Climatic conditions and characteristics of rice growing areas

China has a vast rice growing area. Do you know the climatic conditions in the rice growing areas? The following are the climatic conditions of rice growing areas that I have carefully arranged for you. Let's have a look.

Climatic conditions in rice growing areas

1. Rich in heat resources, it is suitable for developing various rice planting systems. The average temperature during the rice growing period in China is 65438 08 ~ 25℃. The average monthly temperature in the hottest rice areas in China is generally above 20℃, which is consistent with the period when rice needs high temperature. The accumulated temperature of > 10℃ in the rice planting area of Hainan Island is above 8000℃, and rice can be planted all year round. The accumulated temperature from the south of the Yangtze River basin to South China > 10℃ reaches 5000 ~ 8000℃, and double cropping rice can be planted. The accumulated temperature from the north of the Yangtze River basin to North China > 10℃ is 4000 ~ 5000℃, which can be used for planting single-season mid-season rice. The accumulated temperature of > 10℃ in northeast and northwest rice areas is 2000 ~ 4000℃, which can be used for planting early rice.

Due to the control of subtropical high and the influence of the mainland, the summer temperature in rice-growing areas in China is higher than that in many parts of the world at the same latitude. The average temperature in July is 32? 00? n)28.0℃； Kagoshima, Japan (3 1? 34? n)27.2℃； Jinan (36? 42? n)28.2℃； Algiers (36? 08? n)24.8℃； Qiqihar (47? 20? n)22.0℃； Zurich (47? 23? N) is 18.4℃. Superior heat conditions make the rice distribution in China farther north than other countries.

2. Superior light energy resources are beneficial to high yield of rice. The total solar radiation of rice in the middle and lower reaches of the Yangtze River and the Yellow River valley in China is (256 ~ 342)? 107j/m2； And the same latitude in Japan is (2 17-290)? 107J/m2, China is about 18% more than Japan, especially in autumn, when rice is heading and filling, most rice areas in China have sufficient sunshine, which is very beneficial to high yield of rice.

3. China is influenced by the monsoon climate of light, heat and water in the same season, and the precipitation in rice areas is basically concentrated in summer; And summer is a season with high temperature and strong sunshine. Therefore, in the rice growing areas of China, the three most important climatic resources, light, heat and water, are mostly concentrated in the rice growing season. At this time, an extremely important advantage of rice climate in China is that rice has become the most important food crop in China. Other regions in the world with similar latitudes to China, such as rice-growing areas in the western and southern parts of the United States, the Middle East, North Africa and other places, have little or no precipitation in summer, or cannot grow rice, or need a lot of irrigation.

4. There are many meteorological disasters in rice. The climatic conditions of rice in China also have disadvantages, mainly due to frequent meteorological disasters. Because China is backed by Eurasia, cold air from Siberia will attack from autumn to spring, so all rice growing areas in China will suffer from freezing injury. Heading and flowering period is the most sensitive period to chilling injury, and chilling injury at heading and flowering period poses a threat to rice production in double cropping rice areas in northeast, northwest and south China.

China coastal rice areas, in 7? In September, everyone was threatened by a typhoon to varying degrees. Typhoons cause rice to lodging, grains to fall, and sometimes floods.

Due to the influence of monsoon climate, the interannual change of monsoon intensity in China causes great interannual change of climate. Therefore, the drought and flood disasters in rice-growing areas in China are more serious. The spring drought in northern rice areas is heavier, which is not conducive to raising seedlings. The summer drought in Central China is heavier, and the autumn drought in South China is heavier. Not good for mid-late rice.

Characteristics of rice planting areas

(1) Small-scale agriculture. Rice production takes the family as the unit. Due to the shortage of arable land per capita, there is very little farmland cultivated by each household. The rice planting area of each household in southern China is generally less than 1 hectare.

(2) The output per unit area is high, but the commodity rate is low. Farmers intensively cultivate in the fields, which makes the yield of rice per unit area higher. However, due to the small scale of production, the total output of rice per household is not large, and restricted by traditional concepts and economic level, farmers keep a considerable part of the collected rice for their own use, while the rice sent to the market for sale is limited; But Thailand is a special case, with a lot of exports.

(3) The level of mechanization and technology is low. Farmers generally engage in manual labor. Although electric irrigation threshing has developed rapidly in recent twenty years, and the use of chemical fertilizers and pesticides has gradually increased, the overall mechanization and scientific and technological level are still relatively low; The mechanization level of rice production in other Asian countries is still very low except Japan, which has made great progress in the mechanization of rice fields.

