Technical specification for scientific fertilization of cowpea

Cowpea (scientific name Vigna unguiculata), commonly known as carob beans, ginger beans, beans, hanging beans. Cowpea is divided into two kinds of cowpea and rice, belonging to leguminous plants. Cowpea is a leguminous annual plant. There are three kinds of stems: dwarf, semi-tendril and tendril. Southern cultivation is dominated by tendrils, followed by dwarfs. Annual twining herbs of the family Papilionaceae, having 3 leaflets, the terminal leaflet rhomboid-ovate, 5 - 13 cm long and 4 - 7 cm wide, sharply pointed at tip, subrounded or broadly cuneate at base, glabrous on both surfaces, lateral leaflets obliquely ovate; stipules ovate, ca. 1 cm long, spreading downward into a short distance. Calyx campanulate, glabrous; corolla lilac, ca. 2 cm long, upper part of style with yellowish hairs. Pods linear, pendulous, up to 40 cm long. The flowering period is from June to September.

Morphological characteristics of cowpea

Annual twining, herbaceous vines or suberect herbs, sometimes apically twining. Stems subglabrous. Pinnately compound leaves 3-foliolate; stipules lanceolate, ca. 1 cm long, insertion decurrent into a short spur, lineate; leaflets ovate-rhombic, 5-15 cm long, 4-6 cm wide, apex acute, margin entire or subentire, sometimes lilac, glabrous. Racemes axillary, long pedunculated; flowers 2-6 clustered at the top of the inflorescence, often fleshy glands between pedicels; calyx light green, campanulate, 6-10 mm long, teeth lanceolate; corolla yellowish white and slightly purple, ca. 2 cm long, each petal with peduncle, flag oblate, ca. 2 cm wide, apex slightly concave, base slightly auriculate, wings slightly triangular, keel slightly curved; ovary linear, hairy. Pods pendulous, erect or obliquely spreading, linear, 7.5-70 (90) cm long, 6-10 mm wide, slightly fleshy and swollen or firm, many-seeded; seeds oblong or cylindric or slightly reniform, 6-12 mm long, yellow-white, dark red or other color. The flowers bloom from May to August.

The leaves are trifoliate, 20~25cm long pedicels are sprouted from leaf axils, 2~4 pairs of flowers are born at the tip, white, red, lilac or yellow, generally only two pods are produced, the pods are slender, and vary according to varieties, about 30~70cm long, and the colors are dark green, light green, red purple or red spots. Each pod contains 16~22 seeds, kidney shape, red, black, reddish brown, red and white seeds, etc., root system developed, there are pink nodules on the root.

1) Cultivate strong seedlings: protected cultivation should select varieties with middle and late maturity, high yield, disease resistance, strong adaptability and suitable for dense planting. Generally, root protection seedling method can reduce root injury and is beneficial to slow seedling. Seed treatment methods, nutrient soil preparation, bed seedling soil disinfection and other methods are basically the same as kidney bean. Nursery generally adopt nutrition bowl root protection seedling method, in order to reduce seedling root injury, conducive to planting after slow seedling strong seedling. The diameter of the bowl is 8 cm. Nutrient soil should be loose fertile garden soil that has not been planted with cotton and leguminous crops within 3 years. 2 parts of decomposed chicken manure, 2 parts of horse manure and 4 parts of garden soil can be fully mixed and sieved, and then loaded into the nutrient bowl. Do not fill the soil too full, preferably to 3/4 of the height of the nutrition bowl. Put them neatly on the seedbed. Seedling bed application 50% carbendazim wettable powder 500 times or 10% double effect Ling 250 times solution, uniform irrigation seedbed.

Before sowing, first irrigate sole water, after the water seeps down, plant 3~4 seeds in each nutrient bowl, cover 3 cm thick nutrient soil. Strengthen seedling stage management, timely release air to refine seedlings, control excessive growth of seedlings, and pull out sick seedlings in time.

2) Heavy application of base fertilizer, timely planting: cowpea continuous cropping is avoided, it is better to select plots that have not been planted with cotton and leguminous crops within 3 years, clean up the garden fields after harvesting of previous crops, apply decomposed high-quality organic fertilizer of more than 75000 kg/ha, mix well with soil, and make ridges or ridges. When planting, apply 300~4500 kg/ha of calcium superphosphate, 750~1050 kg/ha of plant ash or 150~225 kg/ha of potassium sulfate in furrows, mix well and flatten.

Before planting, close the shed and disinfect the soil with formalin 50~100 times solution 1~1.5 kg/m2, close it for one day and night, plant it after 7~10 days, or spray disinfect the soil, roof and surrounding surface of the shed with 50% carbendazim wettable powder 500 times solution.

When planting to prevent aphids, the ground laid silver-gray film, but also in the shed around the hanging silver-gray film strip, strip width of 15 cm.

3) Skillful topdressing: after planting, mainly squatting seedlings, controlling stem and leaf excessive growth, promoting reproductive growth, so as to form more inflorescences. After pod bearing, combine watering, ditching, topdressing decomposed human excrement 15000 kg/ha or compound fertilizer 75~120 kg/ha, then topdressing urea once every two harvest pods, 75~150 kg/ha, potassium sulfate 75~120 kg, or topdressing once every harvest, the dosage can be halved. In order to prevent premature senescence of plants, after the first yield peak appears, we must pay attention to fertilizer and water management, promote the germination of lateral branches and the formation of lateral flower buds, and make the original inflorescences on the main vine continue to flower and bear pods, and prolong the leaf age. In this way, the second full pod period appears about 20 days after the first full pod period, which can last for about 30 days.

In the peak growth period, foliar fertilization with 0.3% potassium dihydrogen phosphate can be used to prevent premature aging.

In order to promote early symbiotic nitrogen fixation of cowpea nodules, nitrogen-fixing bacteria can be used to dress seeds and artificially inoculate rhizobia, the same method as kidney beans.