The geographical factors that restrict agricultural production are the problems that Quaternary environmentology must pay attention to. At present, soil erosion has become one of the serious environmental problems. Soil erosion is a severe challenge for China's modernization. The soil with the highest natural fertility in China is black soil, which is one of the important grain-producing areas in China, but now the soil erosion in black soil is extremely serious. Experts in China have warned that the black soil in northeast China may disappear within 50 years. In the middle reaches of the Yellow River, the upper reaches of the Yangtze River and the red soil areas in the south, this problem is very prominent, which not only destroys the local ecological environment, but also brings endless harm to the downstream areas because of sediment deposition. Over the past decades, geology, geography, soil and water conservation and other different disciplines have done a lot of work in this field and achieved many results. However, the study of soil erosion can't be effective in a single discipline, and it needs the cooperation of all disciplines. Quaternary geologists can give full play to their rich knowledge of Quaternary environment, especially Holocene environmental evolution, neotectonic movement, external force process, river development and so on, and can make incomparable functions and contributions to other disciplines. The direction of future efforts is to develop prediction models of soil erosion in different typical areas and regions, so as to provide a more comprehensive scientific basis for decision-making and industrial departments to implement prevention and control.
Land desertification is widespread in arid and semi-arid areas in northern China, and also appears in eastern coastal areas. The control of land desertification has been an important project since 1949, and a lot of work has been done for decades, but it is still serious because of its large distribution area and relatively complicated problems. Quaternary geologists rely on in-depth analysis of desertification forming factors (including environmental background and human factors), and can put forward comprehensive views on regional differences in spatial distribution characteristics of desertification land, different ways of desertification land evolution, hazard assessment and governance models, and make unique contributions. The direction of future efforts is to cooperate closely with adjacent disciplines, carry out interdisciplinary comprehensive research, strive for new breakthroughs in theory and methods, and actively cooperate with local governments to make the research results more adopted and applied.
1. Development of agricultural geology abroad
The term "agricultural geology" was first put forward by German geologists F. A. Fellow and F.V. Richthofen in the middle of19th century, but there is no clear definition, and it is simply used to explain the formation relationship of soil. It was not until 19 16 that R. H. Rastall of Cambridge University published Agricultural Geology, and 1946 that F. v. Emeison of Louisiana State University published Agricultural Geology, which systematically introduced the geological knowledge of rocks, minerals and structures to people engaged in agricultural research for the first time and discussed it.
Since 1950s, with the increasingly prominent contradiction among population, resources and environment in the world, environmental geology has gradually emerged, and quite a few agricultural geological problems have been classified as environmental geology.
1986 American scientist D. C. Adriano published the book Trace Elements in Terrestrial Environment, which systematically introduced 22 trace elements closely related to human beings in terrestrial environment-arsenic, boron, cadmium, chromium, copper, lead, manganese, mercury, molybdenum, nickel, selenium, zinc, antimony, barium and cobalt. Silver, thallium, tin, titanium, vanadium, etc. The economic value, natural occurrence state, circulation and behavior of elements in soil-plant system, plant demand and toxicity tolerance, healthy limit of elements in drinking water and food and their sources in the environment were discussed.
Russia, the United States, Canada, Australia, Britain and other countries have carried out ecological geological surveys and special geological surveys, and interpreted agricultural geology as "geology serves agriculture" (Peter van Straaten, 2002).
In recent years, soil chemists and environmental chemists have done a lot of research on the effectiveness and ecological effects of nutrient elements, especially on the ecological effects of organic pollutants and heavy metals, which has become a hot spot in international environmental science.
2. Research progress of agricultural geology in China.
Before the founding of New China, the geological work rarely involved agriculture, and the only work focused on soil science research and some agricultural mineral surveys under the guidance of geology. Since the founding of New China for decades, great progress has been made in the work of geology for agriculture in China, and a large number of monographs and papers have been published, which has also promoted the development of the national economy. The main work includes:
Hydrogeological exploration of farmland water supply and improvement of saline-alkali land in 1960s and 1970s, China carried out1∶ 50,000 ~1∶ 65,438+million hydrogeological exploration of farmland water supply, which is the most important geological work except1∶ 200,000 hydrogeological investigation and urban water supply exploration, and completed 65,438+exploration of farmland water supply. Saline-alkali land is improved in a wide range, such as Huanghuaihai Plain, Kanto Plain, Inner Mongolia Hetao Plain, Yinchuan Plain, Northeast Songliao Plain, the northern foot of Tianshan Mountain and Hexi Corridor. It has made important contributions to increasing grain output, accumulated a lot of practical experience and developed the theory. This work is still going on in Hebei Plain, Yinchuan Plain and Hetao Plain. , and has been deeply involved in the storage and management of water resources.
