Cultivation Guide for Cowpea Series

1, Sowing Time

Timely sowing. For the open-field cultivation, these varieties can be sown for three times a year. The main way to achieve high benefit is to arrange the sowing time within the best cultivation and benefit period. For the Spring cultivation, the sowing time is in middle and late Mar., covered with mulching film aftre sowing, and enter market in late May. For the Summer cultivation, the sowing time is in early May, and enter market in middle Jul. For the Autumn cultivation, the sowing is in early Aug., and enter market in early and middle Sept.

2, Requirement of Cultivating Circumstance and Conditions.

2.1, Temperature

The cowpeas are heat-resistant crops. The lowest sprouting temperature is about 8-12 degree centigrade, and the proper temperature is 25-30 degree centigrade. The suitable temperature for sowing is about 20-25 degree centigrade, and 25-28 degree for blossom and fruiting. These varieties are more resistant to high temperature, and some of them will normally grow, blossom and fruiting under about 33 degree centigrade condition. The cowpeas are sensitive to low temperature. The growth will be restrained when the temperature is bellow 10 degree centigrade, frosted bellow 5 degree centigrade and die in zero degree centigrade.

2.2, Illumination

The cowpeas belong to short-day crops, but most of the varieties do not strictly require the time of illumination. Shorten the illumination time will forward the blossom and fruiting, and lower the first blossom node. The plants require sufficient illumination in both blossom and fruiting period, otherwise, it will causes dropping of flowers and pods.

2.3, Moisture

The cowpeas have deep root system, and the water absorbing power is strong, and the transpiration amount is small, so they are more drought-resistant. The plant requires proper amount of moisture in growing period. But when the soil moisture is too high, it will easily causes yellowing and dropping of leaves, even root-roting, death of seedling and dropping of flowers and pods, and it also goes against the activity of root nodules.

3, Season of Cultivatin and Selection of Varieties

For most areas in south China, the cowpeas can be cultivated from Spring through Fall. The seeds can be sown when the soil temperature is stably above 10-12 degree centigrade. To lengthen the supplying period, sow the seeds of same variety or different varieties by stages, to cultivate early in Spring or tardily in Autumn.
 
For the cultivation in Spring, it is suggested to select varieties such as Jinlubao Cowpea, Taiwan No. 8 Cowpea, Productive-Quality No. 22 Cowpea, Taiwan Small-Five-Leaves Cowpea, Zhengyuan Precocious King Cowpea, Shanyou No. 4 Cowpea, and so on.
 
For Summer cultivation, it is suggested to select varieties such as Karachi Cowpea, Santoni Cowpea, Hongkong Oil-Green Cowpea, Summer-Treasure Productive No. 3 Cowpea, and so on.
 
For Autumn cultivation, all the varieties of Linong are basically suitable for sowing.

4, Cultivation Techniques

4.1, Transplanting in Spring Cultivation

For Spring cultivatin, transplanting after culture of seedling will ensure the full stand, and promote precocity and increase yield. Culture seedlings in high plastic tunnel or low tunnel, and arrange sowing time according to different cultivation modes.
 
For cultivation in low tunnel, culture the seedlings in middle to late March, set the plants in tunnels at the beginning of April, and harvest from the middle to late May to middle July. For cultivation with ground film, culture the seedlings in late March to the beginning of April, set the plants in open-field in middle April, and harvest in early June to middle August.
 
Before sowing, select seeds carefully, then sun the seeds for 1-2 days. It usually does not need sprouting. For to protect the root system, it is better to use nutrient pot or nutrient clod to culture seedlings. Sow 3-4 grains of seeds into one pot, water the soil to keep moist, and then build up low plastic tunnels covered with thin films. From germination to transplanting, maintain the seedbed temperature in about 20 degree centigrade, not higher than 25 degree or lower than 15 degree centigrade. Keep the seedbed soil moist, pay attention to the ventilation, strictly prevent attack by cold wind and frost, and improve the illumination condition, so as to culture strong seedlings.

4.2, Preparation of Soil and Supply of Base Manure

As the root system of cowpeas is deep, it is resistant to barren soil and drought, but not to rain and waterlogging. The cowpeas are widely adaptable to soil. Avoid continuous cropping, otherwise the plants will be invaded by diseases easily. Because the planting density is high, and the vegetative growth and reproductive growth process at the same time, it requires abundant quantity of fertilizer. Along with ploughing and preparing of field, supply per acre of field with 12000-18000kg of finished organic manure such as human excreta or pig and duck dung, adding 180kg of calcium phosphate and 450kg of wood ashes, 30-600kg of potassium sulphate, or 180-240kg of compound fertilizer. Prepare the soil carefully and form ridge, mainly by high one. Generally, the ridge is about 1.4m wide including ditch and 17-20cm high, planted in two rows. For Spring cultivation, it is usually cultivated with mulching film. After forming ridge, cover them with milching film. The films should be strained and covered flat, clinging on ground.
4.3, Plant Setting or Direct Sowing
For Spring cultivation, it is usually cultivated by transplanting after culture of seedling. It is better to choose young seedlings and set earlier, which is call ‘Planting Buds’ by farmers, that means to set plants when the first pair of main leaves are still unfold after germination. If for culture of seedling in nutrient pot, the transplanting can be delayed to the appearance of the 2nd-3rd compound leaf. For open-field cultivation, it is better to set in middle and late April. Generally, the width of the ridge including ditch is about 1.4m, planted in two rows, each hole planted in 2-3 plants, and the planting distance is about 24-27cm. Cultivate 19200-22400 plants per acre. Choose sunny and warm day to transplant. Water the root with clear water or 10% human excreta, to benefit the revival.
 
