nitrogen (N)：
Function: Essential for plant vegetative growth. It is a key component of chlorophyll, which is necessary for photosynthesis.
Deficiency symptoms: Yellowing of older leaves, stunted growth, and weak stems.
phosphorus (P)：
Functions: Essential for energy transfer and root development. It contributes to DNA and RNA formation and is crucial during flowering and fruiting.
Deficiency Symptoms: Leaves turn dark green or purple, root development is poor, and flowering is reduced.
Functions: Essential for overall plant health, including water regulation, enzyme activation, and protein and carbohydrate synthesis. It enhances plant disease resistance and helps form strong stems and buds.
