Soilless cultivation techniques of Strawberry

Soilless cultivation techniques of Strawberry

Strawberry fruit is sour, sweet and delicious, juicy, high nutritional value, rich in vitamins and minerals, such as vitamin C 50~100mg per 100g fresh strawberry fruit. Strawberries can be eaten fresh, but also can be processed into strawberry juice, strawberry jam, strawberry wine and other food, the market demand is very large, deeply loved by consumers. In addition to being eaten raw as fresh fruit, strawberry is also a kind of potted flower with great ornamental value. it has a long flowering and fruiting period and is easy to cultivate, so it has been paid more and more attention in the market. [Jishan Huayao]

In recent years, the soilless cultivation of strawberry has developed rapidly. At present, strawberry is cultivated all over the world. The main methods are NFT hydroponic culture and rock wool culture.

(1) Biological characteristics

Strawberry (Fragaria ananassa Duch.), a perennial herb of Rosaceae, has a height of about 30cm, whisker root and shallow distribution. There are three kinds of strawberry stems, namely, new stem, rhizome and stolon. The new stem is the same year's stem, the rhizome is perennial stem, the new stem of the previous year is this year's rhizome, and the stolon is the reproductive organ of strawberry. Strawberry leaves are pinnately compound and alternate. The flowers are white and self-pollinated. About 20 flowers usually grow on an inflorescence and bloom one after another. The fruit is made of enlarged receptacle, soft and juicy, red on the face, white, red and pink in the pulp, medullary in the middle, larger in early flowering and smaller in later flowering.

(2) cultivation season and variety selection

The virus-free seedlings were planted in the seedling bed in October, covered with a small shed, overwintered with white non-woven cloth or cold yarn, and planted in the nursery in March, causing a large number of creeping stems to form seedlings. The seedlings were collected in July for soilless breeding, and then treated with artificial low temperature and short days to induce flower bud differentiation, which could be planted in the greenhouse in September, began to bear fruit in December of that year, and could be supplied until April to May of the following year. This is the whole process of strawberry cultivation.

In addition to early maturity, high yield and good quality, soilless strawberry varieties should also have the characteristics of strong fertilizer tolerance and short dormancy period, so that strawberry growth is not easy to weaken in winter. At present, the most commonly used varieties are Nufeng and Fengxiang and so on.

(3) Induction of flower bud differentiation

After the strawberries cultivated in open field were planted in late autumn, the seedlings dormant and overwintered, the flower buds differentiated in the second year, and harvested in May. Soilless cultivation of strawberries, multi-row greenhouse or greenhouse to facilitate cultivation, early to November to December, strawberries can be harvested until May of the following year. For this reason, varieties with shallow or almost non-dormancy must be selected and artificial flower bud induction treatment must be carried out. The traditional method is to move the seedlings to high-altitude mountains in August high temperature season to promote the formation of flower buds. Under the condition of soilless seedling raising, interrupted N supply treatment and low night temperature treatment were often used to induce flower bud formation.

(4) cultivation and management

1. Cultivation methods and planting strawberries can be planted in a variety of soilless cultivation forms, such as NFT hydroponics, DFT hydroponics, trough or bag substrates, three-dimensional cultivation and spray culture.

When planting strawberry seedlings in DFT water culture, the small gravel at the bottom of the planting cup is put into the bottom of the planting cup, and then the strawberry seedlings are fixed with a small amount of gravel. Do not directly put the roots on the bottom of the planting cup, so as to prevent the roots of the seedlings from rotting when soaked in nutrient solution for too long. The planting cup of the seedlings has been moved and placed in the planting trough, and the suitable row spacing is about 20cm × 20cm.

When planting strawberries in NFT water culture, it is best to plant strawberry seedlings in 8cm × 8cm × 5cm rock wool seedling blocks, and then put them into the planting trough to let them grow.

When strawberry is cultivated in trough medium, strawberry seedlings can be directly planted in the substrate according to the row spacing of 20cm × 20cm. The nutrient solution should be added in the form of drip irrigation, and the nutrient solution or water should not be supplied in the form of sprinkler irrigation, because the nutrient solution sprinkler irrigation will cause too much humidity and rot of strawberry fruit, and it is not conducive to the cleaning of strawberry fruit.

