The autumn breeze is blowing, walking along the wooden plank road into the Yellow River Delta, looking at a fiery red from afar, the local endemic plant Suaeda salsa is like a huge "red carpet" spread on the tidal flats, which is particularly dazzling in the sun.
The Yellow River Delta is at its best time of year – tourists from all over the country are strolling through the reeds to enjoy the harmonious coexistence of man and nature, and to see the "distinct" nature of the Yellow River flowing into the sea.
The Yellow River Delta is located in the coastal area of the Yellow River estuary in the southern part of the Bohai Sea, and has the most intact wetland ecosystem in the warm temperate zone of the mainland, which plays an important role in promoting the high-quality development of the Yellow River Basin and marine ecological protection.
Ecological hydration, bare-blank and then put on a new "red makeup"
In the hinterland of the Yellow River Delta National Nature Reserve (hereinafter referred to as the reserve), there is a place called "Kendong 12", where you can stand here and have an unobstructed view of the open tidal flats.
"Previously this was a drilling rig in the Shengli Oilfield, and in 2017, the reserve reached an agreement with the Shengli Oilfield Company to permanently mothball all 300 oilfield production facilities, including here." Zhou Licheng, head of the planning and construction section of the Yellow River Delta National Nature Reserve Management Committee, stood next to the stone tablet engraved with the words "Kendong 12" and recalled that there were dozens of oil lifters distributed on the surrounding tidal flats at that time, and oil extraction through oil extraction wells had a certain impact on the natural environment and ecological safety of the reserve.
In order to protect the health of wetland water bodies and promote the effective restoration of biodiversity, the withdrawal of Shengli Oilfield from the core area and buffer zone of the nature reserve has become one of the important measures to protect the Yellow River Delta.
The Yellow River Delta is a land of receding from the sea, and the natural ecological environment is congenitally insufficient, and the ecosystem is very fragile due to factors such as high soil salinity, lack of freshwater resources, and sediment accumulation in the Yellow River. With the ecological protection and high-quality development of the Yellow River Basin elevated to a national strategy, and with the goal of establishing the Yellow River Estuary National Park, the reserve has started ecological water replenishment.
According to Zhou Licheng, the reserve has implemented a wetland ecological restoration project, adding 74,000 mu of freshwater swamp wetlands, building an ecological water replenishment system of "diversion, transport, storage and drainage", which has exceeded 530 million cubic meters in the past three years, and dredging 241 kilometers of water system, while restoring the hydrological connection between the Yellow River and the Bohai Sea, the wetland water level has also been effectively regulated and dynamically managed.
With the opening of the water system in the Yellow River Delta and the improvement of the water level, the "indigenous" plant Suaeda salsa has returned to its homeland, and the tidal wetlands have been covered with "red makeup" again. As an excellent plant for improving saline-alkali soils, Suaeda salsa can absorb a large amount of salt, thereby increasing soil nutrients and maintaining soil stability. At the same time, its growth also provides habitat for other organisms, promoting biodiversity.
"At present, about 52,000 acres of Suaeda salsa have been restored in the reserve, and the overall effect is good, and the population of Suaeda salsa will be gradually restored, naturally successed, and stabilized for a long time." Zhou Licheng said.
The picture shows Suaeda salsa in the Yellow River Delta, also known as the "red carpet".
Ecological management, tidal flats are revitalized
Thanks to the nourishment of the Yellow River, the Yellow River Delta has become an important stopover for bird migration, with millions of birds stopping here every year, so it is known as the "international airport for birds". Not long ago, China's Yellow (Bohai) Sea Migratory Bird Habitat (Phase II), including the Yellow River Estuary Migratory Bird Habitat in Dongying, Shandong Province, was successfully inscribed on the World Heritage List.
However, before 2010, it was subjected to large-scale invasion of the alien species Spartina alterniflora, which not only encroached on the habitat and foraging grounds of migratory birds, but also caused the deterioration of the water exchange capacity of tidal wetlands and the decline of water quality.
Spartina alterniflora can reach 200-500 plants per square meter and the root system is very dense, with strong vitality and fecundity. "They are like spider webs, crowding out all the living environment of other animals and plants, causing the disappearance of native plants Suaeda salsa and seagrass beds, the death of benthic organisms such as small fish and small crabs, and even affecting the entire ecosystem, and the migratory birds that often come here for the winter are also missing." Zhou Licheng recalled.
