Question

Agriculturists have reported about 40-50% higher yields of rice by applying

• A. Azolla
• B. Cyanophycean members
• C. Mycorrhizae
• D. Thorn forest

Answer 1

The correct option is A Azolla

In the atmosphere, nitrogen is present as diatomic stable gaseous form. This form of Nitrogen cannot be used by plants. Plants depend on Nitrogen present in Nitrogen compounds like nitrates, nitrites and ammonium form. These form of nitrogen are called as fixed form of nitrogen.

Azolla is an aquatic pteridophyte common in rice fields. This plant harbors Anabaena (cyanobacteria) in leaf pockets. The Anabaena present in leaf pockets fixes atmospheric nitrogen.

So, the correct answer is option A.