Choose good cultivation soil and varieties The best texture of the soil is sandy loam or loam, and the soil is deep. The suitable thickness of the tillage layer is 20 to 30 cm, requiring good drainage conditions. At present, there are main varieties of the United States, such as the black potato 1, smoke purple 300 and so on. Preparing for transplanting Leveling and arranging finely ploughed soil, so that no waste scum, combined with site preparation Shi Shifei, Mushi two tons of high-quality organic fertilizer, urea 6 to 7 kg, 12 kg of ammonium phosphate, 14 kg of potassium sulfate; ridge cover, according to ridge The bottom width is 50 to 60 cm, the ridge height is 20 to 25 cm, the width of the ridge back is 25 to 30 cm, and the ridges are separated from each other by 10 to 13 cm. The ridges are ridged, and the ridges are immediately covered with mulches. Transplanting The suitable planting period for Tianjin is from April 28 to May 10. Sweet potato seedlings are supplied by specialized nursery farmers or the corresponding farmer cooperatives. The suitable density for spring potato planting is 35000 plants/mu to 4500 plants/museum with 25 cm plant spacing. Transplanting method is: hole in the ridge back hole, depth 5 to 7 centimeters, two-thirds of the yam buried under the soil, first with soil to stabilize the seedlings, and immediately poured enough water, "at home," pay attention, The yam must be placed horizontally under the soil to facilitate ventilation and rooting. Immediately after sowing, a soaked stalk is placed in the hole around the seedling to provide moisturization and improve the survival rate. Field management After transplanting for 4 days, if dead seedlings are found, they should be planted in time, and after removing the seedlings, the weeds should be removed at any time. After mulching, the vines should be cut off and roots must be removed immediately. Do not turn over the ridges, remove the tops, and control the length of the main stem and the topography on the ground. It is conducive to tuber enlargement; for potato fields that are growing too prosperous, chemical control is required. During the middle growth stage, that is, during the peak period of ridge growth to stem and leaf growth, about 60 to 100 days after transplanting, 50 to 60 grams of paclobutrazol per acre is used. Water 50 kg foliar spray, usually 2 to 3 times, 7 to 10 days apart; After the beginning of autumn, the leaves can be sprayed with potato fertilizer and sprayed once every 10 to 15 days with a concentration of 0.3% potassium dihydrogen phosphate and 1 % of urea mixed solution, spray 2 to 3 times; remove water after rainfall; damage the main pest of black sweet potato is sweet potato wheat moth, can be used 10% imidacloprid WP 1500 times, before the third instar larvae Spray leaves to prevent and cure when rolling leaves. Timely harvest When the temperature drops to about 15°C, the harvest begins. Generally, the harvest is completed when the temperature drops to 12°C in the middle and early October, and it is prone to freeze damage later in the day. Greenhouse Dutch Buckets,Dutch Bucket,Tomato Dutch Bucket,Plastic Dutch Bucket JIANGSU SKYPLAN GREENHOUSE TECHNOLOGY CO.,LTD , http://www.spgreenhouse.com