Key Production Techniques for Green Food German Bunching Onion

1 Base Conditions

The production base for green food German bunching onion should be selected in areas with unpolluted air and a good ecological environment, away from industrial and mining areas, main highways and railway lines, and avoiding the influence of industrial and urban pollution sources. The environmental quality should comply with the Class I standard listed in the National Ambient Air Quality Standard GB3095-82. At the same time, the soil and water resource conditions should be suitable for high-quality, high-yield and sustainable production of German bunching onion.

2 Variety Characteristics of German Bunching Onion

German bunching onion is a thermophilic plant, relatively heat-tolerant but not cold-tolerant, with an optimum growth temperature of 22-24°C. In winter when it snows or the temperature is relatively low, the aboveground part dies back and the plant enters dormancy; when the temperature rises in spring, new shoots can sprout and continue to grow. It is suitable for slightly acidic (pH 6.5-7.5) loam or sandy loam; clayey soil is more favorable for bunching onion to safely pass through the hot summer. German bunching onion likes moisture and avoids dryness, and the field must be kept moist regularly.

3 Seed Selection

Seeds harvested in the previous autumn and winter should be selected. The seed plumpness and purity should reach 97%-98%, the purity level should be above 95%, and the germination rate should be above 80%. The selected seeds should be sown in spring or summer of the same year to help cultivate strong seedlings.

4 Seed Treatment

(1) Determine the seed germination rate before sowing. Sowing in the field can be carried out only when the germination rate is about 80%. Seeds with poor germination vigor should not be used, so as to avoid failure of seedling emergence in the field and affecting the sowing season.

(3) Soak the seeds in a 0.2% potassium permanganate aqueous solution at room temperature for about 30 minutes, which has the effect of killing pathogens attached to the seed coat and helping drought-resistant emergence.

5 Seedling Raising

5.1 Seedbed Preparation

Select sandy loam with loose soil texture, rich organic matter, flat terrain and convenient drainage and irrigation. Apply 45-60 t of decomposed organic fertilizer and 750 kg of ordinary superphosphate per hectare, plow deeply and harrow finely, level and make beds; the bed length is 10-12 m and the width is 1.5-1.7 m.

5.2 Sowing

For small-area seedling raising and transplanting. When sowing in January-February in spring, small arched sheds covered with film are needed for seedling raising; when sowing in March-April in summer, arched sheds covered with shade nets are needed for seedling raising, so as to prevent sunlight from scorching young buds and affecting emergence. After sowing, cover with a little soil and irrigate fully so that the soil absorbs water and reaches a completely saturated state.

5.3 Seed Rate

Each hectare of field requires 3.75-4.50