Which one of the following is INCORRECT about organic fertilizers...

Organic fertilizers are derived from animal matter, animal excreta, human excreta, and vegetable matter (e.g., compost and crop residues). They are formed from products or dead materials of biological origin.

Biofertilizers are preparations containing living cells or latent cells of efficient strains of microorganisms (bacteria, fungi, algae) that help crop plants' uptake of nutrients by their interactions in the rhizosphere, such as nitrogen fixation and phosphorus solubilization.

Inorganic or chemical fertilizers involve the addition of inorganic minerals in definite proportions to the field. Therefore, the statement that organic and biofertilizers include the addition of inorganic minerals in definite proportions is incorrect.

Answer: It includes addition of inorganic minerals in definite proportion in the field.