(4) The scale of water conservancy projects is large. Irrigation is the basis of rice production. Frequent floods and droughts in monsoon region pose a great threat to rice production. Small-scale farmers are unable to build water conservancy projects and need the government to invest and organize water conservancy projects.

Besides Asia, rice is also cultivated in Egypt, Nigeria in Africa, Spain, Italy in Europe, Cuba, Venezuela and Brazil in Latin America. In the lower reaches of the Mississippi River in the United States, there are also large areas of rice fields, but large-scale dry land direct seeding technology is used for production. It is one of the eight major agriculture.

Rice planting conditions

① Super rice varieties with great yield-increasing potential.

Super rice varieties have the comprehensive characteristics of high yield, high quality and multi-resistance, and have obvious yield-increasing potential, which can reach 700 kg, 800 kg and 900 kg per mu at different latitudes, respectively, which is the main condition for super high yield of rice.

Based on the population quality theory, super rice should have the morphological and structural characteristics of high grain/leaf (cm2) ratio, erect leaves and heavy grains per spike. Under the condition of limited suitable leaf area index (LAI), it is beneficial to form more total spikelets and larger total sink capacity, so as to seize excess high yield. The grain/leaf (cm2) ratio of multi-spike and small-grain varieties is low, and the total sink capacity should not be increased, so it is not qualified for super rice.

(2) It has suitable climatic conditions.

(1) High-yielding rice with temperature needs suitable atmospheric temperature conditions all its life, especially during 40 days from 15 days before heading to 25 days after heading, harmful temperatures below 15℃ and above 35℃ cannot appear. The observation results show that the average daily temperature at the heading stage of japonica rice is about 25℃, which is most beneficial to improve the seed setting rate. The average daily temperature from filling to maturity is about 265,438 0℃, and the 1000-grain weight is the highest (the daily temperature is about 26℃, the night temperature is about 65,438 06℃, and the temperature difference between day and night is about 65,438 00℃). The average annual temperature in rice growing areas in northern cold regions is below 0℃. However, there are very suitable climatic conditions during the growth of japonica rice, especially for more than 40 days before and after heading, and super-high yield can also be recorded. For example, the highest output of Hongwei Farm in 2005 was 733 kg/mu, and that of Qixing Farm in 2006 was 830.5 kg/mu.

⑵ Strong thermal radiation is another climatic factor for super-high yield of rice. In high latitude and high altitude areas, the solar radiation is large and the rice yield is high. For example, the yield per mu of high-yield fields in Taoyuan Township, Yongsheng County, Yunnan Province can reach11200 kg, and the yield per mu of high-yield rice in Qixing Farm, Heilongjiang Province can reach 830 kg, which shows that solar radiation is closely related to rice yield.

⑶ Low atmospheric humidity is also an important factor for super-high yield of rice. First of all, the low atmospheric humidity is the result of less rainy days and less rainfall, which means that the daily radiation is large, which is conducive to improving the photosynthetic productivity of the population. Secondly, under the condition of high temperature and strong light, lower atmospheric humidity can increase transpiration, which can significantly reduce the temperature of rice plants, avoid the harm of high temperature and ensure the normal operation of photosynthetic production and various physiological activities. Third, when the atmospheric humidity is low, the incidence is light, which is conducive to high yield.

(4) Disastrous and destructive weather disasters, such as typhoons and tornadoes, are also required in high-yield areas with disastrous weather.

③ Good soil conditions.

(1) Soil organic matter and soil nitrogen supply level In the same soil, soil nitrogen supply capacity increases with the increase of soil organic matter content, but the relationship between organic matter and soil nitrogen supply cannot be calculated by a unified formula for different soil types. That is, different soils with the same organic matter content have different nitrogen supply.

⑵ The relationship between soil total nitrogen content and soil nitrogen supply level is the same as that between soil organic matter content and soil nitrogen supply level.

(3) Fertile soil is also a necessary condition for super-high yield, especially a certain basic yield (the yield of blank fields).

(4) Super-high-yield cultivation fields with irrigation and drainage conditions that can control soil moisture can not only ensure timely irrigation, but also ensure timely drainage, especially in the middle and late growth period. In order to improve root activity, intermittent irrigation must be used to drain accumulated water in time.