Several eco-agricultural models

1. Tangji agriculture in the Pearl River Delta Tangji agriculture is a unique agricultural production mode created by the people in the Pearl River Delta according to local natural conditions. Mulberry, sugarcane and fruit trees are planted on the pond foundation of the fish pond, which together with the fish pond are called mulberry pond, sugarcane pond and fruit pond. Foundation ponds promote each other, and Sangji fish pond is the most typical one. Tangji agriculture is a characteristic agriculture in the Pearl River Delta, concentrated in Shunde, Nanhai and other cities. Tang Ji's new agricultural model and scientific methods have made agricultural and sideline products more diversified, improved in quality and more competitive in Hong Kong, Macao and international markets. Residents in the Pearl River Delta Plain dig low-lying and waterlogged areas into pond culture, and the excavated pond mud is piled around, which is called "dike". Fruit trees, sugar cane, mulberry trees, flowers, etc. They are all planted on the levee, which can not only prevent floods, but also increase income. The materials produced in the process of crop processing can still be put into ponds as feed, which is an agricultural management model with ecological characteristics. Second, the fish pond-terrace model in the Huang-Huai-Hai Plain is also summarized from Tangji agriculture, aiming at the phenomenon of low terrain, serious waterlogging and soil water and salt movement in North China. The water in fish ponds develops fisheries. Because of the high terrain and low groundwater level in OTA, it is beneficial to the infiltration of surface water, thus reducing the salt on the surface of OTA and improving the middle and low yield fields in North China. In the heavy saline-alkali land where agricultural planting is impossible, according to the principle of digging ponds (digging ditches) to infiltrate saline-alkali, dig ponds to build terraces, so that the built terraces will become saline-alkali-free fertile fields after saline-alkali infiltration, plant various crops or establish mulberry planting bases to raise silkworms. And then pond culture, which is a good successful model to transform saline-alkali land. Comparative analysis of fish pond terrace model and Tangji agriculture: both are three-dimensional agricultural models. Digging ponds in lowlands, pond culture, and developing planting, forestry and fruit industry on this basis. Difference: Different kinds of crops. Tang Chi's agriculture in the Pearl River Delta is based on planting sugar cane, or fruit trees or mulberry trees, which are linked with local agricultural products processing, forming sugar-making based on sugar cane, canned food based on fruit, and sericulture-reeling industry based on mulberry trees. The "one-field fish pond" in the Yellow Sea Plain has formed a pattern of fish fruit grain, fish fruit cotton, fish fruit vegetables and fish fruit grass (feed). Reason: The landforms of the two places are similar, both are flat landforms with low terrain, and both have formed landforms with low terrain and undulating hills. Digging soil and pond in low-lying land is a good way to effectively use land; It is suitable for developing planting industry based on Taiwan Province field. The specific purpose of utilization is different. The Pearl River Delta is located in the subtropical humid area in the south of China, with rich hydrothermal conditions. In order to make full use of water and heat resources, the ecological model of "Tangji Agriculture" has been created, while the Huang-Huai-Hai Plain is located in the warm temperate and semi-humid area of China, and the climate of spring drought and summer rain is easy to cause drought and salinization. It has created a model of "one pond and one field" to control wetlands and transform saline-alkali land, which is an ecological agriculture with advantages and disadvantages. Fish pond-terrace system is an artificial land-water ecosystem that is planned, implemented and built according to ecological principles and economic principles. As an organic whole, fish ponds and terraces have formed a three-dimensional production mode of mutual utilization, mutual promotion, multi-level and multi-orientation, and achieved a high degree of combination of micro-specialization and macro-integration, which can maintain the best economic output in production and maintain and improve the ecological environment. The paddy field system in Xindian has developed a three-dimensional planting and breeding model, making full use of space and water resources and improving the utilization rate, and initially formed four species structure models centered on fish: (1) fish, grain and fruit; (2) Fish, vegetables and fruits; (3) Fish, cotton and fruits; (4) Fish, grass (feed) and fruit. Fish ponds and terraces have their own species structures. From the species structure of fish ponds, ducks are raised on the surface, silver carp and bighead carp are raised on the upper layer, grass carp is raised on the middle layer, and carp and crucian carp are raised on the bottom layer. Grass carp feeds on grass, and its feces can be used as nutrients for zooplankton in water, which can increase flocs in water and become feed for silver carp and bighead carp. Ducks move on the water, and their excrement falls into the water, which continuously provides carbon, nitrogen and phosphorus sources and improves the natural food biological yield of fish in fish ponds. Judging from the variety structure of Taiwan Province field, fruit-grain intercropping: the grain crops include wheat, corn, sweet potato, soybean, peanut and mung bean. And the fruit tree is an apple; Fruit-cotton intercropping: planting cotton among apple trees; Fruit and vegetable intercropping: apple and vegetable intercropping (leek, cabbage, eggplant, tomato, lentil, green pepper, cucumber, zucchini, wax gourd, garlic, green onion, radish, carrot, etc. ) intercropping with grapes and vegetables. The fish pond-terrace system includes two subsystems that interact and promote each other. Salt, nutrients and organic matter on the dining table and slope path are lost through the surface, which affects the water quality of fish ponds. Taiwan Province, a fruit-oriented three-dimensional agricultural layout and land use structure model, is an ecological agriculture based on a virtuous cycle, which is conducive to strengthening regional