Not long ago, Shandong Province, Dongying City, new household town grain growers Wang Jumin reclaimed a saline land, a bumper crop of winter wheat. Wang Jiamin grabbed a few ears of wheat, rubbed two, hands left full of wheat grains, "planting or believe in science." He could not help but to send such a sentiment.

The "science" Wang Jiamin said refers to the ecological management of saline land engineering technology model explored by Hu Shuwen's team, a professor at China Agricultural University, after more than 10 years of research. A few years ago, the land under his feet is still white saline land, it is impossible to grow crops, in some places, seedlings can not be developed, and even the grass does not grow. Now, the saline wasteland has become ecological good land, "the land finally has the appearance of land".

According to different saline types, bio-based modified materials were invented to improve the desalination efficiency of soil by more than ten times

On the wall of Hu Shuwen's office, a map of China hangs, and a colored peg marks the location of the test sites: the river-loop irrigation area, the Songnen Plain, and the Yellow River Delta ...... On his desk, the most conspicuous is a soil science monograph of nearly 900 pages. "To do soil improvement, I am a complete 'layman', but the good thing is that I can learn more, and now understand more deeply." Hu Shuwen said.

These words are not modest. Hu Shuwen obtained his doctorate in polymer materials from the Institute of Chemistry, Chinese Academy of Sciences, and even when he arrived at China Agricultural University, his initial research was on functional fertilizers modified with natural polymer materials, which was "a mountain away" from soil improvement. Hu Shuwen recalls that around 2008, while researching functional fertilizers, he noticed that saline soils were particularly sensitive to fertilizers. For example, with acidic fertilizer can play a neutralizing role, the crops will grow better; after wrapping the fertilizer film, the fertilizer dissolves slowly, and the yield increase is more obvious. On the other hand, if the saline land uses fast-acting fertilizer, the crop will soon be "burned".

"The impact of a single fertilizer is so great, if the soil can be improved, how good it is!" This made Hu Shuwen interested in soil improvement, and his research focus gradually shifted from functional fertilizers to soil improvement. "The idea was so bold that some friends advised me at that time, 'Engaging in saline land improvement is not your line of work, there will be many difficulties'." Hu Shuwen, however, insisted on his choice, "Difficult problems encountered in scientific research are often formed by several factors of limitation, and cannot be solved by only one or two disciplines, so multi-disciplinary intersection is needed."

After reading a lot of soil-related literature and monographs, Hu Shuwen realized that the fundamental difference between normal soil and saline soil is that normal soil has a granular structure and is permeable and breathable; saline soil is fine-grained and does not have the granular structure of normal soil, which is manifested as slab, dry and hard, impermeable and impermeable, so saline is difficult to wash off with water. "If we start from the perspective of changing the agglomeration structure of soil, invent a bio-based 'binder' to bond the fine saline soil particles into large particles and create a 'agglomeration structure'. In this way, soil permeability is improved, and saline can not be more quickly washed away?" Hu Shuwen came up with a bold idea.

It was a brand new idea, and designing materials happens to be Hu's old job. "If the designed material can 'grab' the particles in the saline soil like an 'octopus' through ligand action, it can promote the formation of soil agglomerates." While learning, experimenting, thinking, and going deeper, Hu Shuwen has plunged headlong into the new field in such an unconventional way. "There is a saying that 'people don't learn the art after 40', but I am interest-driven, and as long as I am interested, I will do it immediately. Although I didn't study this profession, I was never afraid to learn."

Hu Shuwen set out to test a variety of soil improvers and repeatedly screened them, finally inventing bio-based modified materials according to different saline types, which are non-toxic and harmless and can also promote the formation of soil agglomerates. In this way, the desalination efficiency of the soil was increased by more than ten times at once, and the salt of the cultivated layer could be basically removed by using 300 cubic meters of fresh water per mu at one time. Compared with other technologies, the use of fresh water is reduced by more than 90%.

Soil drilling, profile digging, soil sample measurement, repeated exploration and optimization, solving problems in the field that are difficult to think of in the laboratory

Saline land improvement is a worldwide problem and a complex system project. Soil structure, salinity, nutrients, microbial communities, crop varieties, water resources, planting management and many other factors are intertwined and affect each other. They must all be adjusted to an optimal state for healthy crop growth. "The actual governance process, if the lack of overall systematic governance program, such as engineering facilities and soil improvement does not match, not only do not have the crop growth conditions, but also constantly repeat the 'desalination - back to salt', the effect is easy to repeat, the improvement cycle is long. " Hu Shuwen said.

What to do? Different from the invention of bio-based modified materials "bright idea", this time Hu Shuwen came up with a "dumb solution": "saline land management or to start in the saline land. To find a way to make the saline land grow crops, we must build the laboratory in the field, optimize various technical parameters, and establish a variety of management models in each saline area."

In this way, Hu Shuwen led his team, together with soil drilling, digging profiles, measuring soil samples, repeatedly exploring optimization schemes, and solving in the field those problems that were difficult to think of in the laboratory.