The utilization and development of agricultural rock and mineral resources include mineral fertilizer and mineral feed. The biggest advantage of rock ore as fertilizer is its low cost and large reserves. The agricultural development of China's rock mines mainly includes traditional agricultural fertilizers such as phosphate rock and potassium ore, which has played an important role in China's agricultural development and output improvement. In recent years, the agricultural utilization of nonmetallic minerals has made great progress, mainly including zeolite, montmorillonite, illite, kaolinite, attapulgite, sepiolite, glauconite, vermiculite, limestone, dolomite, gypsum, medical stone, apatite, diatomite, magnesite, serpentine, lignite, peat, mung bean rock, perlite, tuff and volcanic slag. Great progress has also been made in the research and development of rock mineral feed additives in China, such as the development and utilization of rock salt, gypsum, medical stone, lime, bentonite and diatomite as feed additives. Zeolite or bentonite containing sodium, potassium, silicon, aluminum and other elements can help digestion, promote animal growth and development, improve reproductive capacity, decontaminate and deodorize, avoid parasitic infection, eliminate diseases caused by lack of trace elements, promote smooth and bright fur or bright feathers, and have delicious meat. Using lime and stone powder as feed additives, the ornamental birds fed have high egg laying rate, thick eggshell and high compressive strength.
The investigation, evaluation and zoning of regional agricultural geological environment and the evaluation of regional ecological environment quality involve a wide range of fields and contents. For example, the comprehensive evaluation of eco-geological environment quality in ecologically fragile zone and agricultural sustainable development, and the comprehensive evaluation of regional agricultural eco-geological environment quality provide scientific basis for protecting and managing the ecological environment, tapping the potential of agricultural natural resources in this area and formulating sustainable development plans. In recent years, the situation of agricultural ecological construction in various places has greatly promoted the study of local agricultural eco-geological zoning. Sichuan, Guangxi, Hubei, Shandong, Hebei, Henan, Jiangxi, Guangdong, Anhui, Jiangsu, Jilin, Zhejiang, Yunnan, Guizhou, Liaoning and other provinces (regions) have carried out different degrees of agricultural eco-geological regionalization, which provides decision-making basis for scientific adjustment of agricultural structure and rational utilization of regional water and soil resources, such as Sichuan Basin.
Investigation, Evaluation and Development of Agro-ecological Geology of Famous Agro-forestry Crops Since 1980s, the investigation and evaluation of Agro-ecological Geology of Famous Agro-forestry Crops has been carried out in a vivid way, involving more than 100 famous products, mainly including Sichuan citrus, Fuling mustard tuber, Shatian pomelo in Guangxi, Feicheng peach in Shandong, Turpan grape in Xinjiang, Zizhou jujube in Hebei, litchi in Guangxi, Yunnan, Guizhou, Henan, Shandong tobacco and Yunnan. Sugarcane in Liujiang, Guangxi, bananas in Nanning, Taishan (northeast foot) in Shandong, Qian 'an in Hebei, chestnuts in Changping, Beijing, etc. , has achieved fruitful results, accumulated a lot of data and information, summed up many theories and understandings, and used these data and information and their laws to discover or discover many new advantageous areas of agriculture and forestry, expanded planting and greatly promoted local economic development.
3. The relationship between Quaternary geology and agriculture
Rock is the material basis of soil and one of the five soil-forming factors. Weathered rock accounts for about 95% of the total weight of soil, which is not only the basic skeleton of soil, but also the mechanical support foundation of crops. The soil-forming parent material has a direct influence on the physical and chemical properties of soil. What kind of parent rock there is, there will be what kind of soil. Therefore, rocks are the material basis of soil. Accurately mastering the knowledge of identifying various rocks and minerals is the key to determining the attribution of soil types.
Rocks provide various nutrients necessary for crops and human health, such as potassium, phosphorus, calcium, carbon, silicon, boron, molybdenum, iron, sulfur and iodine, which mainly come from soil. During the growth process, plants absorb nutrients from rocks and soil matrix through roots for their own growth and utilization, and return to the soil in the form of litter, thus enriching soil mineral nutrients, improving soil fertility and laying a rich nutritional foundation for the healthy growth of crops. Under the intervention of the same vegetation, climate, topography and human activities, it is precisely because of the different parent rocks that different levels of soil fertility and agricultural productivity are produced.
