Obviously, the purpose of constructing an optimized agricultural eco-geological environment system is to lay a foundation for the sustainable economic and social development of commodity grain bases. Making greater contributions to the country is a good thing that will benefit the present and the future. Therefore, it is of great practical and historical significance to study the optimization of eco-geological environment system in Sanjiang Plain for the further development and utilization of Sanjiang Plain.
First, do a good job in the investigation of agricultural eco-geological environment
The focus of regional agro-ecological geological environment investigation is different from that of regional adjustment. The investigation contents mainly include geological problems closely related to agriculture, such as eco-geological structure, eco-geochemistry, eco-hydrogeology, etc., and emphasize the investigation of basic geological conditions related to agricultural sustainable development. The most important things in the eco-geological structure are: ① to find out the geological and geomorphological properties of soil. (2) To find out the spatial distribution law of geochemical elements in soil and its influence on organic matter (such as the relationship between the content and effective amount of nutrients in agricultural eco-geological structure and nutrients in cash crops, and its influence on the supply of nutrients in crops), so as to provide guidance for fertilization, management and agricultural production layout in agricultural production, and to evaluate the pollution of industry and agriculture to the ecological environment and the quality of soil environment through soil geochemical investigation. (3) Find out the characteristics of eco-hydrogeology, the distribution and migration law of water resources, the quantity of water resources, and the transformation relationship among the four waters (surface water, groundwater, atmospheric precipitation and soil water), and focus on the study of the abundance and shortage of water resources and the influence of water quality on agricultural ecological environment, so as to provide a basis for the healthy development of agriculture.
For example, through analysis, it is found that landform is an important factor affecting the dispersion and enrichment of geochemical elements in Sanjiang Plain. Under the long-term external force, elements are concentrated from hills to depressions. Hills are located in areas where geochemical elements are separated, slopes are areas where elements gather and transit, and depressions are areas where elements are enriched. The distribution of soil geochemical elements in the study area is influenced by the distribution of alluvial sediments in various rivers since the late Holocene. In the plane, the river zone-river zone sediments are alternately arranged, forming a regular strip distribution of "hills, slopes and depressions". The geochemical characteristics and distribution of elements in soil profiles vary with different soil structures. In addition, due to the different composition of soil mechanical particles, the element content is also different. For example, the content of various trace elements in sand is low, while the composition in clay is complex and the content of various trace elements is rich.
Secondly, divide and establish the types of agricultural eco-geological environment system.
The research results of system theory and the existing research results of agricultural eco-geology show that the structure of the system controls the function and behavior of the system in the whole nutrient circulation system of agricultural eco-geological environment. The material basis of eco-geological structure is the structure of the whole nutrient circulation system, which is the framework for controlling the "supply and transportation" of nutrients for the optimal growth of agricultural and forestry crops. It not only controls the supply and transportation of nutrients, but also affects the intake and consumption of nutrients, thus affecting the bioavailability of mineral nutrients.
Therefore, the classification and establishment of agro-ecological geological environment types should follow the following principles: ① Investigate and study the geological environment and agro-ecology as a whole system, taking into account the difference of agricultural ecological quality on the ground, so as to achieve the purpose of sustainable utilization. (2) Grasp the leading factors in the whole system and make a comprehensive analysis. (3) The macro characteristics of various agro-ecological geological types are obvious under the influence of leading factors, which is beneficial to field identification, easy comparison and easy operation.
In a word, the ecological environment of Sanjiang Plain is fragile and its environmental capacity is limited. In view of the above problems, we must put forward scientific basis from the perspective of eco-environmental geology, carry out comprehensive development and management, and make Sanjiang Plain truly realize the all-round sustainable development of agriculture, forestry, animal husbandry and by-fishing.
Third, rationally develop groundwater to ensure a virtuous cycle of groundwater resources.
In the agricultural development of Sanjiang Plain, groundwater is pumped for irrigation in many places, and there are more than 3× 104 pumping wells. However, due to the simple well completion technology and the random pipe running position, pumping will occur when the water level drops. In addition, due to the uneven distribution of groundwater and low water level, it is impossible to extract enough groundwater, which makes groundwater form a downward funnel. Scientific arrangement of well irrigation areas, rational utilization of groundwater and protection of groundwater resources should become extremely important principles in the process of agricultural development. Therefore, for the layout of well irrigation area, we must first understand the types of soil, land and crops, and then decide its development scale according to its actual hydrogeological conditions and water quality and quantity, and must not blindly expand. On the basis of finding out the hydrogeological conditions, rationally arrange and limit the use of water, maximize the development of well irrigation areas, and give full play to the benefits of well irrigation. For areas with unsuitable conditions, irrigation and comprehensive utilization should rely on water conservancy facilities.
