Potato Frost Protection and Post-Disaster Mitigation Measures After Snow and Ice Damage

(1) Functions and Uses

1. The effects of low temperatures on seed potatoes during storage and on seed potatoes and young sprouts (seedlings) after sowing.

2. Reduce the severity of snow and ice damage; promote the recovery of potato growth.

(2) Technical Measures

1. Preventive measures against frost damage

(1) During the storage of seed potatoes, pay attention to keeping them warm. Before low temperatures arrive, take preventive measures: place a straw mat under the seed pile and cover the top of the seed pile with straw mats or other coverings to prevent frost damage.

(2) Adjust the sowing period appropriately to prevent frost damage. In light of the climatic characteristics of different areas in our region and the actual production situation, it is recommended that, on the premise of ensuring economic returns, the sowing period be adjusted appropriately in production to avoid the effects of frost damage as much as possible.

(3) Take preventive measures to enhance the cold resistance of crops

① Dig ditches for drainage: Drain standing water in the field in a timely manner to improve soil permeability and reduce the effects of frost damage and waterlogging on crops. ② Cover for warmth: Use rice straw, crop stalks, plastic film, etc. as mulch to raise soil temperature. Where conditions permit, small arched sheds can also be built. However, after temperatures rise, the coverings or small arched sheds should be removed in a timely manner to prevent seedling burn caused by excessively high temperatures or the occurrence of diseases. ③ Ridge formation and soil covering, hilling for warmth: After sowing, form high ridges; after emergence, combine intertillage and weeding with timely hilling in the field. Where conditions permit, heated farmyard manure such as burnt soil fertilizer and plant ash can also be applied along with hilling to improve cold and frost resistance.

2. Mitigation measures after frost damage

After suffering frost damage, potato growth is affected to varying degrees. After the frost damage is relieved, field surveys should be carried out as soon as possible to understand the degree of frost damage, and corresponding mitigation and remedial measures should be taken to minimize the losses caused by frost damage.

(1) Never use potatoes with frozen tubers as seed potatoes

Potatoes that suffered frost damage during storage have weaker sprouting ability, and soft rot is likely to occur after temperatures rise. Therefore, never use potatoes with frozen tubers as seed potatoes.

(2) Measures to be taken for potatoes after sowing

① Dig ditches. For fields with lower terrain, drainage ditches should be dug as soon as possible after the frost damage is relieved to lower the water level, remove standing water, avoid tuber rot caused by accumulated water, and at the same time raise soil temperature as quickly as possible to promote plant recovery.

② Intertillage and hilling. After low-temperature frost damage, the soil is relatively compacted and has high moisture. After potatoes suffer frost damage, root vigor decreases. At this time, intertillage and hilling can loosen the soil, raise soil temperature, and promote root growth and development.

③ Check for gaps and replant. For plots where seedlings have not emerged, check the frost damage to underground seed potatoes. Where seed potatoes are found to be frozen and rotted, re-sprout and replant to avoid gaps that affect yield.

④ Fertilization. Fertilization should be carried out after the frost damage is relieved and the plants have resumed slow growth. Never fertilize immediately after frost damage. Method: For lightly frost-damaged plots, foliar fertilizer can be sprayed, such as 0.2%-0.5% potassium dihydrogen phosphate (60-80 kg/mu), to enhance plant resistance and promote growth recovery. For plots with moderate or severe frost damage after emergence and plots where seedlings have not yet emerged, apply quick-acting complete fertilizers such as biogas slurry and manure water, or apply 10 kg/mu of urea per mu, to promote plant recovery and tuber sprouting.

⑤ Disease prevention. After low-temperature frost damage, potato fields are prone to two soil-borne diseases: Verticillium wilt and Rhizoctonia solani damping-off. Therefore, in addition to routine control of late blight, bacterial wilt, and other diseases, active measures should be taken to prevent these two diseases. Control methods: Use 50% carbendazim wettable powder at 600-800 times dilution + 3% guangkuling at 600-800 times dilution as a root drench to prevent Verticillium wilt and Rhizoctonia solani damping-off; use 3% zhongshengmycin wettable powder, 100 g per mu in 60-80 kg of water, or agricultural streptomycin (2 million units) at 2000 times dilution for spraying to prevent bacterial diseases such as bacterial wilt; use 80% dasen wettable powder at 600-800 times dilution or 25% metalaxyl (ridomil) at 400-500 times dilution to prevent late blight.

⑥ Pay attention to preventing low-temperature frost again. Pay attention to weather forecasts. If frosty weather occurs, cover with plastic film or other coverings before frost and remove the film after frost, generally using 10 kg of plastic film per mu.