Detailed Explanation of Key Techniques for Winter-Planted Potato Cultivation
How to Cultivate Winter-Planted Potatoes
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Guangdong has warm winters and abundant water sources, giving it resource advantages for developing winter-planted potatoes. The winter-planted potatoes that come to market earliest in Guangdong are a full 3 months earlier than those from other regions, making them the earliest fresh potatoes to reach the market in the world, with a market advantage. Winter-planted potatoes are currently one of the more ideal winter crops, and they are easy to cultivate, have a short production period, low cost, high yield and wide uses. The main cultivation techniques are as follows:
1. Seed Treatment
Before sowing, sprouting and sunning of the seed potatoes is required. After harvest, potatoes have a dormancy period of 50-60 days, and all seed potatoes that have not sprouted must be forced to sprout. Sprouting methods:
1. Spread out in storage. After buying the seed potatoes, spread them evenly in a dry, ventilated indoor place. If some tubers are found to be partially rotten, cut off the rotten parts.
2. Cutting into pieces. Do this 10 days before planting. The apical bud eyes of the potato sprout first and inhibit the sprouting of the middle and lower bud eyes; if the apical young sprout is damaged or removed, the other bud eyes will sprout rapidly. In order to obtain more seed potatoes, the potatoes must be cut into pieces. The method is as follows: (1) Cutting method for large potatoes of 2.5 liang or more: cut horizontally from the middle, then cut the apical part vertically into 2-4 pieces, each piece having 1-2 bud eyes and all connected to the apical part. Cut the navel end into 2-3 pieces. (2) Cutting method for potatoes of about 2 liang: one horizontal cut and one vertical cut, i.e. divide into four pieces. (3) Cutting method for small potatoes of about 1 liang: one vertical cut, divide into two pieces. (4) Cutting method for small potatoes under 1 liang: just cut off 0.6-0.8 cm at the top; do not cut completely through.
3. Disinfection of cut pieces. After cutting the seed potatoes, spray with a 0.2% carbendazim or chlorothalonil solution (100 jin of water plus 2 liang of the chemical) for disinfection; just spray until moist. Wood ash can also be applied to the cut surfaces. After drying, carry out sprouting in a sand bed.
4. Sprouting in a sand bed. Carry out sprouting in a dry, ventilated indoor place. Use clean river sand in a ventilated, shady place to make a sprouting bed. Spread the cut potato pieces densely and flatly on the ground, then cover with wet river sand 3 cm thick. On the river sand, densely lay small tubers, then cover them with river sand again. In this way, one layer of small potato pieces and one layer of wet river sand (2-3 layers is suitable); after laying, cover well with gunny sacks or rice straw. After 6-8 days, when most potato pieces have sprouted (the sprouts grow to the size of a peanut kernel), they can be sown. During sprouting, frequently check the moisture of the river sand; if too dry, spray water in time, and avoid water accumulation at the bottom.
2. Field Cultivation
1. Soil selection. Choose fertile sandy soil with convenient drainage and irrigation. Planting should be carried out immediately after the late rice is harvested; planting from late October to early November is most ideal. It is not suitable to choose paddy fields with heavy, sticky soil that easily becomes compacted. To prevent the spread of diseases, avoid continuous cropping with peanut, tobacco, tomato and other Solanaceae crops.
2. Opening furrows and making beds, applying sufficient base fertilizer. The sowing rate per mu is 80-100 kg. Generally, 3500-4000 plants are planted per mu. Each bed is 1.3 m wide, with a bed surface width of 80-90 cm; planted in double rows, with a row spacing of 28 cm and a plant spacing of 25 cm. It is best to plant with deep furrows and high beds; the furrow depth is about 18-20 cm and the furrow width is about 45-55 cm, which is good for drainage and field operations. Apply sufficient base fertilizer: apply sufficient organic fertilizer in the field; per mu, apply 1000-2000 kg of farmyard manure and miscellaneous fertilizer plus 20 kg each of phosphate fertilizer and compound fertilizer, and 5 jin of potassium sulfate as base fertilizer, mixed and applied in the middle of the bed.
3. Sowing. Open two planting furrows on the bed surface, with a spacing of 28 cm between them; place the seed potatoes, with 25 cm between each seed potato piece, bud eyes facing upward, and cover with soil. Immediately after planting, irrigate once with running water, irrigating to 2 cun below the bed surface; never let it flood over the bed surface, so as to avoid causing the seed potatoes to rot. After 1-2 days, use 2 liang each of Dual and Lasso, or 1 liang of Gold Dual, mixed with 60 jin of water and spray on the bed surface for weed control, and finally cover with rice straw.
4. Topdressing in the field. (1) When 60-70% of seedlings have emerged, apply 5 kg of urea and 5 kg of compound fertilizer per mu, mixed with 40 dan of water, and pour on. The compound fertilizer should be soaked overnight to facilitate dissolution. (2) When the seedlings are about 10 cm tall, apply 5 kg of urea and 5 kg of compound fertilizer per mu, mixed with 40 dan of water, and pour on. Also carry out small hilling. (3) After the rows close, apply 5 kg of urea and 7.5 kg of compound fertilizer per mu, mixed with 40 dan of water, and pour on, and carry out large hilling. It is best to use low-concentration pig urine water and apply frequently in small amounts; in this way the marketable rate is higher and high yield is easy. Large hilling is the key measure determining the marketable rate of potatoes; hill well so that tuber formation and tuber expansion both occur within the soil, avoiding tubers being exposed and becoming green potatoes.
5. Water management. After planting, keep the soil moist to facilitate early emergence, and afterward also keep the soil moist. When the field soil surface turns "white" and the soil is short of water, irrigate, with the water amount reaching half the bed height as suitable; after the water has seeped through the bed surface soil, drain. Before harvest, there should be no waterlogging at the bottom of the furrows in the field; just keep the soil moist. When there is too much rain, pay attention to drainage; especially in the 15 days before harvest, there must be no waterlogging in the field, to prevent the tubers from absorbing excessive water and cracking or rotting.
6. Pest and disease control. Diseases include late blight, soft rot, viral diseases, scab, etc.; insect pests include aphids, potato tuber moths, lady beetles, etc. (1) In the early stage of winter growth, high temperature and drought make the plants prone to aphid damage, which can be controlled with dimethoate; for other pests such as potato tuber moths and lady beetles, use 800-fold trichlorfon solution, 1000-fold 50% dichlorvos emulsion, or 300-400-fold 2.5% ammonium phosphosulfate emulsion. (2) In the middle and late stages, late blight is likely to occur; use 1:2:200 (copper sulfate:lime:water) Bordeaux mixture for early control at the initial stage of disease onset, and strengthen field management inspection; immediately pull out and remove diseased plants when found, to prevent the spread of disease. Chemical control: 1000-fold mancozeb solution or 600-800-fold 75% chlorothalonil solution.