Obviously, the formation and development of landforms are closely related to the geological conditions of a region, because landforms are realized by a series of repeated tectonic movements through the interaction of various physical forces. It is reported that Yongxin is located in the continental tectonic unit of Luo Xiao-Yunkai arc basin and Yunnan-Vietnam-South China geosyncline. Caledonian orogeny caused fold uplift and coastal sand deposition in some areas, and Indosinian orogeny caused Caledonian basement to be involved in folds to varying degrees, that is, it played the role of basement fold and caprock fold. After uplift and recoil, it gradually grew into the embryonic form of today's terrain. In addition, the erosion of rivers will also change the topography of the outer layer. Heshui River, a tributary of Ganjiang River, passes through Yongxin, with a subtropical monsoon climate and abundant rainfall in summer. River movement and rainfall will inevitably cause erosion, transportation and accumulation of soil and soil layers, but this only changes the outline, and the most basic terrain only fluctuates slightly after it stabilizes.
China's huge latitude and longitude span often creates a variety of natural landscapes and natural conditions. Soil is integrated, showing different colors, and different colors have different physical and chemical properties behind them. As we all know, there was no soil on the earth at first, and bare rocks covered the surface of the earth. The attachment of lichens and the organic acids produced by their life activities make rocks soft, so plants can grow on them and continue to evolve, and finally a relatively stable soil type is produced. From this, we can infer that plants growing on the soil have changed the soil. We usually think that the nature of soil determines which plants can grow on it. Is this contradictory? Obviously not, because these two discussions are not held at the same time.
The soil in Yongxin is acidic red soil. As for why there is such a characteristic, we can analyze it from the material composition of soil. Soil consists of solid phase, liquid phase and gas phase. The minerals in the solid phase usually determine the color of the soil. It is reported that the soil in Yongxin contains a lot of goethite and hematite (mainly iron oxide), which shows its color. There are many factors that affect the acidity and alkalinity of soil, including chemical fertilizers and pesticides applied by human beings, but here we only analyze the acidity and alkalinity of soil in our hometown from the most natural point of view. After all, agricultural activities there are scattered. Because of the high temperature and rainy weather, the annual rainfall is 1, 530.7 mm In the same season of hot and humid weather, the weathering and pedogenesis of soil is very strong, and the circulation of biomass is very rapid. Alkali is highly unsaturated, and its pH value is generally 4.5-6. At the same time, the oxides of iron and aluminum have accumulated obviously, and the soil has become sour and thin. Tea tree is very popular in our country because of its acidity.
But too strong acidity can also cause some problems. For example, nutrient availability is low or lacking, nitrogen, phosphorus and potassium are generally lacking, and many soils are deficient in calcium and magnesium, which generally affects plant growth and creates a "bare mountain" scene; There is also a problem related to the health of our people: too many heavy metals, such as Al-Mn-Fe, seep into the groundwater from the soil, affecting the urban and rural water supply systems; Runoff to rivers and lakes affects the growth of aquatic organisms, and we are bound to eat aquatic organisms. According to biological enrichment, the harm to human body is several orders of magnitude higher than that of drinking water.
Another environmental problem that any developing region should encounter is air pollution. Since ancient times, our county has been dominated by agriculture. However, with the advancement of national industrialization, we have to introduce some industrial enterprises. Because talents are not particularly dense, high-tech enterprises generally don't come to us. Some polluting enterprises that can't stay in big cities do have ideas, and because the government is particularly willing to attract investment, the review and supervision are relatively loose. Therefore, the waste gas is basically discharged without treatment. In China, smog is not the most serious, but SO2 and NOX. It's not a year or two since people living near factories have felt the stench, and sometimes they feel uncomfortable living in the central city.
It's a long way to go, Xiu Yuan. If you want to know more about what you have and where it comes from, you will naturally feel awe and be cautious.