This work should be carried out from the following aspects. First, according to the distribution of groundwater sources, combined with agricultural development planning, scale and planting types, the water intake area should be rationally arranged, and the area with easy exploitation, sufficient supply, abundant water and large quantity should be selected as the water source of the water intake well irrigation area, so as to fundamentally ensure that groundwater will not deteriorate, be exhausted and be lacking. Second, for those sections that are not suitable for well irrigation and water diversion projects, we should fully consider the compensation of groundwater, compensate for the abundance of groundwater, and combine the supply of surface water and atmospheric precipitation to intercept and store surface runoff appropriately. Groundwater can also be used as the main water intake layer. Third, the comprehensive utilization of surface water should be given priority in areas unsuitable for pumping groundwater for irrigation.
Four, rational development of minerals, do a good job in land reclamation.
At present, the management of minerals is chaotic, and there is no unified management and mining production plan, which will inevitably lead to the waste of resources. Therefore, it is necessary to implement the Mineral Resources Law and other relevant laws and regulations, adhere to the principle of "developing in protection and protecting in development" for minerals and sandstone, exploit stone, sandstone and soil in a planned and purposeful way, resolutely ban unlicensed small mines, and realize resource conservation, orderly utilization and sustainable development. Avoid the loss of land resources and the destruction of the ecological environment. It is necessary to organize relevant departments to demonstrate repeatedly, formulate a land reclamation project library, actively raise funds, and strengthen the comprehensive improvement of disaster-stricken areas, abandoned areas, idle areas and wasteland. According to local conditions, gradually reclaim and repair desertified land, abandoned land and abandoned mines to make them available, increase the effective utilization area of land and improve the utilization rate of land. In particular, it is necessary to speed up the pace of mine ecological environment management. It is necessary to increase capital investment so that the mine land can be reasonably improved and utilized, and the ecological environment of the mine and its surrounding areas can be continuously improved.
Five, to carry out afforestation in the region.
The important value of forest lies not in wood itself, but mainly in its ecological functions of preventing soil erosion, conserving water, purifying air and regulating climate. According to relevant data, woodland has more groundwater per 20m3 than bare land, which is called "green reservoir". When the forest coverage rate of an area reaches 1/3 or more, it will have a great regulating effect on the surrounding environment. According to the actual situation in Sanjiang Plain, the occurrence of soil erosion on the platform, wind erosion and desertification of plain soil and the arid and windy climate in the region are all directly related to the destruction of vegetation such as deforestation and reclamation of sandy land. Therefore, the status of forest vegetation in environmental geological conditions is second only to water resources. Therefore, Sanjiang Plain should focus on building shelter forests, combining protection, timber and firewood, and greening and beautifying plain areas, and constantly improve the forest coverage rate in plain areas, and strive to achieve 30% in front of the mountain, 20% in low plains and 15% in valley plains. In order to prevent natural disasters, adjust the ecological environment and meet the needs of production and life. For example, some island forests should be resolutely protected and not cut down, and some ancient rivers and floodplains should be converted from farmland to forests.
The restoration and protection of the intransitive verb swamp
The negative effect of wasteland changing into cultivated land has aroused great concern. From June, 5438 to October, 2000 10, the government decided to completely stop further reclamation of the Great Northern Wilderness in order to protect the Sanjiang Plain wetland which was seriously damaged by over-reclamation. But stopping reclamation does not mean abandoning land, and protecting wetlands is to make better use of wetlands. Natural wetland is an ecosystem with extremely high biological productivity, and its productivity even exceeds the most intensive agricultural production system.
Sanjiang Plain is the largest and most concentrated wetland in China with rich biodiversity. It is listed in the list of important wetlands in China Wetland Protection Action Plan, and it is a wetland of international significance in China Biodiversity Protection Action Plan.
The key protection and construction areas in this region are the wetlands and their biodiversity in Shuichengzi, Wusuli and Naoli River basins in Luobei. This area is the best preserved area with relatively concentrated biodiversity in Sanjiang Plain. There are many primitive wetlands in this area, and the ecosystem types are complex and diverse. There are about 100 national rare and endangered species. Habitat diversity is the epitome of Sanjiang Plain.
