What issues should be noted when harvesting sweet potatoes
The sweet potato is a vegetative propagule with no obvious maturity standard or harvest period, but the timing of harvest affects the yield, seed preservation, storage, processing and utilization, and crop rotation of sweet potatoes. Harvesting too early will significantly reduce the yield of sweet potatoes; harvesting too late, sweet potatoes are often affected by low-temperature chilling injury, do not store well, and the drying rate declines. Therefore, sweet potatoes must be harvested at the right time.
The suitable harvest period for sweet potatoes should be determined according to climatic conditions, safe storage time, and the arrangement of the following crop. When the ground temperature is around 18°C, the weight of sweet potatoes increases very little; when the ground temperature is around 15°C, sweet potatoes stop expanding; when the ground temperature remains below 9°C for a long time, chilling injury will occur. Therefore, harvesting of sweet potatoes generally begins when the ground temperature is 18°C, and is completed before the killing frost. Spring sweet potatoes used for drying or those followed by winter wheat are generally harvested before Cold Dew; summer sweet potatoes kept for seed are harvested before Frost's Descent; sweet potatoes stored for eating are harvested a little later, but must be completely harvested before the killing frost.
Soil that is too dry or too wet is unfavorable for sweet potato harvest. If too dry, the soil moisture content decreases, the ground temperature varies greatly, sweet potatoes are prone to chilling injury, and it is not easy to dig them out. If too wet, the soil moisture content is too high, and not only is it difficult to dig out the sweet potatoes, but they also have a high moisture content and do not store well after harvest. When the soil is too wet, the sweet potato vines should first be cut off, dried for a few days, and harvesting should wait until the soil is slightly dry.
Summer sweet potatoes kept for seed should preferably be harvested on a sunny morning, dried in the field for a while, and put into the cellar that afternoon; do not leave them in the field overnight, so as to avoid chilling injury.
After sweet potatoes are dug out, the tubers can be selected in the field, removing diseased, damaged, and water-soaked tubers, and stored separately according to different uses and varieties. From digging to storage, the number of times they are turned over should be minimized, and care should be taken to handle, place, load, and transport them gently, so as to avoid bruising the skin of the tubers.