Detailed Guide to Mung Bean Cultivation: How Long Until Flowering, When to Sow and Harvest by Month
Mung bean belongs to the Fabaceae family. Also known as green small bean, lu bean, zhi bean and so on, it has a cultivation history of more than two thousand years in China. So how long does it generally take to flower? When should it be sown and harvested by month? What are the cultivation methods? According to Vigna genus data, the flowering period of mung bean is June to July for spring sowing, and the fruiting period is August. For summer sowing after the wheat harvest, flowering occurs in August and the pods ripen in mid-to-late September. Upright types with a short growing period flower early. Vining tall types with a long growing period flower late. Flowering is continuous, with buds gradually appearing, flowers opening and pods setting as the plant grows. From emergence to flowering, summer-sown types with a short growing period begin to flower in about 50 days. Spring-sown types with a long growing period begin to flower and set fruit in about 60 days.
In which months is mung bean sown and harvested?
1. If the woodland is idle, the sowing date can be arranged in early April; if there is a preceding crop, sowing can be arranged after the early spring crop is harvested and the beds are opened. The suitable sowing date must be arranged before late May to ensure a full stand and obtain a high yield. Persist in seizing the time and soil moisture, and sow promptly when the soil is moist after rain; in case of drought, after sowing, drench the holes with clear manure water. Sow no more than 1 kg of seed per mu, and use 10 g of ammonium molybdate dissolved in 10 kg of water per mu to dress the seed (set aside any leftover water for later use), then sow after the seed has dried. The sowing specification is: for pure cropping, open beds 2 m wide, with 50 cm row spacing and 40 cm hole spacing, sowing 3200-3400 holes per mu, 5-6 seeds per hole, thinning to 2-3 plants per hole, and about 9500 plants per mu after thinning; for fruit-tree woodland, on the basis of leaving 40 cm between the rows and the base of the fruit trees, open beds 2 m wide, roughly the same as the sowing specification for pure cropping; for intercropping, refer to the pure cropping specification and determine the sowing rate per mu according to the situation. Base fertilizer application: generally use 20 kg of calcium magnesium phosphate fertilizer per mu plus 1000 kg of ash fertilizer or 25 kg of plant ash, then evenly mix with 300 kg of sandy loam soil to cover the seed. Using only 15 kg of Tianbishi high-quality bio-organic fertilizer per mu, crushed and mixed with 300 kg of sandy loam soil to cover the seed, gives the best effect.
2. Mung bean begins to be picked in August, and generally comes onto the market in the first half of August. Its ripening is uneven, so it should be harvested as it ripens according to the situation. In large-scale planting, where a single harvest is often required, the sign of timely harvest should be when 2/3 of all mung bean pods have turned brown-black. Under high temperature conditions, mature pods tend to split, so harvesting should be done in the morning before the dew has dried or in the evening. The harvested pods can be sun-dried, threshed and cleaned before being stored in the warehouse or sold.
What are the cultivation methods?
1. Apply sufficient base fertilizer. Although mung bean rhizobia have nitrogen-fixing ability, applying more farmyard manure and phosphorus and potassium fertilizers has an obvious yield-increasing effect. Farmyard manure can be applied once before sowing, then plowed into the soil. If there is no time to apply base fertilizer, a certain amount of nitrogen and phosphorus fertilizer should be applied in the early growth stage, that is, at branching and early flowering, to enhance the nitrogen-fixing ability of rhizobia and increase flower bud differentiation.
2. Sowing. Mung bean can be spring-sown or summer-sown. Spring sowing is from late April to early and mid-May. Summer sowing is in mid-to-late June, and early sowing should be strived for. Mung bean seeds contain 10% small hard seeds, which are very difficult to germinate after sowing and easily cause missing plants and broken rows, so they should be screened out before sowing. The sowing rate per mu is generally 1.5-2 kg, and the sowing depth is preferably 3-5 cm.
3. Field management
1. Thinning and final thinning. When mung bean seedlings reach the two-leaf-one-heart stage, clustered seedlings should be removed. Final thinning is done at the 4-leaf stage, with a plant spacing of 13-16 cm, a row spacing of about 40 cm for sole cropping, and preferably 10,000-12,500 plants per mu.
2. Intertillage and weeding. From emergence to flowering and row closure, mung bean is generally hoed at least four times, with intertillage depth going from shallow to deep and then to shallow again.
3. Irrigation and drainage. The flowering and pod-setting period of mung bean is the peak period of fertilizer and water demand. If drought occurs during this period, water should be applied in time to keep the soil moist. But the flowering and pod-setting period often falls in the rainy season, causing excessive vegetative growth of stems and leaves, resulting in a large number of flower and pod drops, or death from waterlogging. Drain in time to ensure normal growth of mung bean.
4. Intercropping and relay intercropping. Mung bean has strong shade tolerance and is often intercropped, relay intercropped or mixed with tall-stalk crops in production. Several forms are introduced:
Spring maize relay intercropped with mung bean. Spring maize is planted in wide and narrow rows, with wide rows 1 m, narrow rows 50 cm, and plant spacing 33 cm, about 2650 plants per mu; or wide rows 1.6 m, narrow rows 50 cm, and plant spacing 26 cm, about 3000 plants per mu. After maize pollination, relay intercrop 3-4 rows of early-maturing mung bean with a short growing period, small plants and concentrated pod setting in the wide rows. The row ratio is 2:4, or the row ratio is 1:1, that is, single-row spring maize intercropped with single-row mung bean; this pattern makes mung bean too shaded and affects yield.
Summer maize intercropped with mung bean. Summer maize is planted in wide and narrow rows, and two rows of early-maturing mung bean are relay intercropped in the wide rows. If maize is relay intercropped in wheat fields and mung bean is also to be intercropped, mung bean can be sown immediately after wheat harvest following stubble clearing; if maize is planted after wheat harvest, mung bean can be sown simultaneously with maize in a 2:2 form.
Mung bean mixed with summer sesame. After wheat harvest, mung bean and sesame are mixed and sown at the same time. After sesame harvest, mung bean is at the full flowering and pod-setting stage, with sufficient light, which is favorable for mung bean growth and full grains.
Mung bean intercropped with foxtail millet. For mung bean intercropped with summer foxtail millet, after wheat harvest, intercrop in a 4:2 or 2:2 form at the same time as sowing foxtail millet. In short, when mung bean is intercropped or relay intercropped with maize, foxtail millet or sweet potato, generally the row spacing is adjusted to intercrop mung bean without affecting the density of the main crop. If mung bean is used as green manure, plowing it under at the full flowering stage gives the best effect. If mung bean is relay intercropped in wheat rows, after wheat harvest the mung bean becomes a sole crop.
4. Pest and disease control. Mainly control the mung bean weevil; adults lay eggs on bean grains or tender pods, and after hatching the larvae bore into the bean grains to cause damage. Control methods: before storage, treat the bean grains at a high temperature of 50°C to kill insects; fumigate with 1.5 kg of sodium cyanide per thousand cubic meters for 48 hours at a temperature above 20°C, with an insect-killing efficiency of 100%, and without affecting the germination rate; store sealed with low oxygen; for small amounts, soak in boiling water for 20 minutes, remove and dry in the sun, and place in a jar, where they can be kept for a very long time without affecting the germination rate.