The key points of ecological function protection and restoration in swamp areas are to strengthen the protection of existing wetland resources and biological diversity, strengthen the construction of ecological function protection areas, implement the ecological project of returning farmland to humidity, establish wetland nature reserves, and adjust local climate and ecological functions. Strengthen the construction of soil erosion control projects in ancient rivers and Wusuli River, and establish an international biological multi-related conservation ecological corridor.
Natural wetland is an ecosystem with extremely high biological productivity, and its productivity even exceeds the most intensive agricultural production system. From the perspective of unit land, the benefits of wetland products are much higher than those of other habitats (including those formed after wetland drainage). Natural products of wetlands include peat, wood, fruits, vegetables, meat (fish and birds), reeds, resins and medicinal materials. The annual yield of Cinnamomum camphora grassland in Sanjiang Plain wetland is 369× 104t, and the livestock carrying capacity can reach 1 19000 (cattle unit). Abies, larch and alder in wetland are all good forest materials. There are more than 200 kinds of medicinal plants in wetland, which contain various bioactive substances such as glucose, glycosides, tannins, alkaloids and ether oil. There are hundreds of terrestrial animals in wetlands, many of which are economic animals. According to the principle of man and nature, analyzing, evaluating, planning and designing the landscape ecology of wetlands, establishing a wetland ecological agriculture model with high productivity and good ecological benefits, developing products with high productivity and economic value that are adapted to wetland niche and formed through manual management, recycling and comprehensively utilizing limited resources, and constructing a "rice-reed-fish" wetland composite agricultural ecosystem can not only improve the output value and profit of poor wetlands, It can also play the role of wetland in regulating river runoff, homogeneous flood process, regulating climate, purifying water quality and improving soil conditions, so as to realize the protection and sustainable utilization of wetland ecological environment. It provides important conditions for scientific research and becomes a paradise for germplasm resources, gene bank and eco-tourism.
Seven, the construction and expansion of nature reserves
The key of Sanjiang Plain Nature Reserve should be wetland reserve, which is the key to restore ecological balance. Nowadays, the wetland nature reserve is facing a dilemma. Since 1984, Sanjiang Plain has established 12 nature reserves at all levels to protect wetlands, with a total area of about 13.2× 104 hm2. However, compared with the whole area of Sanjiang wetland, these protected areas only account for about 30%, and nearly 70% of the wetlands are not protected. Strengthen the protection of wetland forests, expand the scope of nature reserves, facilitate the habitat and reproduction of mammals and waterfowl, protect biodiversity and rare and endangered species, and restore the local original ecological environment. In order to meet the requirements of building ecological agriculture and realizing sustainable economic development, plans and measures for wetland protection and rational utilization should be formulated and incorporated into the planning and construction of comprehensive development of Sanjiang Plain. Make overall arrangements to synchronize wetland protection with agricultural development and construction. Strengthening scientific research and publicity and education is of great historical and practical significance. Therefore, it is necessary not only to protect the existing protected areas, but also to designate some swamps and forests as protected areas, and to increase the efforts of returning farmland to forests in some ancient rivers (such as Jiang Qinglong River and Fuyuan Yalu River).
Strengthen the construction of nature reserves, ecological function protection areas and ecological demonstration areas, further improve and perfect the management system, and increase management efforts. Establish nature reserves in representative areas with multiple relationships between wetlands and organisms, strengthen the construction of national ecological function protection zones in Sanjiang Plain, establish a number of ecological function protection zones such as Naoli River source and Shuichengzi in Luobei, further strengthen the construction of ecological demonstration zones, give play to their demonstration role of coordinated development of resources, environment and economy, and promote the economic development of surrounding areas and regions. At present, in addition to continuing to strengthen the construction of national and provincial natural areas, all cities, counties, farms, forest farms and towns should divide protected areas and protected areas, and production teams and families should also divide some wetlands, woodlands, landforms and water systems to form a protected area network, restore the Sanjiang Plain ecosystem and improve the agricultural ecological environment.
It is necessary to formulate laws and effective measures to protect nature reserves, resolutely stop the destruction of the expansion and continuation of nature reserves, and prohibit mining and poaching activities in nature reserves. Those who violate the criminal law should be investigated for responsibility. It is necessary to evaluate, investigate and monitor the protected areas, strengthen publicity to the people, and let everyone care about the protected areas.
