A great article on developing characteristic agriculture in saline alkali land (Beautiful China, Focus on saline alkali land management ⑤) Crops | China | Saline alkali land
In Yanwu Township, Qingyun County, Shandong Province, agricultural machinery shuttles through the improvement of saline alkali land.
Photo by Li Xuemei
In the dry alkali wheat breeding experimental field of the Agricultural Science Institute of Zhongjie Industrial Park in Huanghua City, Bohai New Area, Cangzhou, Hebei Province, technicians conducted yield testing on wheat.
Photo by Xinhua News Agency reporter Luo Xuefeng
Core Reading
There is a large amount of saline alkali land in China, and the trend of salinization of cultivated land in some areas is intensifying. Therefore, it is of great significance to carry out comprehensive transformation and utilization of saline alkali land. In recent years, China has made significant progress in coordinating protection and development, fully tapping into the potential of comprehensive utilization of saline alkali land, by understanding the family background, classifying and transforming, and adapting to different types of land.
The second meeting of the Central Committee of Finance and Economics held on July 20th pointed out that the comprehensive transformation and utilization of saline alkali land is an important aspect of farmland protection and improvement. China has a large amount of saline alkali land, and the trend of farmland salinization is intensifying in some areas. Therefore, carrying out the comprehensive transformation and utilization of saline alkali land is of great significance.
Farmland is the lifeblood of food production. What is the current situation of saline alkali land resources in China? What improvement measures are there? How to fully tap into the potential of comprehensive utilization of saline alkali land and do a good job in the characteristic agriculture of saline alkali land?
Understand the family background and carry out comprehensive utilization of saline alkali land
This summer's harvest, villagers from Xiaowu Village, Yanwu Township, Qingyun County, Shandong Province, achieved a new high in wheat yield per mu on 240 acres of improved saline alkali land. "One acre of saline alkali land can grow up to a thousand kilograms of wheat, which was unimaginable in the past!" said Chen Guohong, a grain grower in Xiaowu Village. In the past, "spring was white and vast, and summer was watery." The villagers tasted the hardships of saline alkali land.
Transform saline alkali land, do whatever you say! The local area is laying underground drainage and irrigation pipelines in saline alkali land, which dissolve soil salt and seep into underground water bodies to be discharged through pipelines. The salt content of the cultivated soil has decreased from the previous 5 ‰ -8 ‰ to the current 2 ‰ -3 ‰, and the quality of cultivated land has been improved by 0.5-1 levels. The grain yield has also increased accordingly. Yanwu Township has improved a total of 12000 mu of saline alkali land, added more than 2100 mu of arable land, and increased grain production by more than 5 million kilograms per year.
Requesting food from various saline alkali land resources, the example of Xiaowu Village is a microcosm of China's comprehensive utilization of saline alkali land. China has a large area, multiple types, and wide distribution of saline alkali land. There are both saline alkali land without cultivation and utilization value, reserve arable land resources that can be cultivated, and already cultivated saline alkali arable land. Li Yuyi, Chief Scientist and Researcher of the Salt alkali Land Improvement Team at the Institute of Agricultural Resources and Agricultural Regionalization of the Chinese Academy of Agricultural Sciences, said that salt alkali land poses a great threat. Soil salinization can cause soil compaction and decreased fertility. Excessive soil salinity can lead to crops being unable to effectively absorb water and nutrients, thereby hindering their growth, especially affecting crop emergence.
China has a large amount of saline alkali land and great potential for development. The results of the third national land survey show that by the end of 2019, China had a total of 115 million acres of saline alkali land. The Ministry of Natural Resources defines the scope of saline alkali land from the perspective of land classification, and conducts surveys based on the current land use status. For saline alkali land that has already been planted with crops, it is recognized as "cultivated land" during land classification surveys; For saline alkali soil mainly composed of herbaceous plants, it is identified as "grassland" during land type investigation.
On the basis of the "Three Adjustments", the Ministry of Natural Resources has launched a new round of national investigation and evaluation of arable land reserve resources. From the aspects of ecology, climate, soil, and location, the investigation and evaluation of whether four types of unused land, including saline alkali land, are suitable for development as arable land, have been conducted. From the preliminary results, the saline alkali land that is currently suitable for development as arable land is mainly distributed in Jilin, Inner Mongolia, Xinjiang, Heilongjiang, and Gansu, and this part of saline alkali land can be prioritized for development and utilization under the premise of ecological control.
In 2022, in conjunction with the third national soil survey, China implemented a survey of key areas of saline alkali land. Approximately 112000 saline alkali soil survey points were set up in 198 counties in 14 provinces, focusing on the types, distribution, degree, causes, and development and utilization of saline alkali land. The potential evaluation of saline alkali wasteland development and utilization in key areas was also carried out, and a preliminary classification and grading map of saline alkali land was formed based on counties.