soil and water conservation and has good environmental benefits. There are also a variety of agricultural and sideline products that can promote local current and long-term interests, increase farmers' economic income, and achieve poverty alleviation, which has good social benefits. Three-dimensional agriculture in southern hilly areas 1. China's basic national conditions: China has a vast mountainous area, accounting for about 2/3 of its land area. With the growth of population in mountainous areas in China, the unreasonable utilization and uncontrolled development of mountainous resources have destroyed the ecology of many mountainous areas, which not only affects the social and economic development of mountainous areas, but also makes the plains and cities more and more at risk of natural disasters. The vast areas south of Huaihe River, east of Yunnan-Guizhou Plateau, north of Leizhou Peninsula and east of the ocean are concentrated in low mountains and hills, which are called "southern hilly areas". The renovation and development of hilly and mountainous areas in southern China is an important content of land renovation in China. 2. Analysis of Natural Characteristics of Hilly and Mountainous Areas in South China The natural geographical characteristics of hilly and mountainous areas in South China are mainly compared with other countries and regions in the same latitude in the world to find out the particularity of this area in China. On a global scale, a large area of desert or arid grassland is distributed in the vast area near the Tropic of Cancer, which is called the "Returning Desert Belt". Due to the influence of the East Asian monsoon caused by the difference in thermal properties between Asia and Europe and the Pacific Ocean, the hilly areas in southern China at the same latitude have formed a warm and humid subtropical and tropical monsoon climate with abundant precipitation and humid climate. Natural vegetation is mostly subtropical and tropical evergreen forests, which has become an "oasis" for the return of desert areas. Affected by topography and geological conditions, the temperature, precipitation, soil and vegetation in mountainous areas show obvious vertical zonal characteristics with the change of altitude. The mountainous area is rich in mineral resources and hydraulic resources, and has the benefits of diversified management. 3. Advantages and existing problems of agricultural resources in hilly and mountainous areas of southern China. When analyzing the agricultural resources in the hilly and mountainous areas of southern China, we should grasp the main influencing factors: hot and humid monsoon climate and rugged hilly and mountainous terrain. Advantages: abundant light and hot water resources, good cooperation in most areas (high temperature and rainy summer, rain and heat at the same time), and great agricultural production potential brought by climate; Biological species are rich and diverse, plants grow fast, the renewal cycle is short, and there are many dominant species; The land types are diverse, the natural environment is diverse, and it has a variety of operating benefits; There are many rivers and abundant water resources, which are beneficial to the development of hydropower and agricultural irrigation. The main problems are: rugged terrain, inconvenient transportation, occlusion and relatively backward culture and education; Affected by meteorological disasters such as drought and flood, low temperature freezing injury and dry hot wind; The utilization of biological resources is single, the protection is weak, species decrease, endangered species increase, and biological advantages have not been transformed into economic advantages; In the soil, poor and low-yield soil is widely distributed and needs to be reformed. Vegetation in many places has been destroyed and soil erosion is serious. In some areas, soil erosion on hillsides has become difficult to use, such as bare rocks. Heavy rain, heavy rainfall intensity, strong surface erosion and complex terrain increase the difficulty of development and utilization; The ecological environment is fragile. The hilly and mountainous areas in southern China have a long history of development, high population density, heavy land load and prominent contradiction between human and land. To sum up, this area is one of the areas with the greatest agricultural development potential and less difficulty in China, with abundant labor resources, proximity to commodity grain bases, industrial cities and seaports, and broad market. 4. Soil erosion and ecological construction Soil erosion are the main ecological problems facing the southern hills. The causes of serious soil erosion are as follows: ① Natural causes: mainly mountainous and hilly, with large terrain slope; There is much precipitation in the south, with high rainfall intensity and strong surface erosion; ② Man-made reasons: excessive land reclamation and deforestation caused by energy shortage and large population and small land have destroyed the surface vegetation and aggravated soil erosion. The harm caused by soil erosion is very serious and the economic loss is huge. Closing hillsides to facilitate afforestation is an effective measure for soil and water conservation. But closing hillsides to facilitate afforestation must first solve the problem of farmers' living energy. The main measures are as follows: ① vigorously promote domestic coal; ② Popularizing firewood-saving stoves; (3) Making biogas to create a fast-growing firewood forest; (4) Where conditions permit, actively develop small hydropower. 5. Comprehensive Development of Agricultural Resources in Mountainous Areas ① Objective: Make full and rational use of the rich natural resources in hilly areas to make the economy in mountainous areas increasingly prosperous. ② The three-dimensional agricultural model of Qianyanzhou in Taihe County, Jiangxi Province: from the top of the mountain to the valley, it is "timber forest-economic forest or bamboo forest-orchard or artificial grassland-farmland-fish pond" in turn. This three-dimensional agricultural layout of "forest and grass on hills, pond between hills, fruit and fish food on gentle slopes" and land use structure with forest and fruit as the main part are ecological agriculture based on benign ecological cycle. Realized the coordination of economic benefits and ecological benefits, short-term interests and long-term interests.