As a rule, the nutrient requirements of the vegetable species can only be insufficiently satisfied with manure.
Manures are primarily soil improvers. With them, the soil is mainly supplied with humus. The nutrient content of the manure is low. They contain on average only 0,5% nitrogen, 0,25% phosphoric acid, 0,6% potash and 0,3% Calcium. Good harvests could only be achieved with very large amounts of manure, which are mostly not available. That is why additional fertilization with inorganic (mineral) Fertilizers absolutely necessary.