Key Techniques for High-Efficiency Cultivation of Soybean Intercropped with Melon

Soybean intercropped with melon at a 4:2 ratio, with Chinese cabbage replanted as the following crop after melon harvest, achieves three harvests from one field and an income of more than 15,000 yuan per hectare, making it a new high-yield and high-efficiency planting model.

1. Selecting new varieties

1.1 For the soybean variety, select Jinta soybean, which has strong branching and super-high yield. Jinta soybean has 6 outstanding characteristics: 1) Strong growth vigor. Jinta soybean has a plant height of 70-80 cm, thick and sturdy stems, and high resistance to lodging; 2) Strong branching ability. A single plant has 8-10 branches, with a maximum of 16 branches. The branches grow upward, and the plant takes on a fan shape without breaking branches, overcoming the tendency of strongly branching soybeans to break branches, resulting in an ideal plant type; 3) Dense pod setting. A single plant sets 200-250 pods, with a maximum of 400 pods. The pods are so dense that the stems are hidden, 2-3 times that of other soybeans. Most pods are 3-seeded, with a yield of 75-100 g per plant and a maximum of 400 g; 4) Excellent quality. The beans are golden yellow, large and uniform, with a 100-seed weight of 22-25 g and high oil and protein content; 5) Strong stress resistance. The growth period is 120 days and requires an effective accumulated temperature of 2450°C. It is drought-resistant, moisture-tolerant, and salt-alkali tolerant, and prefers fertilizer and water. It is suitable for planting in Jilin, Liaoning, Heilongjiang, and Inner Mongolia in areas with an effective accumulated temperature above 2450°C; 6) High and stable yield. The yield per hectare is 4000-5000 kg, making it a high-yielding, high-quality soybean variety.

1.2 For the melon variety, select early-maturing, high-sugar varieties.

2. Cultivation model

Jinta soybean has strong plants, many branches, and dense pods, so it should be planted sparsely. A new model is adopted with 4 rows of soybean intercropped with 2 rows of melon, and Chinese cabbage replanted as the following crop after melon harvest. Soybean hills are spaced 40 cm apart with 2 plants per hill or 20 cm apart with 1 plant per hill, with 57,000 plants per hectare maintained. In this model, soybean has good ventilation and light penetration, giving play to the edge-row advantage, preventing soybean flower drop, increasing pod-setting rate, and increasing soybean yield; melon uses soybean for shade, reducing the harm of high temperatures to melon, enabling early maturity and increased yield of melon, and achieving high benefits.

3. Cultivation techniques

3.1 Adhere to sparse planting for soybean

Land preparation and fertilization: apply 15-20 cubic meters of farmyard manure per hectare, 150-200 kg of diammonium phosphate, 150 kg of potassium fertilizer, or 300 kg of ternary compound fertilizer, then deep plow and ridge, with a ridge spacing of 60-65 cm.

Timely sowing: sow in Jilin Province from late April to early May, and sow at the appropriate time according to local conditions in other areas. Before sowing, mix 20 g of ammonium molybdate with 500 g of water and coat 10 kg of seed, which has a significant yield-increasing effect. Dig holes and sow with water, with hole spacing of 40 or 20 cm, sowing 2-3 seeds per hole, with a sowing rate of 25-30 kg per hectare. Plant 4 rows and leave 2 rows empty, cover with 3-4 cm of soil, and press to preserve soil moisture.

Thinning and final singling: thin seedlings at the 3-4 leaf stage, leaving 1 plant per hole, or 2 plants per hole when the hole spacing is 40 cm. If missing plants are found, replant or reseed with water in time.

Intertillage and weeding: generally cultivate and ridge 3 times, loosen the soil and remove weeds, and ridge up large ridges before closing the rows. Herbicides may also be used for weed control.

Increasing flowers and pods: from the seedling stage to the flowering stage, spray with 10 g of Shengnongsu, 0.25 g of gibberellin, 100 g of boron fertilizer, and 50 g of urea, adding 15 kg of water. Spray once every 10-15 days for 3-4 consecutive sprays. This can not only effectively prevent and control soybean diseases, but also significantly enhance drought resistance, lodging resistance, resistance to premature senescence, flower production, and pollination and fertilization capacity, resulting in more pods, full grains, earlier maturity, and super-conventional yield increase. Spraying this mixture in the later stage can also prevent cold damage and extend the growth period.

3.2 Adopt the "four earlies and one replanting" cultivation method for melon

Early variety selection: select early-maturing super-sweet melon varieties.

Early seedling raising: sow and raise seedlings in small arched sheds in early April in Jilin Province. The seedling age is about 30 days. Strengthen management and cultivate strong seedlings.

Early protection with plastic film: in mid-May, cover the empty rows where soybean is planted with plastic film and transplant melon, with a plant spacing of 40 cm.

Management to promote early maturity: prune in time. From the seedling stage onward, spray with 10 g of Shengnongsu, 25 g of copper sulfate, and 50 g of urea, adding 15 kg of water. Spray once every 10-15 days for 3 consecutive sprays. This can not only effectively prevent and control diseases, but also multiply flowers and fruits, advance maturity by 5-7 days, and significantly increase yield. After melon harvest, replant Chinese cabbage.

4. New methods for disease prevention

4.1 Prevention and control of soybean diseases

For soybean viral disease, bacterial angular leaf spot, and leaf scorch, use 10 g of Shengnongsu, 7.5 g of agricultural streptomycin, and 50 g of urea, adding 15 kg of water, and spray once every 5-7 days at the early stage of disease onset for 2-3 consecutive sprays.

For fungal diseases such as soybean root rot, Fusarium wilt, sclerotinia rot, leaf spot, and downy mildew, use 10 g of Shengnongsu, 25 g of fenarimol, 100 g of boron fertilizer, and 50 g of urea, adding 15 kg of water, and spray once every 5-7 days at the early stage of disease onset for 2-3 consecutive sprays.

4.2 Prevention and control of melon diseases

For melon Fusarium wilt, gummy stem blight, Phytophthora blight, anthracnose, and bacterial angular leaf spot, use 10 g of Shengnongsu and 25 g of copper sulfate, adding 15 kg of water, and spray once every 5-7 days at the early stage of disease onset for 2-3 consecutive sprays.

For melon viral disease, use 10 g of Shengnongsu, 7.5 g of agricultural streptomycin, and 50 g of urea, adding 15 kg of water, and spray once every 5-7 days at the early stage of disease onset for 2-3 consecutive sprays.

For melon powdery mildew, use 10 g of Shengnongsu, 12 g of fenarimol, 15-20 g of jinggangmycin, and 50 g of urea, adding 15 kg of water, and spray once every 5-7 days at the early stage of disease onset for 2-3 consecutive sprays. When spraying, the front and back of leaves and the fruits must all be covered. Generally, powdery mildew can be eliminated within 24 hours.

For melon downy mildew, use 10 g of Shengnongsu, 25 g of mancozeb, and 50 g of urea, adding 15 kg of water, and spray once every 3-5 days at the early stage of disease onset. Two consecutive sprays can achieve control.