Sharing Experience and Key Techniques for Greenhouse Potato Cultivation

Mr. Diao Jinzhu of Diaosha Village, Longyang Town, Tengzhou City, Shandong, grows potatoes yielding over 5,000 jin per mu, with an output value reaching 10,000 yuan. His cultivation experience is as follows.

1. Use virus-free seed potatoes, the virus-free potato variety Holland No. 7 introduced from Northeast China.

2. Seed potato treatment: prepare about 200 kg of seed per mu. In mid-January, choose a sunny and warm midday to sun-dry the seed potatoes for 1 day, and remove diseased, rotten and deformed potatoes. Then place the seed potatoes indoors at 20-25°C for 15 days for pre-sprouting; once the buds begin to sprout, pre-sprouting is complete. Then cut them into pieces, each 20-25 g. For large potatoes, cut diagonally toward the top in a spiral pattern, and finally cut the top part where the eyes are concentrated into 3 pieces to give play to apical dominance. After cutting, in an insulated room, spread a 5 cm thick layer of fine sandy soil on the bottom, then arrange the potato pieces in sequence with the eyes facing up, trying to make the top edge even while the bottom need not be, and after arranging, cover with 5 cm of fine sand. Following the above arrangement method, arrange the second and third layers of potato pieces in sequence. On the last layer, cover with 5 cm of fine sand, and cover with straw matting on top. The temperature is 15-25°C. The moisture of the sprouting bed soil should be such that it forms a ball when squeezed in the hand and breaks apart when dropped. Sprouting is carried out under dark conditions for 20 days. When the potato pieces have sprouts 1-2 cm long, take them out and move them to a room at 10-15°C with scattered light to air-dry; when air-drying, it is best to spread a layer of moist sandy soil on the bottom. Use low temperature and scattered light to control the growth of the apical buds and promote the mass sprouting of lateral buds.

3. Building and covering the shed: In early February, use concrete columns and bamboo poles to build a large arched round shed with 3 rows of upright columns, 200 cm high and 8 m wide. Cover it with plastic film in good time to raise the soil temperature.

4. Sowing: Apply 5,000 kg of farmyard manure per mu, plow deeply before winter, and after the soil thaws the following spring, harrow finely twice and level the land. Before sowing, use 200 g of no-deep-plowing soil conditioner per mu, add 100 kg of water, and spray it on the ground surface. In mid-February, when the soil temperature at a depth of 10 cm inside the shed is above 0°C, choose a sunny day with no strong wind and no cold current for sowing. Adopt double-row ridging cultivation. The ridge spacing is 80 cm, with 2 rows planted per ridge. The plant spacing is 20-25 cm, and the sowing density is 6,000-8,000 plants per mu. On the ridges, open 2 shallow furrows at a small row spacing of 20 cm. After sowing, apply 10 kg of no-till fertilizer per mu in the gaps. The soil covering depth is 10-12 cm, and the ridge height is 15 cm. After sowing, shape the top of the ridge into a "concave" shape, then cover the ridge with 90 cm wide plastic film, pulling it tight and pressing it firm.

5. Fine management: About 20 days from sowing to emergence. During the growth period, maintain 16-20°C during the day and 12-15°C at night. In the early growth stage, open small vents at noon to release harmful gases. In mid-to-late March, when the temperature reaches 20°C, begin opening the shed film for ventilation at 9 a.m. every day, and close the vents at around 3 p.m. From late April, when the outside temperature is above 20°C during the day and above 12°C at night, remove the film entirely for ventilation day and night. When the temperature is low, still cover with film. During the growth period, frequently shake the shed film with a bamboo pole to make the water droplets on the film fall to the ground, increasing the film's light transmittance. After emergence, at the rosette stage, and after ridge closure, water once each. During the tuber bulking stage, water twice to keep the soil moist. Do not let the water flow over the top of the ridge; maintain soil aeration to promote tuber bulking. After ridge closure and during the bulking stage, topdress 30 kg of compound fertilizer per mu each time. At the rosette stage, spray once with a 1:10,000 solution of natural brassinolide.

6. Timely harvest: Harvest in early-to-mid May when the potato tubers reach a diameter of 5-6 cm or more.