Cowpea is not suitable for continuous cropping. It is best to choose a field that has not been planted with bean crops for three years. Cowpea field should be plowed early and turned deep, so as to achieve fine soil preparation, improve soil water and fertilizer conservation ability, improve soil structure and improve soil fertility. The rhizobia of cowpea are poorly developed, and their nitrogen fixation ability is weak in the early stage of plant growth. In order to promote the early growth and development, we should apply enough organic fertilizer as base fertilizer, and increase the application of phosphorus fertilizer can obviously increase the yield of cowpea. Amount of base fertilizer per 667m: more than 5,000kg of organic fertilizer, 25-30kg of calcium superphosphate, 50-75kg of plant ash or 0/0-20kg of potassium sulfate/kloc. Before deep ploughing, apply slow-acting fertilizer to the lower soil, and then apply fully decomposed quick-acting fertilizer to the surface soil when preparing the soil for border. Before planting, prepare the soil and build a high compartment with a width of 1.3m and a depth of 25-30cm. Spraying a proper amount of herbicide, and immediately covering with plastic film.

(2) Cultivate strong seedlings

Spring cowpea, especially early spring cowpea, has low temperature and slow germination after direct seeding. In case of low temperature and rainy weather, seeds are easy to mildew and seedlings are not good. Therefore, proper seedling raising can also advance and extend the harvest period. Cowpea can be raised in cold bed or nutrition plate in early spring. In Sichuan, seedlings are sown around the vernal equinox 1 week, and cold bed seedlings are transplanted (such as hotbed seedlings and large seedlings can be transplanted for early cultivation). After careful selection, the seeds are sown on the seedling tray, which is filled with loose materials such as garden soil, sawdust and cottonseed hull. Sow every three seeds together with a spacing of 3-4 cm. Before sowing, water them, cover them with a layer of soil, line them up and cover them with plastic film. Pay attention to seedling management, don't uncover the film before it is unearthed. From excavation to transplanting, the temperature in the film should be kept at about 20℃, and the minimum should be not lower than 5℃, and it should be kept moist at all times to avoid excessive humidity and excessive growth. Usually need ventilation, but also pay attention to regular ventilation, so that seedlings grow neatly and vigorously after transplanting.

(3) Colonization

Seedbed seedlings are usually planted before the development of the first compound leaf, and in sunny and warm days. Cut the plastic film with a blade and plant it. After planting, the pores around the seedlings are closely covered with fine soil.

(4) Site management

① Top dressing Cowpea does not need too much fertilizer and water before it blooms and pods. For example, if there is too much fertilizer and water, the leaves of vines will grow vigorously, the number of flowering and podding nodes will increase, the number of inflorescences will decrease, the lateral buds will germinate, and empty vines will be formed in the middle and lower parts. Therefore, it is appropriate to control fertilizer and water to inhibit growth in the early stage. When plants bloom and bear pods, it is necessary to increase fertilizer and water to promote growth, and bloom and bear pods more. At the early stage of pod harvest, more fertilizer and water are needed. If fertilizer is removed and dehydrated, flowers and pods will fall off. Therefore, it is necessary to continue topdressing, promote flowering, prolong harvest and increase yield. The amount of topdressing is about 1 0,000 kg of human excrement, 3 kg of urea,10.5 kg of calcium superphosphate and 7 kg of potassium chloride. It is applied in early July, and the film is still covered after application until the harvest is over.

(2) When pruning plants and starting to pull vines, set up scaffolding and pull the vines to the herringbone frame. After scaffolding on vines, bind 1 ~ 2 times. When the lateral buds at the base of the plant grow to about 65,438+00 cm, all of them are removed, and when the lateral branches at the middle of the plant grow to 3-4 nodes, 2 nodes are left for coring; When the plant grows to the top of the scaffold, pick the tender branches and grow the upper side branches, leaving two nodes for coring.

(5) collecting and preserving seeds.

When the tender pods are fully developed and the seeds are just exposed, they can be harvested. Cowpea has more than 2 buds per inflorescence. At first, it opened two flowers and produced two pods. Later buds can also blossom and bear pods. Therefore, the remaining buds should not be damaged during harvesting to facilitate pod setting. You can leave fruit pods about 1 cm for harvesting, and don't hurt the flower buds at the base. Topdressing 1 time at the late harvest stage can make these buds blossom and pod, and make them harvest 4 ~ 5 times more.

Cowpea seeds should be left in the base and middle pods of the disease-free plants, and the inflorescence should bear paired pods neatly. If the pod has the characteristics of this variety, the seeds should be picked in time and harvested when the pod turns yellow and soft.