Timely harvest and safe storage of sweet potato

? (1) timely and safe harvest

1. The best harvest time of sweet potato

There is no obvious maturity period of sweet potato, which usually depends on the local temperature. Early harvest affects the yield of fresh potato, and too late harvest is vulnerable to cold injury and storage. There were significant differences in yield, quality and storability with different harvest time. The harvest time should be treated separately for different uses and different situations, such as stubble, sweet potato processing, fresh food, seed retention and other reasons.

Look at the temperature: the normal harvest period should be when the local daily average temperature drops to 15 ℃ to start the harvest and end at 12 ℃. It is usually harvested before Frosts Descent.

Second, the use of sweet potato: ① spring potato processing zone is mainly used for drying and processing starch, which should be harvested from the beginning of October to the middle of lO month. During this period, the sweet potato yield and drying rate are high and the weather is good, which is conducive to processing. ② needs to remove stubble early and can be harvested in late September, but sweet potato production is reduced by about 10 per cent. ③ seed for sweet potatoes, must be in Frosts Descent (that is, October 23. Before harvest, sweet potato is not damaged by cold, and the temperature of early harvest is high, so it is easy to cause diseases when entering the cellar. Other uses, such as fresh edible commercial potato, can be harvested early (the growing period from spring potato to late August is 120 days), and appear on the market early with high price and good benefit. Especially precocious varieties such as Sushu 8, Anping 1, Yushu 10, etc., grow for 100 days. Spring potato can be listed in mid-August, with a yield of 2000 kg per kilogram and an output value of 2000 yuan per mu, and can also grow seasonal winter vegetables.

two。 Safe harvest

(1) to achieve "four light" and "five precautions" when collecting and planing. The "four light" means light planing, light loading, light transportation and light handling, and the "five defenses" are anti-frost, rain, overnight, bruising and disease prevention. The harvest must be carried out on a sunny day, and the cellar must be collected on the same day.

(2) cushion grass in the basket during shipment to avoid bruising.

? (2) safe storage

1. Carefully selected in front of the cellar, different varieties of potato pieces of different sizes are separated from the cellar. To achieve "ten do not enter the cellar": mud, broken injuries, sick, insect bites, frozen, rain, flooding, germination, outcrop green, cracks and other potato blocks are not allowed in the cellar.

2. Choose the cellar site: to build the cellar, you should choose the place where the cellar is leeward and sunny, the terrain is high and dry, the soil is not hard, and the groundwater level is low. A variety of cellar types can be adopted, such as semi-underground high-temperature cellar, improved well cellar, fixed voucher cellar, well cellar, shed cellar and so on.

3. Chemical treatment of potato seeds: chemical treatment can kill the germs on the surface of potato pieces and shallow wounds, and play a role in disease prevention and preservation. But it has no effect on physiological changes such as low temperature, wet injury, bruise and so on. Still keep the right temperature.

The main results are as follows: (1) Sweet potato fresh-keeping powder is a compound of many kinds of pesticides, and the disease control effect is ideal.

(2) 50% carbendazim 300 times solution. Seed soaking: it is a kind of internal absorption with high efficiency, low toxicity, low residue and wide range of sterilization.

Sexual fungicide has a good effect on the prevention and control of black spot and soft rot.

(3) 500 times solution of 70% methyl topiramate. Seed soaking: it is also a highly efficient and low toxic pesticide with the same properties as carbendazim, but its disease prevention effect is better than that of carbendazim.

4. The management of potato cellar: the suitable temperature of potato during storage is 10-14 ℃. If the temperature is lower than 9 ℃, it is vulnerable to chilling injury. If it is higher than 15 ℃, the respiration is exuberant, a large amount of nutrients and water are consumed, and the weight of potato is lost, and the temperature is higher than 16 ℃. Potato pieces are easy to germinate and develop diseases. According to the characteristics of potato chips and weather changes, the management of potato cellar can be divided into three stages:

The main results are as follows: (1) in the early stage, the early stage of potato cellar is mainly ventilation, cooling and dampness dissipation. Because when entering the cellar, the outside temperature is high, the breathing intensity of potato pieces is high, and a large amount of water vapor, carbon dioxide and heat are released, resulting in high temperature and humidity in the cellar. This creates good conditions for potato cubes to sprout and infect diseases, especially for diseased potato lumps to spread due to bacterial infection.

A large number of rotten potatoes, commonly known as "burning cellar". If the temperature is right, the potatoes will only sprout and not rot. Potato cubes in the cellar within 30 days (especially within 20 days) should often pay attention to the changes of temperature and humidity and adjust them. In order to promote wound healing 5-7 days before entering the cellar, the pit temperature should be kept at 15-18 ℃. Be careful not to raise the pit temperature above 20 ℃. 5-7 days after entering the cellar, the pit temperature should be controlled at no more than 15 ℃, preferably 12-14 ℃, and the relative humidity should be kept at 85% 90%.

(2) in the middle period: this period refers to the period from 30 days after the potato pieces entered the cellar to around the Beginning of Spring in the coming year, mainly to keep warm and prevent cold. In this stage, the temperature is low, the respiration intensity of potato is weak, and the heat release is small, which is the most vulnerable period of cold injury. Notice that when the pit temperature drops to 12-13 ℃, it begins to keep warm. Such as sealing soil, closing doors, windows and vents, covering the potato pile with hay (and preventing condensation water from soaking the potato block to prevent dampness), if the pit temperature is reduced to 9-10 ℃ in severe winter, the apparent pit temperature should be heated properly.

(3) in the later stage, the Beginning of Spring should strengthen ventilation before coming out of the cellar. In this period, due to the gradual rise in temperature, but continuous cold snap, the weather is changeable, due to the long-term storage of potato pieces, the respiration is weak, the resistance is greatly weakened, can not withstand the excessive change of pit temperature, can not stand the attack of low temperature. Therefore, we should pay attention to the weather change at any time, adjust the doors, windows and vents in time, keep the temperature in the cellar at 12-14 ℃, and the relative temperature is not lower than 85-90%.