How to raise sweet potato seedlings with cold bed and double film

Seedling raising techniques of sweet potato in cold bed

Now it's time to raise sweet potatoes. Sweet potato is not only delicious but also nutritious, and it is very popular with everyone. Recently, some listeners called and asked for live broadcast of sweet potato seedling raising technology. Please pay attention to the cold bed seedling raising method of sweet potato in the open field.

First of all, the first item of sweet potato seedling cultivation is to choose the location of seedbed. No matter in plain, mountainous area or semi-mountainous area, we should choose places with leeward and sunny, fertile soil, high terrain, good drainage, close to water source and convenient management to dig pits and build beds. According to the quantity and management requirements of seed potatoes, the seedbed is east-west, with a width of two meters, a length of four to six meters and a depth of about one and a half feet. The soil at the bottom and around the seedling pit should be leveled, and then the fertile soil of about half a foot should be backfilled and stamped with the feet to facilitate the placement of seed potatoes and membrane buckles.

Second, talk about the time of sweet potato seedling. Generally, according to the planting time in our field, it will be pushed forward for 40 to 45 days. In our Shijiazhuang area, most seedlings are raised in the middle and late March of the solar calendar. At present, the high-quality sweet potato varieties promoted include Hebei 35 1, Ji Shu 98, Ji Shu 99, Jing 553, Xinong 43 1, Xu Shu 18 and other dual-purpose or special varieties. It is more suitable to choose sweet potato pieces that are straight, bright and smooth, and are not frozen, hurt or sick. The single piece size is three to half a catty. In order to control and reduce the occurrence of diseases such as black spot and soft rot, seed potatoes should be treated with chemicals before entering the cold bed. The specific method is to soak the seed potato 10 minute with 700 times of 70% thiophanate methyl, and then place the seed potato after the surface moisture of the seed potato disappears. When placing, the head should be tilted upward and master the principle of being flat on the top and uneven on the bottom. Generally, 30-50 kilograms of seed potatoes are used per square meter. After draining, fill the gaps between potato pieces with sand, and then water them. After the water permeates, gently press the seed potato with a flat plate, and then cover it with sand for about an inch. In this way, the process of placing seed potatoes is completed. Next, fasten the seedbed with transparent plastic film, seal the seedbed with soil, and cover it with straw mats or keep warm at night to prevent catching cold.

Next, the third item of sweet potato seedling raising is seedbed management. Strengthening seedbed management is the key to improve the emergence rate and cultivate strong seedlings. Before emergence, measures should be taken to increase the temperature and keep warm, so as to accelerate germination at high temperature, have appropriate moisture, and strive for early emergence, more emergence and no bed rot. After emergence, the temperature should be lowered appropriately, the seedlings should grow steadily, and attention should be paid to watering and ventilation to prevent bud burning. Seedlings should be tempered at low temperature before picking and fertilized after picking. Specifically, the following four tasks need to be done: First, adjust the temperature. Under normal circumstances, in the sunny morning, uncover the straw mulch to increase the temperature, and cover the straw mulch to keep warm around 4 pm. Within 3 days after the seed potato goes to bed, the potato layer temperature is kept at about 35 degrees, the bed temperature is kept at 30-32 degrees before emergence, and gradually drops to about 25 degrees after emergence; Second, on the basis of full watering, the seed potato seedbed is generally not watered before budding. After the seedlings are fully grown, before the seedlings are tempered, the next day after the seedlings are collected, water is poured once, and a small amount of water can be poured between floods if necessary. The third is reasonable topdressing. Combined with watering and topdressing after picking seedlings every time. Top dressing should be mainly urea, and ammonium bicarbonate should never be used to avoid burning seedlings. Of course, it is better to cooperate with phosphorus and potassium fertilizer. Generally, one kilogram of urea and one or two kilograms of potassium dihydrogen phosphate are used for 10 square meter, and the two fertilizers are mixed evenly and spread evenly. The fourth is to temper seedlings. The method is to choose the potato seedlings to come out in sunny weather and gradually ventilate them to gradually reduce the bed temperature. When the sprouts grow to about four inches, the temperature is stable, and the bed temperature can be ventilated day and night to 20-22 degrees. 2-3 days before picking seedlings, all the grass films and films can be removed.

When the seedlings grow to 6 inches high, they should be picked in time. Picking seedlings usually adopts the method of cutting seedlings, advocating high cutting seedlings and leaving stubble about one inch, which is more conducive to disease prevention. It is best to pick the seedlings in the morning and plant the cut seedlings on the same day. If it is not planted in time, it can be placed in a cool and ventilated place and planted as soon as possible the next day. After cutting the seedlings, film mulching should be used to raise the temperature during the day, film mulching should be used at night, and water and topdressing should be done the next day. One or two days after picking seedlings, the temperature should be raised and kept warm, and then the seedlings should be tempered at low temperature. Generally, seedlings can be picked after five or six days.