What is the fertilization standard for watermelon? How to fertilize after sitting on melons? (with fertilization technology included)

The general principle of fertilization for watermelon is to re-apply organic fertilizer, appropriate amount of nitrogen fertilizer, stable application of phosphorus fertilizer, increased application of potassium fertilizer, combined application of nitrogen, phosphorus and potassium, and appropriate supplementary application of medium and trace elements fertilizer. So what is the fertilization standard for watermelon? How to fertilize after sitting on melons?

The amount of fertilizer application is determined by the target yield. for example, under the condition of medium fertility in North China, when the target yield is 2500 to 3500 kg / mu, 20 kilograms of nitrogen, 12 kilograms of phosphorus and 30 kilograms of potassium are required.

Fertilization should refer to the law of fertilizer requirement of watermelon at each growth stage. As a fertilizer-loving, temperature-loving and water-tolerant crop, watermelon has a preference for potassium and boron, and the demand ratio of nitrogen, phosphorus and potassium is about 3 ∶ 1 ∶ 4.

Generally speaking, the nutrient uptake of watermelon was less in the early stage, more in the middle stage and less in the later stage. The total absorption of nitrogen, phosphorus and potassium at the seedling stage accounted for about 0.18%-0.25% of the whole growth period; with the rapid growth of stems and leaves during the spreading period, the absorption of nitrogen, phosphorus and potassium also increased, accounting for 20%-30% of the whole growth period; after sitting melon, the absorption of nitrogen, phosphorus and potassium in the expansion stage reached the peak of the whole growth period, accounting for 65%-75% of the whole growth period; and the total nutrient absorption in the mature period accounted for 5%-10% of the whole growth period.

During the whole growth period, watermelon absorbed the most potassium, followed by nitrogen and phosphorus. Nitrogen fertilizer is the main fertilizer before setting melon, and the absorption of potassium increases sharply after setting melon; the absorption of nitrogen and potassium decreases obviously in the mature stage, while the absorption of phosphorus increases relatively; the amount of nitrogen and potassium absorbed in the depilation stage is basically the same. The N, P and K uptake ratios of watermelon at different growth stages were 3.8 ∶ 1 ∶ 2.8,3.6 ∶ 1 ∶ 1.7 and 3.5 ∶ 1 ∶ 4.6 at seedling stage, vine stage and peak growth stage, respectively.

Therefore, sufficient nitrogen fertilizer is needed in the early growth stage to ensure and promote vegetative growth. In the seedling stage, topdressing nitrogen fertilizer; in the middle stage, we should pay attention to the appropriate amount of phosphate fertilizer; after entering the expansion stage, we should mainly apply potassium fertilizer to promote the improvement of fruit yield and quality. The critical stage of nitrogen and phosphorus nutrition of watermelon is in the seedling stage, the critical period of potassium nutrition is in the extension stage, and the maximum nutritional efficiency of watermelon is in the melon-bearing stage.

In addition, in the current watermelon cultivation process, there are too much nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, organic fertilizer, lack of trace elements and other problems, melon farmers should pay attention to avoid.

Base fertilizer

Base fertilizer is the basis of nutrition supply of watermelon in its lifetime, which not only provides nutrients for growth, but also improves soil and soil fertility. The amount of fertilizer used in the whole growth period accounts for 1, 2, 2, 2, 3.

One is organic fertilizer. Generally apply fully mature chicken manure or cow manure and other organic fertilizer 1 square meter or commercial organic fertilizer 200kg / mu, rotten cake fertilizer 80kg / mu (bean cake is the best).

The second is chemical fertilizer. Apply compound fertilizer (15-15-15) 25kg / mu or other proportions of compound fertilizer and diammonium hydrogen phosphate 615kg / mu.

Topdressing

Principle: light application of seedling fertilizer, skillful application of extended vine fertilizer, and heavy application of expanded melon fertilizer.

