Refined management of jujube trees during the rainy season: master these technical key points

Since the beginning of summer, after a period of high temperature and drought, a soaking rain across the province on July 18 brought our province truly into the hot and humid season. As the rainy season arrives, how jujube trees should be managed at this time and which main tasks are involved have become a topic of concern for the vast number of jujube farmers. Below, the management of jujube trees at the seedling stage and the fruiting stage is discussed separately.

I. Seedling stage management: pay attention to topdressing to promote vigor

For sour jujube rootstock seedlings sown this year, the hot and humid season is the season of their fastest growth. Due to the earlier drought, the seedlings grew slowly. Therefore, we should seize the favorable opportunity of high temperature, high humidity and rapid seedling growth at the present stage, and timely apply urea 1-2 times, at an interval of about 20 days, at 7-10 kg per mu, to promote seedling growth. At the same time, timely carry out intertillage and weeding to create a good environment for seedling growth. In terms of pest and disease control, attention should be paid to the control of red spiders and jujube leaf rollers, and 2% abamectin at 4000-5000 times, 20% fenpropathrin at 1500-2500 times, and 10% chongmanling at 2000-3000 times can be selected for control. Diseases in the rootstock nursery are not serious, so control may be unnecessary. For plants that grow rapidly and reach a height of more than 60 cm, light pinching can be carried out to promote thickening growth.

The grafted finished seedlings cultivated in the same year all grow rather vigorously. Generally, after entering August, nitrogen fertilizer is no longer applied as topdressing. Instead, potassium dihydrogen phosphate can be applied as a foliar topdressing each time pesticides are sprayed for pest and disease control, at a spray concentration of 0.2-0.3%. After the seedlings reach a height of 1-1.2 m, pinch moderately to promote thickening growth.

II. Careful management at the fruiting stage for yield

In jujube cultivation in our province, large jujubes are mainly distributed along the line of Fuping, Xingtang, Zanhuang, Neiqiu and Wu'an in the Taihang Mountain area in the west, golden silk small jujubes are mainly distributed in Cangxian, Xianxian, Qingxian and other counties in Cangzhou, and fresh-eating varieties are mainly distributed in Huanghua, Yanshan, Gaocheng, Gaoyi and other counties. The rainy season is also an important period for jujube tree management. Based on experience from previous years, the following tasks should be done well for jujube trees at the fruiting stage:

1. Rational fertilization: In early August, do not apply nitrogen fertilizer to jujube trees that are growing and fruiting normally, and appropriately apply phosphorus and potassium fertilizer as topdressing. Generally, 0.3-0.5 kg of diammonium phosphate is applied per tree, and jujube trees with many fruits and weak growth may be given appropriately more. Compared with other jujube varieties, winter jujube should receive a slightly larger amount of fertilizer. At the same time, in conjunction with pesticide spraying, spray foliar fertilizers such as potassium dihydrogen phosphate, photosynthetic micro-fertilizer, or multi-element foliar fertilizers such as Guowang, Yeba and Aiduoshou 2-3 times to promote the rapid enlargement of young fruits.

2. Timely summer pruning: Jujube trees are plants that greatly favor light. Poor light will bring serious consequences such as excessive vegetative growth of the tree, increased fruit drop, and a high incidence of pests and diseases. In mid-August, timely thin out overly dense branches, water sprouts, diseased and pest-infested branches, and weak slender branches. Except for jujube heads responsible for expanding the canopy, all should be appropriately pinched to improve the tree's light conditions and nutrient distribution, and promote accelerated fruit growth.

3. Scientific control of pests and diseases: Hot and humid weather creates favorable conditions for the occurrence of many pests and diseases. August is the peak period of damage from jujube fruit rot disease, jujube rust, anthracnose, fruit shrinkage disease, peach fruit borer, red spiders, green plant bugs and jujube leaf rollers. According to the different main pests and diseases, use 800 times liquid triadimefon plus 1500 times liquid 20% fenpropathrin to prevent jujube rust and red spiders; for jujube fruit rot disease, 400 times liquid copper hydroxide and 400-500 times liquid copper oxychloride can be used for control; for jujube anthracnose, 500-600 times liquid carbendazim-thiram can be used for control; for jujube fruit shrinkage disease, 600-800 times liquid Suoguoling No. 1, agricultural streptomycin at 100-140 international units/ml, and agricultural oxytetracycline at 200 international units/ml can be used for control. For the pest red spider in jujube orchards, 2000 times liquid pyridaben, 2000 times liquid fenpropathrin, and 4000-5000 times liquid abamectin can be selected for control; for Lepidoptera pests such as fruit borers and jujube leaf rollers, 800 times liquid diflubenzuron No. 3, 2000 times liquid Taoxiaoling, and 2000-3000 times liquid Kungfu Xiaozi can be selected for control. Adding spreaders to the pesticide, such as Hailiping, cellulose, soybean milk, etc., can effectively improve the control effect.

For varieties with heavier fruit drop such as golden silk small jujube, spraying 30 ppm Zaofengling No. 2 in early August and 20 ppm Zaofengling No. 2 in late August once each, or adopting a spraying method of naphthalene acetic acid at 15 ppm around August 10, 20 ppm after 7-10 days, and 15 ppm in early September, has a significant effect on preventing pre-harvest fruit drop.

4. Intertillage and weeding: Vigorously growing weeds not only compete with jujube trees for fertilizer and water, but are also intermediate hosts for pests and diseases. Therefore, intertillage and weeding should be carried out in a timely manner, and herbicides such as glyphosate and paraquat can also be used (these two herbicides are non-selective, so be sure not to spray them on jujube trees). The removed weeds can be turned under as green manure or used to cover the tree disk. After rain, timely carry out intertillage or hoeing around the tree disk to prevent surface crusting, improve soil permeability and maintain soil moisture.

5. Drainage and drought prevention: The vast majority of rainfall in our province is concentrated in the rainy season. Mountain orchards should build water-collecting facilities such as fish-scale pits and water storage ponds to accumulate rainwater and prevent autumn drought. Jujube orchards in plain areas should dredge drainage ditches, and in case of continuous rainfall, promptly remove accumulated water to prevent waterlogging.