Huaibei plain

First, the natural environment of Huaibei Plain.

The area from the north of the main stream of Huaihe River to the south of Sha Ying is called Huaibei Plain.

Huaibei plain

The agricultural area in Huaibei Plain has a total land area of 37,400 square kilometers, an agricultural population of15.263 million, and a cultivated land area of 32.065 million mu, accounting for 47.8% of the province's cultivated land area, with a per capita cultivated land of 2 1 mu, making it the largest and most populous agricultural area in our province.

This area is located in the southern edge of warm temperate zone, with annual average temperature 14~ 15℃, accumulated temperature ≥0℃5 100 ~ 5500℃, accumulated temperature ≥ 10℃4500 ~ 4800℃ and frost-free period 200 ~. The distribution of crops is mainly dry farming, and the farming system is mostly three crops in two years, two crops in one year and five crops in three years. The multiple cropping index is about 180% in the far field and thin land for more than one year. Crops with sowing area accounting for more than 70% of the province include sweet potato, soybean, flue-cured tobacco and sorghum. More than 60% is wheat, corn, sesame and so on; Cotton and peanuts account for more than 40%. This area is an important producing area of grain, cotton, oil, tobacco, hemp and fruit in our province, but at present, the grain output is in the middle and lower level in the whole province, and the low-yield area is still very large. The low-yield soil accounts for about 60% of the cultivated land area, among which the black soil in Jiang Sha is the largest, with the output of about180,000 mu, and the cotton output is also low. However, from the typical example of high yield in this area, there is great potential for increasing production and broad development prospects. There are forest land 1 160000 mu, mulberry garden 5000 mu and orchard 25 1000 mu in the whole region, which can be used to develop fruit and sericulture production. This area is the key fruit area in our province. The orchard area accounts for 6 1.5% of the orchard area in the province, and the annual fruit variety 1 1.3 million tons, accounting for 54.2% of the fruits in the province. There are good forage and feed resources in this area, which can be used to develop animal husbandry.

Drought and flood in summer and autumn are the main meteorological disasters that determine the agricultural abundance and shortage in this area, followed by "rotten rain" in summer harvest. Dry hot wind and late frost and freezing damage often occur, resulting in low and unstable output.

Second; The main types of disasters,

Huaibei Plain is located in the south of Huang-Huai-Hai Plain, with superior natural conditions, which is suitable for the comprehensive development and utilization of "two highs and one excellent" agriculture. It is one of the important commodity grain production bases in China, with broad prospects for agricultural development. Suzhou now governs four counties and one district, with an area of 9786.06 square kilometers, 505,400 hectares of cultivated land, a population of 56,365,438+600,000, and a grain output of 654.38+900,000 tons 1999, ranking fourth in Anhui Province. However, Suzhou belongs to the transitional zone between the north subtropical zone and the warm temperate zone in the natural division of China. Its climatic resources have both advantages and disadvantages in North and South, with frequent meteorological disasters and unstable grain output. In recent years, agricultural meteorological disasters have increased, and the impact on agricultural output has gradually increased. Therefore, it is of great significance to discuss the sustainable development countermeasures of dryland agriculture in Suzhou from the perspective of agrometeorology.

1 Advantages of Agricultural Climate Resources in Suzhou

1. 1 The solar radiation is strong, the sunshine is sufficient, and the light energy utilization potential is great.

Huaibei plain is located in the southern edge of the belt rich in light energy resources in the national solar energy division. The annual total solar radiation reaches 5200-5400 MJ/m2, and the annual sunshine hours are more than 2300h, which is higher than that along the Yangtze River and the south of the Yangtze River, ranking first in Anhui Province. But at present, the utilization rate of light energy in Huaibei Plain is only 0.6%, which is lower than the average level of the whole province. The utilization rate of light energy in agricultural science and technology demonstration park is as high as 2%. If the utilization rate of light energy in Huaibei plain is generally increased to 2%, the grain output can be increased by more than 3 times. It can be seen that the potential of photosynthetic yield increase in Huaibei Plain is huge.

1.2 has abundant heat, large temperature difference between day and night, and high accumulated temperature effectiveness.

The average annual temperature in Huaibei Plain (1958-206d * * 43a, the same below) is about 14.7℃, the accumulated temperature ≥0℃ is 5300-5600℃ d, and the accumulated temperature ≥ 10℃ is close to 4800℃ d ... The large daily temperature difference is beneficial to the accumulation of photosynthetic substances, so the accumulated temperature is efficient.

1.3 The same season of rain and heat is beneficial to improve water use efficiency.

The average annual precipitation in Huaibei Plain is more than 850mm, which provides abundant precipitation resources for crop growth, 95% of which is concentrated in the crop growing season (≥0℃). Synchronization of water and heat is beneficial to improve the utilization efficiency of natural precipitation.

