Respuesta :
Beans are the members of the family fabaceae or leguminoceae. The roots of legumes (beans) have root nodules. In the root nodules symbiotic nitrogen fixing bacteria such as Rhizobium is present that fixes atmospheric nitrogen to the soil. No plants can fix atmospheric nitrogen to the soil except nitrogen fixing bacteria. Mr. Hammond tilled (mixed) back beans plants into the soil to get nitrogen fixed in the soil by root nodule bacteria present in beans plants for next year’s crops.
The modern farmers plant legumes in order to influence the growth of nitrogen-rich fertilizers for their other crops. It is not the beans that are producing the fertilizer for the other crops, it is the nitrogen-fixing bacteria, that is, Rhizobium that generally performs the function of nitrogen fixation.
The legumes, like beans, develop in a symbiotic association with soil-dwelling bacteria. The bacteria utilize gaseous nitrogen from the air in the soil and feed this nitrogen to the legumes, in return the plant gives food in the form of bacteria to the bacteria.
When the plant dies, the fixed nitrogen is discharged, making it accessible to other plants, this also facilitates to fertilize the soil.
