Causes and Control Methods of Hollow Main Stems in Broccoli
Broccoli, also known as green cauliflower, is suitable for growing under cool climate conditions. Its produce is tender in texture, unique in flavor and rich in nutrients, especially very high in vitamin C, making it a fashionable high-grade vegetable. Because of the higher altitude in the mountainous areas of Lantian County, the summer climate is cool and humid with few pests and diseases, making it suitable for broccoli growth, especially...
The hollow main stem of broccoli, which does not rot, is formed due to physiological disorder. If the variety selection and planting management are improper, causing physiological disorder in the plant, hollow stems will form, seriously affecting the quality and commercial value of the marketable curd and causing losses.I. Symptoms of hollow main stem
The hollowness mainly forms at the curd maturity stage. Initially, several small oval gaps form within the stem tissue. As the plant grows and matures, the small gaps gradually expand and connect into a large gap, causing the stem to form a cavity; in severe cases the cavity extends to the flower stalk. The surface of the cavity becomes lignified and turns brown, but does not rot, and no pathogens can be detected in the discolored tissue.
II. Causes of hollow main stem
1. Excessive plant and row spacing during planting and excessive nitrogen fertilizer application, especially during the curd growth period, cause the plant to grow too fast, which easily leads to hollowness.
2. Water shortage or improper watering during the vegetative growth period and the curd growth period easily causes hollow stems.
3. Broccoli is a cool-loving crop, with a suitable growing temperature of 15-22°C. If the planting season is arranged improperly and the curd growth period encounters high temperatures (above 25°C), the curd grows too fast, which easily causes hollowness.
4. Severe boron deficiency in the field can induce changes in the cell wall structure of the stem tissue, causing degradation of the stem tissue, accompanied by a lignification process, resulting in hollow formation.
5. Different varieties have certain differences in susceptibility to hollowness. Some varieties have wide adaptability and are not prone to hollowness, while some varieties are prone to hollowness.
III. Control measures
1. Choose varieties that are not prone to hollowness.
2. Sow at the right time, cultivate strong seedlings, transplant at the right time, and stagger the curd growth period to avoid high-temperature weather.
3. According to the characteristics of the variety used, plant at a reasonable density. The suitable plant spacing is 30-45 cm, and the row spacing is 60-70 cm.
4. Fertilizer and water management. Water management: keep the soil alternating between dry and wet, generally requiring watering every 5-7 days. Fertilizer management: on the basis of applying sufficient base fertilizer, apply 6-8 kg of nitrogen fertilizer per mu with watering, following the principle of small amounts applied multiple times, and increase the application rate of phosphorus and potassium fertilizer during the curd growth period. For boron-deficient soil, apply 0.5 kg of boron fertilizer per mu as base fertilizer, then use another 0.5 kg as topdressing or for root irrigation.
5. Harvest at the right time. Harvesting can be done 10-15 days after the curd appears. If too early, the curd has not fully grown and the yield is low; if too late, hollow stems easily form, and the curd easily becomes loose with withered buds, losing its commercial value.