Rock is the main factor that determines the agricultural utilization rate. In some places, the cultivated land area is large and the agricultural output rate is high, while in some places, the agricultural output rate is low. The main reasons are related to the rock types in these places: generally, red clay, purple sand shale and slate shale have large cultivated land area, high agricultural utilization rate, while limestone, gravel and granite have less cultivated land and low agricultural utilization rate. For example, there are 6.5438+0.04 million mu of soil and 7.34 million mu of paddy fields in the Quaternary laterite parent material in Hunan, accounting for 70%. 58% of these parent materials. There are 77.26 million mu of soil developed from limestone parent material, forming 6.99 million mu of paddy fields, accounting for only 9.5% of the whole country. 05% of this parent material. In addition, limestone area is the main poverty-stricken area in Hunan, with rugged terrain, sparse vegetation, developed sinkholes, serious water leakage, easy to be affected by drought and unstable harvest. Shao Heng, Chayong, Changliu and Ma Yuan basins in this province are mainly developed from purple sand shale parent materials, and paddy fields and dry fields are widely distributed, which is one of the important agricultural production advantage areas.
Geological conditions are an important basis for agricultural scientific planning and crop distribution. Because of the variety of rocks and parent materials, the soil is rich and thin, acidic and alkaline, sandy and sticky, thick and thin, dry and wet, and there are many kinds of soil. Therefore, in the long-term agricultural production practice, we have repeatedly stressed the need to adjust measures to local conditions and follow the laws of nature. At present, the strategic adjustment of agricultural structure is to select suitable crop varieties according to local conditions according to these characteristics of soil, biological characteristics of crops and market demand, and give full play to the maximum production potential of soil and agricultural production efficiency.
Combining earth science with agricultural science closely, accelerating the application of geological science achievements in agriculture, strengthening agricultural earth science research and strengthening exchanges and cooperation will promote the sustained, rapid and healthy development of agriculture.
4. Development trend of agricultural geology in China.
Since the founding of New China, China has made remarkable achievements in agriculture, feeding 22% of the world's population with 7% of the world's arable land. At present, the overall situation of China's agriculture is as follows: first, the quality of major agricultural products is insufficient, especially after China's entry into WTO, the agricultural structure needs to be adjusted urgently; Second, the utilization level of agricultural land and resources needs to be improved; Third, the contradiction between agricultural and rural economic development and ecological environment construction is prominent.
Paying attention to agro-ecological environment is a bright spot in the development of agro-ecological geology in China. Since 2002, the multi-objective mapping plan implemented by China Geological Survey in cooperation with local governments has strengthened the evaluation of agricultural eco-geological environment quality, and provided a scientific basis for protecting and governing the ecological environment, tapping the potential of regional agricultural natural resources, and making sustainable development plans.
Agricultural eco-geological engineering design will provide technical support for the sustainable utilization of land resources. Focusing on national needs, such as the construction of grain and famous fruit bases, the construction of agro-ecological provinces (counties), and the ecological construction of returning farmland to forests and grasslands. Taking the western development as an opportunity, combined with the investigation of land and resources, agricultural eco-geological engineering design is carried out to realize the unity of social, economic and ecological benefits.
From the analysis of agricultural geological background in 1980s to the proposal of agricultural ecological geology in 1990s, the concept of sustainable development has been generally recognized. Eco-geochemistry and eco-hydrogeology are another breakthrough in theoretical innovation of agricultural eco-geology. Studying the eco-geochemical cycle mechanism of mineral nutrients in rock (soil)-water plants and paying attention to the role of soil water as the carrier of plant nutrients and nutrient elements in the nutrient supply, transportation and consumption system will solve the basic theoretical problems for realizing the goal of "low input, low consumption and high output".
5. Application of Quaternary geological comprehensive service field
Land resources and their rational utilization are key issues related to agricultural development. According to the field investigation, using new remote sensing information such as large-scale topographic maps and aerial photographs, the land resource map, ground slope map and land use map are compiled to evaluate the quality of land suitable for agriculture, forest and grazing, and put forward reasonable development suggestions.
The construction of grain and fruit base, its scale and reasonable layout are greatly influenced by the local Quaternary environment, including climatic conditions, geomorphological conditions, hydrogeological conditions and geochemical conditions. Using the intersection and infiltration of Quaternary geology and agriculture and other related disciplines, we can put forward valuable opinions on the basis of finding out these situations and play an irreplaceable role in other disciplines.
Comprehensive agricultural development and rational distribution, that is, the core of building sustainable agriculture is to improve the agricultural ecological environment, increase agricultural productivity, consume the least production factors, obtain the largest agricultural products, and realize the coordinated development of maximum productivity, optimal economic benefits and optimal ecological environment. These aspects need to apply Quaternary geology to do a lot of basic investigation and comprehensive research to provide scientific basis for them.
The function of agricultural eco-economic system is a comprehensive function, which is mainly reflected by economic benefits, ecological benefits and social benefits. The benefits of these three aspects are reflected in different aspects, and each element is an index to characterize its principle characteristics. The combination of these factors and indicators constitutes the index system of comprehensive evaluation of agricultural eco-economic system functions. Among them, the elements of ecological benefits were put forward completely under the background of Quaternary geological environment, which is the material basis and energy source of the whole agricultural eco-economic system.