What are the high-yield cultivation measures for potatoes?

1. Select good varieties. At present, the main varieties cultivated in Yunnan Province are high-yielding varieties such as virus-free Mira, Marko, Kexin No. 1, Zihuabai and Atlantic. For early-maturing spring cultivation, early-maturing varieties such as Favorita, Kexin No. 4, Zaodabai and Mengshu No. 9 can be selected.

2. Reasonable crop rotation, deep ploughing and fertilization. Potatoes should not be continuously cropped with Solanaceae crops. It is best to carry out a 3-5 year rotation with non-Solanaceae crops. Potatoes are a deep-ploughed crop and require deep, loose loam or sandy loam soil, with deep ploughing of 22-25 cm. Concentrated application of base fertilizer gives better results, that is, applying 1500-2000 kg of high-quality farmyard manure per mu in furrows or holes.

3. Seed potato selection and treatment. 15-20 days before sowing, select tubers that have the characteristics of the original variety, are intact, have smooth skin, are free from pests and diseases, and have bright colour; remove rotten tubers, and discard tubers that are pointed, cracked, have aged skin, protruding eyes, or dull skin colour. Spread the selected seed potatoes in a warm, sunny room, keep the temperature at about 15°C, and turn them once every 3-5 days. Generally, they will sprout in about 10 days. Then carefully select them once more, and once the sprouts turn purple, they can be cut and sown. Cutting is carried out 2-3 days before sowing. The size of each cut piece should preferably be 30-50 g, and each piece should carry at least 1-2 eyes. When cutting potatoes, prepare 2-3 knives and soak them in a 0.1% potassium permanganate solution for disinfection. Change to another knife at intervals, using them in rotation. If diseased or rotten potatoes are encountered, remove them and replace the knife at the same time to prevent the spread of pathogens and infection.

To give full play to the advantage of the apical bud and prevent the cutting knife from transmitting pathogens and viruses, farmers with the conditions can sow healthy whole tubers. This generally increases yield by 15%-20% compared with cut-piece sowing. The weight of whole tubers should preferably be 50 g.

4. Sowing

(1) Sowing time. The optimum temperature for potato tuber enlargement is about 20°C, so under permitted temperature conditions, sow as early as possible so that the potato has completed its growth before high temperatures arrive. However, in dry areas, determining the suitable sowing period should consider matching the tuber enlargement period with the rainy season. The sowing period for spring potatoes is from mid-to-late March to early-to-mid May.

(2) Planting density. Row spacing 55-65 cm, plant spacing 25-30 cm, about 3000 plants per mu. Apply base fertilizer in the furrow, cover with 3 cm of soil, then place the sprouted seed pieces with the sprouts facing up. After sowing, cover with soil and level it with a rake so that the bed surface is flat, fine and clean.

(3) Sowing depth. Sowing depth should be determined according to soil texture and soil moisture. In dry plots and loose soil, sow deeper, generally 10-15 cm; in moist and heavy clay soil, sow shallower, preferably 5-8 cm. For film-mulched potatoes, a sowing depth of 10-12 cm is best.

5. Field management

(1) Intertillage, weeding and earthing up. Carry out intertillage 2-3 times throughout the growth period. The first intertillage and weeding should be done promptly after the seedlings are fully established; the second intertillage at a seedling height of about 10 cm; the third intertillage at the tuber initiation stage combined with earthing up. During intertillage and weeding, pull out diseased plants in the field.

(2) Watering and topdressing. From budding to flowering is the peak water demand period for potatoes. At this time, water supply must be ensured. This can not only lower soil temperature and favour tuber enlargement, but also prevent the formation of secondary tubers. Potatoes are generally topdressed twice: at the seedling stage with clear manure water or 7-10 kg of urea per mu diluted in water and sprinkled; the second time at the bud stage with 15-20 kg of urea and 10-15 kg of potassium sulfate per mu. Topdressing combined with irrigation gives better results.

(3) Disease control

1. The main potato diseases include viral diseases, late blight, ring rot and blackleg. When plants with late blight, ring rot or blackleg are found in the field, they should be pulled out immediately and taken out of the field for disposal, and 1000-fold Ridomil MZ solution should be sprayed, once every 7-10 days, for 2-3 consecutive sprays. For viral diseases, virus-free seedlings should be used.

2. Pests are mainly soil-dwelling pests. For control, 1.5-2 kg of 30% carbofuran granules per mu can be applied into the sowing furrow along with sowing.

6. Timely harvest. When 70% of the plants in the field have yellowed stems and leaves, it indicates that the potatoes are mature and should be harvested immediately. Harvesting should be done on a sunny day. After harvesting, dry the potatoes for several hours; once the surface soil falls off and the skin is dry, they can be stored.

7. Potato processing. Besides being eaten fresh, potatoes can also be processed into potato jam, potato maltose, fresh potato vinegar, potato strips (slices), mashed potatoes, etc. However, at present, more than 95% of potatoes in our country are eaten fresh as vegetables, and potato processing is also limited to producing crude starch and making vermicelli, sheet jelly, noodles, alcohol, etc. Not only is the quantity small, but the degree of processing is also insufficient, and the economic benefit is not high. In the future, in-depth development and research are needed to further improve the economic benefits of potatoes.