Source: Agricultural Science and Technology News
Experts of this issue
Liang Jun, professor and doctor of the College of Horticulture, Northwest A & F University, is mainly engaged in the research and promotion of environmental quality, fruit quality and safety, apple quality improvement, fruit tree nutrition diagnosis, organic apple production, fertilization and fertilizer.
In April, the temperature gradually increases, the sap flow accelerates, the tree body accelerates, and enters the flower bud dew red, inflorescence separation, flowering, fruit setting and spring shoot growth period, which is the second important stage of fruit tree management throughout the year.
To this end, Shaanxi University of Continuing Education and Heyang County Association for Science and Technology jointly held an apple planting technology training meeting, and invited Liang Jun, a professor from the College of Horticulture of Northwest A & F University, to Yangjiazhuang Village, Tongjiazhuang Town, Heyang County, Weinan City, to explain the current orchard management related knowledge to local fruit farmers, and help fruit farmers run an "important stick" of orchard management and protection.
In the training process, Liang Jun suggested that at present, we should focus on pre-flowering double cutting, chemical flower thinning, auxiliary pollination, top dressing irrigation, wind disaster prevention, etc., so as to lay a solid foundation for apple harvest, stable yield and improve fruit quality.
Pre-flowering pruning: refers to the pruning of fruit trees from budding to flowering, the purpose of which is to improve the germination rate, increase the amount of branches and leaves, inhibit the apical dominance, ease the tree potential, adjust the amount of flower buds, and balance the relationship between growth and fruit. It mainly thins out too many and too dense flower branches, shrinks weak flower branches and axillary flower branches, and prunes off diseased and insect branches, dry branches and weak fruit branches that are missed in the winter pruning process.
Chemical thinning: It is a method of spraying certain chemicals during the flowering period of apple trees to make a part of the flowers fall off to achieve the purpose of thinning. Generally, the first spray of flower thinning agent is sprayed at the beginning of the apple tree's flowering, that is, when 80% of the central flowers are open, and the second spray is sprayed when 75% of the flowers of the whole tree are open during the full flowering period. For varieties with many axillary buds, it can be sprayed once at the end of full flowering, that is, when more than 95% of the flowers of the whole tree are open.
Commonly used flower thinning agents are: stone sulfur mixture at a concentration of 0.5-1 Baumé, or olive oil at a concentration of 30-50 g/L, or calcium formatate at 7-10 g/L. When spraying pesticides, a sprayer with good atomization performance should be selected, focusing on evenly and carefully spraying the flower parts.
Assisted pollination: It is one of the important factors to improve the yield of orchards, especially for orchards with large planting areas or complex planting environments. Manual pollination, bee pollination and spray pollination are all common and effective methods, and growers can choose the right method for their needs.
Manual pointing: Use pine nut powder or corn starch as filler to dilute the pollen, and then dip the pollen and point it to the stigma of each central flower. This method works best, but it is not suitable for large orchards, which is time-consuming and labor-intensive.
Bee pollination: Placing beehives on a farm or orchard can effectively promote pollen transfer and pollination.
Spray pollination: Pollination takes place around 40%-70% of the flowers. The pollen, sugar and borax are prepared into a suspension, sprayed with an ultra-low amount sprayer for pollination, and the pollen liquid formula is: 250 grams of sucrose + 5 kg of water + 10 grams of pollen + 5 grams of borax + 250 grams of milk, and then diluted to 15 kg.
Top dressing irrigation: At this stage, reasonable fertilization should be carried out according to the specific needs of fruit trees, and low-phosphorus balanced fertilizers can be used. At the same time, pay attention to keeping the soil moist, and you can use drip irrigation, sprinkler irrigation and other methods for irrigation. It is also necessary to beware of stagnant water, which can affect the growth of fruit trees.
Wind disaster prevention: The Loess Plateau is windy in spring, and attention should be paid to prevention, especially in dwarf orchards, which will make dwarf trees easy to break from the rootstock grafting joint. Wind during flowering can also affect pollination. Facilities such as windbreak walls, planting windbreak shrubs, or strengthening support poles to secure orchards should be installed.
Agricultural Science and Technology News, China Agricultural Science News Network Reporter: Gu Xing, Zhang Huan