Now it has become an "oasis of fish and rice". In this vast and barren land of Gansu, the annual evaporation in the region is more than ten times that of precipitation. Saline alkali land | Fishermen | Baimang

Jingtai County in Gansu Province was once a severely affected area of land salinization, with 65000 acres of abandoned farmland due to salinization, falling into a situation of "no treatment for salinization and no eradication of poverty". Now, this "white desert" has become an oasis of fish and rice that can be planted on top and farmed on the bottom, and Jingtai County has also achieved poverty alleviation under the drive of industry.

At the 2023 Symposium on High Quality Development of Salt alkali Land Fisheries Utilization held yesterday, the attending experts had in-depth exchanges on basic research on salt alkali land aquaculture and typical demonstration practices in various regions, promoting the green and high-quality development of salt alkali aquaculture.

"China is one of the countries with the most severe soil salinization in the world, with a total of 1.487 billion mu of saline alkali land resources covering 19 provinces, cities, and autonomous regions. The area of secondary saline alkali soil is constantly expanding. This not only has adverse effects on the ecological environment, but also is a 'roadblock' for farmers to increase their income and wealth." Han Gang, Vice President of the China Academy of Fishery Sciences, pointed out.

How to utilize modern agricultural science and technology to develop and utilize saline alkali land, and achieve "turning waste into treasure"? In recent years, the East China Sea Fisheries Research Institute of the Chinese Academy of Fishery Sciences has explored the new concept of "reducing salt by fishing and treating alkali by fishing", and studied and promoted the comprehensive utilization model of salt alkali land by fishermen and farmers. During the 13th Five Year Plan period, relying on the national key research and development plan, the "Inland Saline Alkali Water Oasis Fisheries Model Demonstration" project was demonstrated and carried out.

The so-called "oasis fishery" refers to the organic integration of saline alkali soil and water management, saline alkali land planting and breeding industry, and the construction of a comprehensive ecological system for saline alkali land fishing and agriculture, forming a new industrial belt. "According to the type of saline alkali water quality, choose suitable aquaculture varieties to turn saline alkali water into treasure. At the same time, the organic matter produced by aquaculture can also increase the fertility of saline alkali land, reduce soil alkalinity, and make better use of land that was previously unable to be cultivated or had poor effects." Lai Qifang, director of the East China Sea Fisheries Research Institute, told reporters.

Jingtai County is a typical case. The annual precipitation in this region is only 100 to 200 millimeters, but the evaporation is as high as 3000 millimeters. The soil is severely salinized and has been abandoned for over a decade. Originally, the local plan was only to engage in aquaculture in saline alkali areas. With the suggestion of the Lai Qifang team, they excavated ponds and used the excavated soil to raise land, developing a comprehensive aquaculture model for agriculture and fisheries.

Salt comes and goes with the water. After excavating the pond, the groundwater level in the surrounding area drops significantly, and soil salinity converges with the water into the pond. The soil salinity and pH value of the new farmland cultivation layer significantly decrease, making it suitable for the growth of various alkali resistant plants. Agricultural crops such as sweet barley, celery, and cabbage are growing well.

For example, the demonstration site in Dawukou District, Ningxia has created a comprehensive utilization model for fish and farmers, including pond dry field integration, by combining pond and saline alkali land management and transformation. After aquaculture, the carbonate alkalinity of saline alkali water decreased from 6.78 before aquaculture to 3.36. The improved field yields 502 kilograms of rice per mu, while the heavier saline alkali field yields 160 kilograms of rice per mu, but it also changes the original situation of no grass growing.

Currently, the East China Sea Fisheries Research Institute has established various new models tailored to local conditions, including dual effect alkali reduction and characteristic ecological aquaculture in Northeast China, salt reduction and alkali removal and precision aquaculture in Northwest China, salt washing and alkali removal and comprehensive aquaculture in North China, and agricultural and fishery engineering aquaculture in East China. The demonstration and promotion area in 11 provinces, cities, and autonomous regions has exceeded 2 million mu.

"The comprehensive utilization of saline alkali water, soil, and fishery not only ensures the safety of agricultural planting and production, but also increases reserve arable land resources, which is a strong support for practicing the 'big food concept' and maintaining the red line of 1.8 billion mu of arable land." Han Gang said that based on previous demonstration applications, the "oasis fishery" model will be promoted on a larger scale to form a new industrial belt and achieve the unity of ecological, economic, and social benefits.