2 Huaibei Plain, the main disadvantages of agricultural climate resources

2. 1 Frequent droughts and floods are the dominant factors restricting the development of dryland agriculture in Huaibei Plain.

Although there are abundant precipitation resources, the average water resource per mu is only 239 m3, which is less than a quarter of that of Anhui Province (1029 m3), and more than 70% of natural precipitation resources are concentrated in summer, mostly in the form of rainstorm, which not only leads to large surface runoff, but also leads to low overall utilization efficiency of precipitation and easy to form local waterlogging. In addition, the annual precipitation in Huaibei Plain also changes greatly, with an average of more than 23%, and the difference between rainy and dry years can reach more than 900 mm, so the dryland agriculture in Huaibei Plain is generally prone to waterlogging and drought.

According to the statistics of precipitation data and drought and flood disaster data in Huaibei Plain for 43 years, it is found that the characteristics of drought and flood in Huaibei Plain are obvious, mainly as follows: ① There are many types of drought and flood. It occurs all year round, and the main types of drought are spring drought, early summer drought, summer drought, summer drought, autumn drought and winter drought, among which summer drought and summer drought have the most serious impact on agriculture. Flooding (including waterlogging) mainly includes spring waterlogging, early summer waterlogging, summer waterlogging and autumn waterlogging, among which summer waterlogging is the most likely and harmful. ② Drought is greater than waterlogging, and waterlogging is heavier than drought. The main performance is that the drought season is continuous, such as 1994, which lasts for more than 7 months and covers the whole Huaibei plain. However, floods are mostly local waterlogging, once formed, it will cause serious production reduction or even no harvest. For example, 199 1, the harvest of winter wheat is in sight, but since May of 17, heavy rains have caused flooding in early summer, resulting in high yield and poor harvest of wheat. In the afternoon of that year, grain production was reduced by more than 50%. ③ As far as specific years are concerned, droughts and floods are easy to occur alternately, which are mainly manifested as drought in a waterlogged year and waterlogging in a dry year, or waterlogging first followed by drought, or waterlogging first followed by drought, or waterlogging in the middle of two droughts, or waterlogging in the middle of two droughts, and all of them turn from drought to waterlogging and from waterlogging to drought quickly. For example, there was a drought in the spring of 2000, but the continuous precipitation in late June caused heavy rainfall, which caused local waterlogging while alleviating the drought.

2.2 Disasters such as dry hot wind, continuous rain, low temperature frost and hail cannot be ignored.

The dry-hot wind in Huaibei plain mainly occurs in the middle and late May, which mainly harms the normal filling of winter wheat and forces it to mature and reduce production. According to the daily maximum temperature ≥30℃, 14h wind speed ≥3m/s, and 14h relative humidity ≤30%, the meteorological data of five stations in four counties, one district and five stations in Suzhou in the 30 days before the wheat harvest in 65438-2000 were counted, and it was found that there was a dry-hot wind of 58 1d at five stations. From the time of occurrence, it is the most frequent in late May, with 5 stations reaching 360d days in 43 years, accounting for 62% of the total days of dry-hot wind, and the greater the probability of dry-hot wind after that. Therefore, late wheat is more vulnerable than early wheat.

Continuous rain in Huaibei Plain can be divided into continuous rain in spring, continuous rain in afternoon and continuous rain in autumn. Continuous rainy days in spring mainly endanger jointing, heading, flowering and filling of winter wheat, sowing of spring crops and crop growth in protected areas. According to the statistics of continuous rainy days ≥3d, daily rainfall ≥0. 1mm and process rainfall ≥ 10mm, the frequency of continuous rainy days in spring is 21.5% (average of 5 stations, the same below), 5a. Continuous rain in the afternoon mainly harms the mature harvest of winter wheat and the sowing of summer crops. According to the statistics of continuous rainfall days ≥3d, daily rainfall ≥0. 1mm and process rainfall ≥20mm, the frequency of continuous rainfall in the afternoon is 14.3% and the frequency is 7a 1. Continuous rain in autumn mainly harms the mature harvest of autumn crops and the sowing and emergence of overwintering crops. According to the standard statistics of continuous rainy days ≥3d, daily rainfall ≥0. 1mm and process rainfall ≥5mm, the frequency of continuous rainy days in autumn is 37%, and the frequency is 3 1.

