What are the key techniques for open-field cultivation of spring potatoes?

Potatoes are nutritious, high-yielding, easy to store, and have a long market period. They can be used as both a vegetable and a staple food, and are deeply loved by consumers. Open-field cultivation of potatoes in spring is the most common cultivation method, and almost every farming household plants them. To achieve high quality and high yield in open-field spring potatoes, the first step is to select good varieties. Potato seed potatoes must be original seed of varieties such as "Dongnong 303" and "Kexin No. 4" introduced from the north. Do not use self-saved seed, and even more so, do not use local seed that has been planted for many years, has an aging variety, and seriously degraded seed characteristics. "Dongnong 303" and "Kexin No. 4" have shown high quality, high yield, and early maturity after years of planting. The yield per mu can reach 1500-2000 kg. The seed requirement per mu is about 150 kg. Large tubers can be cut open for planting, with each seed tuber weighing 20-25 grams and having 2-3 eyes. Because the sources of potato seed tubers are complex, farmers should purchase them from legitimate agricultural supply stores.

Second, sow at the right time. Sowing at the right time is one of the key technical measures for achieving high quality and high yield in potatoes. Each region should sow at the right time according to the growth characteristics of potatoes and local climatic conditions. Based on many years of production practice and the climatic conditions in our area, the best sowing period for open-field spring potato cultivation is between the Beginning of Spring and Rain Water, that is, mid-to-early February. As latitude and altitude increase, the sowing period can be appropriately postponed. If sown too early, the seedlings are prone to damage from late frost and cold snaps in late March and early April after emergence, causing the stems and leaves to freeze to death and reducing yield; if sown too late, although frost damage can be avoided, the vegetative growth period is shortened, and rising temperatures in the later growth stage are unfavorable for tuber expansion, so the goal of high quality and high yield cannot be achieved either.

Third, apply sufficient base fertilizer. For potatoes, it is recommended to apply all fertilizer at one time. When plowing, broadcast 50 kg of 45% sulfur-containing ternary compound fertilizer per mu. Do not apply chlorine-containing chemical fertilizers, so as not to affect quality. After plowing, make beds, open holes, and sow. The holes should be made larger and deeper. First apply 10 loads of concentrated human manure and urine per mu into the holes, then apply a handful of livestock and poultry manure, cover with a layer of soil, and then place the seed potatoes, so as to avoid direct contact between seed potatoes and fertilizer, which would affect emergence. The amount of farmyard manure per mu is more than 1000 kg. Excess fertilizer can be applied in furrows between rows and then covered with soil, so that fertilizer can be supplied continuously and no further topdressing is needed afterward. The planting density is generally 5500-6000 plants per mu.

Fourth, chemical weed control. To prevent weed damage, after sowing and covering with soil, use 100 ml of 50% acetochlor per mu diluted in water and spray finely over the whole field. Note that when applying the pesticide, the soil should be moist and the field surface level to improve the weed control effect.

Fifth, chemical regulation. By using the effects of paclobutrazol to control excessive growth and promote sturdy, compact growth, from the beginning of flowering to full flowering of potatoes, use 30 ml of uniconazole per mu, dilute in 50 kg of water, and spray evenly. This can effectively prevent excessive growth, reduce disease, and increase yield. Generally, it can increase yield by more than 10%.

Sixth, disease and pest control. During the potato growing period, the main disease is late blight. When scattered diseased plants are found, they should be pulled out promptly, and then the whole field should be sprayed with 25% Ridomil at 800 times dilution for control. The main pests are the 28-spotted ladybird beetle and aphids. When they occur, 80% dichlorvos at 500 times dilution and 10% imidacloprid at 1500 times dilution can be sprayed for control.