Spreading a Colorful Picture Scroll on Saline and Alkaline Land (Beautiful China, Pay Attention to Saline and Alkaline Land Management ②) Technology | Saline and Alkaline Land | Picture Scroll

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Facing the Bohai Sea and the Yellow Sea, Liaoning has a coastline of over 2000 kilometers. For thousands of years, waves, seawater intrusion, and tidal erosion have formed barren saline alkali land in many coastal areas. In recent years, Liaoning has persisted in promoting the transformation and comprehensive utilization of saline alkali land, currently developing and utilizing approximately 7 million acres of saline alkali land. The saline alkali land that has been repaired and treated is gradually achieving a dual harvest of ecological and economic benefits.

At the site of the Yantian Land Reclamation Project in Yingkou City, Liaoning Province, there are two contrasting images on the display board: one is a large area of hardened and cracked saline alkali land, resembling the cracked skin of the earth, which is shocking; The other one is a contiguous paddy field, with tender green seedlings unleashing vitality, making people feel relaxed and happy.

"Due to the high salt content of the soil, this used to be a barren land, but it has now been transformed into a rice field through comprehensive management. Last year, the yield per mu was over a thousand kilograms," said Que Fuchao, Deputy Director of the Institute of Saline Alkali Land Utilization, Liaoning Academy of Agricultural Sciences.

For many years, Liaoning has persisted in promoting the transformation and comprehensive utilization of saline alkali land, and currently has developed and utilized approximately 7 million acres of saline alkali land. The dark brown soil, green seedlings, green and red persimmons, and red salsa grass... On the once dormant saline alkali land, now colorful scrolls are slowly unfolding.

More than 3 million acres of coastal saline alkali land, with a significant decrease in soil salinity

The horizon is the vast and vast Bohai Sea; In front of me is a 2-kilometer long embankment. On one side of the dam, there is over 1.1 million tons of irrigation water stored in the reservoir, while on the other side, there are over 1500 acres of paddy fields divided into more than 30 regular squares by ditches and canals, with tender green seedlings spreading in the wind.

"Last year, we produced over 1140 kilograms of rice per mu, and this year we are striving to reach a new high." Standing on the embankment, Lin Yuexian, who is over sixty years old, gazes with great anticipation. Lin Yuexian is the Deputy General Manager of Yingkou Guofeng Ecological Agriculture Development Co., Ltd., specifically responsible for the implementation of the Yingkou Salt Field Land Reclamation Project.

"Previously, the soil here had a salt content between 16 ‰ and 94 ‰, a pH value of around 7.5, and almost zero organic matter content. When the sun shone, the soil solidified and became harder than bricks; when it rained, it became softer than tofu," said Lin Yuexian.

The turning point began 4 years ago when the Yingkou Salt Field Land Reclamation Project began to be implemented. Guofeng Company cooperates with the Salt alkali Land Institute to take engineering and biological measures to restore and treat this saline alkali land. On both sides of each grid, there are two ditches, one deep and one shallow. The shallow is the water supply channel and the deep is the drainage channel. "According to the water salt movement law of 'salt comes with water, salt goes with water', it is necessary to divert surface water to 'wash' the salt fields," said Lin Yuexian.

"Under the guidance of the saline alkali land institute, we also change the soil structure and improve fertility by applying desulfurization gypsum, deep tillage, and returning straw to the field." Lin Yuexian said that the soil salt content of 1500 acres of paddy fields has been controlled within 3 ‰.

"The salt in the coastal mudflat mainly comes from the seawater reverse irrigation and tidal erosion. Following the natural law of 'salt comes with water, water disperses with air, and air disperses and stores salt', the barren saline alkali land has been formed for thousands of years." Li Zhenyu, the director of the saline alkali land institute, said that the main purpose of improving and utilizing the saline alkali land is to irrigate, press salt, wash salt, and drain salt, and improve soil fertility.

"In response to the formation and characteristics of saline alkali land in the whole province, we have integrated innovative restoration and management technologies such as' deep loosening cultivation and salt removal technology 'and' straw burying and interlayer salt pressing agricultural machinery and agronomic matching with organic fertilizer application technology '. We have promoted more than 3 million mu of land in coastal areas such as Panjin and Yingkou, reducing the average soil salt content from 4 ‰ to 2 ‰ and increasing the organic matter content from 18.5 g/kg to 21.5 g/kg," said Li Zhenyu.

Good variety and matching methods help stabilize and increase rice yield

"In 1996, I started contracting land to grow rice, and I made a great decision at that time. Why? Because this is saline alkali land, the soil salinity is high, and the rice yield is low." Li Jicai, the chairman of Changcai Agricultural Machinery Professional Cooperative in Dawa District, Panjin City, recalled that the first year after transplanting seedlings, the seedlings sank deep into the ground. He thought it was because the workers were not meticulous in their work, but after trying it out on his own, he realized that the problem lay on the land.