Eight, the control of land desertification
The following measures should be taken: ① Plant solidification. Planting grass in sandy land, building shelter forest or sand-fixing forest, and establishing forest-grass composite ecosystem have the functions of preventing wind and fixing sand, conserving water and regulating climate. ② Returning farmland to forest and grassland. For farmland with serious wind erosion and potential desertification, we must resolutely return farmland to forests and grasslands to curb the development of land desertification. For example, Luobei, Suibin and other places are sandy soil, so it is necessary to return farmland to forests and wet areas to prevent desertification and maintain a good ecological environment. ③ Improving sandy farmland. In the farmland with slight desertification and erosion, which is not suitable for returning farmland to forest and grazing, measures such as artificial bedding, flood diversion and siltation promotion, and green manure are adopted to improve the soil structure and stop the sandstorm from advancing. ④ Water and sediment regulation. Where there are water resources, water is diverted to pull sand, control and cultivate sand, transform and utilize desertified land, build basic farmland and prevent sand erosion.
Nine, salinization control
The following countermeasures should be taken to prevent salinization: ① Long-term renovation and water conservancy construction. Dredging rivers in low plains: On the premise of ensuring the water for reed industry and fishery in scattered areas, Kaiminggou must lower the groundwater level to eliminate surface water and lower the groundwater level, so as to achieve the purpose of desalination and soil improvement. Considering the drainage outlet, main ditch, branch ditch and hair ditch should be opened respectively. In the closed flow area, a short ditch can be dug and a small pumping station can be set up to discharge the water into the main soil ditch. Deep well irrigation can play the role of drought resistance, yield increase and surface salt washing. Irrigation of shallow wells with large wells can reduce the groundwater level. ② Biological improvement measures. First, afforestation is the first priority of biological improvement. Afforestation should be combined with farmland shelterbelt construction. Planting saline-alkali tolerant trees in saline-alkali areas can inhibit ground salt return and promote soil desalination. Afforestation can change the microclimate and make the ecological environment develop in a virtuous circle. Tree species should be adapted to local conditions: Robinia pseudoacacia planted high, willow planted low, elm planted in sand dunes, poplar planted in weak alkali land and willow planted in heavy alkali land. Second, plant salt-tolerant crops, sugar beet, sunflower and so on. High yield can also be obtained on mild saline-alkali soil. However, in order to achieve the dual effects of increasing production and improving saline-alkali land, it is necessary to stop stubble rotation. The third is to grow rice. Irrigation of rice with fresh water can wash away soil salt and make rice yield high. Fourth, green manure crops are widely planted. Planting saline-alkali tolerant vegetation, alfalfa, Sophora alopecuroides, sesbania, black grass, etc. These green manure crops are not only high-yield, high-quality and low-cost, but also increase the content of organic fertilizer and nitrogen in the soil, and can also return salt from time to time. In recent years, planting sesbania in some areas has achieved remarkable results in improving saline-alkali land. In addition, leveling the land, applying organic fertilizer and improving the soil, the above measures, combining far and near, and highlighting key points will achieve the expected results.
X. Controlling soil erosion
The control of soil erosion should focus on water conservancy and soil and water conservation construction, combine engineering measures with agricultural measures and biological measures, pay equal attention to protection and management, and make overall arrangements for restoration and improvement, community management and watershed management. Engineering measures are mainly to repair terraces, dig ditches, intercept slope water layer by layer, differentiate water potential and maintain soil and water. Horizontal terraces, sloping terraces, planting soil and water conservation forests, etc. It should be built on sloping farmland of 5 ~ 10. Agricultural measures include cross-slope soil cultivation, deep tillage and shallow loosening. Establish a scientific farmland fertilization system, soil tillage system and rotation system, and establish a soil erosion control model according to local conditions. According to the investigation of relevant departments, the area of low-and medium-yield fields in Sanjiang Plain is about 40× 104hm2, accounting for 67.9% of the cultivated land area, which seriously restricts the agricultural production in this area. Therefore, it is necessary to raise funds for the transformation of low-and medium-yield fields through multiple channels, adopt preferential policies to mobilize farmers' enthusiasm for transforming low-and medium-yield fields, increase material input for transforming low-and medium-yield fields, improve the input service system, select transformation technologies suitable for low-and medium-yield fields, combine the transformation of low-and medium-yield fields with the development of high-yield, high-quality and efficient agriculture, and gradually build low-and medium-yield fields into high-and stable-yield fields. Biological measures mainly include planting soil and water conservation forests and planting biological protection belts on gentle slopes. Farmland with a slope greater than 15 should be returned to forest and grassland, and deforestation is prohibited.
Eleven, mainly to increase food production.
