Detailed Explanation of Key Cultivation Techniques for Autumn Potatoes

The growing conditions for autumn potatoes are exactly the opposite of those for spring potatoes: high temperatures and frequent showers in the early stage, and low temperatures and frost in the late stage, with a shorter growing period than spring potatoes. The seed potatoes are tubers harvested from spring planting, planted in August and September. Only 40-50 days pass from harvest to sowing, and the tubers are still in a dormant state. If seed potato treatment is not carried out, emergence will be late and uneven, and large numbers of tubers will rot, causing autumn planting to fail. Therefore, it is necessary to select excellent early-maturing varieties with a short dormancy period, carry out seed potato treatment to break dormancy, and sow late at the right time to prevent seed rot; only then can success be achieved.

1. Seed potato treatment

When using seed potatoes from spring planting and autumn harvest as seed, before sowing the tuber dormancy must be broken and sprouting promotion treatment carried out so that seedlings emerge in time. The method for promoting sprouting is as follows:

(1) Cutting into pieces For autumn potato piece-cutting and sprouting promotion, the key is to keep things "cool" to avoid seed rot and ensure full and strong seedlings. 7-10 days before sowing, select disease-free, uninjured seed potatoes of moderate size (single tuber weight 70-80 g), and use a sharp knife to cut lengthwise downward along the apical bud into 3-4 pieces (cut each 500 g into 20-25 pieces), leaving 1-2 buds per piece. For seed potatoes over 90 g, cut according to the eyes; the cut surface should be flat. Seed potatoes that are too small (20-30 g) may be planted directly without cutting. If, when cutting the potatoes, the vascular bundles are found to be brownish, they are diseased potatoes (ring rot). They should be removed, and the knife should be disinfected to prevent the spread of pathogens. Immediately after cutting, place the cut pieces into cool water and wash off the starchy sap on the cut surface to help the cuts heal and prevent piece rot. Then soak them in a 0.5-1 ppm "gibberellin" aqueous solution for 15-30 minutes. After removing them, spread the potato pieces with the cut side facing up for three to four hours to dry. Once the cut surface has formed a skin (suberized), they can be put into the sprouting bed to promote sprouting.

(2) Sprouting promotion The sprouting bed should be set up in a ventilated empty room without direct sunlight or under a cool shed built in the shade of trees outdoors. Spread clean wet sand on the ground (wet enough that it holds together when squeezed tightly in the hand and crumbles when the hand is opened), about 9 cm thick, with a bed width of 1 m. When promoting sprouting, place the potato pieces with the eyes facing up, arranged closely in one layer without overlapping, and cover with wet sand about 7 cm thick. If there are many potato pieces, stack two or three layers, alternating one layer of potato pieces and one layer of sand. Finally, pat the bed surface firm, cover with straw pieces or plastic film to retain moisture, and keep the bed temperature at 25-28°C. The humidity should be such that the surface soil does not become too dry; if the bed sand is too dry, sprinkle a small amount of cool water with a watering can to retain moisture. After 4-6 days, sprouts will emerge. When the sprouts are 1 cm long, they can be taken out for sowing. If the weather is unfavorable, they can be placed under diffused light for 2-3 days of hardening so the sprouts turn green and become sturdy before sowing.