The history of farming in Xinjiang is a history of controlling salinization. As the largest distribution area of saline-alkali soil in China, Xinjiang regards the treatment of saline-alkali land as a long-term task and a regular work, vigorously promotes the systematic project of saline-alkali land transformation and upgrading, and strives to do a good job in the characteristic agriculture of saline-alkali land. After years of unremitting efforts, scenes such as "the fragrance of wheat flowers in saline-alkali land", "new grain in saline-alkali land" and "granary building in saline-alkali land" have been seen everywhere in Xinjiang.
"You see, we used to have no grass here, but now we can hit an average of more than 400 kilograms of winter wheat per mu, and we can catch up with normal land with any more effort." In Huangshan Village, Shanghugou Kazakh Township, Fukang City, Xinjiang, a saline-alkali land has been transformed into a wheat field. It's May, and the green wheat fields here are growing well and vibrant. Diao Wangxuan, head of Fukang Evergrande Farm, who manages the land, lamented that "it is indeed difficult to ask for grain from saline-alkali land, but it also has great potential."
Fukang City has about 65,1462 mu of usable arable land, nearly one-third of which is salinized. In Xinjiang, about one-third of cultivated land has varying degrees of salinization; Saline-alkali land accounts for about one-third of the country's area. Xinjiang's saline-alkali land treatment has a long front and heavy tasks, which means that there is great potential for comprehensive utilization of saline-alkali land. Tian Changyan, researcher at the Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences and director of the Key Laboratory of Saline-alkali Land Biological Resources and Evaluation and Utilization (Northwest Inland Saline-alkali Land) of the Ministry of Agriculture and Rural Affairs, told reporters that according to the preliminary judgment of the third soil census, 190.<> million mu of saline-alkali wasteland in Xinjiang has development potential, which can add <> billion jin of grain every year.
Xinjiang regards the treatment of saline-alkali land as a long-term task and a regular work, and has explored a series of effective means with remarkable results. In recent years, Xinjiang has carried out a series of key research actions to ensure national food security and secure China's rice bowl, which is accelerating the awakening of sleeping arable land resources.
Consolidate the results of scientific management
Xinjiang's topography and geomorphology are complex, and the overall pattern of "three mountains and two basins" is likely to lead to soil salinization. On the one hand, most of Xinjiang's rivers are inland rivers, and molten salt from mountainous areas continuously transports salt to the basin; On the other hand, strong evaporation and low precipitation cause saline groundwater to accumulate to the surface through rising water, forming saline-alkaline soil.
"There are alkalis and salts in the ground, and you can't get rid of them completely, so you can only find a way to take them out of the cultivated land, collect them, and manage them so that they do not cause harm." Abdurim Mijti, a farmer in Ayikul town, Aksu City, said: "Salt and alkali are not a question of whether they are or not, but where they are, and how much or less. ”
"Affected by topography, climate and other factors, Xinjiang's saline-alkali land will exist for a long time, which is an objective fact." Tian Changyan said that after years of practice, saline-alkali land treatment technology has been very mature, and the key is how to produce the best treatment benefits at the lowest cost for a certain block.
In the process of saline-alkali land treatment, Xinjiang pays special attention to the promotion of classification, focusing on prevention in irrigation areas that do not produce secondary salinization. Implement simultaneous prevention and control of irrigation areas that have produced secondary salinization; For irrigation areas where the improvement of saline-alkali land has achieved results, the focus is on consolidating and improving the results of treatment.
Taking the salinized arable land in Fukang City as an example, more than 80% of it is secondary salinization, and the salt composition is mainly sulfate. This soil structure, muddy when wet and compacted when dry, makes it difficult for crops to emerge. "In the process of governance, Fukang City has implemented policies for the classification of saline-alkali land in each block and achieved good results." Fang Yong, director of the Agricultural Technology Extension Center of the city's Agriculture and Rural Bureau, said that saline-alkali land treatment is a regular work, and it is necessary to pay close attention to changes in land salinity indicators, and adopt different treatment methods at each stage.
