Detailed Guide to Shallot Cultivation Techniques: Key Planting Points in Keshan County

Shallots are a cash crop. They were formerly grown only in farmers' small garden plots, mostly for home consumption. In 2002, our county began introducing new shallot varieties, including "Acheng Shallot," "Tieli Shallot," "Fujin Shallot," and "Yi'an Shallot," and started demonstration planting in open fields. The returns were 8 to 10 times those of field crops. The public was very enthusiastic about growing shallots, and because of the good returns, the area kept expanding, and purchases by outside buyers also increased. For this reason, in 2007 the county government began with adjusting the cropping structure, seized the excellent opportunity, and vigorously promoted our county's shallot industry both inside and outside the province through various means, and made shallots a key extension program project. A good harvest was obtained, with an average yield of 1650 kg per mu, and many farmers became well-off. The shallot cultivation techniques of our county are introduced below:

I. Selection of Excellent Varieties and Seed Bulbs

Shallots are a tillering onion. Each plant produces 1 or more than ten irregularly sized bulbs by tillering (4 to 6 is optimal), copper-yellow in color, and tolerant of storage. The plants have extremely strong cold resistance, rarely flower and set seed, and are propagated by small tiller bulbs. Local varieties with strong cold resistance suited to our province's climatic conditions should be selected, such as "Acheng Shallot," "Tieli Shallot," "Fujin Shallot," and "Yi'an Shallot." Seed bulbs should be medium in size, plump and full, highly mature, not heat-damaged, and not frost-damaged.

II. Land Preparation and Fertilization

Autumn fertilization, autumn plowing, and autumn ridging should be adopted to help preserve soil moisture and allow timely sowing in spring. Apply 5000 kg of decomposed barnyard manure and 10 to 15 kg of diammonium phosphate per 667 sq m as base fertilizer, plow the land to mix soil and fertilizer thoroughly, and form ridges at 70 cm row spacing.

III. Timely Sowing and Reasonable Close Planting

Sow in time in early April. Before sowing, first rake the ridge surface into a flat platform, and sow 3 to 4 rows per ridge. With a plant spacing of 15 cm, sow in a staggered pattern to form "crooked seedling" arrangement, keeping 19057 to 25410 plants per 667 sq m. The seeding rate is 225 to 300 kg per 667 sq m. A sowing depth of about 3 cm is appropriate. If too deep, aboveground growth is excessive, the bulbs are not easy to swell, and they tend to become deformed. If too shallow, root growth is poor, the plants tend to lodge, and the bulbs are exposed and prone to splitting or turning green from sun exposure. In the early stage of bulb swelling, for plants with excessive tillering, it is best to remove some tillers and retain 4 to 6 tillers per plant.

IV. Field Management

1. For watering, adopt autumn ridging and timely early sowing in spring. Generally soil moisture is very good, so no watering is needed after sowing until emergence. After the seedlings emerge completely, water once thoroughly. When the soil surface is slightly dry, promptly hoe the ground to loosen the soil, carry out intertillage to preserve moisture, raise soil temperature, and control weeds. During the seedling stage, the principle should be to keep the soil neither dry nor wet. Entering the peak leaf-growth stage, water management should be strengthened. Water 7 to 10 days before the bulbs begin to swell, then restrain seedling growth to promote bulb formation and swelling. After the bulbs begin to swell, this is the key period for fertilizer and water management; watering should be frequent to keep the soil moist. As maturity approaches, watering should be gradually reduced, and watering should stop 5 to 7 days before harvest.

2. For topdressing, apply 20 kg of diammonium phosphate per 667 sq m once during the peak growth period (combined with watering); then apply 20 kg of potassium sulfate plus 15 kg of urea per 667 sq m once at the beginning of bulb swelling (combined with watering).

3. Chemical weed control. Because shallots are planted at high density, it is not easy to hoe and intertill for weed control. Chemical herbicides work very well. "Stomp" can be used at 200 g per 667 sq m, applied to the field before or after sowing.

4. Pest and Disease Control

(1) Insect pests are mainly leafminers and root maggots. To control leafminers, promptly clear weeds and dead leaves from the field and field edges to eliminate sources of the pests; once larvae are found mining, promptly spray a mixture of 800-times dimethoate solution and 2000-times decis solution. To control root maggots, the manure applied to the field must be fully decomposed, or the manure can first be mixed with a certain amount of insecticide. When onion flies (their adults) are numerous, promptly spray 2000-times decis, once every 7 days, for 2 to 3 consecutive sprays.

(2) Diseases are mainly onion gray mold and onion downy mildew, which can be prevented by spraying 1:1:150 Bordeaux mixture; once disease occurs, promptly spray 500-times chlorothalonil or 400-times sandofan.

V. Harvest and Storage

Shallots are generally harvested in early to mid-July. Harvesting should be done on sunny days, and after harvest they should be dried in place for 2 to 3 days, taking care to sun only the leaves and not the bulbs. This promotes after-ripening and dries the bulb skins. Then store them in a shady, ventilated, dry place. The yield per 667 sq m can reach 1500 to 3000 kg. Seed bulbs should be placed in woven bags by the end of October (before the ground freezes) and buried in the open field in pits 50 cm deep to overwinter safely.