The low-temperature frost in Huaibei Plain has a great influence on agricultural production, mainly in late spring, from late March to mid-April, which mainly harms early spring crops, protected crops and winter wheat after jointing stage. From mild frostbite to severe frostbite, and even freezing plant stems, such as the frost at the end of March of 1993, the winter wheat "Xi 'an 8" did not heading or headed abnormally. Taking the daily minimum temperature after March 15 ≤0℃ as the general frost standard, and counting the meteorological data for 43 years, the general frost occurrence probability is 32.8%, which occurs once every three years. Taking the daily minimum temperature ≤-2℃ as the criterion of heavy frost, the occurrence probability of heavy frost is 15.5%, and the occurrence rate is 7a 1.

There are different degrees of hail disasters in Huaibei Plain every year, mainly in spring and summer, often accompanied by strong winds and showers, which usually last for several minutes to ten minutes. They are affected in strips, generally in a small range, but the harm is quite serious, from damaging plant stems and leaves to affecting crop growth, resulting in reduced production, to destroying crops, leading to crop failure. According to the disaster data of 43 years, the average hail disaster area is 970,000 hm2/a, and the average grain loss is 46,800 t/a. ..

2.3 The peak value of solar radiation is consistent with the main stubble replacement period, and the light energy resources are wasted greatly.

The solar radiation in Huaibei Plain in June is 590-650 MJ/m2, accounting for 1/9 of the total solar radiation in the whole year, ranking first in each month. At this time, the crops in the afternoon have been harvested, and the crops in the autumn are just in the stage of sowing and emergence, so the leaf area coefficient is small and the photosynthetic utilization rate of solar energy is very low. Especially in June, meteorological disasters are frequent, such as drought, waterlogging and continuous rain in early summer, with a probability of 62.5%, which prolongs the crop replacement period and wastes more light energy resources. In June 5438+ 10, the solar radiation also reached 4 10-430 MJ/m2. At this time, it is the period of crop replacement in summer and autumn and the period of meteorological disasters, and there is also the problem of wasting light energy resources. Huaibei plain is located in the mid-latitude position, forming a transitional feature of climate. Frequent activities of cold and warm air masses and changeable weather have affected the interannual variation and seasonal distribution of precipitation, and often brought floods and droughts to Huaibei Plain. Severe weather such as rainstorm, low temperature and continuous rain, hail, frost and dry-hot wind has adversely affected agricultural production in this province. Coupled with excessive logging and reclamation, it has caused serious soil erosion. Serious soil erosion leads to land degradation, reduced productivity and even bare bedrock. At the same time, soil erosion increases the siltation of rivers, lakes and reservoirs, and intensifies the frequent occurrence of floods and droughts.

With the continuous improvement of industrialization and urbanization in Huaibei Plain, environmental problems are becoming more and more serious, and the agricultural ecological environment is deteriorating. This is mainly manifested in the following aspects: First, the agricultural ecological environment is seriously polluted by industry. Urban-centered industrial pollution is still developing and spreading to rural areas. Second, the improper development of agriculture itself has caused the destruction of agricultural ecological environment. The extensive use of chemical fertilizers and pesticides has led to increasingly serious agricultural non-point source pollution. With economic development and population growth, people's demand and consumption of resources are increasing, and the contradiction among population, resources and environment is becoming increasingly acute. Due to the one-sided pursuit of maximizing economic benefits, ecological protection has been neglected in the process of resource development, resources have been destroyed to varying degrees, and the ecological functions of resources have weakened. Ecological destruction has become a limiting factor of economic development. The ecological damage in Anhui Province is mainly manifested in the following aspects: ① the destruction of forest resources. According to statistics, in the early days of the founding of New China, the forest coverage rate in Anhui Province was as high as 60% ~ 70%. In 2002, the forest area in Anhui Province was 3 17 10000 hectares, and the forest coverage rate was only 27.95%. Moreover, the forest morphology has changed greatly, and the forest phase has changed from the original multi-level structure of trees, shrubs, grass and ground cover to a simple structure dominated by shrubs and grass, and the tree height has dropped greatly. The present situation of forest area decreasing sharply and simple structure has aggravated soil erosion, greatly increased the sediment concentration of rivers and silted up rivers and lakes. . (2) the destruction of water resources. Due to the intensification of soil erosion, reservoirs, ponds and lakes are silted up and the water storage capacity is reduced; River siltation shortened the navigation mileage. Reclaiming land around the lake not only reduces the flood control ability of the lake in flood season, but also causes losses in fisheries and other industries, simplifying the complex and diverse ecological cycle. ③ Destruction of land resources. First, the soil erosion is serious, resulting in a large number of soil organic components loss. Second, the cultivated land occupied by secondary and tertiary industries is increasing year by year, and the secondary potential of soil is serious. Third, the phenomenon of land desertification in Huaibei Plain has accelerated and the quality of land has declined.