Analysis on the production potential of light and temperature climate in Guangdong Province

Due to the differences in latitude, distance from the sea and topography, the climate in Guangdong Province is different to some extent. First of all, the annual average temperature in Guangdong Province gradually increased from north to south, from 19℃ in northern Guangdong to 23℃ in the southwestern Leizhou Peninsula. The average temperature from north to south is 20.3℃ in Shaoguan, 265,438 0.8℃ in Guangzhou, 22.4℃ in Shenzhen and 23.65,438 0℃ in Zhanjiang. The weather in Guangdong is hot in summer, and the average temperature in July is around 28℃ ~ 29℃, with little difference between north and south. Because the terrain is high in the north and low in the south, the summer monsoon comes from the tropical ocean, and the warm and humid airflow drives in directly. It is generally rainy and seldom hot in all parts of the province. According to the calculation that the average temperature in summer is higher than 22℃, the summer in Leizhou Peninsula in the southwest is as long as 7 months, and the number of summer days in the north is reduced, 6 months in the Pearl River Delta and more than 5 months in northern Guangdong. 65438+ 10 is the lowest month in the whole year, and the winter temperature in Guangdong Province is quite different, and its law is still gradually increasing from north to south. In June 5438+ 10, the average temperature gradually increased from 9℃ in northern Guangdong to 16℃ in Leizhou Peninsula, with a difference of 7℃ between north and south. In Guangdong Province, the temperature in 65438+ 10/0 is mostly between/kloc-0℃ and 20℃, which is generally warm and pleasant, but there are 5 ~ 6 cold waves from the north (cooling within 24 hours 10℃ or above) invading every year, affecting the whole mainland of Guangdong Province, so there are occasional extremely cold and frost in winter in Guangdong. The cold wave gradually decreases from north to south, and the extreme low temperature gradually increases from north to south. The extreme low temperature in northern Lian County is -8.9℃, Shaoguan -4.3℃, Guangzhou 0℃, Shenzhen 0.2℃ and Zhanjiang 2.8℃. The frost period in the northern mountainous area of Yingde is more than 60 days, and gradually decreases to the south. From the south of Yingde to Xijiang-Qingyuan-Zijin line, the frost period is about 30 days, and the southern coastal areas generally only have 1 ~ 10 days, with occasional light frost in the morning. According to the calculation that the average temperature is lower than 10℃ every five days as winter, there is no winter in the strict sense of climatology in Guangdong. The heat distribution in different areas of Guangdong Province is also different. The annual radiation balance value in the north is 54 kcal/cm2, and it increases to 65 kcal/cm2 in the south. Except for Lianshan in northern Guangdong, the continuous accumulated temperature of daily temperature ≥ 10℃ in most parts of the province is above 6000℃ ~ 8000℃, and the duration of 10℃ generally exceeds 300 days.

Due to the influence of various geographical factors, the topography of Guangdong Province is varied and changeable, resulting in vertical changes of regional microclimate and climate. With the elevation, various climatic factors generally change regularly. For example, with the elevation, the temperature decreases and the precipitation increases. The vertical decline rate of annual average temperature in mountainous counties of northern Guangdong is between 0.6 1 ~ 0.72℃/ 100 m. Due to the influence of topographic factors, there are obvious differences in climate around the country, forming various mountain microclimates. Mountains are often obstacles to air masses and frontal activities. The southeast slope of the mountain range is often rainy, while the northwest slope is less rainy. In addition, due to the influence of mountains, the cold air invading from north to south in winter is blocked by mountains and sinks, which reduces the temperature. In basins that are open to the south or close to the north, cold air is prevented from invading to the south in winter, and abundant heat and precipitation brought by the southeast monsoon are received in summer, so these places often form a good microclimate with little annual change.