For Summer and Autumn cultivation, it usually cultivated by derect sowing. If the soil is droughty, irrigate it first. Sow 4-5 grains of dry seeds into each hole, in 2-3cm deep, and then press tightly. Before seedlings coming up of earth, cover the ridge with sunshade net, to benefit the germination. It costs about 12kg of seeds per acre. For Summer cultivation, the growth and development is in the seasons full of high temperature, highlight and rainstorm, the fruiting period is short, and the fruiting fastigium comes within the high temperture period which is full of frequent rainstorm, these will result in low and unstable yield, and increasing the difficulty in field management. Pay attention to the excessive growth of stems and leaves, no podding and abnormal pods phenomenons in early stage, and to prevent senilism in the late period.
 
In addition, it is the outbreak period for diseases and pests in Summer seasons. Therefore, it is better to arrange the sowing time rationally, select disease-resistant varieties, and cultivate on high ridge with deep ditch, so as to abate the occuring of diseases and insect pests, and to ensure the normal growth.
4.3.1, Selection and Preparation of Field and Supply of Base Manure
A, Selection of Field
The cowpeas fear continuous cropping as other beans, because it will retains abundant of pathogens and pests in the fiel which is continuously cropped by cowpeas. After the germination of seedling, the diseases will spread rapidly, so do the insect pests, therefore, the loss of yield will be serious. After the pods are harvested, the radix of diseases and pests sources will inceases. If the field is still cultivated with cowpea by the coming year, the damages of diseases and insect pests will be more serious, resulting in the increase of supplying amount and times of pesticide. In that case, it will be difficult to make sure that the content of toxic substance of pods is not out of limit. Therefore, the cultivation of cowpea should be alternated with shallot and garlic, or rotated with poaceae crops for 2-3 years, which will substantially reduce the occurrence rate of diseases and insect pests in the field.
 
Cultivate on the field which has fertile soil with well irrigation and drainage, and is not continuous cropping for more than one year, so as to lay the foundation for reducing the use of pesticide and pollution to the environment.
 
B, Preparation of soil
In Summer, the ploughing depth should be above 30cm, and sun the soil for 2-3 days. Then prepare the soil carefully, to make the field flat and the soil in small pieces, and then form the ridge regularly.
 
C, Supplying of Base Manure
For each acre of field, supply 18000-30000kg of finished pollution-free farmyard manure, 180-300kg of calcium super phosphate, 900kg of wood ashes, and 24000kg of BYM, or 360kg of NutriSmart 301 and 180-240kg of ammonium hydrogen carbonate as base manure. After forming ridge regularly, furrow in the enter ridge and supply the manure above into the chimbs. This will reduce the loss of fertilizer when washed out by rains or leekage, concentrate the nutrient for the growth, and increase the use ratio of fertilizer.
4.3.2, Selection of Varieties
The requirement of variety for Summer sowing is that, high podding rate, resistance to high temperature, long period of podding, high yield and commodity character, and strong resistibility.
4.3.3, Deep Ditches and High Ridge
For Summer cultivation, as it rains a lot, if for ridge cultivation mode, choose deep ditch and high ridge. The ridge should be more than 15cm high, and about 30-40cm wide including 25-30cm deep ditch. This complement of ridge and ditch will helps to timely drain the waterlogging, irrigate to fight against drought, promote the growth of root system, profit the absorbing of water and fertilizer, provide the plants with moisture and nutrient in time, and ensure the abnormal growth
4.3.4, Timely Sowing
The timely sowing of cowpea in Summer cultivation is critical to the achievement of high yield and benefit. Therefore, the best period for sowing, growth and development, and harvest should be combined organically. Try best to sow seeds before the increasing of rain, so as to win as much suitable podding time as possible. For Summer cultivation, it is usually sown from May to Jul., and supply for the low season market in Aug. and Sept., as to achieve good benefit.
 
The sowing principles are as follow. The variety which are middle late maturity is sown first, and then the precocious ones. The seeds are generally sown in dry state. The sowing requires sufficient moisture, if not, it will causes poor germination and rotten buds. The planting distance is about 60cm by 35cm, in two rows with 2-3 plants in each hole, about 21800 plants per acre.

