Detailed Explanation of Key Scientific Planting Techniques for Plums

The plum is a temperate fruit with a very wide distribution range. Because of its strong vitality, it is cultivated in most regions of our country. Because its yield is very high, every year when the plum ripening season arrives, it can be seen everywhere on the market, and both its edible value and its functional properties are very strong.

Scientific Planting Techniques for Plums

1. Seedling selection. Choose plum seedlings with pure variety, complete root systems, vigor, plump buds, no quarantine objects, and no pests or diseases.

2. Field planting. The general spacing between plants and rows is 2.5 m × 4 m, and planting should be done before the buds sprout (preferably before April 20). Plums exhibit self-incompatibility, so a single cultivar should not be planted alone; different cultivars with the same flowering period should be planted at certain distances as pollinizer trees, at a ratio of 4:1 or 8:1.

Growing Conditions for Plums

The plum's temperature requirements vary by species and cultivar. Plums native to northern China, such as Jiaomen plum, Hongganhe plum, and Huangganhe plum, can withstand low temperatures of —35 to —40°C, while Furong plum and Sanhua plum, which grow in the south, have poorer adaptability to low temperatures. Xingmei plum originated in North China and has relatively strong cold tolerance. European plum originated in the southern Mediterranean region and is suitable for cultivation in warm areas. American plum is relatively cold-tolerant and can overwinter safely in Northeast China. The optimum temperature during the plum flowering period is 12—16°C. Chinese plum flowers relatively early, and in the North China Plain it is prone to frost damage that affects yield. However, if the orchard site is chosen correctly and the favorable conditions of the microclimate are used, frost damage can also be prevented or reduced. European plum flowers later than Chinese plum and can generally avoid the harm of early-spring frost.

Fertilization Techniques for Plums

1. Base fertilizer. Base fertilizer is the basic fertilizer that can supply plum trees with multiple nutrients over a relatively long period. It is generally dominated by slow-release farmyard manure, such as compost, barnyard manure, crop straw, green manure, and fallen leaves. Base fertilizer is best applied in autumn. For adult plum trees, apply 50—100 kg of farmyard manure per tree.

2. Topdressing:

Topdressing before flowering: 10 days before plum trees sprout, apply 0.5—1 kg of quick-acting nitrogen fertilizer or 25 kg of decomposed human excrement and urine per tree.

Topdressing after flowering: quick-acting nitrogen and potassium fertilizer should be applied in time to reduce physiological fruit drop. From late May to mid-June, apply 0.5 kg per tree.

Topdressing during fruit enlargement and flower bud differentiation: after physiological fruit drop and before the fruit enters the rapid enlargement stage, apply quick-acting nitrogen, phosphorus, and potassium compound fertilizer, 0.5—1 kg per tree.

Topdressing during the late fruit growth stage: apply fertilizer from the beginning of fruit coloring to the harvest period. This time, phosphorus and potassium fertilizers are the main focus, and quick-acting nitrogen fertilizer is best applied as a foliar spray at a concentration of 0.2—0.3%, combined with pesticide spraying.

Pest Control for Plums

1. Plum red spot disease. Control methods: thoroughly clean diseased leaves and diseased fruits from the orchard and burn them in a centralized manner. Pay attention to drainage to reduce orchard humidity. Before budding, spray 3~5 degrees Baume lime sulfur mixture. During the growing season, spray 50% carbendazim 600 times or 70% thiophanate-methyl 800 times, or 70% mancozeb 600 times every 10~15 days.

2. Plum fruit sawfly. Agricultural control: turn over the tree disk in early winter to turn larvae in the soil to the surface so they freeze to death. Chemical control: during the period when larvae leave the fruit, spray the ground with 25% phoxim microcapsule formulation, or 48% Lesben 200~300 times. After spraying, lightly rake the soil so the pesticide and soil are mixed evenly. When 80~90% of plum flowers have fallen, spray 5% beta-cypermethrin 2000 times, methomyl 2000~3000 times, or 2.5% deltamethrin 3000 times.

3. Plum fruit borer. Control methods: the key periods for controlling plum fruit borer are the peak adult stage and peak egg-laying stage of each generation and the period when the first-generation mature larvae enter the soil. Spray 90% trichlorfon 0.8% solution, 50% malathion 1% solution, or 50% dichlorvos. Before physiological fruit drop of plum trees, apply 50% phoxim 1%~1.5% solution once to the soil under the canopy. At the end of flowering (95% of flowers fallen), when young fruits are the size of wheat grains, spray the first application. Dichlorvos, decamethrin, fenvalerate, and fluvalinate may all be used, spraying once every 7~10 d. From the perspective of integrated control, biological agents such as Beauveria bassiana may also be used to treat the soil under the canopy. After autumn, fallen fruits should be swept up completely to reduce the source of insects the following year.

Plum planting techniques are still quite simple. When planting, we should choose high-quality seedlings for planting and observe whether their surfaces have insect holes; those with insect holes cannot be selected. Cultivar selection is also very important. In the north, cultivars with slightly stronger cold resistance should be selected, while in the south there are more choices.