1. Seedling stage

The period is in the period of 2 to 4 leaves.

The application of a small amount of available fertilizer in the seedling stage of watermelon can accelerate the growth of seedlings.

The first method is to open an arc ditch 15 centimeters away from the seedlings, and the other is to make a hole 10 centimeters away from the seedlings, sprinkle the chemical fertilizer into the hole, seal the soil and level the ground, and then water each plant with 2 kilograms and 3 kilograms.

The fertilizer selection is mainly nitrogen fertilizer, and the general application of urea is 815kg per mu.

two。 Extension stage

During the period, the watermelon entered the spreading stage after 5 or 6 leaves (when the vine was about 15 cm long).

After the effect of watermelon vine extension, the growth rate is accelerated and the nutrient requirement is increased. At this time, topdressing fertilizer can promote the rapid growth of watermelon vine and expand the leaf area.

Methods A topdressing ditch with a depth of 10 cm, a width of 10 cm and a length of 40 cm was opened between the two watermelon seedlings. Application of chemical fertilizer ditch can be smaller, 5-6 cm deep, 7-8 cm wide and 30 cm long. Water should be watered once after fertilization to promote the absorption of fertilizer. Cake fertilizer should be watered one more time.

The fertilizer chooses the combination of organic fertilizer and chemical fertilizer. Apply rotten cake fertilizer 40kg / mu or biogas fertilizer 100kg / mu. Add urea 1520kg and potassium sulfate 1520kg. The amount of topdressing for seedling transplanting can be appropriately more, and the amount of ammonium sulfate or urea per mu is 20,25kg.

3. Flowering and melon setting period

Generally, there is no topdressing or watering. However, when it is found that the plant grows poorly, the ovary is small, and it is not easy to set fruit, measures should be taken as soon as possible. When entering the female flower, the growth of the plant should be observed, and when topdressing is needed, it can be remedied by foliar topdressing. Prepare 0.3% potassium dihydrogen phosphate solution, spray fertilizer on the leaf, spray once in about 5 days, spray in the evening, the effect is the best, strictly prevent spraying around noon. Spray fertilizer 2 times 3 times, found that the growth is very weak, can also be in blossom after a fertilizer, watering once, fertilizer is mainly nitrogen fertilizer, the amount should be small, can apply urea 5kg / mu or so.

4. Melon expansion stage

During the period, when the female flower of the normal melon part sits on the melon, and the young melon grows to the size of an egg, it enters the expanding stage.

It can promote the expansion of melon and prevent premature senility.

Methods the ditch was opened at the distance of 30-40 cm from one side of the plant to the root, and watering was carried out combined with fertilization.

The main fertilizer is phosphorus and potassium fertilizer, combined with nitrogen fertilizer, if the nitrogen fertilizer is excessive, the quality will decline. Turnip fertilizer is generally applied in two stages. The first time was when the young melon grew to the size of an egg, and this period was dominated by nitrogen and potassium fertilizer. 1520kg diammonium phosphate and 10kg potassium sulfate are applied per mu. The second time was when the melon grew to the size of the bowl mouth. Topdressing urea 5kg / mu and potassium sulfate 5kg / mu can be watered immediately after topdressing or spreading with water.

Skillful application of foliar fertilizer and flushing fertilizer

Spraying 0.1%-0.2% borax solution twice before flowering and at the beginning of expansion of watermelon can not only effectively prevent the melon skin from being too thick and hollow, but also increase yield, promote thin skin and lift sweet meat.

After the application of expanded melon fertilizer, there is generally no topdressing before harvest to prevent the maturity from being delayed. If there is a lack of fertilizer (such as withered and premature senescence of melon vines), 0.2% urea and 0.2% potassium dihydrogen phosphate can be used for foliar spraying. After ridge sealing, watermelon seedlings can also be irrigated with water-soluble fertilizers such as humic acid and amino acids to enhance root activity and improve yield and quality.