Wang Zhi is a major cotton farmer and the head of a pro-agricultural planting professional cooperative in Fukang City. He used an acid-base balancer for three years in saline-alkali land, and the average cotton yield climbed from 3 kilograms to 300 kilograms last year. "This year, 470 mu of soil improvement conditions are relatively good, and we are ready to rush to 880 kg per mu." He told reporters, "I have been fighting with saline-alkali land for many years, and I have become more and more confident. ”
The treatment of saline-alkali land should adopt a centralized continuous and large-scale treatment method, with high efficiency and guaranteed effect. "Guiding farmers and herdsmen to transfer cultivated land to planting enterprises and agricultural cooperatives to carry out saline-alkali land treatment not only ensures the income of settled herdsmen, but also reduces the land into pieces, and promotes saline-alkali land management as a whole, killing two birds with one stone." Yuan Bin, secretary of the party committee of Miaoergou Township, Changji City, said.
In Miaoergou Township, Changji City, continuous saline-alkali land has been transformed from wasteland into cotton and wheat fields, and has become arable land allocated to settled herders who have relocated from the mountains. Herdsman Hanaen settled down in 2013 in Hexianghe Village, Miaoergou Township, where his family was allocated 54 acres of arable land. He transferred these cultivated lands to Changji Longyuan Ecological Agriculture Co., Ltd. at a price of 1200,6 yuan per mu, and the annual turnover fee income alone reached 48,<> yuan.
"The treatment of saline-alkali land is actually to do a good job in scientific management, grasp the links of seed selection, land preparation, fertilization, irrigation, etc., and persevere and make contributions for a long time." Only large-scale land management can better achieve effective treatment of saline-alkali land. Zhao Zongping, head of Changji Longyuan Ecological Agriculture Co., Ltd., told reporters, "We have transferred and operated a total of 1,77 mu of land in Hexi Village, although they are all saline-alkali land, but whether they grow cotton or wheat, the yield is steadily increasing." ”
The key to effective governance lies in water
Salt comes with water, salt goes with water, water is not only a factor of soil salt accumulation, but also a carrier of soil desalination. Therefore, the key to effective treatment of saline-alkali land lies in water, and the relationship between water and salt must be coordinated, especially for Xinjiang, where water resources are scarce. "No matter what technology is used for the improvement and utilization of saline-alkali land, the key is the guarantee of water. It can be said that the history of farming in Xinjiang is a history of controlling salinization. Tian Changyan said.
In the past, Xinjiang often used "large-scale irrigation and drainage" to dilute the salinity in the soil to remove salinity and alkali, which required intensive development of water resources. But due to water constraints, this approach is not sustainable. Tian Changyan said that how to remove more salt with less water has always been a topic explored in the treatment of saline-alkali land.
In order to make intensive and efficient use of water resources, Bayingolin Mongolian Autonomous Prefecture has promoted water-saving and salt control technology, and greatly reduced the water consumption of salt displacement through the combination of spring irrigation "dripping seedlings" and "dry sowing and wet production". Experiments conducted in lightly salinized cotton fields in Aksupu Township, Yuli County, showed that the application of water-saving and salt-control technology saved an average of 75 cubic meters of water per mu compared with flood irrigation. The average seedling emergence rate was 81.3%, which was 7 percentage points higher than that of flood irrigation. "We combine high-standard farmland construction to promote the application of new technologies." Mamet Yimin Kurban, director of the Agricultural Development Center in Aksupu Township, Weili County, said that local water resources are relatively scarce, and the use of "dry sowing and wet production" and other technologies only need to drip after sowing to "emerge seedlings", which not only saves water but also increases yield.
In some areas, salt is washed by planting rice according to the idea of harmonious production ecology. This move not only has certain economic benefits, but also has the effect of reducing soil salinity. Tofuhan Town, Wensu County, has relatively abundant water resources, and currently has more than 2,<> mu of rice planted in an area of more than <>,<> mu, making rice the second largest agricultural industry in the town after forest fruits. "Saline-alkali flats in the past, rice fields are planted today" has become a vivid portrayal of local rice planting to carry out saline-alkali land treatment.
However, rice cultivation also faces water constraints. Large-scale rice cultivation will raise the regional groundwater table, further aggravating the problem of salinization. In this regard, some areas of Xinjiang have adopted the method of water and drought rotation to ensure land productivity. Specifically, rice planting for one year, after washing the salt of the soil tillage layer, can ensure the growth of dryland crops for three or four years; Three or four years after planting dryland crops, it will lead to salinization of the soil tillage layer, affecting crop growth, and another year of rice planting.
