Detailed Explanation of High-Yield Winter Potato Cultivation Techniques

Developing winter potatoes makes full use of winter resources and has the characteristics of improving land utilization, saving time and fertilizer, a short growth cycle and quick results. Not only can planting be done earlier and maturity achieved earlier, seizing the main spring season to plant spring corn, realizing one early season leading to many early seasons and multiple seasons with multiple harvests, but because of the earlier market listing, it also alleviates the spring vegetable shortage, serving both as a vegetable and as a grain, achieving value addition and increased income. In recent years, the winter potato planting area has continued to expand, and cultivation techniques have gradually matured, developing from ordinary open-field cultivation to plastic film mulching cultivation, and remarkable economic benefits have been obtained. The cultivation techniques are introduced as follows.

1. Select good varieties. Extra-early-maturing or early-maturing virus-free varieties free of disease and injury should be selected. In the Sichuan region, the main recommended varieties are Chuanyu No. 5 and Zihuabai. The ideal seed potato size is 25-50 g.

2. Choose the field soil. Potatoes have wide adaptability, and their main soil requirement is looseness, because the potato root system consumes much more oxygen than other crops, and in addition tuber enlargement requires loose, breathable soil. Therefore, sandy soil or loam with higher terrain, loose soil, deep soil layers, convenient drainage and irrigation, and fertility should be selected.

3. Land preparation and fertilization. After the previous crop is harvested, immediately plow deeply 20-25 cm to prepare for sowing. Before sowing, break up the soil finely, and open beds 1.0-1.2 m wide, with furrows 25 cm wide and 10 cm deep. The absorption ratio of nitrogen, phosphorus and potassium nutrients by potatoes is 2.5:1:4.5, with potassium absorbed in the greatest amount; potassium supply mainly depends on organic fertilizer, and crop straw contains a large amount of potassium. Apply heavy organic fertilizer, and apply sufficient basal fertilizer in one application before sowing to supplement potassium, applying the fertilizer on the bed surface while preparing the land. For basal fertilizer, use 1500-2000 kg of decomposed organic fertilizer and 30 kg of ternary compound fertilizer per 667 sq m.

4. Pre-sowing sprouting. If 10-15 days before sowing the seed potatoes have not yet passed dormancy, dormancy must be broken. The method is to cut the seed potatoes into pieces: generally the cut pieces are required to weigh no less than 30 g, and each cut piece must carry at least 2-3 buds. When cutting, note that the pieces should not be too small; when a diseased potato is cut, it should be destroyed, and the knife should be disinfected at the same time, otherwise the pathogen will spread. Sprouting method: after cutting the potato pieces, dry the wounds so that a cork layer forms. Once the pieces are dried, they can be sprouted. A common sprouting method is to sprout directly indoors: spread the pieces on the ground in a layer 10-15 cm thick, and the sand used to cover the seed potatoes should first be sprayed with water to moisten it; the sand moisture should be such that no water comes out when squeezed in the hand, then scatter it over the seed potatoes. During sprouting, humidity should not be too high; as long as the sand is not very dry, generally do not water. When the sprouts reach 1.5-2 cm in length, place the sprouted pieces under indoor scattered light for 1-2 days; the sprouts turn green, and after sowing they emerge quickly and the seedlings are strong.

5. Sow at the right time. In the Sichuan region, the optimal period for plastic film mulching is from the end of December to the beginning of January, and no later than the end of January. Generally use a row spacing of 40-45 cm and a hill spacing of 25-30 cm, with a sowing depth of 7-9 cm, and plant 4500-5000 hills per 667 sq m. After sowing, use micro-film flat mulching cultivation, firmly pressing down the film edges, and eliminating "nail staking" and air leakage.

6. Field management

(1) Breaking the film to let seedlings out. In potato plastic film mulching cultivation, attention should be paid during the seedling stage to promptly breaking the film to let seedlings out; letting seedlings out too early risks late frost damage, while letting seedlings out too late makes it easy for the film surface to scorch the seedlings. One day before letting seedlings out, first break the film above the seedlings to ventilate and harden the seedlings; on the second day, lead the seedlings out of the film and seal around the seedling holes with fine soil.

(2) Water and fertilizer management. Potato fertilization is mainly basal fertilizer; after full emergence, apply a seedling-promoting fertilizer, using 7 kg of urea per 667 sq m diluted in water or applying decomposed human manure. At the bud stage, apply a topdressing, evenly broadcasting 5-7 kg of chemical potassium fertilizer per 667 sq m. After flowering, foliar fertilizer can also be sprayed, mainly monopotassium phosphate, to promote tuber enlargement and starch accumulation.

(3) Pest and disease control. 1) Potato late blight. Late blight is spread by airflow and expands and spreads very quickly; it is a devastating disease and can cause large amounts of potato rot both in the field and during storage. When potatoes enter the early flowering stage and central diseased plants appear in the field, promptly use the high-efficiency, low-toxicity systemic fungicide 25% metalaxyl or metalaxyl mancozeb, mixed into a 500-800 times solution for spraying, and it can also be poured around the hills. 2) Cutworms mainly bite the potato stems near the ground, causing missing plants and broken rows. Sugar-molasses traps or light traps can be used. You can also use 50% pyrimidinyl oxyphosphorus emulsifiable concentrate to make 5% poisonous soil or granules and scatter them on the soil surface around the base of the seedlings, or spray the plants with a 2000-3000 times solution of 50% monocrotophos. 3) The adults and larvae of the 28-spotted ladybird mainly feed on potato leaves; a 500-800 times solution of 60% trichlorfon can be sprayed, which has strong killing power against both larvae and adults. When the damage is severe, spraying can be done multiple times, once every 2 weeks.

7. Harvest. In late April and early May, in the late tuber enlargement stage of winter potatoes, they can be harvested and marketed.