"The coastal mudflats in Tianjin, Hebei, Jiangsu and Shandong have a shallow water table, and the soil is susceptible to sea tide erosion, and the improved soil is prone to re-salt. The first step is to build a dike and a gate to control the water table and prevent the return of salt, while improving the soil."

"In some regions of Hebei, Shanxi and Inner Mongolia, mineralized water irrigation brings salinity, and channel leakage raises the water table, causing saline soil zones, resulting in salinity and drought. It is necessary to establish irrigation and drainage systems, control the groundwater level and export the salts; reshape the soil structure and quickly remove the salts from the soil cultivation layer, while saving water for irrigation and maintaining soil moisture."

Hu Shuwen stood in front of the map and introduced the situation of each saline area like a treasure. These experiences come from their team's long-term "immersion" in the front line of saline land, the establishment of 133 test sites across the country, digging more than 300 soil profiles, collecting more than 32,000 soil samples ...... a large number of rich first-hand information, both to form a "database", also helped them to create a systematic governance technology model.

After painstaking exploration, Hu Shuwen's team has established more than a dozen large demonstration areas across the country. In Jilin Songwon Qianguoerros Mongol Autonomous County, the rice yield reached 506 kg/mu in the demonstration field of soda-type alkaline soil improvement; in Inner Mongolia Bayannur Linhe District, the seedling retention rate of sunflower was significantly improved and the yield reached 174 kg/mu; dryland crops planted in Shanxi Shuozhou and Gansu Jiuquan achieved medium-high yields in that year and the local average yield in the second and third years, and the demonstration field was continuously Under the conditions of continuous cultivation and control of groundwater level, none of them had recurrence of salinity ......

On this basis, Hu Shuwen's team developed special functional fertilizers, anti-saline seed treatments and resilient materials for the composition and fertility of saline soils. They also worked closely with domestic experts to solve the problem of single microbial community structure of saline soil, and carried out the screening of salt-tolerant varieties, etc. Finally, they created a system engineering system for ecological restoration of saline soil based on the principle of "reshaping soil, efficient desalination, combining dredging and blocking, and reclaiming good fields". The saline is removed from the cultivation layer and exported through rainfall and irrigation.

Scientific research should not be done in a hurry, but with the attitude of "the flowing water does not compete for the first, but for the continuous", and more importantly, "write the thesis on the motherland".

Most of the saline land is located in remote areas, the traffic is not convenient. Hu Shuwen is in the field seven or eight months a year, and his students are out longer. They built an experimental station in the field, a simple bungalow, which served as a laboratory, office, canteen and dormitory. During breaks, Hu Shuwen and his students squeezed together in a bunk. Eat up, seven or eight bowls of noodles to the table, a plate of bean sprouts fried meat, a plate of pepper bean skin, teachers and students together to eat very fragrant ......

The company's main goal is to provide the best possible service to its customers. In order to test the soil, Hu Shuwen sometimes can not be bothered to wear boots, barefoot standing in the paddy field to step on it, he said "this is better than wearing boots to understand the soil plough bottom layer situation". In order to collect saline soil samples, the students jumped into the soil pit to dig the profile, a squat is half a day, the wind and sun, so these young people after 90 skin as dark as the old farmers. "My students are great! They have a strong sense of mission and an infinite love for the cause of saline land management. The little progress they make makes me very happy." Hu Shuwen's words are full of pride.

It is said that "do for the farmers to see, lead farmers to do", Hu Shuwen in the field "more" to do one thing, is to learn from farmers. "For us in agriculture, farmers are the most grounded and experienced teachers. They have a wealth of practical experience, more familiar with the local climate, planting conditions, but also really understand the various problems of saline soil, accumulated down some fragmented experience." Hu Shuwen said, "Our theoretical knowledge is just enough to string together these fragmented knowledge of our farmer friends, so that a scientific and systematic governance model can be formed more quickly."

China Agricultural University has a profound accumulation in saline land management. Thanks to the university's multidisciplinary advantages and support from various sources, Hu Shuwen's team has gathered professors and graduate students from various fields such as breeding, water conservation, soil, fertilizer and cultivation to carry out saline land management experiments and demonstrations in all aspects. "Before the students came to the team, their research experience was generally less and they did not know much about research work. At the beginning of each semester, I would talk to the students and exchange with them their research experiences and insights over the decades." Hu Shuwen said, he often told students that scientific research can not be rushed, to have a "flowing water does not compete for first, the competition is continuous" attitude.

Hu Shuwen engaged in soil improvement, is the first to do engineering and technology model, published papers on the back. "In recent years, our engineering technology model has become very mature, and the publication of papers is also very good, because at this stage, the publication of papers is a matter of water." More importantly, he said, "is to 'write the papers on the motherland', and to manage saline land is to find ways to make crops grow on saline land and have higher yields. Constantly around the various problems in the saline land, repeatedly push, test, feedback, until the problem is solved. This is the mission given to us in the new era, and this is what we are most proud of."

Translated with www.DeepL.com/Translator (free version)