The Contrast Between The Sand At The Foot Of Desert Flowers And The Vast Desert In The Distance

In the first ten days of November, under the cold weather in early winter, the desert of Alashan League in Inner Mongolia was even more desolate. In sharp contrast, it was the residual vitality in the experimental base of "sand to soil".

"If you come here in the summer, it's a lot of green, the contrast will be more obvious." Yi Zhijian, vice president of Chongqing Jiaotong University, told reporters. Despite the lack of color contrast, when the reporter stood in the experimental base, the difference between the sand and the vast desert in the distance was still very obvious.

? ? ? In the test base, the reporter saw patches of watermelon, tomato, pepper, white radish and peanuts that had not yet been harvested. The staff said that after a frost fall in October, these fruits were not suitable for picking, and the reason why they were not harvested early was to keep the fruits for people to visit, and on the other hand, these fruits rotted in the ground, which was more conducive to improving the sandy soil Fertility.

It is also an important part of soil improvement. There is a view that as long as there is water, the desert can grow plants, and there is no need to transform the desert. But Yi Zhijian told reporters that there is water in the desert, which can make the sand plants grow, but even if there is water, the non desert plants will not continue to grow to a certain extent.

In the experimental base, the sandy land after soil transformation can be planted with all kinds of plants. In terms of water consumption, Yi Zhijian introduced that the average irrigation amount was less than 400 cubic meters per mu, far lower than the local water-saving irrigation quota of 550 cubic meters per mu because of the obvious effect of water conservation and fertilizer conservation after desertification. If the drought tolerant plants are planted, irrigation is needed only at the germination stage, and no irrigation is needed for the subsequent growth.

In the process of planting crops, there is also a surprise discovery, that is, the roots of the plants planted on the sandy soil are more developed, the yield is higher, and the fruits are more delicious. "We just wanted to be able to grow plants, but we didn't expect plants to grow better than ordinary fields." Yi Zhijian said.

This phenomenon is caused by the unique soil structure of desertification. Generally speaking, "sand to soil" will soil the 20-30 cm sand on the surface of the desert, which makes the profile structure of these plots divided into two layers, the upper layer is a relatively tight soil layer which can preserve water and fertilizer, and the lower part is the original discrete sand.

Under this structure, the root system of the plant will be very developed, so that it can absorb more water and fertilizer. Last year, the agriculture and Animal Husbandry Bureau of Alxa League organized a sorghum yield test. The highest per mu yield of the experimental base was 932kg, and the average yield was 789kg, far higher than the highest average yield of 324kg in 2017.

In 2019, the fruits harvested by the experimental base will be sold in supermarkets under the "desert promise" brand, which is very popular. This also makes Yi Zhijian more confident in "changing sand into soil", because it proves that the implementation of desertification can make local people rich.

As for food safety, Yi Zhi insists that the binding materials are extracted from plants, non-toxic and harmless, and have passed the test. Moreover, the experimental base in Inner Mongolia has passed the environmental testing of green food producing areas, and the agricultural products planted this year have also passed the green food certification.

As for the construction cost of 2000-2000 mu of materials, we only need to add 5000 yuan to the cost of the whole reconstruction process.

Magic "sand to soil"

Before 2008, Yi Zhijian almost knew nothing about the desert. An accidental thought made him an indissoluble bond with the desert.

Yi Zhijian has been vice president of Chongqing Jiaotong University since 2003. He has been engaged in teaching and scientific research of mechanics, roads, bridges and materials for a long time. In 2008, when he was studying the porous concrete pavement with ductile polymer skeleton, he suddenly found that the change from particulate matter to concrete is actually a state change, and the mechanism of change is that the state of particulate matter is determined by constraints (physical terms).

At that time, Yi Zhijian's first thought was the desert. If the discrete sand bodies could be gathered together by restraint, the desert would change to the soil state.

For a long time, the control of desertification is a world-class problem. Now, global desertification is expanding at a rate of 50000-70000 square kilometers per year. China's desertification land area has reached 1.73 million square kilometers, causing economic losses of hundreds of billion yuan every year. Nearly 400 million people directly or indirectly receive the impact of desertification.

