Nitrogen is the main component of the nutrients needed for the apple tree, and it is the main component of organic compounds such as proteins, chlorophyll, vitamins, hormones, nucleic acids and enzymes. The profit and loss of apple tree nitrogen nutrition is the basis for fertilizing apple trees. one. However, the apple tree has a certain limit on the amount of nitrogen, and in the annual growth cycle, the application of nitrogen fertilizer time and application amount will affect the effect of fertilization. If the supply of nitrogen is too much or insufficient, it will not only affect the yield and quality of the apple, but also lead to a prolonged or weakened tree.
The status of nitrogen nutrition in apple trees is different, and the external morphological characteristics of trees are significantly different. The application of nitrogen fertilizer in apple tree cultivation management is one of the basis for fertilization.
First, Wang Changshu:
In the annual growth cycle of apple trees, the proportion of shoots and long shoots in the canopy is high, and the growth shoots of the shoots are large and mostly appear secondary growth; the trees have long branches and shoots, the buds do not have sufficient quality, and the autumn shoots are large. For such prosperous trees, special attention should be paid to controlling the application of nitrogen fertilizer at the spring shoot stoppage, and watering should be controlled.
Second, the weak tree:
In the annual growth cycle of this type of tree, the growth of the tree is slow, the new tender shoots are hard and short, the leaves are erect and thin, the leaves are yellow and brittle, and the top shoots of the shoots grow multiple times. This growing tree is debilitating. The performance of these trees to apply nitrogen fertilizer, should pay attention to before and after the bud, after flowering and autumn, each topdressing once.
Third, the output of a stable tree:
Steady-yielding trees, vegetative and short-resulting branches on the tree grow stoutly, occupy moderate proportions in long, medium, and short branches; various organs grow in harmony, the leaves are large and neat, and the leaves are green in colour, giving this type of tree Fertilization, do not apply a single nitrogen fertilizer, the best fruit tree fertilizer.
In addition, there are still the following experiences in applying nitrogen fertilizer to fruit trees.
1. In the late growth period of the tree, if the soil contains high nitrogen, the coloration of the fruit is unfavorable. During the period from May to June, excessive nitrogen fertilizer was applied, and the color of the fruit in the later period was poor. During the period before fruit picking, nitrogen fertilizer was controlled; after summer, more potassium fertilizer was applied. The combination of phosphate fertilizer and potassium fertilizer was best.
2. In the fruit trees with the phenomenon of pumping, the nitrogen fertilizer application time should be mainly in the early stage of the annual growth cycle, and the application of nitrogen fertilizer should be appropriately reduced in the later period, which is beneficial to the prevention of fruit stripping.
3. Applying nitrogen fertilizer before defoliation of fruit trees can rapidly increase nitrogen nutrition in leaves in a short period of time, and can receive the effect of improving storage nutrition.