What field management experience is there for sweet potatoes planted in June?
From early June, summer sweet potato planting in Huaibei of our province gradually comes to an end and enters the field management period, so field management of sweet potatoes should be strengthened. Checking seedlings and filling gaps Within one week after planting sweet potatoes, check seedlings and fill gaps to ensure a full stand. When filling gaps, select strong seedlings, water them thoroughly, and after they survive, apply extra fertilizer to the weaker seedlings, so as to help the small seedlings catch up with the large ones.
Intertillage and weeding Intertillage can break up surface crusting, loosen the soil, enhance soil aeration, and promote rooting and recovery of sweet potato seedlings. After intertillage, the soil capillaries are cut off, making it difficult for water in the lower soil layer to rise to the surface along the capillaries, thus reducing water evaporation. Therefore, intertillage helps drought resistance and moisture conservation, and at the same time removes weeds. Intertillage generally should be carried out 2~3 times: the 1st time after seedling recovery, the 2nd time at the branching stage, and the 3rd time before ridge closure. Hoe thoroughly and evenly, do not miss any spot, and do not injure the sweet potato seedlings. The 3rd intertillage should be combined with trenching and earthing up to restore the ridge shape. When trenching and earthing up, be careful not to damage the sweet potato vines and not to cover the ridge surface with too much soil, so as to avoid increasing the thickness of soil covering the sweet potato roots, which is unfavorable to root growth and tuberous root enlargement.
Topdressing Topdressing should be applied according to the seedlings and the field conditions.
(1) Skillfully apply fertilizer at the cluster-forming stage The cluster-forming stage of sweet potato refers to the period when the main stem of the sweet potato grows to about 35 cm and branches have already emerged from the leaf axils at the base. At this stage, according to the application of base fertilizer and the condition of the seedlings, apply a quick-acting nitrogen fertilizer either generally or selectively. General application means applying 4~5 kg of urea per mu in holes between two plants. Selective application means applying less to strong seedlings and more to weak seedlings.
(2) Foliar spraying fertilizer Generally used in the late growth stage of sweet potatoes, that is, 40~50 days before harvest. ① Potassium dihydrogen phosphate solution: use 150~200 g of potassium dihydrogen phosphate per mu, add 75~100 kg of water, stir, and spray. ② Sweet potato enlargement agent: use 10 g of sweet potato enlargement agent per mu, add 75 kg of water, and spray. ③ Calcium superphosphate solution: use 2~3 kg of calcium superphosphate per mu, add 75~100 kg of water, stir fully to dissolve, filter, and spray with a sprayer. Spraying after 4 p.m. on a sunny day gives better results.
Drought resistance and drainage In case of long-term drought, irrigate in time, especially during the peak period of tuberous root enlargement. When irrigating, the water depth should reach 1/3~1/2 of the ridge height, and alternate-ridge irrigation can also be used. Irrigate and drain promptly, and loosen the soil in time. Sweet potatoes are not tolerant of waterlogging, so drain promptly according to the field water accumulation.
Lifting vines That is, gently lift the sweet potato vines from the ground, break the adventitious roots, and then place them back in the original position. Under general conditions, this is not necessary. However, after rain and waterlogging, when the sweet potato vines are silted in the soil, lifting the vines has the effect of ventilating and dispersing moisture and facilitating drainage. For fields with abundant fertilizer and water and excessive growth, lifting the vines can break the adventitious roots, reduce the ability to absorb fertilizer and water, and inhibit excessive vegetative growth. If a tendency toward excessive growth appears, measures such as pinching the growing tips, lifting the vines, and pruning old leaves all have a certain inhibitory effect. In many areas, people have the habit of turning the vines in the middle and late growth stages of sweet potatoes. A large number of experiments have proved that the more times the vines are turned, the greater the yield reduction. Therefore, except when turning is necessary in the early stage for field management measures such as fertilizing, intertillage, earthing up, and trenching for drainage, generally do not turn the vines.