How to keep carrots for a winter?

I. On-site storage

This method is suitable for areas in southern China where the coldest winter temperature is above 0℃. The carrots planted are not harvested and stored in winter, and then harvested and listed in the Spring Festival. But we must catch up with the harvest at the latest, otherwise it will germinate, and the growth of new leaves will consume nutrients, making its quality worse or bolting lose its commercial value. However, there are also areas where the coldest temperature in winter is -3℃, and the soil with a thickness of 3 ~ 5 cm is covered with agricultural film and stored in place for wintering, and harvested when the price is high. Before freezing, plastic film should be covered and covered with soil, and the plastic film should be compacted to prevent it from being blown off by the wind, and the soil layer should be covered to keep warm and overwinter safely.

Second, open storage.

Open-air storage is a simple and feasible storage method, which is suitable for wintering storage in warmer areas. In cold areas, it is generally only used to temporarily store a large number of carrots in autumn and winter. It can also be used in areas where the temperature is -8 ~ 3℃ in winter. Specific practice: After harvesting carrots, twist off the leaves, select carrots without pests, branches and cracks, and pile them into a round pile on the spot. The diameter of circular pile is generally 1 ~ 1.3m, and the pile height is about1m. Don't pile it too high, so as not to generate a lot of heat in the pile, which will lead to carrot rot. After stacking, cover the pile with 10 ~ 15 cm thick wet fine soil and tamp it to prevent water loss caused by wind. When the weather gets cold and the local night temperature drops below -3℃, cover the soil for the second time, thicken the soil to 20 ~ 25 cm, and add a layer of hay to keep warm and moist, so that carrots will not freeze. Carrots stored in this way can be listed around the Spring Festival.

Third, ditch storage

In places with high terrain, low groundwater level, heavy soil and strong water retention, the trench shall be excavated in the east-west direction, with a width of 1 ~ 1.5m and a depth of1~1.2m. The excavated topsoil shall be stacked in the south of the trench for shade. The lower mound is covered with soil to the north side of the ditch. After harvesting, when the temperature is 0 ~ 5℃, the carrots are scattered in the ditch, head down, roots up, one layer of carrots and one layer of soil. You can also pile three or four layers of carrots before covering the soil, and cover the soil layer by layer with the weather change, with a total thickness of 70 ~ 100 cm. When the humidity is low, a certain amount of clear water can be poured to make the soil water content reach 18% ~ 20%. But there can't be water in the ditch, and it is usually listed in the ditch at one time.

Fourth, cellar storage

The cellar storage method has the advantages of large storage capacity, high freshness, convenient management and inspection, being ready to go out of the cellar and being listed in batches. Pit storage is mostly used in northern areas. The structure of cellar is the same as that of potato cellar. Pits are generally dug in the north-south direction, with a depth of 100 ~ 150 cm. Take soil from the pit and build an earth wall with a bottom width of 80 cm and a top width of 65 cm around the pit. The cellar is about 300 cm wide and unlimited in length, but it is generally between 10 ~ 50 meters for the convenience of operation and management. After the earth wall is completed, a beam will be erected every 1.5m, and a column will be erected at both ends. Then set up 4-6 wooden purlins on the beams, cover them with straw with the thickness of 15cm, and finally cover them with soil about 30cm for compaction. There are several pits (skylights) at the top for access and ventilation. The number and size of pit openings should be determined according to local climate and pit size. Generally, a 60 cm× 60 cm square pit mouth is opened at the center of the pit top from both ends 100 ~ 150 cm. In addition, dig a 25 cm× 25 cm cellar hole at the bottom of the earth wall every 200 cm to strengthen ventilation. Specific operation method: pile carrots selected and processed before storage into a pile with a width of 60 cm and a height of 80 ~ 100 cm along the cellar wall. The outer layer of the stack should be neat and smooth, so that one layer of carrots faces inward and the other layer faces outward to prevent dumping, and the stack can be scattered. The stack can be covered with a layer of 2 ~ 3 cm thick wheat straw, which can not only prevent freezing, but also keep moisture. In the middle of the pile, a straw can be inserted as a ventilation hole every 3 ~ 4 meters. Spread a layer of straw mud on the outside of the pile to keep the water in the pile.

Temperature control and management measures change with seasons, which are generally divided into three stages. The first stage is from light snow to heavy snow. During this period, the average outside temperature was about 2℃, and the pit temperature was greatly influenced by the outside world. Because of the high temperature and vigorous breathing, more heat is released. At the same time, because of its large storage capacity and large evaporation capacity, it is easy to cause high temperature and high humidity environment. So at this time, we must pay attention to strengthen ventilation, and the pit mouth and pit eyes should be completely opened to reduce the pit temperature and emit moisture. The solar term of heavy snow is coming. In order to prevent the rainstorm, the caves in the northwest are closed one by one. After a few days, the caves in the southeast are blocked, leaving only the skylight for ventilation. At the same time, due to the difference of temperature and humidity between the upper and lower layers of carrot, the upper layer has low temperature and humidity, while the lower layer has high temperature and humidity. If the upper and lower floors are not reversed, the accumulated temperature and humidity gap will increase and the carrots in the lower floors will rot. Therefore, the carrot pile in the cellar should be inverted regularly, and it should be inverted three times at the initial stage of entering the cellar, with an interval of 10 days each time. When folding, put the original upper layer on the lower layer and the lower layer on the upper layer. At the same time, pick out the rotten carrots and pile them up again. The second stage is from heavy snow to beginning of spring. During this period, we will experience the coldest winter solstice solar term, and the lowest temperature in Beijing is-10 ~- 18℃. As the temperature drops and the respiratory function weakens, the problem of decay has been relegated to a secondary position, and the management focus is on preventing frostbite. To manage the pit mouth well, slowly expand the pit mouth during ventilation, let the cold air outside slowly flow in and spread to all corners, let the cold and warm air convection slowly, and the pit temperature will gradually drop. Never let the cold air suddenly invade carrots. The outdoor time should not be too long, so that the pit temperature will drop to about -2℃. During this period, the times of superposition can be reduced, and it can be flipped 1 time in 20 days. In case of strong wind or snowy weather, when ventilation is needed, the mat covering the pit can be propped up with the wind, which can not only ventilate, but also prevent the invasion of snow. The third stage is from beginning of spring to the vernal equinox and Qingming, with the temperature rising continuously and the cellar temperature rising rapidly. At this time, the focus of management is ventilation. In addition to opening the pit mouth, we should gradually open the pit eye on the wall to make the air convection between the pit mouth and the pit eye smooth. At the same time, we should extend the outdoor time. After entering March, the outside temperature continues to rise, and it is still difficult to cool down by the above methods. Therefore, it is necessary to change the outdoor time. During the day, the pit is tightly sealed with pu pad to prevent light from entering and high temperature from invading. At night, the pit is opened for outdoor air after the outdoor temperature drops. In addition, it is necessary to strengthen stacking. Under suitable conditions, it can be preserved until April of the following year.