in which it is grown. It has light green pinnate leaves and sheafs of pink or violet flowers. The plant is a legume, so it is rotated into fields to improve the soil in the same way that other legume crops such as alfalfa and beans are. It shows resistance to drought.

 

Gliricidia maculate: It is a shrub, which takes up a tree habit under favourable conditions of soil and climate. For green leaf purposes, the shrub should be kept low by pruning or lopping at a height of 2-3 m. The shrub can be pruned two or three times a year and it withstands repeated lopping. Within two. years after planting, the plants are ready for lopping. Each plant gives five to ten kg of green leaves annually.

 

Leucaena leucocephala (Subabul): It is a small, fast-growing mimosoid tree which belongs to the family Fabaceae. The legume provides an excellent source of high-protein cattle fodder. This plant has been considered for biomass production, as its reported yield of foliage corresponds to a dried mass of 2,000–20,000 kg/ha/year, and that of wood 30-40 m³/ha/year, with up to twice those amounts in favourable climates. It is also efficient in nitrogen fixation, at more than 500 kg/ha/year. It has a very fast growth rate, young trees reach a height of more than 20 ft in two to three years.

 

Cassia auriculata: This is an evergreen shrub that grows in many parts of India and in other parts of Asia. The flower, leaves, stem, root, and unripe fruit are used for treatment, especially in Ayurvedic medicine. Propagated by seeds. During flowering tree is topped (stem and branches cut) and loppings used for green leaf manuring.

 

(Reference: Kerala Agriculture Department)