Focusing on the efficient use of water resources, drip irrigation and water-saving technology have gradually been popularized in Xinjiang, which also brings new challenges to the management of saline-alkali land. Tian Changyan said that drip irrigation technology can directly transport water and nutrients to crop roots, and also desalinate the salt of plant roots in the soil, but it cannot discharge salt from the farmland, resulting in soil salt accumulation. "The popularization and application of drip irrigation technology has also formed a process from the prevention and control of salinization to the rise of new salinization." Tian Changyan believes that in the long run, the formation of impervious salt plates 40 cm or 60 cm below the surface of the soil should be prevented, and for farmland with high groundwater table or heavy soil salinity, alkali drainage canals should be restored, and the amount of salt washing in spring and autumn irrigation should be appropriately increased. Strengthening the construction of windbreak belts is also a necessary measure to prevent secondary salinization of soil.
In this regard, from July 2016 to June 7, Xinjiang implemented the project "Research and Integrated Demonstration of Key Technologies for Ecological Treatment of Saline-alkali Land in Arid Areas of Xinjiang", focusing on major scientific and technological issues in the treatment of saline-alkali land, and developed key technologies for high-efficiency water-saving farmland desalination and salt suppression in arid areas of Xinjiang. This technology can improve the efficiency of water resource utilization, effectively control the salt content of the root layer, realize the unity of salt displacement and deep water saving, and provide a solution to solve the new salinization trend caused by the popularization of drip irrigation technology.
Precise measures according to local conditions
The saline content in saline land changes dynamically, and the salinity content of the same block changes under different seasons, different weather conditions and different farming methods. A rain or even a wind will also cause the salinity content to fluctuate, which is a difficult problem in the treatment of saline-alkali land.
In this regard, in the process of governance, Xinjiang has responded to changes with no change, that is, soil improvement and utilization through universal and universal traditional methods such as land leveling and establishing shelterbelts. On the other hand, according to the salinity content of different plots at different stages, the corresponding organic fertilizer and other chemical improvement measures are applied precisely to change the strain.
Before this year's spring planting, in Chang'an Town, 60th Regiment of Aral City, First Division of the Xinjiang Production and Construction Corps, everyone used deep ploughing and crushing rippers to carry out soil loosening operations. Equipped with an auger bit, this farm machine can rotate at high speed 500 centimeters below the surface, crushing the soil plate into granular powder, which can then settle to the bottom of the deep ploughing layer with irrigation water. Last year, the local area carried out experiments in 50 mu of cotton fields, and the effect of increasing production was obvious, increasing the yield by 100 kg to <> kg per mu.
"The soil is compacted and uneven, which will cause more water in low places, less water in high places, and salt accumulation in high places, which will affect the growth of crop emergence." Chen Guogang, secretary of the party branch of the 3000th Company in Chang'an Town, Shituan, introduced, "The <>th Company has nearly <>,<> mu of relatively heavy sticky hardened land, and through deep ploughing and crushing loose soil cultivation methods, it can effectively change the permeability and water permeability of the soil, and can effectively control salinity." We are confident that low-yield fields will be transformed into high-yield fields. ”
At present, there are various means of saline-alkali land treatment, but each has advantages and disadvantages, and has a certain scope of application and conditions. Some experts suggest that we should base ourselves on the fact that the salinity content changes dynamically, adapt measures to local conditions, adapt measures to time conditions, and take comprehensive measures to play a combined fist of governance. For example, in some places, gypsum is used in saline soil, and then irrigated with water to wash salt; In some places, salt-tolerant plants are promoted to improve saline-alkali soil, and microorganisms and plants are used to improve together; In some places, "special fertilizer for crops + soil amendment" has been adopted in a timely manner, and good treatment results have been achieved.
Although the regional saline-alkali content changes dynamically, Xinjiang is located inland, and salt and other substances circulate in the region, which is basically balanced as a whole. Based on this fact, objectively requires that the treatment of saline-alkali land should have an overall view. Zhang Long, an expert from Xinjiang Water Conservancy and Hydropower Survey, Design and Research Institute, said that a unified and perfect drainage and salt discharge system should be established, focusing on regional water-salt balance, unified planning and comprehensive balance of water and soil resources.
"In order to give full play to the role of drainage of the canal system, we should start from the whole river basin, cooperate with each other between localities and corps, and regions and regions, and make unified planning and overall arrangements." Zhang Long suggested in "Analysis and Countermeasures of Changes in Saline-alkali Land in Xinjiang Irrigation Areas in the Past Twenty Years" that the relationship between upstream and downstream, region and region, agricultural environment and oasis edge environment should be correctly handled, and a complete drainage and salt discharge system should be established in the river basin.