As a native of Chongqing, Yi Zhijian has never seen a real desert before, but he thinks that if the research on desertification can be successful, it will be of great significance to curb desertification and increase land use.

Yi Zhijian has been working on this project for 12 years since he proposed the idea of desertification in 2008, followed by material research, desert simulation experiment and large-scale experiment.

For this project, Yi Zhijian is not willing to simply summarize it as "sand to soil", because in essence, the chemical composition of the sand has not been changed, but the physical form between the sand is changed, so it is more appropriate to call it "sand to soil".

Yi Zhijian told the 21st century economic reporter that soil naturally has two mechanical states: one is the solid state when it is dry, and the other is the rheological state when it is water bearing. This also gives the soil the ability of self-healing and self-regulation.

The so-called self-healing ability refers to that the general solid is difficult to repair after it is damaged, but after the soil is dried and cracked in the solid state, it can become a rheological body by absorbing water, and the cracks will disappear. At the same time, the self-regulation property of soil ensures that the change of soil particle arrangement will not affect the soil properties, which is also the reason why plant roots can grow in the soil.

What Yi Zhijian wants to do is just like using cement to make concrete. By adding constraint materials to the desert, the desert has the mechanical state of soil. In fact, when the sand is added into the soil, the process of mixing is very simple.

11 years of sand control

In this process, the core link is the constraint material. Since the idea was put forward in 2008 and the experiment was started in 2009, Yi Zhijian led the team to study the constraint materials and verify the feasibility of desertification. In 2012, the idea of "sand test and soil test" was carried out in the whole area, and the idea of "sand test and soil improvement" was carried out in the whole area.

In 2013, the research team began to carry out a simulated desert experiment in Chongqing. The specific method is to pad 30-50 cm gravel on the simulated plot, then 20-30 cm sand on the gravel, and finally put a layer of soil transformed sand on this layer of sand. On this layer of transformed sand, the team planted fruit.

Yi Zhijian has been doing this desert simulation test for three consecutive years. He told reporters that from 2009 to 2015, the whole team mainly verified the principle and actual effect of desertification through small experimental research, and developed plant fiber adhesive materials (i.e., binding materials). It was in the desert simulation test that the team gradually overcame the problems of stability, safety and durability of the materials Question.

After the desert simulation test was also verified, Yi Zhijian started the large-scale experiment. In 2016, the research team entered the real desert for the first time. They opened a 25 mu experimental base in Ulan Buhe desert, Inner Mongolia. After a series of operations such as desert leveling and soil transformation, seeds were sown in May. More than two months later, more than 70 kinds of plants were lush.

"It gives us a lot of encouragement." Yi Zhijian said. Subsequently, in 2018, the research team further expanded the experimental area of Ulan Buhe desert to 6000 mu. At the same time, the "sand to soil" project also went out of Ulan Buhe desert and carried out experiments in Taklimakan Desert in Xinjiang and Zoige desertified grassland in Aba Prefecture of Sichuan Province, with the test area increased to 10000 mu.

Yi Zhijian said, "in 2016, our experiment was only to verify whether plants can grow in the deserts after soil desertification. By 2018, we have started to select and study dominant plants in large-scale experiments.". In 2019, the territory of the "sand to soil" experiment will be further expanded, with Tibet, the Sahara desert, the Middle East desert, Xisha Islands and reefs added, with an area of 17000 mu.

Refuse to rely on heaven

In fact, with the progress of the whole project, Yi Zhijian's team also encountered some difficult problems. Zhao Zhaohua, vice president of the desert ecology research institute of Chongqing Jiaotong University, told reporters that at the beginning, no one in the whole team understood agriculture, so when they first arrived in the desert, they just asked professional growers to learn from them.

However, as the experiment began to scale up, the research team found that the traditional agriculture relied on the weather, and some decisions were made by experience accumulation, which would bring many risks and uncontrollable factors. For example, traditional land cultivation requires annual ploughing to make the soil soft. However, in the experimental desert, there are scattered sand under the soil layer of 30cm, so the root system can be freely spread without soil turning.