Classification transformation and tapping into the potential of saline alkali land development and utilization
Hongliutan, Pingluo County, Shizuishan City, Ningxia, boasts lush grass and fragrant flowers. Qianyeqing Agricultural Technology Development Co., Ltd. has continuously improved and restored this land through scientific means, giving the once barren saline alkali beach a pleasant name - Qianyeqing Ecological Grazing Grassland.
In order to transform saline alkali land, Qianyeqing Company has established a research and development center and established more than ten independent research and development projects for saline alkali land improvement and grass and animal breeding. The company has planted 11000 acres of various crops, including alfalfa, Hunan millet grass, oats, etc. By continuously planting Hunan millet grass on medium to severe saline alkali soil, 2200 acres of high-yield alfalfa soil have been improved.
"Green manure is an effective means of biological improvement and treatment of saline alkali land." Cao Weidong, the chief expert of the national green manure industry technology system, said that a long time ago, people summarized the use of green manure as a pioneer crop. By planting and pressing green manure, the effect of reducing salt, improving soil organic matter, and improving soil structure can be achieved. In recent years, a series of green fertilizer crops, Tianjing New Variety, have been developed by the green fertilizer system to adapt to different degrees of salinity and alkalinity. They can grow normally in coastal saline alkali soils with a salt content of 3 ‰ -6 ‰. Green fertilizer crops that can effectively improve soil quality in saline alkali soils have also been selected, such as sweet potatoes, February orchids, and tamarisks.
Currently, the improvement measures for saline alkali land in China can be divided into four categories: engineering measures, agronomic measures, chemical measures, and biological measures. The construction of high standard farmland is also an effective measure to prevent and control the salinization of farmland through engineering measures. Various regions continue to promote the construction of high standard farmland, and by the end of 2022, more than 1 billion mu of high standard farmland will be built, greatly improving the irrigation and drainage capacity of farmland and providing a basic condition for preventing salinization of farmland. Li Yuyi said that the problem of saline alkali land is complex, long-term, and repetitive. It should be based on engineering measures, continuously supplemented by agronomic, chemical, biological and other measures, and the combination of prevention and control can be effective in the long term. By improving, integrating, and assembling various engineering, agronomic, chemical, and biological measures, various regions have formed regional characteristic technical models, such as the "subsurface drip irrigation" technology model in the northwest inland region, the "rice control alkali" technology model in the Songnen Plain soda saline alkali land, and the "hidden pipe salt discharge" technology model in coastal saline alkali land.
In order to explore comprehensive management models for different types of saline alkali areas, from 2020 to 2022, the Ministry of Agriculture and Rural Affairs guided 8 provinces in the concentrated distribution areas of saline alkali land in the northwest irrigation area, coastal areas, and western Songnen Plain. A total of 2.4 million acres of saline alkali farmland were implemented over 3 years, and the average quality of farmland in the project area increased by 0.11-0.51 levels. The average soil salt content decreased by about 2 ‰, and the organic matter content per kilogram of soil increased by more than 0.5 grams. The agricultural production conditions were effectively improved.
In recent years, with the increasing development of unused land and the improvement of saline alkali land treatment technology, a large scale of saline alkali land has been transformed and utilized through government guidance and social investment. In particular, the saline alkali land in the Songnen Plain in the western part of Northeast China, the saline alkali land in the coastal mudflat of North China, the saline alkali land in the Yellow River Delta, and the saline alkali land in the coastal mudflat of Jiangsu, which are relatively rich in water resources, have been transformed and utilized to a certain extent.
"Safe and sustainable development is an important prerequisite for the transformation and utilization of saline alkali land." Li Yuyi introduced that there are many technologies for the treatment of saline alkali land currently, but the investment cost is high and financial support is difficult. It is necessary to explore improvement technologies that are suitable for the investment cost and economic situation. Meanwhile, saline alkali areas are often ecologically fragile and sensitive areas, and the technologies and products used for governance and improvement should not only be effective, but also safe and green.
Accelerate the pace of "planting according to the land" and do a good job in the characteristic agriculture of saline alkali land
It is reported that China has been conducting research on salt alkali tolerant crop breeding since the 1950s, and has made positive progress in germplasm screening, breeding technology, scientific research platforms, and other aspects. A batch of salt alkali tolerant germplasm resources have been screened. More than 2000 salt alkali tolerant wheat, soybean, corn, and rice germplasm resources have been identified. Establish a national salt alkali tolerant crop germplasm resource garden, support the construction of a national salt alkali tolerant crop germplasm resource database, and increase the efforts of resource survey and collection.