Guangdong Province is high in the north and low in the south, with Nanling Mountains in the north and low mountains, high hills, low hills, terraces and plains in the south. The mountainous areas in Guangdong belong to middle and low mountains, mainly from northeast to southwest, followed by northwest to southeast, forming arc mountains with each other, and only a few are east-west or north-south mountains. The northern mountains are Nanling mountains, and the eastern mountains are mostly composed of mountains parallel to the coast, which are arranged from the coast to the inland. The hills are distributed around and connected with the mountains, which is an extension of the mountains. Basins and valleys crisscross between hills and are mostly formed by erosion and alluvial of geological structural depressions and faults, and their trend is often consistent with mountains. The larger intermountain basins in northern Guangdong mainly include Nanxiong, Shaoguan, Lianzhou, Xing Zi and Yingde basins. Lighthouses, Xingning, Meixian and Wuhua basins in eastern Guangdong; Huaiji, Luoding, Xinxing and Yangchun basins in western Guangdong. The plains of Guangdong Province are mainly distributed in the lower reaches of major rivers, which are formed by alluvial rivers and mainly distributed in the Pearl River Delta in the west, east, north and downstream. It is the largest plain in the province, with low and wide terrain and dense water network. Followed by Hanjiang, Rongjiang and Chaoshan Plain in the lower reaches of Lianjiang, Jianjiang Plain and Moyangjiang Plain in western Guangdong.

From the distribution and topographic trend of light and heat resources in Guangdong Province, it can be seen that the light and heat resources in Guangdong Province generally show a decreasing trend from east to west, from south to north, from low altitude to high altitude, from leeward to windward, and from sunny slope to shady slope. In other words, the light and heat resources in Guangdong Province are connected from Leizhou Peninsula in the southeast to the Chaoshan Plain in Qingyuan, Shaoguan and Zhaoqing in the northwest, and the overall trend is decreasing.

Rice is the main grain crop in Guangdong Province, and it is also the benchmark crop for agricultural land classification in Guangdong Province. According to the photoperiod and temperature (climate) productivity potential index of designated crops in Guangdong Province calculated by the state, the photoperiod and temperature productivity potential index of rice in Guangdong Province was analyzed. It is not difficult to see that the connection line from Leizhou Peninsula in the southeast to Chaoshan Plain and then to Qingyuan, Shaoguan and Zhaoqing in the northwest shows a decreasing trend as a whole. Its distribution law is basically consistent with the distribution law of light and heat resources in Guangdong Province, and the small anomaly of rice light and temperature production potential index in Shaoguan City is also consistent with the microclimate anomaly in Shaoguan Basin.

The level of land use reflects the development of agricultural land potential. Because the maximum yield of secondary areas under different standard farming systems is different, although the level of land use coefficient of the same secondary area and the secondary area with similar maximum yield level reflects the level of designated crop yield, the level of land use coefficient between secondary areas with different maximum yield levels only reflects the potential of agricultural land in different places. From the table of the highest yield and the largest "yield-cost" index in the secondary areas of Guangdong Province, it can be seen that the rice soil production potential in Chaoshan Plain and Leizhou Peninsula is the largest, close to 700 kg/mu; There is little difference in other secondary areas, about 630 kg/mu. Considering winter crops, the highest yield of sweet potato in Chaoshan plain in winter is much higher than that in other secondary areas, which leads to the highest rice yield in Chaoshan plain in the province.

Paddy fields account for about 70% of the cultivated land in Guangdong Province. Rice is the staple crop in this province, and the sown area accounts for more than 80% of the whole province. Dry land accounts for only about 27%, mainly distributed in Zhanjiang and Qingyuan, and scattered in other parts of the province. Therefore, the distribution law of paddy field utilization level basically represents the distribution law of agricultural land utilization level in Guangdong Province. Looking at the equivalent area table of paddy field utilization coefficient in Guangdong Province, we can see that the paddy field utilization level in Guangdong Province has the following distribution laws:

(1) Most secondary areas in northern Guangdong (except some limestone areas), central and southern Guangdong, southwestern Guangdong and coastal areas have fertile soil, good irrigation conditions, mature rice cultivation techniques, high management level, large investment and high crop yield. The average yield of rice can reach about 440 kg/mu, and the land use level ranks in the upper-middle level of the province. Among them, Gaozhou City, Xinyi City, Nanxiong City, Renhua County, Meixian County, Meijiang District and xingning city have an average yield of more than 550 kilograms per mu, and the comprehensive land utilization coefficient is greater than 0.75, which is a high and stable yield area in Guangdong Province.

(2) The secondary plain of Chaoshan Plain is alluvial from the lower reaches of Hanjiang River, Rongjiang River and Lianjiang River, making it the second largest plain in the province. In addition to Huilai, agricultural production in this area is highly intensive, with an average yield of about 480 kilograms per mu. Among them, the yield of rice in Rongcheng, Jiedong and Chaoan of Jieyang is above 500 kg/mu, which is a famous agricultural high-yield area in the province. However, because the highest yield of flood and drought crops in this secondary area is the highest in the province, the land use level in this area is only at the upper-middle level in the province.

