Detailed Explanation of Strawberry Growth Characteristics and Cultivation Techniques

Growth Characteristics and Cultivation Techniques of Strawberry

The strawberry originates from South America, has a short growth cycle and relatively high yield, and is widely cultivated in China. Because of its good taste, high nutritional value and health benefits, strawberries are favored by people, leading to a marked increase in demand. Strawberry planting management is a task with high requirements for attention to detail and a high level of cultivation skill. How to effectively increase yield and raise economic returns is a question that growers pay close attention to. The growth characteristics and key planting techniques of strawberry are summarized below for the reference of growers.

1 Growth Characteristics

1.1 Early pollen maturation

Strawberry flowering generally requires a temperature above 10 °C, and before flowering its pollen has already begun to mature and has germination capacity. The germination temperature is around 25 °C, and the critical maximum humidity is around 94%. Unreasonable control of temperature and humidity will lead to phenomena such as pollen rupture after anther dehiscence and failure of pollination.

1.2 Dormancy phenomenon

Under the influence of low temperature and short daylight, the strawberry plant becomes dwarfed, the leaves flatten and it flowers, and a dormancy phenomenon occurs; this is a physiological state that appears in strawberry in order to adapt to low winter temperatures. The time for it to resume growth varies with variety; for example, northern open-field varieties usually need more than 500 h, but everbearing strawberries need only about 2 d.

2 Cultivation Techniques

2.1 Variety selection

Reasonably selecting a strawberry variety is very important. First, the ability of the strawberry variety to resist pests and diseases should be considered; second, the flower bud differentiation time of strawberry is relatively short, and in order to ensure normal growth and pollination and fertilization of strawberry under low temperature conditions and to promote fruit development, greenhouse insulation and lighting performance should also be considered when selecting a variety.

2.2 Land preparation and soil disinfection

Land preparation usually begins 20 d before planting, that is, compound fertilizer is evenly broadcast into the soil, and then the land is turned and leveled to keep the surface flat. The ridge surface width and furrow width should be reasonably controlled to facilitate later planting and field management work.

During long-term strawberry cultivation, pest and disease sources and harmful substances accumulate in the soil, affecting plant growth. Therefore, before strawberry cultivation, attention should be focused on soil pest and disease problems, and the soil should be disinfected. After the crops are harvested in July, fertilization should be carried out under conditions of about 60% humidity, preferably with farmyard manure, and plastic film should be covered on the surface to remove bacteria and other harmful substances from the soil.

2.3 Planting

The cultivation time should be chosen according to environmental conditions to ensure the survival rate of the plants. Plant at a reasonable density, and increase strawberry yield as much as possible on the premise of ensuring that strawberry quality is not affected. The planting density must not be too high, so as to prevent effects on light transmission. Strong seedlings should be selected at planting; the standard for strong seedlings is a rhizome length of 10 mm, a seedling age of 40-60 d, and an intact root system.

2.4 Field management

2.4.1 Greenhouse covering. In the whole series of steps from strawberry planting to flowering and ripening, technical control measures should be well implemented, and the ripening period of strawberry should be scientifically determined. The greenhouse covering and insulation time for strawberry can generally start in late October and continue until around February of the following year.

2.4.2 Plastic film mulching. For ease of management, plastic film is usually laid after the greenhouse is covered, and this should be completed before the soil freezes if possible. The purpose of plastic film mulching is to raise soil temperature and promote strawberry growth. But at the same time, laying plastic film also creates a good growing environment for pests and diseases, so doing plant protection work well is very important. Before starting film mulching, clean the surrounding area, spray a 2 000-fold beta-cypermethrin solution, then lay the plastic film flat over the plants and keep it smooth. In cold regions, straw should also be covered on the surface to provide insulation. After the soil thaws in spring, remove the surface plastic film.

2.4.3 Temperature and humidity management. The suitable growth temperature for strawberry is 18-26 °C, and temperatures above 30 °C or below 5 °C will affect strawberry yield. Therefore, in winter, a small tunnel should be set up inside the greenhouse, and plastic film mulching should be done well, keeping the temperature inside the greenhouse at around 25 °C during the day and above 5 °C at night; in summer, when high temperatures above 30 °C occur, cooling and ventilation work should be done in a timely manner. At the bud stage, humidity should be maintained at 70%-80%. At the flowering stage, humidity should be reduced. This is because if humidity is too high during the flowering stage, the quality of pollination and fertilization will decline, yield will decrease, and the rate of deformed fruit will increase. At the ripening stage, humidity should be controlled at around 60%, because excessive humidity easily triggers powdery mildew and other diseases, thereby affecting yield.

2.4.4 Fertilizer and water management. Drip irrigation is the best watering method, and watering should be stopped about 1 week before flowering and started about 15 d after flowering, together with fertilization. The strawberry fruiting period is long, and on the basis of comprehensively considering the soil's own water and fertilizer conditions, topdressing can be done in small amounts multiple times.

2.4.5 Light management. Light is one of the key factors directly affecting strawberry yield. Attention should be paid to cleaning the greenhouse film to ensure light inside the greenhouse. In addition, artificial lighting measures can be taken, such as hanging reflective screens. When taking artificial lighting measures, attention should be paid to strengthening temperature and humidity management inside the facility to prevent effects on strawberry growth and development.