What are the two major problems commonly seen in garlic cultivation?

In recent years, in the main garlic-producing areas such as Jinxiang, Juye, Cangshan, Zhongmu, and Kaifeng, quite a few problems have arisen from a series of causes including continuous cropping, poor management, and unscientific fertilization. They can be summed up in 9 words: "yellow leaves, dry tips, dead seedlings, low yield." The author now introduces to the broad ranks of agricultural technology extension workers and garlic growers the causes of the two most headache-inducing problems that have appeared in garlic cultivation in recent years.

Problem one: the garlic looks normal before winter, with a few yellow leaves and dry tips, but after green-up the garlic seedlings turn severely yellow, the yellow leaves and dry tips rapidly worsen, and after one round of fertilizer application, plants start dying. This phenomenon is the most common in the main garlic-growing areas, and in recent years it has occurred more and more severely. The causes of this phenomenon are many-sided, and the main ones are as follows:

1. Long-term excessive and unreasonable application of chemical fertilizers, combined with many years of continuous cropping (some plots have grown garlic for 30 consecutive years without a break), plus the fact that for more than the past ten years the soil has never been deep-plowed, with only a rotary tiller used to work the land, and in order to save fuel the rotary tillage quality is not high, with the tilled depth often only a little over ten cm. Valuing chemical fertilizers while neglecting organic fertilizers has led to soil compaction, acidification, and salinization. The suitable soil pH for garlic is 6.0-7.0; acidified soil often has a pH below 6.0, which is unfavorable for garlic growth. In addition, excessive use of chemical fertilizers severely disrupts the soil microbial balance, with a lack of beneficial bacteria, worsening soil-borne diseases, and weak stress resistance.

2. Too much nitrogen in the base fertilizer causes slight root burn, and the plants look normal at low temperatures before green-up; after green-up, as air and soil temperatures rise quickly, the damaged root system has a weak ability to absorb water and nutrients, and applying poor-quality fertilizer further irritates the injured roots, causing the garlic seedlings to quickly turn yellow, the dry tips to worsen, and in severe cases the plants to die.

3. Insufficient nutrient supply and excessively wet soil during the mother-clove degeneration period before winter can cause the yellow leaves and dry tips in garlic before winter. Around mid-November, garlic grown under plastic film begins mother-clove degeneration. During this period the root system continues to increase and elongate, the aboveground part continues to differentiate young leaves, the leaves gradually widen and lengthen, and the nutrients of the seed clove are slowly absorbed until exhausted, as garlic transitions from "heterotrophic growth" to "autotrophic growth." At this time the roots are short and few; if the nutrient supply is insufficient or the soil is too wet, causing poor aeration and a weak root system that absorbs water and nutrients poorly, garlic's nutrition will be "caught short," supply and demand will be unbalanced, and yellow leaves and dry tips will appear.

4. Damage from freezing in winter or from a late spring cold snap after the New Year.

5. Damage from underground pests such as garlic maggots. During the garlic growing period, except in winter, garlic may suffer from garlic maggot damage at any time; especially in years with relatively high temperatures, if some garlic farmers apply organic fertilizer that is not fully decomposed, garlic maggots will occur in large numbers. Garlic maggots bore into and feed on the false stem of the garlic plant, causing tissue rot and leaf yellowing, and in severe cases the plant dies.

6. Leaf and stem diseases, such as purple blotch, leaf blight, Phytophthora blight, and bacterial soft rot.

7. Herbicide phytotoxicity.

8. If spring is dry, not watering can also cause yellow leaves.

Problem two: yield has not made a breakthrough, and the proportion of large garlic bulbs has decreased. The author believes the main causes of this problem are four aspects: soil problems, seed problems, scientific fertilization problems, and whether pest and disease control (including leaf diseases, soil-borne diseases, and underground pests) is effective. Of course, climate is also one of the biggest aspects, but climate does not change according to human will and cannot be controlled by people. To sum up, the following aspects are all main reasons why yield has not made a breakthrough and the proportion of large garlic bulbs has decreased:

1. Continuous cropping: the land has not been deep-plowed for many years, the lower layer is too hard, aeration is poor, and at the same time continuous cropping worsens soil-borne diseases; all of these cause poor root growth. If the roots are not deep, the leaves are not lush, and of course the yield cannot rise.

2. Fertilization problems: emphasis on base fertilizer and neglect of topdressing, excessive use of chemical fertilizers, and a serious shortage of bio-organic fertilizer or microbial fertilizer. Because chemical fertilizers have a high nutrient concentration and are relatively expensive, with large amounts used year after year, costs remain high, but what they bring is a series of harms to the soil such as increasing compaction, acidification, salinization, and declining pH, along with poor roots, severe diseases, and no breakthrough in yield.

3. Severe deficiency of medium and trace elements.

4. Applying large amounts of quick-acting fertilizers as base fertilizer results in low utilization, serious loss and leaching, and nutrient deficiency and premature senescence later on, affecting yield. Because the nutrient requirement at the seedling stage is not great, quick-acting fertilizers also release quickly before the New Year, causing the garlic seedlings to stay green and grow excessively, so they are inadequately prepared for the severe winter; once a cold wave arrives, they will certainly freeze. Before overwintering, it is ideal for the seedlings to grow to 5 leaves and 1 heart to 6 leaves, with strong but not excessive growth.