Watermelon is a high-yield economic crop with high temperature and cold tolerance and high fertilizer requirement. Generally speaking, nitrogen fertilizer is the basis of high quality and high yield of watermelon. Adequate phosphate fertilizer can promote the growth and development of plants, promote the differentiation of flower buds, and make them blossom, bear melons and mature early. Potassium is the catalyst of various enzymes in plants, which can promote photosynthesis, protein synthesis, increase sugar and improve the quality of melons. Therefore, scientific fertilization is the key to obtain high quality and high yield of watermelon.
Characteristics of fertilizer requirement? According to the experiment, every 1000 kg of watermelon fruit needs 2.5 ~ 3.2 kg of nitrogen, 0.8 ~ 1.2 kg of phosphorus and 2.9 ~ 3.6 kg of potassium, and the ratio of the three is about 3: 1: 3.5 ~ 4.
Watermelon has to go through germination stage, seedling stage, vine stretching stage, flowering stage and fruiting stage. Different periods have different requirements for nutrients. Generally, the absorption of nitrogen, phosphorus and potassium in seedling stage only accounts for 0.6% of the total absorption, 14.6% in jointing stage and 84.8% in fruiting stage. ?
Second, watermelon fertilization should adhere to the principle of "sufficient base fertilizer and clever topdressing".
? ? 1, sufficient base fertilizer.
Base fertilizer is the basis of high quality and high yield of watermelon, so we should pay attention to applying sufficient base fertilizer in production, and the specific amount of fertilizer can be determined according to the local soil fertility and yield level. Generally, 3000 ~ 4000 kg of decomposed high-quality organic fertilizer, 100 kg of cake fertilizer, 15 ~ 20 kg of urea, 35 ~ 50 kg of calcium superphosphate, 25 ~ 30 kg of potassium sulfate or 50 ~ 60 kg of ternary compound fertilizer can be applied every 667 square meters with deep tillage.
2. Skillful topdressing. During the whole growth period of watermelon, we should focus on applying seedling fertilizer, vine fertilizer and fruit fertilizer.
① Skillful application of seedling fertilizer: generally, seedling fertilizer is not needed for those with sufficient basal fertilizer, and 5 ~ 10 kg of high-nitrogen compound fertilizer or 4 ~ 5 kg of urea is applied for those with insufficient basal fertilizer every 667 square meters, and the fertilization time is controlled after the seedlings grow two true leaves.
② Skillful application of strong seedling fertilizer: strong seedling fertilizer should be carried out according to the growth. Generally, when the vines grow to 40-50 cm, urea 15-20 kg, potassium sulfate 10- 15 kg or 20-25 kg of high nitrogen compound fertilizer should be applied every 667 square meters to promote the growth of the vines.
③ Skillful application of fruit fertilizer: When the first batch of young melons grow to the size of eggs and lose fuzz, apply 25 ~ 30 kilograms of compound fertilizer per mu (combined with watering holes or rope, and cover the soil after application) to promote fruit expansion and accumulation of fruit contents such as sugar.
Third, matters needing attention
Chlorine-containing fertilizer is not suitable for watermelon, because watermelon is a chlorine-free crop, and the application of chlorine-containing fertilizer will affect the quality of watermelon. Don't want excessive fertilization in drought. Don't apply too much fertilizer at the seedling stage, and don't apply fertilizer too close to the roots to avoid damaging the roots and burning the seedlings. Generally, the distance from the main root 10 cm is required.
How to fertilize watermelon