> Dynamic

Focus on the black soil geological survey in northeast China

Aug.01,2018
The black soil in Heilongjiang province and Jilin province is the most fertile land in China and one of the four black soil belts in the world. Agriculture is an advantageous industry in the black soil region of northeast China and an important part of the strategy of revitalizing the old industrial base of northeast China.
In September 2016, at the national science and technology innovation conference of land and resources system, minister Jiang Daming proposed to focus on the world's scientific and technological frontier and fully implement the land and resource science and technology innovation strategy. To implement the innovation strategy of land science and technology, land survey and evaluation should be developed in an all-round way. Zhong Ziran, director of the China geological survey, stressed in the geological science and technology innovation training seminar of the China geological survey that we should rely on scientific and technological innovation to solve resource and environmental problems and basic geological problems. The black soil geological survey is of great significance to national grain security, agricultural green production mode and scientific and technological innovation strategy of land and resources.
Northeast black soil already had geological survey result, be providing strong support for local agriculture development. At present, the geological survey of black soil is also faced with the challenge of "upgrading" in order to meet the new demands of agricultural structural adjustment, transformation and upgrading and to solve ecological problems such as black soil degradation.
Clear understanding, support upgrade agriculture industry
In order to apply structural reforms for agricultural from the supply side, we have to ensure national food security, on the basis of closely around the market demand change, improve the quality and food safety of agricultural products, promote green production mode, enhance the capacity of agricultural sustainable development, to develop characteristic agricultural product standardization production demonstration, to construct a batch of geographical indications of agricultural products and country of origin.
To support the northeast black earth area agricultural development, the Chinese geological survey jointly with the competent department of land and resources in Heilongjiang province, working for more than 15 years, funding nearly 72 million yuan, has completed 1:250000 land quality geochemical survey in Heilongjiang province, with the area of about 11.44 square kilometers, 47.67% of the total area of two main plains area. In the critical areas, 1:50,000 land quality geochemical evaluation and selenium-rich land environment survey were completed, and the land quality in the concentrated area of cultivated land was preliminarily clarified.
The investigation shows that there was no heavy metal pollution in the cultivated land of Heilongjiang's core areas, and the green products were widely distributed. In Songnen plain, 99.44% of arable land was free of heavy metal pollution, and 99.6% was free of heavy metal in Sanjiang plain. The prime and good cultivated land area of Songnen plain is 76.35%, mainly distributed in the north and east part. The cultivated land quality in the survey area of Sanjiang plain is mainly high quality, with an area of 95.7%. The area of suitable area for planting green food in Songnen plain was determined to be 98.7%. The area of suitable area for planting green food in Sanjiang plain was 99.4%. The investigation areas of the two great plains have been completed, which are basically suitable for the development of green agriculture and can promote the development of modern agriculture.
According to the investigation, the selenium rich soil prospect area of 12,000 square kilometers and 0.75 million square kilometers in the Baoqing area of Hailun city and Sanjiang plain was respectively delineated. The investigation in the two prospective areas found that about 2 million mu of green and selenium rich soil, the soil environment quality was clean and concentrated, and the selenium source was relatively stable, which was conducive to long-term development and utilization. The results of this survey have provided support for the development of modern characteristic agriculture and targeted poverty alleviation in Baoqing county and Hailun city. In 2016, Hailun was awarded the "selenium capital of China black soil" by the China nutrition association, and Baoqing plans to fully tap the potential of selenium rich black soil in three years.
In recent years, the grain output of Heilongjiang province has been increasing continuously, and the total amount of grain products ranks first in the country year after year. According to the national bureau of statistics' sampling survey of agricultural production and business households in 31 provinces (districts and cities) and overall statistics of agricultural production and business units, Heilongjiang's grain planting area ranked first, however the output per unit area ranked 21st in 2016, lower than the national average output per unit area. It is of far-reaching significance for the development of characteristic industries such as selenium-rich agricultural products, rational utilization and comprehensive treatment of soil resources in agricultural production, as well as laying a solid foundation for the transformation of agricultural economy to refinement, specialization and commercialization.
