Winter greenhouse watermelon fertilization guide

Watermelon in winter greenhouse is generally cultivated in the greenhouse from January 15th to 20th. Watermelon seedlings are grafted to the gourds when they grow to two leaves to improve plant disease resistance and low-temperature resistance. The grafting method is based on the connection method when the watermelon grows. 4 to 5 true leaves are subjected to low-temperature exercise to prepare for colonization.

Before the planting, it is necessary to apply enough base fertilizer to 2,000 kg of chicken manure per acre, which can be used in combination with 45% (15-15-15) of Jiashiligen Power Compound Fertilizer (80 kg), and then deep plowing. When the watermelon grows to 5 to 6 true leaves, the spacing is 1.5 meters and the distance between the rows is 0.7 meters. The mulch is covered with a small arch shed. At the time of colonization, the grafting interface must be left on the ground in order to prevent the occurrence of adventitious roots.

After planting, it is mainly the integrated management of temperature, humidity and top-dressing irrigation. After the planting, in order to speed up the seedlings, generally do not ventilate, maintain high temperature, during the day 28 °C ~ 32 °C, 12 °C at night.

After easing the seedlings to the flowering period, the shed temperature is not lower than 25°C and the ground temperature is above 15°C to increase the fruit setting rate. After extending the vine, the small arch shed was removed, and the first top-dressing watering was conducted, which allowed 45% (15-15-15) Jiashiligen Power Compound Fertilizer to be 20-25 kg.

After half an hour of flowering, the growth of fruits is accelerated. The insulation work should be done well, and the melon within 8 knots should be eliminated promptly, and the second or third normal developing melon should be selected. When the melon grows to a diameter of about 15 cm, it is combined with watering. For the second time dressing, 45% (15-15-15) Jiashi Ligen Power Compound Fertilizer can be recovered in this time.

Greenhouse soil moisture is high, stems and leaves easy to grow long, so irrigation should pay attention to less watering, sitting in the melon log water, enter the mature period after the control of water, in order to facilitate fruit coloring and increase fruit sugar content and speed up fruit ripening.

Plant adjustment and artificial pollination Watermelon branching strong, must be plant adjustments in order to seize high yield, including pruning, pressure vine, melon, melon and picking heart. The melons are generally selected to have the second or third female flower sitting on the vine, and the main vine can leave the cranberry on the melon when it is unretained. When the fruit is set for 20 days, the shape of the fruit is basically set. Every 3 to 5 days, the fruit can be picked in the sunny afternoon and the fruit is evenly distributed.

Cultivation of watermelons in greenhouses requires artificially assisted pollination, usually at 10:00 am. Large male flowers are selected to expose stamens. The female styule is gently touched to make the pollen evenly on the stigma, in case of low temperatures or poor weather conditions. The male flower was taken off the afternoon of the previous day, placed in a closed container, kept at room temperature at 25°C, pollinated after flowering in the morning, and marked the date of flowering after pollination in order to pick the melon in time.

Watermelon growth needs to absorb many kinds of nutrients. Among them, in addition to the uptake of carbon, hydrogen, and oxygen from air and water, various mineral elements must be ingested through other routes. Among these elements, the most important are nitrogen, phosphorus, potassium, and calcium.

Nitrogen is the main element that constitutes a protein. The amount of nitrogen fertilizer is adequate, and the stems and leaves of watermelon grow well and flourish; if the amount is too much, the stems and leaves will be lengthy, the tissues will be tender, the flowering and maturing phases will be delayed, and the resistance to cold and disease will be weakened; when the nitrogen fertilizer is not enough, the stems and leaves of watermelons will grow slowly and stems Leaves are weak and the yield is reduced.

Phosphorus is an indispensable element in the formation of nuclear proteins, lecithin, and the like. Adequate phosphorus nutrition can accelerate cell division, and is beneficial to the growth of roots and stems and leaves, and can promote the differentiation of flower buds, promote flowering, sitting on melons, early maturation, improve the quality of melons, and improve the disease resistance of plants.

Potassium can increase the photosynthesis intensity of watermelon, promote the formation and operation of starch and sugar in the plant, and have the effect of enhancing the cold, drought and disease resistance of plants. Appropriate supply of potassium fertilizer also has the effect of promoting the absorption and utilization of nitrogen and phosphorus by the plants, and can make the shape of the watermelon neat, the quality of the tannins enriched, and the sugar content increased.

Calcium has a certain influence on the metabolism of carbohydrates and nitrogenous substances in plants, and it can neutralize the excessive and harmful acid produced in the metabolic processes of plants, forming insoluble salts, so that it does not participate in the physiological effects, reducing a certain The occurrence of some physiological diseases. It also has the effect of promoting the absorption of nitrate nitrogen.

