Potato Fertilization Methods and the Best Time for Topdressing Explained in Detail

The potato, also known as earth egg, potato, foreign taro and so on, is the tuber of a plant in the Solanaceae family. Together with wheat, rice, corn and sorghum, it is one of the world's five major crops. So how should potatoes be fertilized? When is the best time for topdressing?

The fertilization technology for potatoes should follow the principle of mainly using farmyard manure, supplemented by chemical fertilizers, mainly using base fertilizer, with appropriate topdressing.

Apply heavy base fertilizer. The potato is a tuber crop, likes loose sandy soil, and requires a cool climate. The amount of base fertilizer generally accounts for more than 2/3 of the total fertilization amount. The base fertilizer is mainly fully decomposed farmyard manure, with a certain amount of chemical fertilizer added, especially phosphorus and potassium fertilizer as base fertilizer. This can improve the physical properties of the soil and is conducive to growth and tuber formation. The nitrogen fertilizer in the base fertilizer accounts for about 50%. The application method is furrow or hole application before planting, at a depth of about 15 cm. The specific fertilization amount for a plot with a yield of about 1500 kg per mu is 1500-2500 kg of organic fertilizer per mu, 20 kg of urea, 20-30 kg of ordinary calcium superphosphate, 10-12 kg of potassium fertilizer, or 40-60 kg of high-nitrogen and high-potassium compound fertilizer. The fertilization amount can be appropriately increased in high-yield areas. Chemical fertilizer should be applied 2-3 cm away from the seed potatoes to avoid direct contact with the seed potatoes, and soil should be covered after fertilization.

Apply topdressing early. Topdressing should be carried out reasonably according to the growth period of the potato. Apply nitrogen fertilizer at the seedling stage, and combine it with intertillage and earthing up by applying 5-8 kg of urea per mu dissolved in water, to help preserve the seedlings. After the potato flowers, generally no root-zone topdressing is carried out, especially no nitrogen topdressing. After the potato flowers, spray 50 kg of 0.3-0.5% potassium dihydrogen phosphate solution per mu on the leaves. If nitrogen is deficient, add 100-150 g of urea, spray once every 10-15 days, for 2-3 consecutive sprays. Potatoes are relatively sensitive to boron and zinc. If the soil is deficient in boron or zinc, 0.1-0.3% borax or zinc sulfate can be sprayed on the outside of the roots, generally once every 7 days, for two consecutive sprays, using 50-70 kg of solution per mu.

When is the best time to apply topdressing to potatoes

1. At the seedling stage, nitrogen fertilizer should be applied as topdressing. Combined with intertillage and earthing up, 20-10-20+TE Moore seedling water-soluble fertilizer can be applied per mu dissolved in water, which is beneficial for preserving seedlings. The traditional method is root application of urea, but it is not conducive to absorption.

Apply seedling water-soluble fertilizer as topdressing at the potato seedling stage

2. Apply high-potassium fertilizer as topdressing after the potato flowers. In the south, the soil is mostly deficient in potassium, so potassium fertilizer should be increased. In the north, the soil is mostly deficient in phosphorus, so phosphorus fertilizer should be increased. However, potatoes have a large demand for potassium, which should also be taken seriously. Immediately after tuber growth begins, apply high-potassium water-soluble fertilizer 15-15-30+TE, and flush-apply once at an interval of about 15 days to promote tuber expansion.

Apply high-potassium water-soluble fertilizer as topdressing after the potato flowers

3. Foliar spraying. If potatoes show nutrient deficiency symptoms in the later growth stage, foliar topdressing can be carried out, spraying sugar alcohol medium and trace elements such as boron and copper. Boron is beneficial to tuber enlargement and can also prevent cracking. It has a special effect on improving the net photosynthetic productivity of the plant. Copper can increase protein content, increase plant respiration, increase chlorophyll content, delay leaf senescence and enhance drought resistance, all with good effects. At the same time, it also has the effect of improving the net photosynthetic productivity of the plant.

It should be especially noted that potatoes are a potassium-loving crop, and special attention should be paid to the application of potassium fertilizer in balanced fertilization. At the same time, do not apply too much chlorine-containing fertilizer, such as potassium chloride. Potassium sulfate should be selected instead, otherwise it will affect potato quality.