In 2006, Yuncheng's Dongzao region in Shanxi Province faced significant challenges with its winter jujube production. Common issues included a low number of flower buds, poor quality, heavy buds, small flowers, and a low fruit set rate. Some orchards were even left barren. A mid-July survey across eight key counties showed a 30-40% drop in yield compared to the previous year. This prompted an in-depth investigation into the abnormal flowering and fruit drop that was affecting the area.
**Causes of Abnormal Fruit Drop**
1. **Natural Factors**
(1) **Frost Damage**: In early April 2006, temperatures in Yuncheng rose sharply, peaking at 29°C. However, on the evening of April 11th, a sudden cold snap from Siberia brought snowfall to several areas, with snow depths reaching up to 15 cm. Other regions experienced heavy rain, and night temperatures dropped as low as 0°C. Frost occurred over several days, causing severe damage to budding jujube trees. Many farmers reported that frost damaged the buds, leading to delayed growth by about 15 days. The new buds were weak, pale, and lacked vitality, resulting in a 30% increase in flowering rates but poor fruit setting.
(2) **High Temperatures**: On June 15, Yuncheng saw extreme heat, with temperatures exceeding 37°C in several areas. The high temperature continued for several days, peaking at 42.2°C on June 16. Only after June 20 did moderate to heavy rains provide some relief. This heat stress disrupted nutrient accumulation in the trees, causing open flowers to fail to set fruit and young fruits to fall prematurely. The fruit drop rate reached around 80% in some areas.
(3) **Pest Infestation**: During the flowering period, the main pest was *Lycorma lucorum*. While farmers managed to control juvenile stages effectively, the timing of the infestation shifted due to weather changes. The hatching of the pests was delayed until early June, and many farmers overlooked the risk. After two light rains on June 2–3, the pest population surged, causing extensive damage to jujube buds. According to surveys, about 60% of the orchards suffered from this infestation, leading to severe losses.
2. **Human Factors**
(1) **Nutrient Deficiency**: Surveys revealed that 30% of demonstration parks had heavy fruiting in 2005, followed by empty branches and weak flower buds in 2006. This was due to insufficient fertilization—only a small amount of fertilizer was applied in spring 2006, while fall applications were also limited. As a result, the trees lacked nutrients, leading to yellowing leaves and premature fruit drop.
(2) **Poor Wound Healing**: Many farmers performed girdling, but improper techniques often damaged the xylem, preventing wounds from healing properly. This led to tree decline, yellowing leaves, and fruit loss, with some trees dying completely.
**Preventive Measures**
1. **Frost Protection**: Apply base fertilizer rich in organic matter, nitrogen, and phosphorus to improve tree resilience. Before expected frosts, spray antifreeze solutions such as 200-times diluted high-fat film or 100–200-times diluted hydroxymethyl cellulose. For already damaged orchards, use 5°Bé lime sulfur to promote recovery.
2. **Heat Stress Management**: At night, spray ash leaching solution (2.5 kg of grass ash per 50 kg of water, soaked for 15 hours). Rice vinegar can also be used to reduce drought stress. Ensure regular irrigation to maintain soil moisture and support young fruit development.
3. **Pest Control**: Establish monitoring points at village levels, assign dedicated personnel to track pest activity, and share timely updates. Strengthen preventive measures to avoid large-scale infestations.
4. **Improve Tree Nutrition**: Prioritize the application of organic or composted fertilizers to enhance tree health and productivity.
5. **Professional Girdling**: In concentrated jujube planting areas, ensure that girdling is carried out by trained professionals using correct techniques to avoid damaging the tree’s vascular system.
By addressing these factors, farmers in Yuncheng could better manage their jujube orchards and improve yields in future seasons.
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