What should we do? Li Jicai gritted his teeth and persisted for a few years before looking again! The persistence of improving soil, cultivating salt tolerant varieties, and learning cultivation techniques has lasted for more than 20 years. Since 2009, the cooperative has received technical support from the Salt Alkali Land Institute, leading to a continuous increase in rice production. Last year, the yield per mu reached over 1400 kilograms, and the soil organic matter content has increased from less than 2% to 2.5% now.

"Based on the ecological environment of saline alkali land and the characteristics of saline alkali tolerant rice, we have completed the technical integration of high-yield and efficient cultivation of saline alkali tolerant rice using two cultivation methods: hand transplanting and machine transplanting, achieving full coverage of different ecological conditions and cultivation forms in saline alkali tolerant rice planting areas." Researcher Fu Lidong from the Institute of Saline alkali Land introduced that "there are several key points to planting rice on saline alkali land: improving field irrigation and drainage engineering, selecting salt tolerant varieties, cultivating older and stronger seedlings, and reasonable sparse planting irrigation and fertilization."

Entering the planting base of saline alkali land, contiguous saline alkali experimental fields, well-equipped greenhouses, and large and small saltwater pools silently witness the hard work of generations of researchers.

"The salt concentration in several salt ponds ranges from 1 ‰ to 6 ‰, in order to test the performance of rice varieties under different soil salinities." Zhang Zhan, director of the routine breeding department of the Salt alkali Land Institute, introduced that he and his team prepare an average of a large number of hybrid combinations every year, create more than a thousand salt tolerant genetic populations, and screen out more than 10 salt tolerant rice varieties to provide feedback to relevant units for further experiments.

It is reported that since its establishment in 1958, the Salt alkali Land Institute has continuously strengthened the breeding and promotion of salt alkali tolerant rice varieties, resulting in a total of 59 salt alkali tolerant rice varieties, with a cumulative promotion area of more than 60 million acres.

Transforming geographical disadvantages into environmental advantages

Entering the greenhouse of Sun Jingjing, a villager from Yuanyuan Village, Xinxing Town, Dawa District, Panjin City, there are green and red tomatoes hanging on the vines. Pick one and take a light bite, the juice overflows and the taste is sweet and sour.

"Panjin is located in the coastal saline soil area of the lower reaches of the Liaohe River plain. The relatively high salinity soil and irrigation water can promote the formation and transformation of tomato sugar, giving birth to the favored alkaline persimmons by consumers." Huo Qiang, the head of the Agricultural and Rural Ecological Construction Service Department of the Panjin Modern Agricultural Development Center, introduced that planting alkaline persimmons on large areas of mild saline alkali land can transform geographical disadvantages into environmental advantages.

In recent years, Liaoning has also explored various ways to scientifically utilize saline alkali land, creating diverse economic and ecological values.

At the Salt alkali Land Institute, there is a discipline on ecological construction of coastal saline alkali wetlands, specializing in research on the cultivation, application value development, and deep processing technology of halophytes. "We have collected over 60 types of halophytes, including major varieties such as Suaeda salsa and white thorn, and have also carried out the breeding of new varieties of salt alkali tolerant crops," said Yang Zhuzhu, Director of the Garden Department of the Salt alkali Land Institute.

In the hot summer season, the Panjin Red Beach is bustling with tourists. Plants of Suaeda salsa, dressed in crimson clothes, grow warmly and vigorously. They are indicative plants of saline alkali land and the protagonist of the Panjin Red Beach National Scenic Corridor. In recent years, Panjin City has effectively protected and restored the marine environment and wetland ecosystem. Panjin Red Beach Tourism Development Co., Ltd. has implemented dredging and tidal ditch cleaning, as well as marine garbage removal work, planting and replanting about 1000 acres of alkali marsh grass.

"Suaeda salsa can grow in saline alkali land, improve mudflat soil, and attract birds to inhabit. We have set up a 'Suaeda salsa' ecological restoration team to carry out various ecological protection and restoration work." Sun Huanxin, chairman of Panjin Red Beach Tourism Development Co., Ltd., said, "The area of red beach in the scenic corridor has increased from 2000 mu in 2018 to 22000 mu last year, increasing 10 times in five years."

"If the salinity in the soil is too high, Suaeda salsa cannot grow, but if the salinity is too low, Suaeda salsa will not turn red, and the ornamental effect will be greatly reduced." Yang Zhuzhu said that since 2019, he and his colleagues have been involved in the restoration of Red Beach wetlands and the replanting of Suaeda salsa every year. "Saline alkali land management cannot be limited to a single method, but still needs to be scientifically utilized and comprehensively implemented to achieve both ecological and economic benefits."