Ques. 1AIPMT 2003
Which of the following plants are used as green manure in crop fields and in sandy soils ?
- Calotropis procera and Phyllanthus niruri
- Dichanthium annulatum and Azolla nilotica
- Saccharum munja and Lantana camara
- Crotalaria juncea and Alhagi camelorum
Answer
(4) Crotalaria juncea and Alhagi camelorum
Solution
Green manuring means growing a fast-growing crop and ploughing it into the soil to add organic matter and nitrogen.
∵ Leguminous plants carry nitrogen-fixing Rhizobium in their root nodules (as per NCERT, a symbiotic biofertiliser), they are the best green manures.
⇒ Crotalaria juncea (sunn hemp) and Alhagi camelorum (camel thorn, a desert legume) are both legumes and are used as green manure in crop fields and sandy soils.
⇒ Calotropis, Lantana, Saccharum munja and Dichanthium (a grass) are not legumes.
Answer: (4)