After long-term efforts, China has made positive progress in the breeding and promotion of salt alkali tolerant varieties of crops such as rice, wheat, soybeans, and potatoes. In terms of rice, the Ministry of Agriculture and Rural Affairs has conducted a national experiment on salt alkali tolerant rice varieties. From 2020 to 2022, 11 salt alkali tolerant rice varieties were approved by the state, which can be planted under freshwater irrigation in light to moderate saline alkali land. In terms of wheat, a national salt alkali tolerant wheat variety trial was established in 2019, and since 2022, a total of 6 salt alkali tolerant wheat varieties have been approved by the government. In addition, local authorities have also approved and registered some salt alkali tolerant varieties such as rice, wheat, corn, soybeans, potatoes, sorghum, etc., with good promotion effects.
The relevant person in charge of the Seed Industry Management Department of the Ministry of Agriculture and Rural Affairs said that by combining "planting according to the land" with "planting according to the land", we should accelerate the selection of salt alkali resistant characteristic varieties, strengthen the development and promotion of suitable salt alkali crop varieties, effectively expand the suitable crop planting area, actively develop deep processing, and do a good job in salt alkali characteristic agriculture.
Jiangsu Yuhang Food Technology Co., Ltd. takes the green planting and breeding circular agriculture pilot county project as an opportunity to apply organic fertilizer with cow manure and biogas residue as the main raw material as the base fertilizer for wheat in the vicinity of Kumen Village, Jianggang Town, Dongtai City, promoting the growth of wheat and the formation of soil particle structure, and accelerating the improvement of soil quality.
Accelerate the pace of adapting to local conditions. The relevant person in charge of the Seed Industry Management Department of the Ministry of Agriculture and Rural Affairs stated that the next step is to strengthen basic research on germplasm resources, farmland protection and utilization, accelerate the improvement of the layout of salt alkali tolerant crop identification bases, promote the establishment and improvement of identification and evaluation standards and methods, and promote precise resource identification and genetic exploration. Transforming breeding concepts, strengthening breeding research, accelerating the selection, experimental approval, and demonstration promotion of salt alkali tolerant crop varieties, shifting from managing crops adapted to saline alkali land to selecting salt alkali tolerant plants adapted to saline alkali land, striving to achieve breakthroughs in key core technologies and important innovation areas, and accelerating the transformation of scientific research achievements into practical productivity.
Extended Reading
Saline alkali land knowledge
What is saline alkali land?
The commonly known saline alkali land refers to soil with a salt content exceeding 0.1%, including saline alkali farmland, saline alkali forests and grasslands, saline alkali unused land, etc. Generally speaking, when the soil salinity exceeds 0.1%, the growth of common crop varieties begins to be affected; When the soil salinity exceeds 0.3%, the yield of most crop varieties significantly decreases.
In the current national standard for land use classification in China, saline alkali land refers to "land with surface saline alkali accumulation and natural salt tolerant plants growing", which is unused land and does not include used saline alkali cultivated land, forest land, grassland, etc.
Where is the distribution of saline alkali land in our country?
Saline alkali land is mostly formed in areas with arid climate, high groundwater level, high groundwater mineralization, and low-lying terrain. China's saline alkali land can be roughly divided into five types of areas: northwest inland saline alkali area, northeast Songnen Plain saline alkali area, coastal saline alkali area, Huanghuaihai Plain saline alkali area, and upper and middle reaches of the Yellow River irrigation area saline alkali area.
Among them, the northwest inland saline alkali area and the northeast Songnen Plain saline alkali area are the main distribution areas of saline alkali land in China, with large and contiguous areas of saline alkali land; The saline alkali area in the Huanghuaihai Plain is a typical area in China that has successfully managed saline alkali land. Its saline alkali land has significantly decreased and is currently only sporadically distributed.
3. What are the main measures for improving saline alkali land in China currently?
Currently, the improvement measures for saline alkali land in China can be divided into four categories: engineering measures, agronomic measures, chemical measures, and biological measures.
Biological measures include planting halophytes, salt tolerant green manure and forage, and applying beneficial soil microorganisms;
Agricultural measures include reasonable irrigation, deep loosening and deep cultivation, increased application of organic fertilizer, straw returning to the field, etc., regulating soil water, fertilizer, air and heat, and improving farmland production capacity;
Chemical measures refer to adding chemical amendments to the soil, reducing soil salinity and alkalinity, improving physical and chemical properties, increasing salt washing and drainage efficiency, and promoting crop growth;
Engineering measures include the construction of irrigation and drainage facilities, land leveling, etc. By improving the irrigation and drainage system, leaching and removing salt from the soil, and controlling the groundwater level, it is an effective way to treat saline alkali land.
