Clever topdressing for sweet potatoes: fast tuberous root expansion
Sweet potato is a potassium-loving crop. Of the nutrients it needs, nitrogen accounts for 30%, phosphorus 10%, and potassium 60%. During growth, potassium deficiency in sweet potatoes at an early stage causes shortened internodes and petioles and smaller leaves; potassium deficiency at a later stage causes severe chlorosis of the veins in old leaves, which gradually drop off, seriously affecting yield formation later on. The method of applying potassium fertilizer is: ...
From late August to early October is the tuberous root expansion period of sweet potatoes. This period is critical for yield formation and is also the period of greatest fertilizer demand. The following three methods can be used for topdressing.1. Hole topdressing method: Use a wooden peg to make a hole about 30 cm deep 20-30 cm away from the main root, put in an appropriate amount of three-element compound fertilizer, and seal it well with moist soil.
2. Crack topdressing method: When cracks appear in the ground as the sweet potatoes expand, use 500 g of potassium dihydrogen phosphate per mu, add 400 kg of water, mix into a fertilizer solution, and pour it into the cracks, 0.7-1 kg per plant.
3. Foliar topdressing method: Spray a 0.3% potassium dihydrogen phosphate aqueous solution on the leaves once a week. This method can increase yield by 18%-20% per mu.