As we said before, there are 16 elements necessary for a plant to maintain its normal growth. Includes: six kinds of abundant elements: carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium; Three moderate elements: calcium, magnesium, sulfur; 7 trace elements: iron, zinc, manganese, copper, boron, molybdenum, chlorine. Just as we get sick from a lack of certain nutrients, a lack of certain elements during plant growth can cause abnormal deficiency symptoms.
For example, the typical deficiency syndrome: nitrogen deficiency inhibits the growth of seedlings, the old leaves first yellow and the new leaves thin; The phosphorus deficient plant had fewer tillers and the new leaf was dark green and the old leaf was purple. Iron deficiency and loss of green apical first, young veins first yellow and so on. Of these 16 elements, carbon, hydrogen, oxygen, and chlorine are supplied by air and water, while the rest are absorbed by the roots from the rhizosphere. Therefore, the prepared nutrient solution should contain the remaining nutrient elements. Nutrient elements to be absorbed by plants, need to prepare nutrient solution of fertilizer in the water has a good solubility, in the state of ions. They are usually inorganic salts, but there are also some organic chelates. The organic fertilizer which cannot be directly absorbed and used by plants should not be used as nutrient solution.
The amount and proportion of each nutrient element in the nutrient solution should meet the requirements of plant growth and development and be physiologically balanced to ensure the full play of the effectiveness of each nutrient element and the balance of plant absorption. In determining the composition of nutrient solution, the fertilizer types should be as few as possible under the premise of ensuring a complete variety of essential nutrient elements for plants, so as to prevent compounds from being brought into plants and causing excess ions or other harmful impurities.
The total concentration (salt concentration) in the nutrient solution should be suitable for normal plant growth. The various nutrient elements in the nutrient solution should be kept in their effective state for a long time in the cultivation process. Its effectiveness does not decrease in a short time due to the oxidation of nutrient air, root absorption and ion interaction.