New Technique for Whole-Seed Potato Cultivation with Plastic Mulch and Double Rows on High Ridges

1. Reasonable crop rotation and stubble reversal To economically and effectively utilize soil fertility and prevent soil-borne diseases, pests, and weeds, avoid continuous potato cropping or planting potatoes on the stubble of other root and tuber crops. Also, do not rotate with other Solanaceous crops such as eggplant and tomato, otherwise yields will be reduced by 15%-20%. Potatoes can be rotated with cereal crops and legume crops for more than 3 years.

2. Land preparation and ridge formation Potatoes are suitable for planting in deep, loose soil, with deep plowing and fine land preparation. After harvesting the previous crop, promptly clear the stubble, plow deeply about 25 cm and harrow finely, while applying sufficient organic fertilizer. According to soil fertility conditions, apply 3000-4000 kg of organic fertilizer per mu, 20 kg each of diammonium phosphate and urea, and 10 kg of potassium sulfate. The ratio of the three elements nitrogen, phosphorus, and potassium calculated as pure amounts is more suitable at 2:1:3. The potato growth period is short, and fertilizer demand is relatively high in the early and middle stages, so one-time fertilization and deep application before sowing are suitable and have a significant yield-increasing effect. Use machinery to form high ridges 20 cm high. For flat fertile land, the ridge width is 1 m; for dry sloping land, the ridge width is 75-80 cm.

Advantages of double-row cultivation on high ridges: 1) The field surface has a large light-receiving area, which helps increase early soil temperature and promote earlier emergence. 2) The covering soil is deep and the soil layer is soft, which is beneficial for stolon growth and for producing more tubers and large tubers. 3) It improves field ventilation and light transmission conditions in the middle and late stages, reduces shading, and increases photosynthetic efficiency. 4) It is easy to drain during waterlogging and avoids tuber rot. 5) It is conducive to mechanized operations.

3. Seed potato selection and treatment In single-cropping areas, choose Kexin No. 1 and Kexin No. 4; in double-cropping areas, choose varieties such as Zaodabai, Youjin, and Chaobai. The planting material is healthy small seed potatoes each weighing 50-70 g. Whole-seed cultivation does not damage the potato skin, can prevent disease transmission and preserve water for drought resistance; it helps increase the number of main stems and better utilize apical dominance; and it is beneficial for seed potato treatment and mechanized operations.

You can use 1 part of 40% formalin mixed with 200 parts water, spray the surface of the seed potatoes or soak the seeds for 5 minutes, then cover them with plastic film and let them sweat for 2 hours, then uncover the film, spread them thinly, and air-dry them, which can further prevent pathogen transmission. Before sowing, using rooting powder or swelling agent to dress the seeds promotes germination and increases yield. The method is to place the seed potatoes on a cement floor or plastic sheet the night before sowing, dilute ABT Rooting Powder No. 8 into a 150,000-fold solution and spray it evenly on the seed potatoes, turn them evenly with a wooden shovel, then cover them with burlap sacks and let them sweat for 8-12 hours, uncover and dry slightly in the shade before sowing. Use 165 g of Suxiang or Guoguang brand swelling agent mixed with 30-45 kg water to dress the seeds, let them sweat for 24 hours, and then sow. This has the effects of disease resistance, increasing large and medium tubers, and promoting tuber expansion.

4. Sowing and film mulching In flat fertile land, double cropping is an effective measure to promote early potato germination and emergence and to achieve uniform and strong seedlings. 20-30 days before sowing, move the seed potatoes from the cellar indoors and place them for 10-15 days. When the buds are just beginning to sprout or young shoots emerge, spread the seed potatoes flat in a bright room so they receive even light, until the white buds become green buds or short, sturdy green-purple buds, and then sow. In flat fertile land, sow early at the appropriate time. The best sowing period is when the temperature of the 10 cm soil layer stably passes 6°C. Too early easily causes frost damage, and too late easily leads to excessive vegetative growth of the aboveground part. In Jianping County, it is generally suitable from April 25 to May 5. Dry sloping land should be sown later at the appropriate time so that temperature and precipitation match the growth needs of potatoes, generally suitable for sowing from May 15-25. In fresh-eating potato double-cropping areas, sow early at the appropriate time and use plastic film mulching cultivation, generally sowing from April 1-10. Sowing depth is 8-10 cm.

For whole-seed potato cultivation, reasonable close planting is key. The principle of reasonable close planting is that fertile land should be sparse and thin land should be dense; large seed potatoes should be sparse and small seed potatoes should be dense; varieties with a long growth period should be sparse and varieties with a short growth period should be dense. Generally, to maintain 25,000-28,000 main stems per mu, 5000-6000 hills need to be sown, with each hill ensuring 4-5 main stems. On flat fertile land, with a ridge width of 1 m, plant 2 rows, with a small row spacing of 30 cm and a hill spacing of 25 cm; on sloping land, with a ridge width of 75-80 cm, a small row spacing of 25 cm, and a hill spacing of 25-30 cm. Plastic film mulching cultivation can advance the potato sowing period by 20-25 days, which is beneficial for tuber expansion and yield increase. After sowing, promptly suppress and shape the ridges, press out a fish-back ridge surface, and then cover with film. When covering with film, pull it tight and spread it flat so that the film fits closely to the ridge surface. The film at the lower sides of both ridge sides should be buried well and compacted to prevent wind from blowing the film open. After the seedlings break through the soil, promptly inspect the field and release the seedlings, and seal the seedling release holes tightly with fine soil.

5. Pest and disease control The main disease of potatoes is late blight, and the pests are underground pests such as cutworms and white grubs. For fields where late blight occurs, first pull out the diseased plants, then disinfect with quicklime, and spray once comprehensively with 25% Ridomil wettable powder at 600-800 times solution or 50% carbendazim wettable powder at 800-1000 times solution. For cutworms, white grubs, and others, apply dichlorvos poisoned soil or poisoned bait during land preparation, during the growth period, and when hilling, or use trichlorfon solution to irrigate the roots at the seedling stage.

6. Harvest 10-15 days before potato harvest, cut off the aboveground part and carry it out of the field, then begin lifting and harvesting. Using whole-seed sprouting and film-mulched cultivation with double rows on high ridges, the potato yield per mu is 2200-2500 kg, with an average yield increase of 20%; the large tuber rate increases by 9%; and the diseased plant rate decreases by 13%. Because of high yield and good quality, the average economic benefit can be increased by 200 yuan per mu.