NPK, the three major nutrient elements of inorganic fertilizer, plays different roles in crop growth. Learning their functions and applying chemical fertilizers scientifically and rationally can improve the efficacy of these inorganic fertilizers.
Inorganic nitrogen fertilizer. Plants need a large amount of nitrogen fertilizer during the vegetative growth period. Rational application of nitrogen fertilizer can make crops green and lush, and improve crop yield and quality. Nitrogen fertilizer as topdressing outside the roots of crops can effectively prevent premature senescence due to nitrogen deficiency in the middle and later stages of crops. However, attention should be paid to avoiding fertilizer damage and burning seedlings. This inorganic fertilizer should not be used as seed fertilizer.
Inorganic phosphorus fertilizer. Phosphorus fertilizer has a strong effect on plant root development. Proper application of this inorganic fertilizer can make the root system of crops developed, branches and trunks strong, not easy to lodge, resistance enhanced, flowering and fruiting, and grain plump. Plants need phosphorus fertilizer at seedling stage. If phosphorus is deficient at seedling stage, it will affect later growth. Phosphorus fertilizer should be used as base fertilizer because its activity is small and it is difficult to be absorbed by crops.
Inorganic potassium fertilizer. Potassium fertilizer is a necessary inorganic fertilizer for plant reproduction, growth and resistance enhancement. Appropriate application of potassium fertilizer can make plant stem and root strong, increase sugar content, grain plump, and enhance cold resistance, drought resistance, lodging resistance and disease resistance. Potassium deficiency symptoms of crops are later than those of nitrogen and phosphorus because potassium has the characteristics of transferring from the lower stems and leaves to the top tender parts for reuse. Therefore, potassium fertilizer should be applied as base fertilizer in advance or at the early stage of reproductive growth.