Focusing on accurately grasping the situation of saline-alkali land in southern Xinjiang and scientifically and accurately reflecting the dynamic evolution of salinization in southern Xinjiang, in 2022, the Urumqi Natural Resources Comprehensive Survey Center of China Geological Survey launched a project to investigate the status of soil salinization in the oasis area around the Tarim Basin. The three-year project plans to combine high-resolution remote sensing imagery to uniformly collect soil samples from 3 to 0 cm in the soil layer through unified distribution points, so as to make the data more accurate and comprehensive.
"Last year, we collected soil samples from about 6000,<> sites in the oasis area of southern Xinjiang, and this year we will refine the work and strive to provide full-scale, high-precision survey results." He Yinfeng, head of the project to investigate the current situation of soil salinization in the oasis area of the Tarim Basin, said that the survey results will provide a basis and basic support for solving the problem of land salinization in southern Xinjiang, and further explore the improvement and comprehensive treatment plan of saline-alkali land in southern Xinjiang.
Cultivate and develop the saltwater industry
In heavily salinized land, is there really no grass? Not really. Today, in Karamay, Xinjiang, the 400rd Regiment of the Second Division of the Xinjiang Production and Construction Corps, and other places, the untreated saline-alkali land is lush and green, and a halophyte grows on it, the salaeda plant. This plant is good at "eating salt", can take away more than 3 kilograms of salt per acre, and after three or four years, it can grow conventional crops. In a cotton field in the Karamay Agricultural Comprehensive Development Zone, it was planted for three years, and cotton was planted in the fourth year, with an average yield of 4 kilograms per acre.
Xinjiang's underground, especially under the desert, is a "saltwater ocean", which is also a resource. Combining the treatment of saline-alkali land with the utilization of salt water and developing the salt water industry has become an important idea and direction for the treatment of saline-alkali land in Xinjiang. Tian Changyan introduced that some halophytes can be edible, some can be used as fodder, some can be used as medicinal herbs, and some can be used as landscape greening, with various uses. The nutrient-rich salaeda can be eaten, cold mixed, stir-fried or dumplings. In addition, halophytes can also be used to make biochar and improve acidified soil.
In the 2000rd Regiment of the Second Division of the Xinjiang Production and Construction Corps, local employees not only successfully planted the salaeda saldeca, but also registered the trademark "Imperial Selenium Vegetables" and displayed the characteristic signboard of "Alkaline Land Treasures", with an average net income of <>,<> yuan per mu. Farmer Adili Haheti sold the salt canopy to Urumqi, Beijing, Guangzhou, Shenzhen, Hangzhou and other places through live broadcasting, broadening the channels for increasing income.
Some areas of Xinjiang also plant halophytes such as salthorn grass, salt claw claw, yellow flower blood replenishing grass, wild elm money spinach and so on saline-alkali land. These plants are both "salty" and economically valuable, bringing to life the once cracked and white-flowered barren land.
The 33rd Regiment of the 2nd Division of the XPCC also made use of the abundant salt water resources underground to build artemia breeding ponds and develop artemia breeding. Artemia is a larval feed for fish and shrimp, which can survive in a high-salt environment and has a broad market prospect. It is estimated that breeding artemia in salt water can generate tens of thousands of yuan per mu of water.
Xinjingzi Town, Second Regiment of the First Division of the Xinjiang Production and Construction Corps, Aral City, diverted saline-alkali water formed by desalinization and pressure alkali, creating a beautiful lake on the desert Gobi. Through vigorous development of tourism, the local area has embarked on a new road of comprehensive management of saline-alkali land. Before the "May Day" holiday this year, the "Wanghu Station" scenic spot built by the lake opened its doors to welcome customers, and local employees ate "tourist rice" for the first time. Zhang Xuehui, secretary of the party branch of the 23rd Company in Xinjingzi Town, Ertuan, said, "We will build a tourist resort integrating eating, living, traveling and shopping along the lake, and promote the integrated development of agriculture and tourism."
Xinjiang's development of saltwater industry has just begun. The basis for the large-scale utilization of halophytes is large-scale cultivation, which has not yet been realized in Xinjiang. In particular, the saline-alkali land in Xinjiang is widely distributed, and it is necessary to develop targeted high-yield and high-efficiency cultivation techniques for different types of halophytes and different regions. "To develop the saltwater industry, Xinjiang has conditions, foundations, and potential, and should carry out top-level design, and all relevant departments should work together to promote it." Tian Changyan said.
Qiao Wenhui (Source: Economic Daily)