2. Nutrient solution management

(1) the selection of nutrient solution formula various forms of strawberry soilless cultivation can use South China Agricultural University fruit and vegetable formula, Japanese garden test formula and Yamazaki formula and so on. Except that the pH value of the Japanese garden test formula will increase during the strawberry planting process (usually not more than pH8.0), the pH of the other two formulations are stable.

(2) generally speaking, the fertilizer tolerance of strawberry is weak, and too high nutrient solution concentration will accelerate root senescence, shorten life span, and then affect nutrient absorption, aboveground growth and yield improvement. However, there are some differences in fertilizer tolerance among different varieties. In the process of strawberry planting, the method of controlling the concentration of nutrient solution is generally adopted to control the lower concentration before flowering, which can control the occurrence of abnormal fruit in the future. after flowering, the concentration of nutrient solution should be increased because more nutrients are consumed by flowering and fruit. in order to prevent the phenomenon of weak plant growth and premature senescence. According to the experiment and production experience, the nutrient solution management concentrations of several strawberry varieties are listed in Table 10mur1 for reference.

Table 10 the nutrient solution management concentration of strawberries in different cultivars

(standard for 1 dose of Yamazaki strawberry formula, 1985)

Since the growing period of strawberries is as long as 8 months (from October of that year to May of the following year), the concentration of strawberries can be determined by electrical conductivity meter within 2-3 months after planting to determine whether or not to supplement nutrients. After this period, depending on the electrical conductivity meter to determine its concentration may not really reflect the amount of nutrients contained in the nutrient solution, which is due to the fact that after a long growing period. Some of the root system death, decay and root exudates accumulate in the nutrient solution, and the accumulation of less or unneeded substances brought by the addition of nutrients, therefore, nutrients can be supplemented by chemical analysis to determine the contents of N, P, K and other main elements in the nutrient solution, and the original nutrient solution can be replaced if necessary.

(3) the optimum pH value of strawberry in nutrient solution pH is 5.5-6.5, but it can grow normally in the range of pH5.0~7.5. If pH does not deviate too much from the optimum range, it is not necessary to adjust it.

(4) if the deep liquid flow technology is used to plant, the timer can be used to control the intermittent supply time of nutrient solution. Before flowering, turn on the pump circulation 10min every hour, and after flowering, the pump circulation time should be increased to 15~20min/h.

If the nutrient liquid film technology is used to grow strawberries, before planting to the formation of the root mat, the flow rate of each planting slot 0.2~0.5L/min can be used to supply liquid continuously, and after the root mat is formed, the flow rate of 1~1.5L/min can be used to supply liquid intermittently by 15~20min/h.

If the substrate is planted with rock wool and other substrates, the relative water content in the substrate should be controlled at about 70-80% according to the weather and plant growth; the liquid supply can also be determined according to the maximum daily water consumption of 0.3-0.8 L per strawberry, and the timer can be used to control the timing of water supply by the water pump.

(5) liquid temperature management strawberry has strong adaptability to temperature, low temperature tolerance, not high temperature tolerance, the suitable temperature for growth is 20: 26 ℃, and the optimum temperature for rhizosphere growth is 8: 21 ℃. Freezing injury will occur when the root system is at-8 ℃ and the terminal bud is at-15 ℃. The high temperature above 30 ℃ will stagnate the growth of strawberry and scorch the edge of leaves.

3. Plant adjustment

The main results are as follows: (1) after the whole vine regenerates the plant, it is necessary to replant the new plant formed by stolon, which has strong vitality and high yield. Or after the harvest is over, all the stolon stems from the plants on the cultivation bed will be removed step by step, and the original fruiting plants still maintain high vitality and production capacity.

(2) when picking old leaves and thinning flowers, the withered leaves and old leaves should be removed in time from 5 to 6 leaves after strawberry planting, and the removal of withered leaves and old leaves should be completed before flowering, which is beneficial to the future growth. After budding, each plant retained 2-3 flower branches and 3-5 fruits per flower branch. There are 815 fruits per plant. The rest are removed to ensure that the fruit is large and tidy, and to prevent the occurrence of small and deformed fruits.

(3) artificial pollination carries out soilless cultivation of strawberry in protected field, which affects pollination and fruit development because there are no insect activities at flowering period. therefore, according to specific conditions, bees can be released at flowering stage, or flower branches can be shaken artificially to increase pollination and fruit setting rate and reduce the occurrence of ineffective flowers and deformed fruits.