A. When the vines of watermelons planted in the open field in late April are about 50cm long, apply compound fertilizer at the next node of female flowers, then put them into vines, cover them with soil and pat them firmly. After that, press the vines every 4 ~ 5 knots. If there is a lack of fertilizer, 7 ~ 5 kg of urea can be applied to the hole per mu at a distance of 40 ~ 50 cm from the plant outside the plastic film and 40 ~ 50 kg of decomposed sesame cake can be used when the vines are pulled. The distance between the main vine and the rhizosphere1.3 ~1.6m, and the distance between the lateral vine and the rhizosphere is about 23cm. That is to say, choose a large one with a long and straight ovary and many hairs. Generally, two melons are selected from three vines of small seed melons, and two vines or three vines of large seed melons are selected 1 melon. B, when the watermelon is directly broadcast in the open field before and after Grain Rain, when 1 real leaf, 30% decomposed clear water manure is applied; When there are 3 ~ 4 real leaves, calcium superphosphate and decomposed clean water manure are applied in the open-loop ditch 5 ~ 7 cm away from the root; The third topdressing is to apply 75g of calcium superphosphate and 25g of urea to each hole at the tip of the main vine. After pulling the vines and before climbing the vines, thoroughly plough and weed. If it is wheat stubble land, after wheat harvest, cover wheat straw between rows about 200kg／/mu, which is beneficial to the growth of melon and improve its quality. When the vines are about 0.3m long, the vines will be pressed, and then every 4-5 knots 1 time, until the melons sit firmly, the stems and leaves will not be damaged by wind. C, promoting flowers and keeping fruits: spraying Zhuangguadiling solution once at the initial flowering stage, the young fruit stage and the fruit expansion stage can thicken the pedicel of melon, strengthen the directional delivery of nutrition, promote the rapid development of melon, and make the melon shape beautiful and the juice delicious; The growth cycle does not drop flowers, melons, cracked melons and deformed melons. At the same time, new high-fat film solution should be sprayed to strengthen the prevention and control of pests and diseases.