Geographical environment of Nangang street
Nangang street is located at the intersection of Dongjiang River and Pearl River, which can be divided into alluvial plains and eroded platform hills of Pearl River and Dongjiang Delta according to the types and forms of flowing water landforms. The north of Guangzhou-Shenzhen Highway is dominated by hills, slopes and erosion platforms, with open fields in the middle. Along Huangpu East Road is a platform, and the south of Huangpu East Road belongs to sedimentary plain and delta alluvial plain. The higher hills in the north are Tonggu Mountain and Yapoji. Tonggu Mountain is144.7m above sea level, and Yapoji is183.3m above sea level. The platform denudation surface can be divided into three levels: 60 ~ 80m, 20 ~ 40m and 10m, among which the level of 20 ~ 25m is the most obvious.
Except for the low hills in the north, Nangang Street is flat and open in most areas, high in the north and low in the south, with a clear distribution of plain platforms and a slight inclination from west to east. The distance between east and west is long, and the distance between north and south is short, showing a strip distribution law. Generally, the low hills in the north are 20-80m above sea level, the highest one is183.3m above sea level, and the southern plain is 5 5- 10/0m above sea level. The hillside terrain is gentle. The climate of Nangang street belongs to subtropical monsoon climate, with abundant rainfall, humid air and distinct seasons all year round.
Temperature: The highest temperature in Nangang Street is in the dog days (July-August) all the year round, which occurs between the summer, summer, beginning of autumn and early summer. The highest outdoor temperature is about 38℃, and the highest average temperature in July is 28.4℃. The annual minimum temperature is 65438+February to February of the following year, that is, solar terms such as winter solstice, slight cold, severe cold and beginning of spring. The lowest average temperature in January is 13.7℃. 2℃ ~ 3℃ at night. The frost-free period is as long as 350 days, and the low temperature frost is about 2 ~ 8 days. The daily average temperature difference is about 5℃, and the low temperature of 0℃ rarely occurs.
Rainfall: Rainfall is closely related to typhoons and monsoons. June to September every year is the typhoon season, which brings heavy rain or heavy rain. In case of rainstorm, the daily precipitation can reach 200mm. After the first frost (65438+1late October), the rainfall decreases, and the next year "rain" to "Grain Rain" (from late February to late April) is the rainy season. The annual rainfall 1200 ~ 2000 mm is generally concentrated in April ~ September, accounting for 70 ~ 90% of the total annual rainfall.
Rizhao: Nangang Street is located in the south of the Tropic of Cancer, with low latitude and large solar radiation angle. The annual solar radiation heat is 106.7 kcal/cm2, the annual average sunshine hours are 1906 hours, and the sunshine rate is 43%. Abundant heat resources and abundant sunshine are beneficial to the growth of tropical agricultural and forestry crops.
Wind speed: the monthly average wind speed is 1.7 ~ 1.8m/s, and the highest wind speed from July to September is 28m/s.
Evaporation: the annual average is about 1000 ~ 1300mm.
Natural disaster weather: Natural disaster weather mainly includes typhoon, freezing injury, flood and drought. The first three are more serious. Due to the influence of geology and geomorphology, the soil in Nangang Street extends in strips from east to west, and is divided into delta reclamation area and hilly farmland area. Soil types in hilly areas have vertical changes; Paddy soil is the main soil type in rice planting area, and the distribution of latent paddy soil and submerged paddy soil is less.
The paddock area south of Huangpu East Road belongs to paddy soil, which is mainly alluvial from Pearl River, Dongjiang River and rivers in the town and matured by artificial hydroponics. These paddy soils can be divided into river sand mud fields, tidal sand mud fields, delta alluvial soil fields, acid returning fields and other soil genera. River sand mud farms are mainly distributed in Canglian, Bigang and Nangang. Tidal sand and mud fields are mainly distributed in Gaowei area south of Huangpu East Road. Alluvial soil field and acid return field in the delta are mainly distributed in the low-lying areas along the Pearl River south of Dongjiang tributary. Dongjiang alluvial soil is more fertile.
North of Huangpu East Road and along Guangzhou-Kowloon Railway belong to paddy soil in Kengtian area. This kind of soil is developed in the wide valley of platform hill and formed by flood wave accumulation and artificial hydroponics. This kind of soil can be divided into Mahongtian, sandy shale red soil field, alluvial yellow soil field and wide valley alluvial land. Compared with paddy soil in reclamation area, the tillage depth is between 9 ~ 17 cm, which is greatly influenced by soil-forming parent material and contains more sediment, mainly loam and sandy clay. However, the content of available phosphorus is slightly higher, which is suitable for rice-peanut rotation.
The natural soil in Nangang Street is mainly distributed in the north, middle and platform hills, and its depth is influenced by the parent rock. From the bottom of the valley, paddy soil, lateritic red soil and stony soil can develop rice, litchi, citrus, olive, white olive, Pinus massoniana and forest respectively. There are many rivers and rich water sources in Nangang street. There are three rivers in this street: Nangang River, Bigang River and Xibei River.
Nangang River originates from Mumuqiang Reservoir in Luogang Town, Baiyun District. After flowing through Luogang, Huocun, Bigang and Nangang, it flows into Dongjiang from north to south and joins the Pearl River, with a total length of 24 kilometers. It flows through Nangang Street in Huangpu District, with a total length of 6.8 kilometers, a rainwater collection area of 85 square kilometers, a transit area of 47 square kilometers, and a maximum flow of 584.2 cubic meters per second.
Bigang River originates from Datian Mountain, flows through Xincun, Dazhuang, Bicun and other places, flows into Nangang River in Yantian from west to east, and flows into Dongjiang River and Pearl River, with a total length of 12km.
Xibei originates from the mountainside of Luofeng Mountain in Luogang Town, flows through Liucun, Canglian and other places, and flows into Dongjiang from north to south, with a total length of 15km.
These three rivers are the main irrigation water sources for some farmland north of Huangpu East Road in Nangang Street, but there are also some floods in Nangang River, which have a certain impact on crop growth.
The main water sources for farmland irrigation in Miaotou, Nanji, Xia Yuan and Shabu villages south of Huangpu East Road are Shantang Reservoir, Hengjiao River and its tributaries, which are often affected by floods and salt tides, causing certain disasters.