Main physiological diseases and prevention of watermelon

1. Young seedlings (small old seedlings)

Symptoms: The main performance is after the seedling stage and planting, the growth is in a stagnant state for a long time, the leaf spreading is slow, and the leaf color is grayish green. The roots are yellow, even brown, with few new roots. The recovery of the stiff seedlings is slow, and once it occurs, it will significantly reduce the output.

Cause: The first is the temperature and ground temperature are low. Followed by soil viscosity, high water content, high humidity, low ventilation. Third, poor seedling quality and long seedling age. The root system was damaged too much when planting, or the soil was rough in the site preparation and colonization, and the root was overhead, affecting the hair root. Fourth, the application of unripe farmyard manure caused burning roots, or excessive application of chemical fertilizers, resulting in excessive concentration of soil solution and injuring the roots. Fifth, underground pests harm the roots. Sixth, the soil is dry.

Control methods: (1) Improve the nursery environment and cultivate strong seedlings. (2) According to the weather forecast, select the cold tail warmer for the sunny planting. (3) Strengthen drainage, increase maturity of farmyard manure, and promote root growth. (4) Strengthen soil management and pay attention to cultivator loose soil in the early stage. (5) Control ants and other pests.

2. Madness

Symptoms: Watermelon seedlings are long, showing fine stems, long internodes, leafy greens, thin leafy leaves, poor disease resistance and resistance, low survival rate after planting, and slow seedlings. Extension of vines and flowering results showed a thick stem, large leaves, dark green leaves, tender tips (head) high Alice, easy to set fruit.

Cause: (1) high temperature, high humidity, lack of light. (2) Nitrogen nutrition is too high, leading to vegetative and reproductive growth disorders.

Control methods: (1) Control the amount of inorganic fertilizer in basal fertilizer, and pay attention to the combination of phosphorus and potassium fertilizer in the early stage. (2) Timely ventilation to reduce temperature and humidity, increase light. (3) Plants that have formed madness can take appropriate measures such as pruning, topping, partial root-cutting and other means to control vegetative growth, and use seated melons to impregnate melons and other measures to promote fruit set-up and allow the growth center to quickly transfer to the fruit.

3. Blade whitening

Symptoms: Watermelon seedlings, cotyledons and young leaves of the real edge chlorosis, bleaching, resulting in temporary suspension of seedling growth, severe dry leaves, resulting in long seedlings or even frozen seedlings, more serious cotyledons, leaves, growth points All were frozen to death.

Cause: Mainly due to improper ventilation of watermelon during the seedling period, resulting in a sharp drop in bed temperature.

Control methods: (1) Keep the bed temperature above 20°C during the day. No less than 15°C at night. (2) Ventilation at the seedling stage should not be premature, and the ventilation volume should be gradually increased, so as not to cause sudden changes in the seedbed temperature and cause injury.

4. Roots

Symptoms: After the root bark produces rust, it rots. The diseased seedlings are easy to pull up. The main root and fibrous roots turn brown and rot.

Control methods: (1) For the low-temperature type alfalfa root, protection seedlings should be taken. The daytime temperature of the seedbed is controlled at 22-28°C, 13-18°C at night, and the minimum is not less than 12°C. (2) For high-temperature type roots, pay attention to lower ground temperature and scatter. (3) Do not apply fresh chicken manure or human waste, should be cooked in advance.

5. Acute withering

Symptoms: At the beginning of the disease, the upper part of the noon is wilting, and it can still recover in the early evening. It will die after 3-4 days.

Etiology: (1) It is related to the type of rootstock. Cucurbit rootstock occurs more often and pumpkin rootstock rarely occurs. (2) Roots have poor water absorption capacity. (3) Excessive pruning inhibited root growth. (4) Weak light.

Control methods: Select appropriate rootstocks, strengthen management, and enhance the absorption capacity of the root system.

6. Sharp fruit

Occurrence conditions: (1) The leaf blade nutrition assimilation function declines, and the fruit is not adequately nutritious. (2) Flowering, high fruit setting rate, easy to produce sharp-nosed fruit or melon. (3) The fruits of late fruit setting will easily become sharp-nosed fruit.

Preventive methods: (1) Top-dressing to prevent defermentation during growth. Practice deep plowing and apply basic fertilizer. (2) Pay attention to pest control and maintain suitable leaf area.

7. Hulu (big belly) fruit

Symptoms: At the top of the fruit, the part near the flower pedicle swells, and the part near the fruit stem is finer.

Occurrence conditions: prone to calabash fruit when malnutrition occurs.

Control methods (1) Strengthen fertilizer and water management to prevent plant aging. (2) Pay attention to pest control.

8. Pygmy fruit

Symptoms: Unbalanced fruit development, one side normal, one side development stopped.

Cause: Inconsistent pollination.

Comprehensive prevention and control measures (1) Strengthen seedling management to avoid the influence of low temperature when flower buds differentiate (2-3 true leaves). (2) Control the seat of the melon and set fruit on the 2-3 female flowers. (3) Apply potassium fertilizer.

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