How to achieve high yield in spring cultivation of edamame?
Edamame, also known as maodou, green edamame, white edamame, refers to fresh-pod soybeans harvested between the full-seed stage and the early-ripe stage. It is a nutrition-rich, delicious emerging legume vegetable. Traditional Chinese medicine holds that edamame is sweet in flavor and neutral in nature, with the effects of strengthening the spleen and removing dampness, moistening dryness and detoxifying. It is rich in nutrients, containing protein, calcium, iron, vitamins and various other nutritional components. Because of its therapeutic food effect of tonifying qi and strengthening the spleen, it is very suitable for elderly people with weak spleen and stomach.
Growth habits of edamame
Edamame prefers warmth and fears waterlogging, and is suitable for temperate regions with high summer temperatures. The seed germination temperature is 10-11°C, and it germinates rapidly at 15-20°C. During the seedling stage it tolerates short periods of low temperature, with an optimum temperature of 20-25°C, and it cannot flower below 14°C. In the later growth stage it is sensitive to temperature: if the temperature is too high, growth ends early; if too low, the seeds cannot fully mature. Plants are damaged at 1-3°C and killed at -3°C. Edamame is a short-day crop; determinate early-maturing varieties have no strict requirement for light duration, while indeterminate late-maturing varieties are short-day crops, which must be noted when introducing them: moving northern varieties southward causes earlier flowering, and moving southern varieties northward delays flowering. Edamame requires a relatively large amount of water. Seed germination requires absorbing slightly more water than the seed weight. During the seedling stage, branching stage, flowering and pod-setting stage, and pod-swelling stage, the required soil moisture-holding capacity is 60-65%, 65-70%, 70-80%, and 70-75%, respectively. Edamame has no strict requirement for soil quality, but soil with deep layers, good drainage, and rich in calcium and organic matter is best, with a pH of 6.5. It requires large amounts of P and K fertilizer. P fertilizer helps retain flowers and pods, promotes root growth, and enhances rhizobia activity. A deficiency of K causes the leaves to turn yellow.
From sowing to the formation of the first flower is the early growth period for edamame. About 30 days before flowering, flower bud differentiation begins. This period is dominated by vegetative growth and is a period of nutrient accumulation. The flowering period lasts about 14-30 days. During this period growth is most vigorous, with vegetative growth and reproductive growth proceeding simultaneously (material accumulation accounts for 55-65% of the total height, total leaf area, and total dry weight formed, and 60% of total nitrogen accumulation). Two weeks after flowering, the beans rapidly enlarge and require large amounts of water and nutrients. Insufficient fertilizer and water supply causes premature aging of the plant, resulting in flower and pod drop.
How to achieve high yield in spring cultivation of edamame?
1. Site selection
1. Soil conditions: Edamame has a well-developed root system. Choose loam or sandy loam with deep soil layers and medium or above fertility for planting, preferably with irrigation and drainage conditions. The soil pH should be about 6.5. When the soil acidity is below 5.5, spread 100 kg of lime per mu for neutralization and improvement.
2. Growth conditions: Edamame prefers warmth. Seeds begin to germinate at 10°C-12°C, with 15°C-20°C being optimal. The optimum temperature during the growth period is 20°C-25°C, and the optimum temperature during the flowering and pod-setting period is 20°C-28°C. At low temperatures, pod setting is delayed, and it cannot flower below 14°C. If the temperature is too high, the plant ends growth early, and the pods and beans are difficult to fill out.
2. Variety selection and treatment
1. Variety selection: According to local production conditions and market demand, select varieties with high yield, good quality, and strong stress resistance according to local conditions. At present, the main varieties suitable for export in our province are edamame 75 and 2808.
2. Seed selection: Because of differences in seed propagation and seed-saving time, production area, and technology, the seed quality of edamame varies noticeably. Therefore, choose small-package seeds with quality reaching Grade 2 or above in the seed grading standard and from a reputable source.
3. Seed treatment: Before sowing, use preservative and soil-insecticide agents such as “thiram + phoxim” to dress the seeds at a ratio of 1:1:100, and sow immediately after dressing.
3. Sowing
1. Timely sowing: Edamame 75 and 2808 generally take about 70 days from emergence to harvest. In southern Fujian, the spring sowing period is from Jingzhe to Qingming, while north of Fuzhou it is best to sow from Chunfen to Guyu.
