Mention the artificial methods involved in the restoration of soil fertility.
Artificial methods That restore the fertility of soil are :
(1) By adding farm yard manure or animal excreta to the soil.
(2) By adding fertilizers, manure.
(3) By green manuring.
(4) By crop rotation.
(5) By controlling over-grazing.
How is nitrogenase enzyme protected ?
The nitrogenase enzyme is very sensitive to the molecular oxygen. It requires anaerobic conditions to work. The leg-haemoglobin in the nodule acts as an oxygen scavenger just meainting the anaerobic condition needed by the enzyme.
Hidden hunger refers to a situation in which a crop needs more of a given nutrient yet has shown no deficiency symptoms. The nutrient content is above the deficiency symptom zone but still considerably needed for optimum crop production