(3) Leizhou Peninsula area (Zhanjiang area), limestone area (Yingde, Lianshan, Lechang, Ruyuan County, Qingxin North, etc. ) and some mountainous counties (Tai Po, Liuhe, Jiexi, etc. Limited by soil conditions and water conservancy facilities, the land use level is low, and the average rice yield is only about 360 kg/mu. Although Leizhou Peninsula is the area with the best light and heat conditions in Guangdong Province, with great potential for light and temperature production, the rice yield level is low due to less precipitation, large evaporation and lack of water sources.

(4) Although the whole Pearl River Delta region, especially Guangzhou, Shenzhen, Zhuhai, Foshan and Zhongshan, is located in the largest river alluvial plain in Guangdong Province, with flat terrain, fertile soil, good irrigation conditions and mature rice cultivation techniques, it was once the main grain producing area in Guangdong Province in history. But in recent ten years, with the development of reform and opening up, this area has become a relatively developed area in our province and even the whole country. Due to the influence of comparative interests, farmers' grain crops are planted extensively, paddy fields are basically not planted in winter, the land use level is low, and the average yield of rice per mu is only about 360 kg.

(5) Fogang, Qingyuan, Qingxin, Longmen, Wuhua and Fengshun are located in the transition zone between the two secondary areas of northern Guangdong and central and southern Guangdong, and are classified as the secondary areas of central and southern Guangdong. Due to the difference of planting system and maximum yield between the two secondary areas, rice fields in northern Guangdong are double-cropped a year, and rice fields in central and southern Guangdong are triple-cropped a year, resulting in rice yield level in two adjacent equivalent areas, although it is not much different from neighboring counties (districts).

The economic coefficient of agricultural land reflects the economic benefit level of agricultural land production and is the output effect evaluation of unit input. Farmland yields are high, but the benefits are not necessarily high. Therefore, agricultural land economic coefficient is not positively correlated with agricultural land quality and socio-economic conditions. The distribution law of paddy field economic coefficient basically represents the horizontal distribution law of economic benefits of agricultural land production in Guangdong Province. The production cost of rice in Guangdong Province is mainly composed of material cost and manual pricing. Material costs mainly include seed and seedling, farm manure, chemical fertilizer, agricultural film, pesticide, animal power, mechanical operation, irrigation and drainage, depreciation, purchase and repair of small farm tools. According to the survey data of thousands of farmers in Guangdong province for many years, the average material cost of conventional rice is about 170 yuan/mu. The price of labor depends on the amount of labor and the daily wage. The province's average labor day wage is about 18 yuan, and the regional labor day wage is between 14 ~ 28 yuan. The average number of workers is about 12, and the number of workers ranges from 6 to 18. The average production cost of conventional rice in the whole province is about 380 yuan/mu, and the production cost is about 360 yuan/mu in the secondary areas of the Pearl River Delta due to the small amount of labor. The average secondary area in the coastal area of eastern Guangdong is about 365 yuan/mu; The average area in southwest Guangdong is about 390 yuan/mu; The average secondary area of Chaoshan Plain is about 400 yuan/mu; The average secondary area of northern Guangdong, south-central Guangdong and Leizhou Peninsula is about 4 10 yuan/mu. It can be seen from the rice yield and input level in the whole province that the benefit level of paddy field production in the whole province has the following distribution rules: (1) the land economic coefficient in northern Guangdong is generally high, basically above 0.6; The economic coefficient of land in central and southern areas is generally low, basically below 0.6. The economic level of the secondary zone in northern Guangdong is not very developed, farmers mainly live on land, and the overall input-output level is high, with the economic coefficient basically above 0.6. The economic coefficients of Liannan, Jiaoling, Xingning, Meixian, Longchuan, Wengyuan, Meijiang and Nanxiong are above 0.7. Except Gaozhou, Xinyi, Gaoyao, Jiedong, Jieyang, Panyu, Fengkai, Yangxi, Leizhou, Xuwen and Haifeng, the economic coefficient in central and southern Guangdong is basically less than 0.6, and some of them are less than 0.5.