Autumn apples enter the fruit expansion period. Once they enter the expansion period, the apple will transform from the nitrogen nutrition period into the sugar nutrition period, and the carbohydrates produced by the photosynthesis of the green organs are transported to the fruit for its expansion. Field management during this period is particularly important for apple production.

1. Check the bagging in time

During the apple expansion period, the weather is changeable and there is more rain. If there is water in the bag after rain, the vents should be cut properly to remove the water. If sunburn, germ infestation and insect biting are found, measures must be taken as soon as possible to ensure the success of bagging.

2. Timely watering and moisture preservation

The swelling period of apple fruit is the later stage of fruit growth, which is the "critical period" of moisture, and the suitable soil relative humidity is 70%. If the water is insufficient, the apple will be smaller. Therefore, in dry weather, watering should be used as appropriate. It is best to use drip irrigation or sprinkler irrigation. Also pay attention to plowing and loosening the soil in time after watering and rainfall to avoid running out of moisture. After heavy rains, attention should be paid to clearing the ditch and drainage, so as not to cause stains and affect the root activities of fruit trees.

3, scientific fertilization

During the period of apple fruit swelling, topdressing should be carried out on the fruit tree in time to avoid nutrient deficiency affecting the size and taste of the fruit. It is recommended to apply 0.5kg/plant in sapling holes and 1-2kg/plant in MAINPAR nitrosulfuryl 13-8-27 in adult tree holes. Cover soil and water in time after fertilization. The MAINPAR nitrosulfur-based compound fertilizer has a quick effect and a long fertilizer effect, and it also has a certain beneficial effect on the color change of the later fruit.