It is better to grow watermelon with compound fertilizer or organic fertilizer.

Organic fertilizer is good for growing watermelon.

Key points of fertilization technology for watermelon

1. Fertilize seedbed

The nutrient soil for watermelon seedling should be rich in organic matter, loose, and strong in water and fertility conservation.

2. Soil preparation and fertilization

Re-application of base fertilizer is the basis to ensure the healthy growth and high yield of watermelon stems and vines. After the previous crop was harvested, combined with deep ploughing and soil preparation, 4000 kilograms of decomposed organic fertilizer was applied per mu, and ditches with a depth of 30 cm were dug according to the specified row spacing. The ditch bottom is covered with 10 cm thick organic fertilizer, 30 kg compound fertilizer or 10 kg urea, 15 kg diammonium phosphate and 15 kg potassium sulfate respectively. Then apply a layer of organic fertilizer with a thickness of 10 cm, and apply 20 kg of compound fertilizer or diammonium phosphate, potassium sulfate and urea 10 kg on the top layer respectively. Mix the chemical fertilizer, organic fertilizer and the soil in the ditch evenly and level it.

3. Topdressing after planting

When watermelon enters the sowing period, the demand for fertilizer and water is gradually increasing. At this time, topdressing should be aimed at promoting vine growth and expanding leaf area, but excessive growth should be prevented. Top dressing is mainly decomposed organic fertilizer, with appropriate amount of chemical fertilizer; When the normal young fruit grows to the size of an egg, the fruit begins to expand rapidly, and the demand for fertilizer in the whole growth period gradually reaches its peak. At this time, it is necessary to reapply expanded melon fertilizer to promote melon body expansion and prevent premature aging. Topdressing is mainly phosphorus and potassium fertilizer, and less or no nitrogen fertilizer is applied to avoid the decline of watermelon quality caused by excessive nitrogen fertilizer.

Cultivation techniques of watermelon

Land selection

It is advisable to choose sandy loam with deep soil layer, loose and fertile soil and convenient irrigation and drainage, and plant in fields where melon crops have not been planted in dry land for 5 years and paddy field for 3 years. ?

Soil preparation and fertilization

Before winter, Gua Tian ploughed deep into the frozen soil and prepared the soil in time before transplanting. Gua Tian needs three ditches to support it, so that the rain will prevent the fields from drying, the soil will be loose and the surface will be flat. The base fertilizer is mainly high-quality organic fertilizer and cake fertilizer, supplemented by inorganic fertilizer, which generally accounts for 60% ~ 70% of the total fertilization. Nitrogen, phosphorus and potassium should be reasonably matched, and micro-fertilizers should be applied at the bottom or sprayed separately according to the lack of elements. The amount of fertilizer applied depends on soil fertility and cultivated varieties. Generally, for fields with moderate fertility, combined with soil preparation, 3000-4000 kg of organic fertilizer, 60-80 kg of 45% nitrate sulfur or potassium sulfate controlled release fertilizer are applied per mu, and chlorine-containing fertilizer is not applied. 20% less fertilizer can be applied for small fruit type and grafting cultivation. It is planted in a high border with a width of 4 ~ 4.5 meters and a narrow border of 2.0 ~ 2.5 meters. Wide border can be planted on both sides of the border, melon vines can climb on both sides or in the middle, and narrow border can be planted on one side and climbed on the other.

Field planting

The seedling age of early-maturing varieties is about 1 month, and 2 ~ 3 true leaves can be planted. The seedling age of middle-maturing varieties is 20 ~ 25 days, and that of late-maturing varieties is 7 ~ 10 days. Wide border planting is 2 rows, narrow border planting is 1 row. Small-fruited watermelons are cultivated in a shed, with 1500 ~ 1800 plants per mu; Climbing cultivation, pruning with three vines or four vines, planting 600 to 750 plants per mu. Medium and large varieties are generally planted with 650 to 700 plants per mu, and grafted seedless varieties are planted with 300 to 400 plants per mu. Dig the planting holes according to the row spacing of plants, put the nutrition bowls into the planting holes along the direction of cotyledons and border surfaces, fill the seedling holes with fine soil, and pour the root water of manure and medicine. When transplanting, cover the film with a width of not less than 80 cm. The film should be thin and flat, close to the soil surface, and the surrounding area should be sealed tightly. The broken film should be sealed tightly with fine soil. ?

Pruning and pressing vines

Usually pruned with three vines. When the main vine has 8 to 9 leaves, choose the main vine and 2 strong side vines, and remove all the other secondary vines and Yang vines. Pruning is not suitable in rainy days to prevent the spread of diseases. When the vines grow to about 50 cm, combine the pruning soil to press the vines, and then press each vine for 2-3 times every 3-4 knots 1 time to make the melons and vines evenly arranged.

Back pressure. If the growth is too strong, use reverse pressure. Dig a pit with a depth of 7- 10 cm, push the vines into the pit in the direction of the root of the melon, arch the vines behind them, and then fill the soil and tamp them, so as to control the flourishing growth and improve the fruiting rate.

Holding a vine. When the second to third female flowers appear, vines can be used to make the melon sit still and grow bigger. At the height above the ground, flatten the vines with two boards about 7 cm to ensure the continuity of vascular bundles.

Lift the valve stem. If you want to make the young melon sit steady, lift it on the vine behind the young melon and hear a bang. "Bang behind, the melon in front will be knotted."

Pinch your head. When entering the expansion stage, the creeping in front of the melon should be properly restrained and cannot grow vigorously, otherwise it will lose nutrition and affect the expansion of the melon. Pinch the tip of the vegetable is to pull back the vine in front of the melon, wrap it around one side and pinch the tip of the vine at will. ?

Sitting melon

We should choose the second and third female flowers on the main vine or 1 and the second female flowers on the side vine to sit on the melon. In order to ensure that the melons sit at the proper nodes, artificial pollination should be used to protect the flowers and fruits in case of low temperature or rainy weather. After the melons sit firmly, pat the ground below the young melons to make a slope, and then place the young melons along the slope to make the young melons and vines in a straight line. When the fruit is fully grown, it should be ploughed in time. Turn the melon in one direction, about 1/3 at a time. ?

Superficial application

When the young melon grows to the size of an egg, depending on the plant growth, the expanded melon fertilizer should be topdressing, generally 45% nitrosulfur or potassium sulfate controlled release fertilizer 15 ~ 20k g per mu.

moisture

In order to promote the formation of developed roots, we should water as little as possible or even not at seedling stage. Control water before flowering and fruit setting to prevent crazy growth; Sufficient water supply should be ensured after fruit setting, which is beneficial to fruit expansion and weight increase. 7 ~ 10 days before harvest is not suitable for watering, so that the fruit accumulates sugar. In case of water shortage, irrigation should be carried out in the early and late night when the temperature is low. Infiltrate soil moisture through furrow irrigation, that is, irrigate the furrow, and immediately drain the remaining water in the furrow after the water permeates the furrow. Drain the accumulated water in the field immediately after irrigation and rain, otherwise it will easily lead to rotten roots and vines. ?