A Preliminary Study on the Prevention Methods of Two Abnormal Garlic Conditions in Cangshan Garlic

Cangshan garlic is renowned worldwide for its large bulbs, thin skins, pure white and neatly arranged cloves, and its pungent, rich flavor, with excellent qualities such as aroma, pungency, and stickiness. In recent years, due to improper planting and management methods, two abnormal garlic conditions have appeared in Cangshan garlic production. One is that the garlic simultaneously produces small garlic leaves (commonly known as "little braids") when bolting, causing difficulties during the harvest of garlic scapes and affecting the yield and quality of garlic scapes. This condition accounts for 5%-10% of the total garlic. The causes are mainly two: one is excessive nitrogen fertilizer, and the other is the effect of low temperature. The other is excessive vegetative growth of the garlic, which neither bolts nor produces bulbs, resulting in total loss of individual garlic plants. This condition accounts for 1%-2% of the total garlic. The causes may be infection by multiple viruses and excessive nitrogen fertilizer.

These two conditions do not occur in patches or over large areas, but sporadically in garlic fields, so the causes are very complex. In the dozens of garlic-growing areas of Cangshan County, this situation exists across 13,300 hectares of garlic land, and once it occurs it cannot be treated. Therefore, prevention is the most important measure and currently the only option. Over several years, through production surveys of nearly a thousand garlic growers, a set of effective planting prevention measures has been summarized.

1 Selection and Storage of Garlic Seed

Cangshan garlic mainly has 3 cultivated varieties: Puke, Caosuan, and Gaojiaozi. Farmers mostly plant Puke garlic and Caosuan garlic, which have stronger growth vigor and adaptability, and are relatively cold-tolerant. Gaojiaozi has milder disease incidence than the first two, but poor adaptability. Regardless of which variety is planted, select vigorous, healthy garlic bulbs with large bulbs and uniform cloves, each bulb consisting of 6-8 cloves, and undamaged at harvest, as seed. After selecting the seed garlic, tie into bundles and hang to dry, but do not expose to blazing sun, and do not let it get rained on. Dry the seed garlic until the stems and leaves become soft and yellow and the outer skin of the garlic is dry, then braid into garlic braids and hang in a dry, ventilated room for storage. It is worth noting that seed garlic should be stored for 30 days before sowing at 15-18°C or 0-7°C, with air relative humidity of 75%-100%, and low temperature with high humidity will lead to the occurrence of abnormal garlic.

2 Land Preparation and Fertilization

The garlic root system consists of string-like fibrous roots, which are relatively fragile with poor vitality, with 80%-90% distributed within the 15-20cm deep plough layer. It prefers a fertile, loose soil environment, and neutral loam is suitable as the soil type. After the previous crop is harvested, plough and turn the soil promptly to conserve moisture, with a ploughing depth of about 20cm. After ploughing, harrow fine and level in both directions, achieving level ground and fine soil, loose on top and firm below, with no visible or hidden clods. Before sowing, conduct a soil fertility test to achieve balanced fertilization. When the soil nitrogen, phosphorus, and potassium contents are 140-150mg/kg, 23-47mg/kg, and 110-120mg/kg respectively (the organic matter content of Cangshan garlic fields is mostly on the low side), apply 100-120kg of bio-organic fertilizer per 667 sq m, and at the same time apply 1500-2000kg of decomposed human excrement and urine, applying chemical fertilizers as little as possible, especially nitrogen fertilizer. Generally, apply 40kg of ammonium bicarbonate, 50kg of superphosphate, 30kg of potassium sulfate, and 15kg of multi-element medium and trace element fertilizer for garlic per 667 sq m. It must be noted that the base fertilizer must be spread evenly.

3 Sowing

① Before sowing, break apart the cloves and select seed, removing those with damaged bud tips or rotten cloves, yellow cloves, insect-damaged cloves, and bare cloves, and selecting complete, medium-sized garlic cloves as seed. The larger the garlic clove, the more likely it is to cause the occurrence of abnormal garlic.

② The most suitable sowing period for Cangshan garlic is October 1-10, when the average daily temperature is 16-17°C and the soil temperature at a depth of 5cm is about 18°C. Be sure to sow on a sunny day, and do not blindly sow early.

③ The planting density is 40,000-50,000 plants per 667 sq m, with a row spacing of 17-19cm and a plant spacing of 5.5-6.5cm. The planting density should be somewhat greater than the traditional density. The furrow depth is about 10cm, and the sowing depth is 6-7cm. After sowing, level the bed surface with a rake, with a covering soil thickness of 4-5cm, which is 1-2cm thicker than traditional experience, and promptly water thoroughly for the first watering. After watering, cover with plastic film 1-2 days later than traditional experience, pressing down both sides with soil.

4 Field Management

① Cangshan garlic is generally cultivated with plastic film mulching. Be sure to release the seedlings at the right time. Once garlic is found to be sprouting and pushing up the film, promptly concentrate manpower and seize the time to release the seedlings, and water thoroughly after the seedlings emerge uniformly.

② Use manual weeding, and never use herbicides at any time.

③ After winter begins, when the temperature falls below 0°C, promptly water well for freezing protection, cover with some weeds to preserve warmth and protect the seedlings, and ensure safe overwintering.

④ After greening up the following year, water well for the greening-up water, and apply 15kg of urea per 667 sq m with the water. At this time, be sure to apply less nitrogen fertilizer, otherwise the condition will worsen. At the same time, guard against cold waves in early spring to prevent garlic from freezing and severe occurrence of abnormal garlic.

5 Other Measures

① In Cangshan garlic cultivation, it is best to rotate with @#@245@#@, and spinach and other crops can be interplanted.

② In controlling garlic diseases and insect pests, use chemical control as little as possible, and adopt methods such as selecting virus-free high-quality garlic seed, strengthening field management, improving plant disease resistance, promptly removing diseased and residual plant material, and reducing sources of disease in the field.

③ Garlic fields with aphids should be controlled promptly to cut off the virus transmission vector.

The above cultivation measures are only a partial summary of production experience, and can effectively reduce the occurrence of the two abnormal garlic conditions.