Sand to soil is a scientific research project in the experiment. If the traditional agricultural planting experience needs to be verified one by one, it will take a long time to say nothing, and it may also have an impact on the project itself. Therefore, in order to study desert agriculture and ecology more scientifically and efficiently, the research team needs to collect and analyze agricultural production data.

Jiang Xuejiao, who joined the team in 2018, is mainly responsible for data analysis. She told reporters that in the process of research, it is necessary to collect many types of data, such as temperature, light, water and other environmental factors, and also need to identify fruits, monitor diseases and insect pests, measure plant height, calculate seedling emergence rate, yield and so on.

Complex data types have also led to a surge in data processing. For example, in terms of crop yield, the team needs to use environmental acquisition system, field plant phenotype acquisition system, hyperspectral acquisition system, full-time video monitoring system to collect a large amount of data, which will generate at least 1t of data per day.

"After data collection came back, how to analyze became a huge challenge." Jiang Xuejiao said, "a teacher in the project team used the deep learning framework to do target detection on a personal computer. After running for more than 800 megabytes of data set for three days, he did not calculate the result. If he wants to process a 1t image, it may take months or even a year to calculate."

And processing such a large amount of data is exactly what Tencent cloud is good at. In fact, as early as 2018, Zhong Yuanhe, vice president of Tencent cloud and general manager of Tencent IDC Platform Department, noticed Yi Zhijian's "sand to soil" project, and actively sent people to contact him, hoping to provide some technical support.

Tencent cloud "entering the bureau"

After one year of contact and communication, Tencent and Chongqing Jiaotong University established a joint laboratory for desert ecology research in October 2019. In this laboratory, Tencent plays the role of science and technology assistant, providing advanced technologies in cloud computing, edge computing, big data, AI, IOT and other aspects for scientific research work of the University.

At present, Tencent cloud nano T-block, an edge data center composed of IOT sensors, edge gateways and integrated cabinets, has been deployed in the Ulanbuh Desert experimental base in Inner Mongolia. According to Liu Lingfeng, senior architect of Tencent cloud data center, with the help of nano T-block, the data required by the scientific research team will be collected through the Internet of things sensing equipment, and then transmitted to the server in the cabinet through the edge gateway. After cleaning and screening the data, the effective data will be uploaded to the intelligent platform on the cloud for classification and identification. At the same time, the AI model trained from the cloud can also sink to the nano T-block edge data center, further promoting the data processing nearby.

Liu Lingfeng told reporters that such a cabinet can support 5120 virtual cores at the same time, which also means that the original research team used ordinary computers to calculate data in four months, and nano T-block only needed one hour to complete.

In fact, Tencent's team has customized the nano T-block for use in desert areas. For example, nano T-block can adapt to the bad weather of minus 45 to 55 degrees, and it also has wind and sand proof components. In addition, the operation and maintenance personnel can realize remote control and operation and maintenance of nano T-block with the help of intelligent platform of Tencent cloud data center.

Yi Zhijian told reporters that if a scientific research project wants to realize real industrialization, it must be tested for three years or even longer. In the process of experiment, mistakes are acceptable, but once industrialization is completed, the cost of making mistakes will be very high. Therefore, the "sand to soil" project will be in the stage of experimental promotion for at least three years in the future. At this stage, the team will also do further research and data accumulation.

In fact, for the "sand to soil" project, Yi Zhijian's team is also studying whether it will change the whole climate. If the ecological restoration brought about by desertification soil changes the climate positively, even if it only increases a little precipitation, it is of great significance to the whole desert area. However, the ecological research involves meteorological data, which can not be achieved only by Yi Zhijian's team, but also by cooperation with Tencent.

Yi Zhijian, who was born in 1963, is nearly 60 years old. He told reporters that many people his age have begun to think about how to keep fit, and he is still running to the desert. For him, the sand to soil project is not only a scientific research project, but also a very meaningful cause, and he enjoys it.

The year before last, Yi Zhijian brewed the sorghum planted in the experimental base and named it "shazhiyue". He said that the name has two meanings. One is constraint, because the principle of "changing sand to soil" is to add constraint materials into the sand, and the other is an agreement. When he was studying mechanics, he suddenly thought of transforming the desert, which seemed to be an agreement between him and the desert.

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