Strengthen research to save black earth
The black soil area in northeast China has a total area of 10 million hectares, and more than 7 million hectares of cultivated land have been reclaimed so far, and its grain output accounted for more than 60% of the total output of Heilongjiang and Jilin provinces
Black soil refers to the land covered with black or dark humus surface soil, which has good physical, chemical and biological characteristics. However, the long-term over-reclamation and predatory development have caused serious ecological problems in the black soil in northeast China -- the area gradually decreased, the soil layer became thinner, the land grade declined, and the fertility declined.
Black soil is fertile because it is rich in organic matter, the level of organic matter can be reflected by organic carbon. The soil organic carbon reserves in Songnen plain and Sanjiang plain were estimated scientifically and accurately according to the soil type, ecosystem, land use pattern and geomorphic units, using the data from the regional geochemical survey project conducted by the China geological survey.
By comparing the variation characteristics of soil organic carbon content in the two great plains of Heilongjiang in the past 20 years, it is found that the soil organic carbon loss in the black soil of Songnen plain is accelerating, while the soil organic carbon in the black soil of Sanjiang plain is on the rise. The reason is that the two great plains of Heilongjiang province have significant differences in the way of farming: in the central and southern part of the Songnen plain, the farmland is mainly operated by individual farmers. The crop straw generated by the farmland is mostly burned or used as livestock feed every autumn. The farmland of Sanjiang plain is mainly state-owned farm, adopting modern and mechanized farming methods. Every autumn, the crop is harvested by mechanization, and the broken crop stalks are returned to the field. The difference of tillage methods between the two plains may be the reason that the soil organic carbon content in the two plains varies greatly.
The urgent need to protect black soil is to strengthen research on the prevention and control of black soil degradation in northeast China and actively explore efficient and low-carbon agriculture. It is imperative to accelerate the black soil geo-ecological survey.
Scientific and technological innovation, "heaven's eye" perspective on the black soil
During the 13th five-year plan period, the northeast black soil geo-ecological survey was included in the national major public welfare geological survey evaluation project. The Shenyang geological survey center of China geological survey takes this work as an important link to help revitalize the old industrial base in northeast China, strengthen the innovation of geological science and technology, improve the achievements of geological survey and serve the economic and social development.
At the end of 2016, Shenyang center held a symposium on geological survey of black soil in Shenyang city, inviting geochemistry, agriculture, aviation remote sensing experts, to communicate on topics of the utilization present situation of northeast black soil regions, problems should be solved urgently, investigation methods, serving local economic development, land resource management, and working plan for the next step. After the seminar, in order to further promote the investigation results and better serve the local economic and social development, Shenyang center sent two groups of demand research teams to the Heilongjiang provincial bureau of agricultural reclamation, Heilongjiang provincial department of land and resources and Heilongjiang provincial bureau of geology and mineral resources for investigation. They have gathered specific requirements from Heilongjiang province: such as comprehensive as soon as possible for two great plains soil integrity land quality geochemical and remote sensing investigation, survey and assessment and to improve the quality of the large scale land selenium-rich detailed survey of land resources. Experts from Heilongjiang province also pointed out that Sanjiang plain showed a trend of weak alkaline soil, and should put forward preventive measures; advanced technology can be applied to dynamic monitoring of crop planting, growth, diseases and insect pests and nutrient status.
New demands put forward higher requirements for geological survey work. Li Zhizhong, director of the Shenyang geological survey center, said that during the 13th five-year plan period, the Shenyang geological survey center will be carefully organized and implemented to make full use of advanced technical means to speed up the northeast black soil ecological geological survey.
Li also said: "we should make full use of advantages of satellite remote sensing survey method for real-time, continuity land survey, and to carry out geochemistry observation, quaternary geology comprehensive investigation in the same period. At the same time, new technologies and new methods such as hyperspectral remote sensing survey should be adopted to carry out rapid dynamic monitoring of soil organic matter content and selenium content in typical areas of black soil, so as to realize " heaven's eye " perspective of black soil, integrate various investigation methods and means, and quickly and accurately serve the development of land science and technology and local economy.
-- by wang shaoyong and dai huimin, China land and resources
Special report专题报道