The management of Spartina alterniflora is imminent. The reserve has revitalized the tidal flats through comprehensive management measures such as tillage + flooding, mowing + ploughing, and manual mowing. "So far, more than 99 percent of Spartina alterniflora has been removed from the reserve, benthic species have increased by 27 percent, and the average biomass has increased by 50 percent." Zhou Licheng said.
The wetland environment has improved, and the number of migratory birds has increased. "Standing in this nest is the Oriental White Stork." Zhao Yajie, deputy director of the Yellow River Delta Ecological Monitoring Center, told reporters that on the big screen of the Yellow River Delta Ecological Monitoring Center, the birds' every move can be observed in real time, and the system can also automatically identify more than 1,400 species of birds, including Oriental white stork, black-billed gull, red-crowned crane, white crane and other national first-class protected birds.
The Oriental White Stork, known as the "Giant Panda of Birds", has received "ceiling" level care in the reserve. "They like to breed on tall trees, so the reserve has built 133 attracting nests to improve the nesting breeding environment, and built a video surveillance system, the country's first Oriental White Stork breeding behavior recognition technology, which can identify 8 typical behaviors such as nesting, mating, egg laying, hatching, egg turning, and brooding, which improves the monitoring efficiency and also improves the protection of flagship species." Zhao Yajie introduced that at present, the Yellow River Delta has become the world's most important breeding ground for oriental white stork. This year, a total of 202 nests of 526 chicks were bred.
The picture shows a demoiselle crane in the Yellow River Delta National Nature Reserve. Photo by Li Xin
The land is determined by water, and the saline-alkali land ushers in a bumper harvest
"Ten years and nine years without harvest, bran vegetables for half a year" was once a true portrayal of the Yellow River Delta region. The Yellow River Delta is a coastal saline-alkali land, although the land resources are abundant, but due to the high groundwater level, large water evaporation, and serious salinization, it once became a "forbidden area" for food.
Jia Xi, director of the Yellow River Delta Modern Agricultural Research Institute of the Shandong Academy of Agricultural Sciences, said that the saltiness of groundwater here is high, far exceeding the national irrigation water standard of 2 grams per liter. Combined with the high water table, the salt will continue to rush to the surface with the water source through the capillary effect.
"General Secretary Xi Jinping proposed to use saline-alkali land according to local conditions and ask for food from all kinds of saline-alkali land resources." Jia Xi said that in the past, some places transformed the saline-alkali land by "changing the land and adapting the species", that is, using methods such as digging deep ditches to increase flood irrigation to reduce salinity, but this method not only consumes a lot of water, but also has a high cost. Moreover, according to the requirement of "determining land by water", it is not applicable in the Yellow River Delta, where freshwater resources are scarce.
"Coastal saline-alkali land is the most difficult to manage of all saline-alkali land, but it is an important political task for us to ask for grain from saline-alkali land." Jia Xi said loudly.
In order to grow grain in saline-alkali land, Jia Xi's team has made many attempts to screen and breed saline-alkali tolerant varieties through the combination of "planting in the right place" and "planting in the right place". "Relying on the adaptability of crops themselves, salt-tolerant varieties are screened and cultivated, such as rapeseed, sorghum, cotton, peanuts, green manure crops, forage crops, etc., which have strong salt tolerance and become the preferred crops on saline-alkali land." Jia Xi said.
In 2023, the Yellow River Delta Modern Agriculture Experimental Demonstration Base of Shandong Academy of Agricultural Sciences will cultivate the "Ludan 510" corn variety with a yield of 928 kg per mu on saline-alkali land with a salinity of 2.8‰. In 2022, the yield of soybean "Qihuang 34" per mu will be 302 kg, setting a new record for soybean yield on saline-alkali land; In 2024, the measured yield per mu of the "Jimai 60" wheat variety was 511.88 kg in the 1,000-mu plot with salinity of 3.3‰, creating a typical high-yield wheat in saline-alkali land, and the selected "Huayu 60" peanut variety achieved a yield of 624.62 kg per mu in the 50-mu demonstration square with a salt content of 2.8‰, and once again achieved a breakthrough in peanut yield in saline-alkali land.
In addition, in recent years, a series of low-water consumption and salt-tolerant crops such as sorghum, field cyan, quinoa, and alfalfa have been selected and bred. "After years of unremitting efforts, we have proved again and again that a bumper harvest can also be ushered in on saline-alkali land." Jia Xi said proudly.
The picture shows a technician inspecting the growth of the crop. Photo by Li Xin