Mung bean has a short growth period, strong adaptability and fast growth: key points of high-yield cultivation techniques
Because mung bean has a short growth period, strong adaptability and fast seedling growth, it is suitable for intercropping and relay intercropping with various dryland crops in hilly areas, and can also be intercropped or mixed with tall crops such as corn and sorghum. The key points of high-yield mung bean cultivation techniques in hilly areas are as follows:
Sowing mung bean
1. Choosing the land. Mung bean has particularly strong adaptability; generally sandy soil, thin hillside land, black soil and clay soil can all support its growth. Mung bean is often intercropped with crops such as corn, sorghum, cotton, sweet potato, sesame and foxtail millet, and can also be planted on field ridges and in gaps between plots. Mung bean should not be grown continuously. Continuous cropping leads to more pests and diseases and poorer quality, and the proliferation of harmful microorganisms inhibits the development of rhizobia. At the same time, mung bean is also an important soil-enriching crop and an excellent preceding crop for cereals. Therefore, when planting mung bean, the land should be arranged rationally and crop rotation should be practiced; it is best to rotate with cereal crops such as corn, sorghum and wheat, and Chinese cabbage is not suitable as the preceding crop. Generally, an interval of 2—3 years is best.
2. Land preparation. Because mung bean is a dicotyledonous crop and its cotyledons emerge above ground, the seedlings have weak ability to push through the soil. If the soil is compacted or there are too many clods, it easily causes missing plants and gaps in the rows or uneven emergence. Therefore, before sowing, deep plowing and fine harrowing are required, with careful land preparation and leveling of clods, so that the soil is loose, stores water and preserves moisture, and is prevented from compacting, being loose on top and firm below, so as to facilitate emergence and allow crop rotation.
3. Selecting improved varieties. Choose varieties with large grains, thin seed coats, a low hard-seed rate, that cook easily and soften readily, and that have good taste and good yield performance, such as Zhonglü 1, Zhonglü 2, Jilü 2 and Yulü 2.
4. Sowing at the right time. Mung bean can be sown in spring and summer. Spring sowing is from late April to early and mid-May. Summer sowing is in mid- and late June, and early sowing should be pursued. Mung bean likes warmth; the suitable temperature for emergence and growth is 15 to 18 degrees Celsius, and it needs relatively high temperatures during the growth period. It begins to germinate at 8 to 12 degrees. During flowering and pod setting, the most suitable temperature is generally 18 to 20 degrees. If the temperature is too high, stems and leaves grow excessively, which can affect flowering and pod setting. In the late growth period, mung bean is not tolerant of frost; when the temperature drops below 0°C, the plants freeze to death and the seed germination rate is also low. Therefore, for summer and autumn sowing of mung bean, attention must be paid to sowing early at the right time so that it can mature normally before low temperatures and early frost arrive. The sowing rate is generally 1.5—2.0 kg per mu, and the sowing depth is preferably 3.0—5.0 cm.
5. Rational close planting. The planting density of mung bean should be determined according to variety characteristics and soil fertility. Generally, the principles are: dense for early-maturing varieties, sparse for late-maturing varieties; dense for upright types, sparse for semi-vining types, and even sparser for vining types; sparse on fertile land, dense on poor land; sparse for early sowing, dense for late sowing. For early-maturing mung bean varieties on low-water and low-fertility plots, the suitable density is generally 180,000—200,000 plants, with 11—15 plants retained per meter of row; for mid-maturing varieties under medium water and fertility conditions, the suitable density is 150,000—170,000 plants, with 8—10 plants retained per meter of row; for late-maturing varieties under high water and fertility conditions, the suitable density should be 120,000—140,000 plants, with 7—8 plants retained per meter of row.
