What are the key points of purple yam cultivation techniques?

AbstractPurple yam is suitable for planting in fields with fertile soil, deep soil layers and convenient drainage and irrigation. When plowing the soil, spread decomposed rapeseed cake fertilizer on the surface; select disease-free and undamaged seed tubers, cut them into pieces, and sow around Qingming Festival, then cover with black plastic film. After emergence, build supports; during the vigorous vine growth period, apply urea and compound fertilizer as topdressing; in the later growth stage, spray urea and 0.3% potassium dihydrogen phosphate solution. During this period, water appropriately according to soil conditions, pay attention to pest and disease control, and harvest at the end of October.

1. Land selection and plowing

Choose fields with fertile soil, deep soil layers and convenient drainage and irrigation for planting. Generally, loam or sandy loam with good permeability is suitable. Then carry out deep plowing and sun-bleach the soil, plow the land and make beds. The bed surface width is about 50cm, the bed height is about 30cm, and the ditch width is about 30cm. The bed surface should be finely broken up and leveled.

2. Seed tuber treatment

Select disease-free and undamaged seed tubers, remove the soil on the surface of the seed tubers. When cutting into pieces, use 75% alcohol to disinfect the knife to avoid viral infection, then cut into tuber pieces about 5cm long and 40-50g in weight. Coat with lime or burnt soil ash, dry the cut surfaces, and then sow.

3. Timely sowing

Sow around Qingming Festival using the single-plant single-row planting method. The suitable plant spacing is about 30cm, the row spacing is about 80cm, and the sowing rate is 2700-2800 plants per mu. In the middle of the well-plowed bed surface, open a sowing ditch 20cm deep. First apply compound fertilizer into the ditch, then cover with 2cm of crushed soil, then place the seed tubers, and cover with a small amount of fine soil so that the sowing spacing and soil covering are uniform and consistent. The seed tuber dosage is about 260 jin per mu.

4. Covering with black film

After sowing, the bed surface should be covered with black plastic film 100cm wide. When covering the film, pull it tight and press the edges firmly. Press down the film with clods of soil every 2m to prevent strong winds from damaging the film. When purple yam seedlings emerge, promptly break the film to expose the seedlings to prevent leaves from touching the plastic film and being scorched. Generally, black film mulching has better effects than white plastic film in warming, moisturizing, preventing weeds and controlling weeds.

5. Building supports

After emergence, build supports promptly so that purple yam can climb upward. Usually, thin bamboo poles can be inserted to form a trellis shaped like the Chinese character "". The trellis height should preferably be 1.6-2.0 m. The supports should be inserted firmly and tied tightly to avoid being blown down by wind. To avoid purple yam vines tangling with each other, the vines can also be evenly trained onto the trellis.

6. Appropriate fertilization

1. Apply sufficient base fertilizer

Before plowing the plot, evenly spread decomposed rapeseed cake fertilizer on the surface, then deep-plow to about 30cm so that the soil and fertilizer are fully mixed. Then at sowing, according to a dosage of 200 jin per mu, bury 45% potassium sulfate compound fertilizer in the sowing ditch. The method is the same as for timely sowing.

2. Timely topdressing

When the vines have fully covered the trellis, apply 20 jin of urea and 50-70 jin of high-concentration compound fertilizer per mu as topdressing. In the later growth stage, spray urea and 0.3% potassium dihydrogen phosphate solution 2-3 times so that the leaves do not show aging.

7. Irrigation and drainage

From April to June, during continuous rainy and heavy rain weather, drain accumulated water from the field promptly to avoid waterlogging damage. From July to August, if there is continuous summer drought weather lasting more than 7 days, spray irrigate promptly to ensure the soil remains moist.

8. Pest and disease control

1. The main pests and diseases of purple yam include: white grubs, cutworms, brown spot disease, anthracnose, bacterial wilt, viral disease, etc.

2. Diseases such as anthracnose: in the early stage of the disease, use 75g of 25% prochloraz emulsifiable concentrate per mu diluted with 100 jin of water for spraying. For severe cases, spray again after 7-10 days.

3. Pests and viral disease: choose virus-free seed tubers for sowing. At the sowing stage or seedling stage, use 5% carbaryl granules for seed dressing or mix with fine sand and broadcast to control pests.

9. Timely harvest

At the end of October, purple yam plants will stop growing, and the tubers in the ground will basically all be mature. Harvest can be carried out on sunny days, and all must be harvested before frost. During harvest, try not to damage the tuber skin and avoid breaking the tubers.