4.4, Field Management

4.4.1, Complementary Planting and Thinning of Seedling and Cultivation
For derect sowing and transplanting, after the germination or suvival of seeldings, thin or complementarily plant the seedling in time. The complementary planting of seedling should be done from the unfolding of the first compound leaf to the second one. For thinning, retain 3 plants of strong seedlings in each hole, and thin the rest ones. After the complementary planting, pour human excreta to ensure the survival. From the survival after setting or trimness of seelding to the building of shelf, cultivate in time to benefit the soil breath, so as to support the growth of root system and occuring of rhizobium.
4.1.2, Building of Shelf, Leading of Vines and Training
When the plant outgrows 5-6 pieces of leaves, the shelf can be built. The shape of the shelf can be A-bracket or better be inverse A-bracket. The intersection height of the bamboo stickers is about 0.8-1.0m, with one third of height bellow the intersection and two third above. This will benefit the ventilation and illumination, and also picking. When the vines grow to be 30cm long, lead them onto the shelf artificially in time in the sunny day afternoon. The training includes wiping out buds and low side branches, top removal of chief vine, and wipping off old leaves. Wipe out the branches which are bellow the first inflorescence on the chief vines. When the chief vine spreads to the top of the shelf, the top removal can be done, and also to the side branches after the podding in late period. In the growing acme, cut off the old and sick leaves in low layers, so as to reduce nutrient consumption, improve ventilation and illumination, and promote the blossom and fruiting.
4.1.3, Top Dressing and Watering
Before blossom and podding, the cowpeas do not require much fertilizer and water. If the fertilizer and water is supplied too much, the vines and leaves will grow prosperously, and the blossom and podding node will be higher, resulting in reducing the quantity of inflorescence and side vines, and easily forming unfruitful vines in middle and low layers. Therefore, the fertilizer and water supply must be controlled in the early period, to promote the forming of first inflorescence, increase the inforescence quantity on chief vines and reduce the occuring of side vines. Entering the blossom and podding acme, increase the supply of fertilizer and water, to promote growth, more blossom and podding. In harvest acme, as the numbers of rootnodules reduce, and the activity will also decline, the plant require more fertilizer and water, so the top dressing should be heavy, so as to promote the forming of side vines and buds, and blossom and podding, prelong the picking period, and increase yield. The management of fertilizer and water is as follow. Control at first and then promote, to prevent vines and leaves from excessive growth, and also senilism. The top dressing should mainly by finished human excreta, nitrogen and potash fertilizer. The first time of top dressing can be done after the survival of seedlings in transplanting cultivation, or germination of seedling in derect sowing cultivation. For each acre of field, supply in 4500kg of finished human excreta. The second time of top dressing is done before building the shelf, supplying 6000kg of finished human excreta per acre. After the first inflorescence pods, in every 7 days, supply fertilizer heavily by pouring human excreta or fertilizer by water, and 60kg of urea and 30kg of potassium sulphate, or 90kg of compound fertilizer per acre. In the whole growing period, top dressing for 4-6 times.
 
From Jul. to Sept., it is the blossom and fruiting acme for the Summer and Autumnn cowpeas, and the plant is in abundant need of moisture. If run into high temperature and droughty weather, the watering times and quantity should be increased, to keep the soil moist. For to cool down the earth temperature and increase the temperature difference from daytime to night, the watering is better done at nightfall, and make sure not be at noon. The watering should not be flooding, so as to prevent waterlogging in the filed and impacting the growth and development.

5, Prevention and Control of Diseases and Insect Pests

For Autumn cultivation, the main diseases are rust, stalk break and virus diseases. They are caused mainly by high temperature and humidity. Prevent and control in the early stage. For rust disease, spray 1000 times of triadimefon or 500 times of moncozeb for control. For stalk break disease, spray 1500 times of procymidone, phosethyl Al(Miconazole nitrate), or diethofencarb for control. For virus disease, the control is mainly by prevention. In high temperature weather, spray oxadixyl mancozeb on leaf once every 7-10 days. The damping off disease occurs mainly in the seedling stage, spray tachigaren on leaf for control. And in the late period, use 400 times of fosetyl-aluminium or 200ppm of streptomycin for root pouring.
 
The main pests includes aphid, cotton bollworm, pod borer, and so on, and the red spider will sometimes cause damage in droughty climate. Use acetamiprid, imidacloprid, fenvalerate, 800 times of 75% chlorothaloril, or 1500 times of 50% iprodione WP for control. Or spray 800 times of 25% meothrin for control, or use high-efficiency and low-toxin pesticide such as BT emulsion, 7216, insecticidal bacteria, or BT-781 for control

6, Harvest

The harvest period of cowpea is short and concentrated. If harvet too late, not only the quality will be aged, it will also speeds up the senilism of the plant. Generally in 10-12 days after blossom, it is the suitable harvest period when the pods are full, with scrisp tissue, not blanch, and the beans are not yet appearring. The yield is about 7200-15000kg per acre.