2. Sowing rate: Generally about 5 kg of seed per mu, with 2-3 seeds per hole, keeping 15000-17000 plants per mu.
3. Reasonable close planting: Use small beds with narrow rows, that is, ditch width 20 cm, bed width 60-70 cm, double-row hole sowing, row spacing 35 cm, hole spacing about 18-20 cm. Variety 2808 has a compact plant type and is suitable for close planting, while variety edamame 75 can be planted a little more sparsely. Do not cover with too thick a layer of sandy soil, otherwise emergence is difficult and seeds rot easily.
4. Scientific fertilization
1. Fertilization principles: Master the practice of mainly applying compound fertilizer in the early stage, and applying little or no urea to prevent excessive nitrogen, which makes leaves dark green and prone to pests and diseases such as aphids and red spiders.
2. Base fertilizer: Apply 70-100 kg of calcium magnesium phosphate per mu.
3. Topdressing: From sowing to the formation of the first flower, edamame is in the vegetative growth stage (about 30 days). During this stage, topdressing can be done twice. Generally, the first fertilization is applied within one week after emergence: use 15 kg of ammonium bicarbonate and 15 kg of superphosphate per mu, mix evenly, prepare 1.5 kg of mixed fertilizer per 50 kg of water, and pour it along the middle of the bed. Six days later (half a month after emergence), apply the second fertilizer: use 20-25 kg of ammonium bicarbonate and 15 kg of superphosphate per mu, mix evenly, prepare 2-2.5 kg of fertilizer per 50 kg of water, and pour it along the middle of the bed. The third fertilization should be around 30 days after emergence (beginning of flowering): apply 5-7.5 kg of urea and 15 kg of compound fertilizer per mu, mix evenly, and apply dry in the middle of the bed. After that, supplement fertilizer according to the seedling condition. Generally, if the seedlings are poor, apply a small amount of supplementary fertilizer; if the seedlings are good, do not apply fertilizer until harvesting the fresh pods. After each fertilization, irrigate once with horse-race water (half-ditch water). If it rains after fertilization, there is no need to irrigate.
5. Field management
1. Cultivation: Carry out the first cultivation when edamame grows to two compound leaves to promote root elongation. At the late branching stage, carry out the second cultivation together with clearing ditches and earthing up. During the pod-setting and seed-filling stage, pay attention to draining field water to prevent pod rot.
2. Water management: Edamame seed germination requires more water, so it is advisable to plow, prepare beds, and sow in sequence. During the flowering period, the soil water content should be 70%-80%, otherwise the flower bud drop rate increases.
3. Fertilization: In terms of fertilizer demand, edamame requires less than 15% of the total fertilizer before flowering, while the flowering and pod-setting period accounts for more than 80% of total fertilizer demand. In terms of fertilizer types, it needs a large amount of nitrogen fertilizer, and also large amounts of phosphorus and potassium fertilizer. When phosphorus fertilizer is lacking, the number of branches and flowers decreases, and flower drop increases. Sufficient phosphorus fertilizer can promote root growth, accelerate metabolic processes in the plant, enhance nodule activity, and mature pods earlier. When potassium fertilizer is lacking, the cotyledons turn yellow and the potassium-deficiency symptom of “golden edging” appears.
4. Pest and disease control: During the edamame seedling stage, mainly control underground pests, using soil insect killers, chlorpyrifos, phoxim, etc. If pests and diseases are found before and during flowering, use metalaxyl mancozeb, thiophanate-methyl, or carbendazim and jinggangmycin combined with phoxim or fenvalerate for control 1-2 times. At the end of flowering, control pests and diseases another 1-2 times, using phoxim or Abamectin etc. plus BT, sprayed on clear evenings.
6. Harvest
Edamame is a fresh-eating vegetable harvested between the full-seed stage and the early-ripe stage. The harvest period is relatively short. The optimal harvest period for a single plant is only 3-5 days, the optimal harvest period for a single plant is only 3-5 days, and the suitable harvest period for a single plant is also only about 10 days. Therefore, it is generally harvested in two batches. Timely harvesting is the final key link to ensure high yield and a good harvest.