What measures are there to protect pear tree leaves after pear fruit harvest?

After the pear fruit harvest, the main goal of the orchard is leaf protection. Whether the leaves can be effectively retained directly relates to whether the nutrients stored by the pear tree can meet the nutrient needs of flowering, fruiting and other life activities the following year. How can leaf protection work be done well? Based on several years of work practice, here are a few suggestions for reference.

First, the moisture preservation work in the pear orchard after fruit harvest is very important. This is because during fruit harvest, wounds are caused to the tree to varying degrees, such as stem-end openings and some leaves being knocked off, and these wounds very easily lose water. Because pear fruit requires a large supply of available water during the ripening process, the physiological functions of the pear tree concentrate a large amount of available water to supply the fruit, and when the fruit is harvested by human action, under conditions where the pear tree is completely unprepared, the tree still supplies water in the direction of the fruit, and because wounds remain after the fruit is harvested, water is lost from the wounds, causing water consumption. What we usually see is that after fruit harvest the leaves instead shrivel, which is caused by physiological dehydration. At this time, if water cannot be supplied adequately, it is very easy to cause large-scale leaf drop. In addition, fruit harvest brings about a shift in physiological functions; for example, if water is insufficient, growth hormones will shift toward abscisic acid, causing physiological leaf drop in the pear tree. When the pear leaf drop rate reaches about 80 percent, it causes flower buds and leaf buds to shift from a dormant state to an active state, forming autumn flowering and new shoot sprouting, which consumes the stored nutrients in the tree body, thereby affecting the next year's pear fruit yield and causing economic losses. Therefore, after fruit harvest, moisture preservation work in the pear orchard is crucial.

Second, matters that should be noted in post-harvest moisture preservation work:

1. Within 15-20 days after harvest, high-concentration fertilizer must not be applied, which is what is usually called post-harvest fertilizer. According to the physiological functions of the tree body, the period within 15-20 days after harvest is the recovery period for the tree's vitality. When the tree's vitality has not recovered, applying high-concentration fertilizer not only is unfavorable to the recovery of the tree's vitality, but instead produces the opposite effect, causing the tree's normal life activities to be damaged and very easily producing physiological leaf drop. For the few individual trees whose tree vigor is truly too weak and which cannot do without a little fertilizer within 15-20 days after harvest, only decomposed human manure and urine with water as the main component and a concentration not exceeding 2 percent may be used for watering, or a 0.5 percent urea dilution may be sprayed on the reverse side of the leaves in the morning or evening. In short, before the tree's vitality has recovered, it is best not to use fertilizer. After the tree's vitality has recovered, fertilizer must be applied to promote roots and leaves with fertilizer, increase the storage of assimilated nutrients, and lay the foundation for a bumper harvest the following year.

2. Within 15-20 days after harvest, before the tree's vitality has recovered, do not carry out chemical weed control in the orchard, and especially do not use glyphosate to spray weeds, because glyphosate weed control mainly kills weeds by destroying their green parts. After weeds are sprayed with glyphosate, the stomata on the leaf surface open wide and water evaporation increases greatly. In order to survive, the weeds must desperately absorb large amounts of water from the soil to replenish themselves, thus forming a situation in which pear trees and weeds compete for water; second, after being sprayed with glyphosate, weeds begin to wither and die in six to seven days. After the weeds die, the area of the pear orchard's surface soil exposed to sunlight increases, and the surface temperature rises quickly, making it very easy to scald the shallow root system of the pear tree due to high soil temperature, thereby affecting the pear tree's water absorption and causing physiological dehydration and leaf drop. Therefore, within 15-20 days after harvest, do not remove weeds. Weeding should also be carried out only after the pear tree's vitality has recovered. This is beneficial to the success of leaf protection work.

3. Within 15-20 days after harvest, avoid spraying high-concentration pesticides during the midday high-temperature period, so as to avoid scalding the leaf surface.

4. After harvest, farmers with the means may use green grass, green rice straw and other straw to cover the ground beneath the pear trees, promoting the pear orchard's moisture preservation function, keeping the pear orchard soil moist, reducing water evaporation, and promoting the success of leaf protection.