After the plum rain season ends in the south, high temperatures strike: how should we cope with the scorching summer?

This year, after the plum rain season ends in the Jiangnan region, sustained high temperatures arrive, and most vegetables in the fields are prone to sunscald, stunted growth, pollen abortion, flower and fruit drop, and other issues. Technical countermeasures should be strengthened to ensure the safe production of vegetables during the high-temperature period.

In vegetable plots with good shade and cooling facilities, make full use of trellises covered with shade nets and multifunctional light-blocking film to reduce sunlight transmission and lower the temperature. For temporary shading, old film and other materials can be used to cover and cool the plot. Moisture-tolerant vegetables such as celery and water spinach can have misting facilities turned on at midday to cool down, but one should not simply rely on misting to water them. For high-end rare vegetables, start water curtain cooling. For conventional vegetables, watering in the morning and evening can be combined to lower soil temperature and ensure root vitality. Aquatic vegetables such as lotus root and arrowhead should maintain a shallow water layer to promote underground growth.

Choose heat-tolerant varieties. In summer, market demand for leafy greens is high, so idle land can be used to hurry-plant a batch to increase production and income. For example, for baby bok choy, choose heat-tolerant varieties such as Huaguan, Huawang, Xiadi, Dongfang 56, Dongfang 18, and Rehuo No. 9. Amaranth, spinach, water spinach, and others should also preferentially use varieties with strong heat tolerance, moisture tolerance, and stress resistance to reduce high-temperature physiological disorders.

Optimize cultivation methods. Reasonably arrange intercropping and relay cropping of vegetable varieties of different heights. For climbing vegetables such as loofah, bitter gourd, and pumpkin grown on trellises, make full use of the open space below to sow shade-tolerant vegetables. For stem- and leaf-use tall-stalk vegetables, reasonably increase planting density so that natural shading improves yield and quality. When pruning over-summer tomatoes, leave 2 to 3 leaves on the topmost fruit cluster. For cabbage, cauliflower, and others, after they form heads, remove outer leaves and cover the head. For melon vegetables such as pumpkin and winter melon, after fruiting, straw can be placed on top and underneath to prevent sunscald from causing fruit rot.

Meticulous management of fertilizer and water. During high-temperature periods, vegetable watering should be thorough. When watering with misting facilities, inspect frequently to prevent high surface humidity while the lower roots lack water. Watering should be done when “the weather is cool, the soil is cool, and the water is cool,” and well water should be preferred as the water source. Do not flood irrigate, to prevent physiological water shortage. Fertilization should be combined with watering, using water to regulate fertilizer and improve fertilizer use efficiency. Appropriately reduce the concentration of foliar fertilizer sprays and increase the amount of water used. In addition to spraying potassium dihydrogen phosphate, superphosphate, and others, appropriately increase spraying of 0.1% zinc sulfate or copper sulfate solution, which can improve plant heat resistance and enhance resistance to fruit cracking and sunscald.