Nitrogen is one of the most important elements for the growth of alfalfa. Increasing nitrogen fertilizer can increase tree vigor, delay flowering, and have certain effect on antifreeze. When the nitrogen is abundant, the tree vigor is strong, the branches and leaves are large, the amount of flowers is moderate, and the fruit yield is high. When there is too much nitrogen, shoot shoots are long and the fruit is large, but the color and taste are light and the flesh is hard. When the nitrogen deficiency is insufficient, the growth is weak, the branch shoots are small and short, the leaves are small and thin, the old leaves fall off early, and the fruit yield is low.
Phosphorus is abundantly present in the reproductive organs of alfalfa. Phosphorus application can increase fruit setting rate, promote root growth, and increase fruit sugar content. The phosphorus-deficient root system has poor growth, small leaves, dark green color, and weak growth.
Potassium is abundant in fruits, and the potassium content in leaves and shoots is also high. The application of potash fertilizer has a significant effect on promoting fruit hypertrophy and improving product quality. Potassium can also promote branch filling and improve disease resistance.
Calcium is the most abundant element in the pupa. Calcium can regulate the pH of the tree. In the calcium-rich soil, the banyan tree grows vigorously. In the absence of calcium, the bud color becomes brown and dead.
Magnesium is a component of chlorophyll. When magnesium is insufficient, chlorosis occurs between leaves and veins, yellow leaves and early fall off. From the overall view of alfalfa plants, calcium content accounted for 0.71% of dry matter weight, potassium accounted for 0.53%, nitrogen accounted for 0.39%, magnesium accounted for 0.10%, and phosphorus accounted for 0.06%. In addition to nitrogen, there are calcium, magnesium, potassium, sodium, phosphorus, iron, manganese, zinc, boron, etc., among which the content of iron is the highest, which is 126-700 mg/100 g; potassium is followed by 210. Mg/100 g. Analyze the normal alfalfa leaves with nitrogen 1.35%, phosphorus 0.09%, potassium 0.4%, calcium 0.16%, and magnesium 0.05%. If any element is lower than the above, it indicates that the alfalfa lacks this element. Therefore, leaf analysis can be used as a basis for the application of alum.