Which of the following plants are used as green manure in crop fields and in sandy soils : -
A
Crotalaria juncea and Alhagi camelorum
B
Calotropis procera and Phyllanthus niruri
C
Saccharum munja and Lantana camara
D
Dichanthium annulatum and Azolla nilotica
The answer is A.
Solution
Green manuring is the growing of a quick-growing crop (usually a legume) and ploughing it into the soil while it is still green. It adds organic matter and, through root nodules, fixed nitrogen to the soil. Crotalaria juncea (sunn hemp) is a leguminous plant widely used as a green manure crop. Alhagi camelorum (camel thorn) is a deep-rooted leguminous desert plant that grows in sandy soils and is used to improve sandy soils. Calotropis, Phyllanthus, Saccharum munja, Lantana and Dichanthium are not leguminous green manures (Lantana is a weed; Azolla, a fern, is a biofertiliser used in rice fields, but it is paired here with a grass). So Crotalaria juncea and Alhagi camelorum are used as green manure.
ConceptLeguminous green manure crops
Microbes in Human Welfare in past papers
81 questions from this chapter have appeared across 26 exam years.
