Nitrogen deficiency Watermelon is sensitive to nitrogen, and the average nitrogen uptake per mu is about 11 kg. The nitrogen is deficient, the plant grows slowly, the stems and leaves are weak, the lower leaves are chlorotic and yellow, the new shoots of the stems are shortened, the young melons are swollen slowly, the fruits are small, and the quality is poor. On the basis of the application of organic fertilizer in Puxi and Fengchangou, urea should be applied in stages, of which about 10 kg per mu is applied; 10 to 12 kg of fertilizer is applied; and the result is 15-20 kg. It can also be used to apply 500-600 kg of manure per acre. At the same time, foliar topdressing is carried out according to the situation, 0.3% urea in the seedling stage, and the fruit setting period is increased to 0.5%. Phosphorus deficiency Phosphorus can promote the growth of watermelon roots and enhance the ability of roots to absorb water and fertilizer, especially in the low temperature season. The amount of phosphorus required for watermelon is lower than that of nitrogen, and the average phosphorus absorption per acre is about 3.5 kg. However, phosphorus deficiency and poor root development. The plant is small, the leaf back is purple, the flower buds are poorly differentiated, the flowering is late, the fruit setting rate is low, and the flower is easy to fall and the "melon". Yellow fiber and lumps often appear in the flesh, the sweetness is reduced, and the seeds are not full. Calcium phosphate can be applied per acre of 15 to 30 kg; calcium superphosphate can also be mixed into organic fertilizer and sprinkled into the melon ditch to effectively prevent phosphorus deficiency. If symptoms of phosphorus deficiency are found, 0.4% to 0.5% calcium perphosphate leaching solution should be sprayed on the leaf surface in time. Potassium deficiency Watermelon has the highest potassium uptake, 1.2 times and 3.4 times of nitrogen and phosphorus, respectively. Plant resistance due to potassium deficiency is reduced. The transport organization is not smooth, nutrient synthesis and transportation are blocked, so the sugar accumulation in the fruit is insufficient, resulting in reduced watermelon yield and poor quality. The plant grows slowly, the stems are weak, the leaves are shrunk, the edges of the old leaves become brown and die, and gradually expand inward. When severe, the leaves develop, the leaves are pale green, and the leaves are scorched. The fruit is swollen slowly, the melon is small, the fruit is difficult, and the melon is small. Moreover, the fruit has a low sugar content, a large sugar gradient, and poor quality. Production should pay attention to the use of potash. Firstly, 60-100 kg of wood ash is applied per mu of ditch, and secondly, about 5 kg of potassium sulfate is applied per mu in the seedling stage; 8 to 10 kg of potassium sulfate is applied per acre before the fruit is plucked; Foliar fertilizer power potassium, every 7 to 10 days. Calcium deficiency Calcium deficiency in watermelon occurs more frequently in the application of calcium-free fertilizer for many years. When the watermelon is deficient in calcium, the parietal lobe is yellow, and the lower part remains green. This is a typical feature of calcium deficiency and nitrogen deficiency, phosphorus and potassium. In addition, the calcium deficiency of watermelon is accompanied by yellowing of the leaf margin, and the leaves are curled to the outside, which is parachute-like, and the top part of the plant becomes brown and necrotic, and the stems stop growing. Due to the lack of calcium in the ovary due to flower bud differentiation, fruit malformation is often caused. The remedy is: applying 50-100 kg of calcium phosphate per mu of ditch; covered with mulch mulch, planting grass in the sputum, moisturizing and moisturizing, preventing drought and promoting calcium absorption; combined with soil fertilization, using powerful calcium leaf spray to supplement root system Insufficient absorption of fertilizer. Boron deficiency The amount of boron absorbed by watermelon is higher in the field, and it is easy to be deficient in the soil with less organic fertilizer and no application of boron fertilizer. In addition, sandy loam soil and alkaline soil are easy to reduce the effectiveness of boron and lead to plant boron deficiency. When the watermelon is deficient in boron, the new leaves do not stretch, the leaf surface is uneven, and the leaf color is uneven; the new vines are shortened, the vines are upright, and the new vines have transverse cracks, which are brittle and fragile. The section is brown, and when it is severe, the growth point dies and stops growing. Sometimes the red-brown paste is secreted on the vines; the lack of boron in the watermelon often causes flower dysplasia, and the fruit is malformed or cannot be normal. Generally, the power boron is sprayed 4 to 5 times in the flower bud period, once every 7 days, the effect is better. Disclaimer: Some articles on this website are transferred from the Internet. If legal rights of third parties are involved, please inform this website. phone We are the one of three leading factory in China, specialized in manufacturing laser distance module since 2004. Bilateral laser distance measurer is one of mutifunctional laser distance device. JRT multifunctional laser measuring device functions include area,distance,length,volume,continuous measurement,addition and subtraction, measuring unit: ft/m/inch. More functions can be customerized. 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The whole growth period of watermelon is focused on prevention of deficiency
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