“Mr. Li, according to the season, this early spring vegetables have already been planted. However, this climate is so cold. Do you have any feasible solutions?†“Yes, yes, yes.†January 20, Nanjiang Agriculture Li Linxiu, deputy director of the Bureau's senior agronomist and Jingzuo Station, asked Zeng Zhengping, a vegetable planter, at Yushu Village in Dongbu Town. He explained on the spot: “The cold weather, vegetable seedlings, and seedbed ground temperature are the main factors affecting seedling emergence. If the temperature is too low, rotten seedlings are prone to occur, therefore, in the cold season, seedlings should be warmed, warmed and moisturized so that the temperature and ground temperature are maintained between 25°C and 30°C, and the minimum nighttime temperature is maintained at 15°C-18. Above °C, it will make it possible to grow seedlings and seedlings as soon as possible."
Specifically speaking, we must grasp the following four issues
The first level:
temperature control
When the seedlings are freshly emerged, the young stems and radicles are very sensitive to temperature and humidity. Under high temperature and high humidity, the young stems and radicles will rapidly elongate, forming leggy seedlings. After the emergence of the seedlings, the management goal is to promote the growth of young shoots and radicles. When the seedlings emerge out of the cotyledon (the top surface of the cotyledons), the plants should be ventilated, cooled, and dehumidified. They should be maintained at about 25°C during the day and 15°C at night. After the first true leaf is unfolded, the night temperature can be appropriately reduced by 1°C-2°C to form a large temperature difference between day and night, promoting the growth of thick seedlings and differentiation of female flowers, and preventing the hypocotyls from being excessively elongated. After cotyledon flattening, management aims to promote true leaf growth, flower bud differentiation and cultivating strong seedlings.
To raise seedlings in greenhouses, the temperature control is mainly controlled by controlling the time of air release and the amount of air release, and the time of uncovering the insulation material. It is necessary to gradually increase the amount of air release and the time of air release as the temperature increases, and try to make the temperature in the nursery bed uniform so that the growth of seedlings is consistent. The part of the vent is the first middle or top wind, and then transition to both sides or bottom. According to the changes in the weather and seedbed temperature changes to control the amount of air release and ventilation site.
About 10 days before planting, it enters the hardening period.
Second level:
Master the moisture
When raising seedlings in early spring, watering too much or too much in the early stage can easily cause the temperature of the seedbed to decline, which is not conducive to the growth of seedlings. If you water at high temperatures, you can easily cause seedlings to grow. Therefore, the bottom water must be poured before planting so as to meet the water requirement for the growth of seedlings and early seedlings. Minimize watering or even watering during nursery.
In the early stage of nursery, it is also possible to use the method of covering the moist soil to adjust the moisture and reduce the contradiction of the ground temperature. In the middle and later stages of raising seedlings, with the increase of temperature, the amount of water evaporation increases, and the method of covering the fluvo-aquic soil can no longer meet the water requirement of the seedlings. At this time, a high-temperature sunny morning can be selected to be sprayed with a watering can. Under normal circumstances do not warm irrigation, so as not to reduce the temperature or cause leggy seedlings.
The principle of watering at the seedling stage is “no cloudy days, sunny days, no afternoon pouring, and morning pouringâ€. Seedlings should be watered before sub-seedling, and seedling water should be poured when sub-seedlings are planted; watering should also be carried out on the first day before cutting seedlings.
Section 3:
Increase lighting
In the nursery of protected land, the light conditions of seedlings are not only related to the climate, but also related to the uncovering management of the opaque covering in the protected land. These managements not only affect the light, but also affect the temperature in the protected area. Seedling stage should be as much as possible so that the seedbed to receive more sunlight in order to improve the ground temperature of the seedbed, generally early cover late. Adequate light during the nursery period is conducive to the cultivation of strong seedlings. Therefore, in the winter and early spring when the low-temperature and low-light season is growing seedlings, the seedlings should be allowed to receive more sunlight as much as possible.
In addition to early release of opaque cover to cover the extension of the lighting time, management should always clean the transparent cover film to increase the amount of light transmission. The film is preferably dripless. On cloudy days, opaque coverings should also be uncovered, and in the rain and snow days, opaque coverings should be uncovered for a short period of time.
If we encounter yin, rain, and snow, the seedlings mainly consume nutrients in their own bodies, which can easily cause seedlings to become yellowish and weak, or even die of yellowing. Therefore, in the event of such weather, opaque coverings should be uncovered as much as possible to allow the seedlings to receive sunlight, and even to fill the light or put reflective film (aluminized polyester film) on the north side of the greenhouse.
Section 4:
Timely soil
Soil loosening can occur when soil moisture is excessive, compaction occurs, or in winter and early spring to improve the ground temperature of the nursery bed.
The loose soil can be used bamboo sticks or 8 small wire to make a small lotus root, loosen or loosen the topsoil, breaking the depth of the principle of not hurting the root. The ripping soil can be carried out once after the seedlings are flushed out, when two cotyledons are flattened and when two true leaves are present.
In order to promote the normal growth of seedlings, foliar fertilization may be performed according to seedling growth conditions and fertility of the nursery bed. Generally, foliar fertilizer can be applied to two true leaves and 3-4 leaves before planting. The foliar fertilizer is mainly composed of 0.2% urea and 0.3% potassium dihydrogen phosphate or other nutrient-type foliar fertilizers. Foliar fertilization usually takes place after 3 pm.
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