Why do cowpeas go into "summer dormancy"? Causes and prevention measures

During cowpea cultivation and production, if the stems and vines grow too vigorously, they can keep flowering and setting pods continuously, but after one high yield, the plant becomes weak, the leaves turn yellow and drop off, the root system grows poorly, and few pods are set. This phenomenon is called summer dormancy. So what causes summer dormancy in cowpeas? How can it be prevented? Let's take a look.

I. Causes of summer dormancy

1. Sowing too late: This causes the plant to miss the suitable growing climate and temperature, and after the first yield peak, the newly sprouted flowering branches have few pods, which inhibits growth, so the second yield is lower.

2. Insufficient nutrients: After the first yield peak, the plant consumes a large amount of nutrients. If there is no sufficient fertilizer and water supply afterward, the plant will suffer from nutrient deficiency or premature aging, with no spare nutrients to grow new branches, and it stops flowering and setting pods, so there is no second yield peak.

3. Environmental factors: During the growth of cowpeas, if the early growth goes smoothly but the later stage encounters hot, rainy weather, this leads to excessive water accumulation in the field, resulting in poor soil permeability, which restricts or damages root growth and reduces absorption capacity, thus causing leaf drop and leaving the plant unable to produce new branches and flower and set pods.

4. Improper pruning: During plant growth, if pruning and pinching are not done in time, the plant will grow excessively, consuming a large amount of nutrients and causing summer dormancy.

II. Prevention measures

1. Sow at the right time: Cowpeas have a wide sowing window, and generally set pods during the cool autumn period, so the sowing time must be well controlled and determined according to the plant's growth period, so that it has a longer time to set pods and accumulates enough nutrients before pod setting. In addition, pay attention to density when sowing; it should not be sown too densely, to avoid affecting the plant's ventilation and light penetration, which would otherwise also cause summer dormancy.

2. Fertilization: Cowpeas themselves have nitrogen-fixing bacteria, so the amount of nitrogen fertilizer applied should be controlled and should not be excessive. When fertilizing, a moderate nitrogen supplement is enough, and phosphorus and potassium fertilizer should be applied additionally to keep the plants growing robustly and meet the needs of later growth. Generally, fertilizer should be top-dressed once each at the seedling stage and the harvesting stage. At the seedling stage, apply 15 kg of ammonium sulfate per mu as a top dressing, and at the harvesting stage, thin manure and urine fertilizer can be applied as a top dressing to prevent premature aging of the plants.

3. Strengthen field management: In the later stage of cowpea growth, pay attention to water control and just keep the soil moist. In summer, during the hot and rainy season, strengthen field drainage and waterlogging prevention measures to avoid excessive water accumulation that affects the roots, and afterward loosen the soil and remove weeds in time to increase soil permeability.

4. Carry out pruning and pinching: When the side branches below the first flower cluster on the main vine grow to 3 cm, remove them promptly, while the side branches on the first flower cluster should have their tips pinched off while keeping the leaves, generally keeping one leaf. In the middle and later stages of growth, keep two leaves, so that the side branches can be used to flower and set pods and increase yield. When the main vine grows to have 15-20 stem nodes, pinch off its tip to promote the emergence of side branches. Through such pruning and pinching, summer dormancy can be avoided.

The above are the causes of summer dormancy in cowpeas and prevention measures. We hope this helps you. To learn more about cowpea cultivation, please follow us.