Analysis of the Causes of Cowpea Summer Decline and Preventive Measures

During cowpea cultivation and production, if the stems and vines grow too vigorously, they can flower and set pods continuously, but after one heavy yield, the plant grows weakly, the leaves turn yellow and drop, the root system grows poorly, and pod setting decreases. This phenomenon is called summer decline. So what causes cowpea summer decline? How should it be prevented? Let's take a look together.

1. Causes of Summer Decline

1. Sowing too late: This causes the plant to miss the suitable growing climate and temperature. After the first yield peak, the newly sprouted flowering branches bear 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 surplus nutrients to grow new branches, and it stops flowering and setting pods, so there is no second yield peak.

3. Environmental factors: During cowpea growth, if the early stage grows smoothly but the later stage encounters high temperature and rainy weather, excessive water accumulation in the field will result, leading to poor soil permeability, which restricts or damages root growth and reduces absorption capacity, thus causing leaf drop, and the plant is unable to produce new branches or 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 decline.

2. Preventive Measures

1. Sow at the right time: Cowpea has a wide sowing window. Generally, it sets 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, so as not to affect the plant's ventilation and light penetration, which would otherwise also cause summer decline.

2. Fertilization: Cowpea itself has 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 sufficient, and more phosphorus and potassium fertilizer should be added to make the plant grow robustly and meet the needs of later growth. Generally, fertilizer should be top-dressed once each during the seedling stage and the harvesting stage. During the seedling stage, apply 15 kg of ammonium sulfate per mu as a top dressing; during the harvesting stage, thin manure and urine fertilizer can be applied as a top dressing to prevent premature aging of the plant.

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, field drainage and waterlogging prevention measures should be strengthened to avoid excessive water accumulation affecting the roots. 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 in time. For side branches on the first flower cluster, keep the leaves and pinch the tips, generally keeping one leaf. In the middle and later stages of growth, keep two leaves. In this way, the side branches can be used to flower and set pods, increasing yield. When the main vine grows to 15-20 stem nodes, pinch its tip to promote the emergence of side branches. Through such pruning and pinching, summer decline can be avoided.

The above are the causes of cowpea summer decline and preventive measures. We hope this helps you. To learn more about cowpea cultivation, please stay tuned to us.