Spring-planted potato early-market cultivation techniques
In the central-southern Hebei region, the key to spring potato cultivation is early marketing to achieve high returns. Growing potatoes in plastic greenhouses or glasshouses allows them to reach the market around May Day, saving labor, being technically simple and requiring relatively little investment, making it a good way to increase income.
1. Choose good varieties and seed potatoes
For variety selection, it is advisable to choose varieties with concentrated tuber set, few branches, upright plant type, high yield and early maturity, such as Holland 7, Holland 15, Kexin No. 4, Kexin 13, Jingdabai, etc. For seed potato selection, strictly choose virus-free seed potatoes, use good varieties with as few propagation generations as possible, and buy seed from reputable seed potato companies. Prepare about 165 kg of seed potatoes per mu.
2. Prepare the greenhouse and soil well
Prepare the greenhouse and promptly prepare the soil well. The greenhouse should be covered in advance. For an old greenhouse, the previous crop should not be a Solanaceae or Brassicaceae crop. It is best to prepare the soil before winter, and at the latest 20 days before sowing. Before soil preparation, according to soil moisture conditions, pre-irrigate to build moisture. Then broadcast 5000 kg of farmyard manure per mu, use a moldboard plow to deep-plow more than 20 cm, then apply per mu 100-200 kg of high-quality organic fertilizer (containing microbial fertilizer) + 100 kg of potassium sulfate compound fertilizer (18-7-20). After broadcasting, rotary-till and level the land. Before sowing, open furrows, broadcast phoxim along the furrows, and then form ridges.
3. Seed potato treatment
Treat the seed potatoes 20 days before sowing, following the three procedures of disinfection, cutting and sprouting. Before cutting, disinfect with potassium permanganate. Generally each cut piece should have at least 1 eye, with a piece weight of about 25 g. After cutting, dry-mix the cut pieces with plant ash, or soak the seed pieces in a 200-fold carbendazim solution. After cutting, place the pieces in a warm indoor area: spread a 5 cm thick layer of fine sandy soil on the bottom, then arrange the seed pieces in sequence with the eyes facing up, and try to make the top edge even while the lower part need not be even. After arranging, cover with 5 cm of fine sand. Following the same arrangement method, place the second and third layers of seed pieces in sequence. Cover the final layer with 5 cm of fine sand, and cover the top with straw mats. Keep the temperature at 15°C-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. Carry out sprouting under dark conditions for 20 days. When the sprouts on the seed pieces reach 1-2 cm, take the seed pieces out and move them to an indoor area at 10°C-15°C with diffused light to spread and air them. When airing, it is best to spread a layer of moist sandy soil on the bottom. Use low temperature and diffused light to control the growth of the apical bud and promote the massive sprouting of lateral buds. Then wait for sowing.
4. Scientific sowing
Sow when the 10 cm soil temperature in the greenhouse stabilizes at 8°C. Too early, adverse weather may affect the greenhouse temperature; too late, the greenhouse cannot play its role in early cultivation. Use high ridges for sowing to increase aeration. After sowing, cover with plastic film, and if necessary add an inner film or build small arches to raise soil temperature and promote early emergence of potatoes. Row spacing about 60 cm, plant spacing about 18 cm.
5. Field management
When the seedlings push up the soil and touch the film, puncture holes to release the seedlings, and at the same time cover the holes tightly with moist soil to prevent air leakage. After the potato seedlings emerge completely, irrigate once to promote seedling growth. From sowing to emergence takes about 20 days; maintain 16°C-20°C during the day and 12°C-15°C at night. During the potato branching stage, focus on ventilation and cooling to ensure the soil temperature in the greenhouse remains at 16°C-18°C. When the air temperature reaches 20°C, begin opening the greenhouse film for ventilation at 9 a.m., and close it around 3 p.m. In April, when the outside air temperature is above 20°C during the day and above 12°C at night, uncover the film fully for day-and-night ventilation. When the temperature is low, still cover with the film. During the growth period, often shake the greenhouse film with a bamboo pole so that water droplets on the film fall to the ground, increasing the film's light transmission.
After emergence, at the rosette stage and after the canopy closes, irrigate once each time, and during the tuber bulking stage irrigate twice. For the canopy-closing irrigation and the bulking irrigation, according to growth vigor, apply 15-20 kg per mu of high-potassium water-soluble fertilizer with the irrigation water. Do not let the water flow over the top of the ridges; maintain soil aeration to promote tuber bulking. At the rosette stage, spray natural brassinolide once. When the plants are budding, uncover the film and cover with soil.
If the plants show excessive vegetative growth, you can control vigor manually: at the first flowering, use a bamboo pole to knock off the flower clusters in a horizontal direction; at the second flowering, use a bamboo pole to knock off the flower clusters in an up-and-down direction, and at the same time break the growth point of the upper main stem. You can also spray 1-2 times with paclobutrazol. In addition, you can spray 50 g monopotassium phosphate + 50 g white granulated sugar + 100 g Youguo calcium + 50 g mancozeb + 15 kg water to promote tuber bulking.
6. Timely harvest
Spring greenhouse potatoes have a relatively short growth period. Generally, in early to mid-May, when the potato tubers reach a diameter of 5-6 cm or more, harvest in time. To reduce the loss of moisture and nutrients in marketable potatoes, store them away from light.
Huang Yongshan, Longyao County Vocational Education Center