Saline-alkali land becomes "black soil" in this way

In the northeast of October, the weather has begun to turn cold, but the Longhai irrigation in Taiping Village, Longnuma Town, Da'an City, Jilin Province is a lively scene of grabbing a bumper harvest: rows of golden rice are swaying in the wind, and the combine harvester is wafting through the place where the fish passes, wafting wisps of rice fragrance.

Just over a year ago, it was a white, saline land with an average soil pH of 9.31, far beyond the range where common plants could survive. Why is there a saline-alkali land in the northeast of Baishan and Heishui? How did these saline-alkali lands become normal arable land or even black soil? With these questions, the reporter of this newspaper conducted an interview.

Pay equal attention to improvement and cultivation, and treat the symptoms and root causes

The management and utilization of saline-alkali land is a global problem. China is a large country in saline-alkali land, ranking third in the world in terms of saline-alkali land area. Among them, the western part of the Songnen Plain is one of the world's three major areas of soda saline-alkali soil, with an area of more than 4500 million mu, and severely saline-alkali land accounts for more than 43.7% of the total area of saline-alkali soil.

"Normally, soils with a pH value of more than 7.5 are judged to be alkaline soils. Among them, soda saline-alkali land has the characteristics of saline-alkali coexistence, soil compaction, poor permeability, and poor nutrients, which is not only harmful to ecology and soil, but also difficult to improve. Wang Hongbin, a professor at the College of Resources and Environment of Jilin Agricultural University, introduced that the Songnen Plain is high in the east and low in the west, and the precipitation is not easy to discharge quickly.

The reporter stepped on an untreated piece of saline-alkali land and found that the surface was very hard and covered with white salt. The water-deficient clods are so hard as cement that they can't be crushed by hand. Local farmers vividly refer to this saline land as "dry like a knife, wet is a mess".

So, is it possible to improve by replacing the soil and planting crops? Experts said that the soda saline-alkali land and the black soil in the Northeast are actually next to each other, and the high terrain is fertile black soil, and the low terrain is easy to form saline-alkali land. If we do not start from the formation mechanism of saline-alkali land, it is difficult to cure the root cause.

Wang Hongbin said that to control this kind of saline-alkali land, we must first lower the groundwater level and control it below the critical depth. At the same time, the soil salinity is controlled within a certain range by excavating field drainage ditches for drainage and desalination, irrigation and salt washing. Finally, soil fertility should be cultivated continuously by applying chemical amendments such as alum and ferrous sulfate and planting saline-alkali tolerant crops.

And this is the main force of Sinochem's scientific and technological workers in the treatment of saline-alkali land on the Songnen Plain.

On the one hand, it relies on the movement of water and salt to improve the soil. "Salt comes with water, and water carries salt away." With the help of this principle, after classifying the saline-alkali land into blocks, technicians build canals according to the saline-alkali composition and content of different plots to "discharge salt" and "wash fields" to control the groundwater level.

On the other hand, the soil is repaired by spreading the improver. After "salt drainage", an amendment is applied in the field in exchange for dealkalinization. In this process, in addition to the traditional chemical amendments, technicians also added microbial agents developed by independent screening and recultivation according to the characteristics of saline-alkali plots in different regions to reconstruct the soil aggregate structure of "macropores" and lay the foundation for soil function restoration.

After the basic work is completed, further screening and planting saline-alkali tolerant crops will be carried out to increase the content of soil organic matter and accelerate the formation of an ecological recycling system. At present, saline-alkali tolerant rice is a major choice with ecological, economic and social effects.

Build high-quality farmland to ensure sustainability

When the alkali falls, the salt drains, the fields are washed, and the rice is planted, can the saline-alkali land become normal cultivated land or even black soil? It's not that simple. According to experts, soil remediation is a systematic, long-term process. Only by forming sustainable benign farming can we effectively consolidate the soil ecology and turn the saline-alkali land into a large granary.

At the site of the Sinochem Environmental Saline-alkali Land Experimental Field, which is about 40 kilometers away from Taiping Village, the freshly harvested rice is piled up into two hills. Not far away, on the ground lay two rows of bagged paddy, ready to be shipped at any time. "At present, the yield of rice per mu here has reached six or seven hundred catties." Ge Yanjun, assistant general manager of Sinochem Environmental Remediation (Jilin) Co., Ltd., pointed to a large paddy field that had just been harvested, saying that for this once saline-alkali land, the focus of governance has shifted to stepping on the agricultural time, improving quality and increasing production. "Agriculture is an industry that depends on the sky for food, and farming time waits for no one. Compared with the natural black soil, the improved saline-alkali land is still not enough to resist drought and flood disasters, and we need to continue to take care of it to ensure that every season of cultivation is on time. He said.

After the improvement of saline-alkali land, there are still many "hurdles" to continue to build high-quality farmland.

