What effect does temperature have on plant growth?

In the process of crop growth and complete development, the required temperature and humidity range varies according to different crop species and varieties.

For temperature, this temperature range includes life temperature range, growth temperature range and development temperature range. Each temperature range is divided into optimum temperature, lower limit temperature and upper limit temperature. When the temperature rises to a certain value, the boundary temperature at which crops stop growing or even die is called the upper limit temperature.

For example, when rice germinates, it can endure the high temperature of 40-42℃, but when it exceeds 45℃, the rice buds will be burned to death by the high temperature, commonly known as "burning buns"; At the late stage of transplanting, when the water temperature in the field reaches above 45℃ for 4-5 days, the seedlings will be "boiled" to death by high temperature.

The highest temperature of citrus and navel orange in full bloom exceeds 33℃ for three consecutive days, which will cause high temperature damage and false flowers; Daily average temperature ≥30℃, daily maximum temperature ≥35℃ and fruit surface temperature ≥45℃ will cause sunburn.

As for water, there are crop water demand, soil water saturation and withering humidity. For example, the booting stage of cereal crops is the most sensitive to water, and the lack of water will greatly reduce production at this time.

If the rainfall for 20 consecutive days is less than10mm and the daily rainfall is less than 5mm, it is a mild drought. If the rainfall for 30 consecutive days is less than 25mm and the daily rainfall is less than10mm, the citrus yield will be seriously affected.

Extended data:

High temperature and drought disasters often occur at the same time, further aggravating the harm to crops. For a long time, people have accumulated and studied many methods and measures to reduce the harm of high temperature and drought to crops, which have avoided and alleviated the harm of high temperature and drought to a certain extent. Its main defensive measures can be divided into long-term measures and emergency measures.

I. Long-term defensive measures

1, analyze and understand the temporal and spatial distribution law of local high temperature and drought disasters, and adjust the agricultural layout. According to the seasonal and regional characteristics of high temperature and drought disasters, we should change to dry farming.

2. Select varieties suitable for local high temperature and drought resistance, and adjust sowing date appropriately, so that the high temperature and drought occurrence period is in the growth period of crops with high temperature and drought resistance.

3. Construction of farmland shelterbelt. It can transform farmland microclimate environment, weaken wind speed, reduce ground evaporation, reduce runoff, prevent soil erosion, improve air humidity and reduce crop canopy temperature.

4. Build water conservancy facilities to improve the ecological environment of farmland.

5. Sprinkler irrigation facilities, drip irrigation facilities, sunshade nets, etc. It can be set in efficient and economical farming areas to achieve the effect of drought resistance and temperature reduction.

The second is the emergency disaster reduction measures taken when high temperature and drought disasters occur.

1, intertillage dryland crops loosen soil and cover soil, cut off soil capillaries and reduce soil evaporation.

2. Water-saving irrigation is realized in paddy field. According to the requirements of water in the development period, timely and appropriate irrigation.

3. Before the highest daily temperature (14 hours ago), spray irrigation on crop canopy to improve the relative humidity of canopy air, reduce the temperature and achieve the purpose of improving crop field microclimate.

4. Seize all favorable weather and actively carry out artificial precipitation enhancement.

China Weather Network-Influence of High Temperature and Drought on Agricultural Production