Biological Nitrogen Fixing Crops

The symbiotic bacteria colonize on the roots of specific legumes to form root nodules which fix atmospheric nitrogen. Rhizobiums live in the soil independently. When they come in contact with the roots of leguminous plants, they infect the root hair and penetrate into the roots.

The organisms enter into the roots and fix atmospheric nitrogen into the soil. Following are the main crops which fix the atmospheric nitrogen:

Table: Average fixation of Nitrogen by legumes

S.No.	Crops	N (kg/ha)
1.	Alfalfa (Lucerne)	194
2.	Ladino Clover	179
3.	Sweet Clover	119
4.	Red Clover	114
5.	Kudzu	107
6.	White Clover	103
7.	Cowpeas	90
8.	Vetch	80
9.	Peas	72
10.	Soybean	58
11.	Peanuts	42
12.	Beans	40