What causes excessive vegetative growth in cowpeas (yardlong beans)?

1. Excessive growth at the seedling stage. The main cause of excessive seedling growth is excessively high temperature, especially excessively high nighttime temperature, which is even more likely to occur when respiration consumes too much. In addition, excessive nitrogen fertilizer and water, sowing too densely, and failure to transplant seedlings in time can also easily cause excessive seedling growth. Excessive growth at the seedling stage can be divided into the following four types:

1. The period from cowpea emergence to cotyledon expansion is the most likely to cause excessive growth. At this time, excessive growth is mainly due to sowing too densely and failure to remove the covering in time after emergence, which makes the seedlings too crowded.

2. Failure to lower the temperature in time after cowpea emergence can also easily cause the epicotyl of the seedlings to elongate excessively, resulting in excessive growth.

3. From cotyledon expansion to the 2-3 leaf stage in cowpeas, failure to thin the seedlings in time, or excessively high temperature without timely temporary planting (transplanting seedlings into pots), makes the seedlings excessively crowded and causes excessive growth.

4. After the seedlings recover from temporary planting and before field planting, excessively high soil and air humidity in the seedbed, too much nitrogen fertilizer in the nutrient soil, and failure to ventilate and provide light in time during management or to thin out crowded seedlings can also cause excessive growth.

Solutions:

1. Sowing density should not be too high, so as to avoid crowding of seedlings after emergence. At the same time, after about 30% of seedlings have emerged, remove the ground covering in time.

2. Thin seedlings and plant out in time.

3. Strengthen ventilation and light exposure, and control temperature and humidity. After the seedlings emerge and before field planting, ventilation and light exposure should be carried out, temperature and humidity should be reduced, low-temperature hardening should be strengthened, and excessive growth of the seedlings should be controlled.

4. Manage fertilizer and water reasonably. In preparing nutrient soil, attention should be paid to the amount of phosphorus and potassium fertilizer, and the amount of nitrogen fertilizer should be controlled. In the seedbed, strictly control water and topdressing. When topdressing is needed, do not apply nitrogen fertilizer alone.

5. Thin seedlings in time. About 20 days before field planting, seedlings often become excessively crowded. At this time, the seedlings should be moved appropriately so that large and small seedlings are separated, and the living space of each individual plant should be expanded.

6. Use chemicals to control excessive growth. Once excessive growth of seedlings occurs, in addition to taking the above measures, a 2000-2500 times dilution spray of 50% chlormequat can also be used.

2. Excessive growth of cowpea plants. The causes of excessive plant growth also include factors such as temperature, humidity, too much nitrogen fertilizer, or excessive nutrients.

Solutions:

1. Apply less quick-acting nitrogen fertilizer: during the cultivation of various crops, especially during the pod-setting stage, too much nitrogen fertilizer often causes excessively vigorous growth and severe flower and pod drop, resulting in excessive vegetative growth and insufficient reproductive growth. Therefore, it is better to apply less nitrogen fertilizer than too much;

2. Nutritional regulation: according to the property of humic acid foliar fertilizer and amino acid foliar fertilizer to control growth vigor at a certain concentration, combined with disease and pest control, adding hormone drugs such as mepiquat chloride and chlormequat has a good effect, and the fruit is uniform in shape and pure in color, with high yield;

3. Hoeing to cut roots: when plant growth is excessively vigorous, the “hoeing method” can be adopted. On the one hand, it increases soil aeration; on the other hand, it can cut off some roots, which is conducive to secondary roots growing downward;

4. Water frequently in small amounts: meet crop needs while reducing soil humidity;

5. Auxiliary measures such as shade nets to lower the temperature.