How to fertilize watermelon? Master the five increases and five avoidances principle
Watermelon is a must-have fruit for relieving summer heat, and how to grow watermelons that are sweet and refreshing is what every melon farmer strives for. To grow watermelons well, fertilization must be done properly. To improve the yield and quality of watermelons, the "five increases and five avoidances" must be achieved in fertilization.
1. Increase organic fertilizer, and strictly avoid applying chemical fertilizer alone
Before sowing or transplanting watermelons, apply 3000—4000 kg of fully decomposed high-quality organic fertilizer and 80—100 kg of decomposed cake fertilizer per 667 sq m while preparing the land. During the vine extension stage and fruit setting stage of watermelon, apply 100—150 kg of decomposed human feces and urine or biogas fertilizer per mu as a top dressing according to the growth condition. This improves the growth vigor of watermelon, enhances stress resistance, increases yield, and improves quality. Strictly avoid applying chemical fertilizer alone; chemical fertilizer can only be used as a supplementary fertilizer in watermelon fields and must never be applied in large amounts, so as not to reduce the sugar content of watermelon and cause the quality to deteriorate.
2. Increase potassium fertilizer, and strictly avoid excessive application of nitrogen fertilizer
Increasing potassium fertilizer is closely related to the metabolism of watermelon and the synthesis, transport, and transformation of carbohydrates. It can improve the assimilation efficiency of watermelon plants, enhance drought resistance and disease resistance, improve fruit quality, and increase the sugar content of the fruit. Generally, 7—8 kg of potassium fertilizer (without nitrogen) per 667 sq m is used as a base fertilizer, and 4-5 kg of potassium fertilizer per 667 sq m is applied as a top dressing during the fruit setting stage, which can significantly increase watermelon yield and sweetness. Strictly avoid applying excessive nitrogen fertilizer alone. According to experiments, watermelon mainly relies on nitrogen nutrition before fruit setting, and after fruit setting the absorption of potassium increases sharply. If excessive nitrogen fertilizer is applied, it easily causes excessive growth of vines and leaves, delays flowering, and may even prevent flowering and fruiting, while disease resistance weakens and watermelon sweetness decreases.
3. Increase boron fertilizer, and strictly avoid applying chlorine-containing fertilizer
Applying an appropriate amount of boron fertilizer to watermelon can effectively prevent the rind from being too thick and the fruit from being hollow, and also has obvious effects of increasing yield, thinning the rind, and sweetening the flesh. Strictly avoid applying chlorine-containing fertilizer; watermelon is a chlorine-sensitive crop, and after applying chlorine-containing fertilizer, it will affect the accumulation of sugar, making the watermelon fruit taste bland and reducing its marketability.
4. Increase cake fertilizer, and strictly avoid using too much human feces and urine
When the watermelon is the size of an egg, dig a hole 10 cm away from the main root, apply 50 g of fully fermented and decomposed cake fertilizer plus 2 g of boron fertilizer per plant, cover with soil, and then water. Strictly avoid applying too much human feces and urine; excessive application easily causes excessive plant growth, difficulty in fruit setting, thick rind, sour flesh, and poor sales.
5. Increase foliar fertilizer spraying, and strictly avoid applying fertilizer too shallowly or too close
During the vine extension stage and fruit expansion stage of watermelon, spray a 0.5% potassium dihydrogen phosphate solution on the leaves, spraying 50 kg per 667 sq m, once every 7 days, and spraying 3 times continuously can increase sweetness. Before watermelon flowering and when watermelon begins to expand, spray a 0.1%—0.2% borax solution 2 times continuously, which can make watermelon high-yielding and sweeter. Strictly avoid applying top dressing too shallowly or too close to watermelon. If the top dressing is too shallow, nitrogen is likely to volatilize, harming the leaves and also reducing fertilizer efficiency. The depth of top dressing must reach more than 10 cm, and it must be covered with soil. Watermelon top dressing generally requires a distance of about 10 cm from the main root. If it is too close, it is easy to burn the roots and affect plant growth.
The above is Tuliu.com's introduction to the "five increases and five avoidances" watermelon fertilization method. Farmer friends who grow watermelons can use this article as a reference. I hope everyone can achieve these five points in fertilization techniques to ensure watermelon yield.