6. Field management. In order to ensure that mung bean grows uniformly at the seedling stage, develops well as a population, produces many flower buds, flowers and pods, has large pods with many and large grains, and achieves high yield and good quality, the "six timely actions" should be carried out: ① Timely compaction. After sowing, for plots with poor sowing moisture, compaction should be carried out in time, pressing as sowing proceeds, so that the seeds are in close contact with the soil, surface moisture is increased, seed germination and development are promoted, and emergence is early and complete. ② Timely checking and replanting of seedlings. After mung bean emerges, if missing plants and gaps in the rows are found, replanting should be completed within 7 days. ③ Timely thinning and final singling of seedlings. To ensure good individual development of seedlings, thin and then set the seedlings. When mung bean seedlings reach the stage of two leaves and one heart, clustered seedlings should be removed. At the 4-leaf stage, final singling should be done, with a plant spacing of 13-16 cm, and a row spacing of about 40 cm for sole cropping. According to the established density, remove weak, diseased, small and mixed seedlings and weeds, and retain strong seedlings. Keeping one plant per position is conducive to robust plant growth. ④ Timely intertillage and weeding. This not only eliminates weeds, but also breaks up soil compaction, loosens the soil, reduces evaporation, raises soil temperature and promotes rhizobial activity; it is one measure for increasing mung bean yield. Generally, after the first compound leaf of mung bean unfolds, the first shallow hoeing is done together with thinning; after the second compound leaf unfolds, final singling begins and the second intertillage is carried out; at the branching stage, the third deep intertillage is carried out, along with earthing up around the roots, and intertillage should continue until the rows close. The depth of intertillage should follow the principle of shallow-deep-shallow. ⑤ Timely irrigation and drainage to prevent waterlogging. Mung bean is a crop that needs more water but is not tolerant of waterlogging and fears flooding. Mung bean has relatively strong drought resistance at the seedling stage and needs less water; the flowering and pod stage is the peak period of water demand. At this time, if drought occurs, it should be irrigated in time. But mung bean also fears waterlogging and flooding. If there is too much water at the seedling stage, root diseases will worsen, causing root rot and dead seedlings. If waterlogging occurs later, the plants grow poorly, show premature aging, flowers and pods drop, and yield declines. Therefore, in the rainy season, mung bean should be drained to prevent waterlogging. ⑥ Timely prevention and control of diseases and insect pests. Mainly control root rot, viral diseases and pests such as aphids and cabbage caterpillars.
7. Rational fertilization. The fertilization principle for mung bean should be based mainly on organic fertilizer, supplemented by inorganic fertilizer, with organic fertilizer and inorganic fertilizer used in combination; the policy is to apply sufficient base fertilizer and topdress appropriately. Fertilization techniques: mung bean has a short growth period and strong tolerance to poor soil, and its root system also has symbiotic nitrogen-fixing ability, so fertilizer is often not applied in production. However, in order to increase mung bean yields on medium- and low-yield plots, fertilizer should be added. Generally, about 10 kg per mu of diammonium phosphate or nitrogen, phosphorus and potassium compound fertilizer is applied as seed fertilizer. Topdressing of mung bean is best done at the flowering stage together with earthing up. Per hectare, 40—60 kg of nitrogen fertilizer such as ammonium nitrate or urea and 100—120 kg of potassium sulfate can be applied as topdressing. On relatively poor plots, foliar topdressing can be carried out at the pod-setting stage, spraying plant growth agents such as monopotassium phosphate, Fu'er 655, Lüfeng 95 and Banger Yibianfeng on the leaves, with relatively obvious yield-increasing effects. On plots with higher fertility, the seedling stage should be mainly controlled and no further topdressing should be applied; too much nitrogen fertilizer will lead to excessive vegetative growth, rampant stems and leaves, shading in the field, plant lodging, serious flower and pod drop, and reduced mung bean yield. Although mung bean rhizobia have nitrogen-fixing ability, adding farmyard manure and phosphorus and potassium fertilizers has an obvious yield-increasing effect. Farmyard manure can be applied all at once before sowing, and then plowed into the soil. If there is not enough time to apply base fertilizer, then in the early growth stage, that is, at branching and early flowering, a certain amount of nitrogen and phosphorus fertilizer should be applied to enhance the nitrogen-fixing ability of rhizobia and increase flower bud differentiation. Applying more organic fertilizer, inoculating with rhizobia and improving fertilization methods can increase the utilization rate of chemical fertilizers. According to relevant reports, the nitrogen supplied by mung bean rhizobia can reach 50%—70% of the total nitrogen required by mung bean. Therefore, rhizobium inoculation is one of the very economical and effective yield-increasing measures.
8. Timely harvest. Mung bean matures unevenly, so it should be picked as it ripens according to the situation. When planting on a large scale, it is often necessary to harvest all at once, and the sign for 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.