After the problem of agricultural development in Sanjiang Plain was put forward, at first, some people put forward a set of perfect ideas, that is, the comprehensive development of agriculture, forestry and animal husbandry, the completion of industrial and commercial transportation, construction and service, the construction of commodity grain base, animal products base, export base and urban non-staple food supply base, and the unification of economic, social and ecological benefits. This is a good wish and the ultimate goal of comprehensive agricultural development. However, agricultural development is a long-term strategic task, which should be implemented in a focused, step-by-step and phased manner under the premise of overall planning, and cannot be achieved overnight. The recent agricultural development in Sanjiang Plain should focus on forming new grain production capacity as soon as possible and moderately developing diversified economy. This is determined by the following factors: First, China agriculture is facing new challenges. Since 1984, China's grain production has been stagnant, the population has been growing, the cultivated land area has been decreasing, and the social demand for grain has been increasing, so it needs to import more than1000 billion Jin of grain every year. The solution of China's grain problem is restricted by international and domestic conditions, and it must not rely on imports. We should do a good job in developing agriculture while grasping conventional agriculture. The country listed Sanjiang Plain as the first batch of key development zones, and the first priority was to increase commodity grain as soon as possible. Second, the "Agreement" signed by the province and the state clearly stipulates the development task, the time to complete the task and the investment amount, that is, it is stipulated that from 2000, 40× 104hm2 will be used to transform low-and medium-yield fields, 20× 104hm2 will be reclaimed, and 14× 00 years will be planted. In this case of tight time, heavy tasks and limited funds, the recent agricultural development in Sanjiang Plain must focus on increasing grain output. Within three years, the funds should be concentrated on the transformation of low-and medium-yield fields and the expansion of cultivated land unsuitable for reclamation, and some diversified business projects should be arranged if conditions permit.
XII. All-round development and all-round development
Sanjiang Plain should be built not only as a commodity grain base, but also as an ecological agriculture and green food production base. For example, the ecological agriculture in Sanjiang Plain should focus on the development of pollution-free planting and aquaculture, and on this basis, develop leisure agriculture and sightseeing agriculture, and develop a number of effective pollution-free green foods. Build a number of ecological demonstration areas, ecological villages, ecological townships and ecological counties (cities). Comprehensive utilization of resources, optimizing the structure of industrial products, promoting the organic integration of agriculture, forestry, animal husbandry and by-fishing, and connecting and supporting farming and breeding. This must proceed from reality, according to needs and possibilities, and be implemented step by step in line with the principle of easy before difficult. Only in this way can we correctly handle the relationship between short-term benefits and long-term benefits, economic benefits and ecological benefits, micro-benefits and macro-benefits.
The eco-agricultural construction in Sanjiang Plain should be based on farmland fertility, vigorously carry out the activities of accumulating farmyard manure, expand the planting area of green manure, actively promote the measures of returning straw to the field, and apply peat to compensate and update soil organic matter and various nutrient elements to ensure pollution-free, safe and original ecology of agriculture, grain and vegetables. While vigorously developing grain production, we should actively develop diversified operations and take the road of deep processing, fine processing and multi-level value-added development. On the basis of reasonable rotation of corn, soybean, rice, miscellaneous grains, beet and sunflower, develop vertical space, appropriately increase the variety level of cattle, pigs, poultry, fish and melons and vegetables, and transform and utilize them in multiple steps and directions.
We think that the proportion of agricultural, animal husbandry, forest and fishing land in Sanjiang Plain should be: agriculture accounts for 35%, animal husbandry accounts for 15%, forestry accounts for 20%, fishery accounts for 3.2%, swamp area accounts for 15%, and the rest are protected areas. The model adopted is "comprehensive management of mountains, water, forests, fields and roads" and "combination of agriculture, forestry, animal husbandry and enterprises" The specific agricultural structure model can adopt dry land ecological structure model, paddy field three-dimensional ecological structure model, agriculture, animal husbandry and fishery three-dimensional structural model, water body ecological structure model and middle and low mountain ecological structure model.
In a word, we need to adhere to the optimization from a high starting point and form the rich ecological environment characteristics of Sanjiang Plain as soon as possible. Features are unique, unique. The stronger the features, the deeper the impression and the greater the attraction. The ecological environment of Sanjiang Plain should have its own characteristics, personality and charm, so that the mountains have the aura of mountains, the charm of water, the scenery of forests, the landscape of fields and the beauty of swamps.
With the development of China's four modernizations, the Sanjiang Plain will soon become an important commodity grain base in China after comprehensive management, and the former "Great Northern Wilderness" will inevitably become a beautiful and rich rice granary.