In the case of irrigation systems, for example, smart drain valves come in handy. "The traditional drain valve is manually cranked, which is difficult to meet the needs of accurate control of inlet and outlet water speed in saline-alkali land treatment. To do this, we used smart drain valves with solar panels and installed canal flow monitors in the fields. Data such as PH value, pressure, water level, water temperature, etc., are uploaded every 10 minutes through the sensor. Ge Yanjun said that in addition to the irrigation system, the experimental field also has the latest intelligent equipment such as unmanned tractors, unmanned plant protection machines, unmanned rice transplanters, and unmanned harvesters to achieve sustainable and efficient management of farmland.

In addition to hardware investment, scientific research in the fields of saline-alkali tolerant rice variety breeding, cultivation technology innovation, and intelligent monitoring should also be continuously followed. Ma Wei, an associate researcher at the Rice Research Institute of the Jilin Academy of Agricultural Sciences, said that to turn saline-alkali land into black soil, it is necessary to unify good land, good seeds, and good laws. "For a long time, rice production has mainly been based on a large number of water and fertilizer inputs and agronomic technology improvement, and the research and development of paddy field cultivated land technology and supporting agricultural machinery and equipment are relatively backward, especially in soda saline-alkali rice areas. To this end, we actively establish a reasonable tillage index evaluation system for soda saline-alkali paddy fields, screen out special agricultural machinery and equipment suitable for saline-alkali land, and realize agricultural machinery and agronomic support. Ma Wei said.

Continuing to ask for grain from saline-alkali land is inseparable from talent. Wang Hanbiao, a graduate student who just graduated from Jilin Agricultural University this year, injected new strength into the Sinochem Longhai Irrigation Project Department. "I study the environment, and the management of saline-alkali land is not only professional, but also the transformation of saline-alkali land is of great significance for the development of agriculture and ensuring food security." Wang Hanbiao said that after coming to the project department, he found that there was a certain difference between the theory of books and the practice in the field, but this also provided a direction for young people to work hard and a stage to increase their talents.

Awaken the sleeping farmland and build a large granary

As the sun sets, the golden sunset and the rice in the fields complement each other, outlining a gratifying harvest picture.

Guo Zongshang, a farmer in Longnuma Town, Da'an City, ended his busy day and calculated the account on the way home: "The annual rent per mu of natural black soil is at least five or six hundred yuan, and it is even more expensive when the land is good." Rice grown on improved saline-alkali land not only produces rice of good quality and can be sold at a good price, but also rents less than 100 yuan per mu per year. Growing rice in saline-alkali land, this 'crab', I can be regarded as eating it right! ”

Guo Zongshang feels that although the cultivation process after the improvement of saline-alkali land is relatively difficult, he has now become a "new farmer" and has grown and improved in the process of farming. "To grow crops in saline-alkali land, it is not enough to have agricultural experience, but you must know some knowledge in the fields of seed industry, climate, geography, chemistry and so on. If the scientific and technological workers of Sinochem continue to work like this, it is not impossible for the saline-alkali land to produce grain like high-quality black soil in the future. He said that after more than a year of participation, he also found out some experience in farming in saline-alkali land. For example, unlike ordinary arable land, rice cultivation in saline-alkali land can achieve the best effect by "small amount and many times", whether it is water drainage or fertilization.

In the interview, a number of experts said that there are two main ways to increase grain production and increase the yield and expand the area of arable land. Taking rice as an example, after years of development, there is not much room for a substantial increase in yield per mu, so it is increasingly important to carry out the comprehensive transformation and utilization of saline-alkali land. From a national point of view, the central and western regions are relatively short of water, and the eastern coastal areas are relatively short of land, while the Songnen Plain in the northeast is flat and rich in precipitation, which is very conducive to the development of large-scale mechanized agriculture. Compared with other regions, the management of soda saline-alkali land in Northeast China is not small, but it is also of greatest significance to food security. In particular, saline-alkali land is often a large area of undeveloped "pure land", awakening this sleeping cultivated land, which can realize the expansion of cultivated land resources, improve quality and increase efficiency.

Wang Qian, deputy director of the Ministry of Ecology and Environment's Center for Soil and Agricultural and Rural Ecological Environment Regulatory Technology, said that healthy soils can provide healthy food, clean water and air, and a stable climate, which is an important guarantee for human health, and its ecosystem services are worth US$125 trillion. She believes that in the future, a variety of treatment technologies should be adopted according to the characteristics of different saline-alkali lands, and a model of saline-alkali land governance and high-quality development should be established with the goal of "water-salt-agriculture-ecology-environment-economy coordinated improvement".

Saline-alkali land is "eliminated", black soil is "growing", and more scientific and technological achievements are being transformed into real productive forces at an accelerated pace.

"Up to now, Sinochem Environment has carried out 4,1 acres of saline-alkali land (paddy field) treatment work in Baicheng City, Jilin Province, and is expected to complete the improvement and restoration in 3 to 5 years, which will add 3,3 mu of first-class paddy fields to Jilin Province, with an annual increase of 3330.3 million catties of rice, and 6,3 mu of saline-alkali land (dry field) treatment work, which is expected to be completed after 4320 years, and will increase the annual output of <>.<> million catties of corn." Qu Fengchen, general manager of the Soil Remediation Business Coordination Center of Sinochem Environment Holdings Co., Ltd., said.

Wang Junling