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[Objective] The present paper aimed to analyze the diversity of bacterial communities in the rhizosphere soil of adzuki bean varieties with different resistance to soybean cyst nematode ( SCN) race 3 and explore the correlation between the composition of rhizosphere bacterial communities and variety resistance. [ Method] In July 2021, the 16S rDNA genome of bacteria in the rhizosphere soil of four different resistant adzuki bean varieties under the stress of SCN race 3 was sequenced by Illumina Miseq high-throughput sequencing technology from the rhizosphere soil of four different resistant adzuki bean varieties in Heihe city, Heilongjiang province, to analyze the changes of bacterial community structure. [ Result] A total of 1959 OTU s were obtained from 4 soil samples, and 30 phyla, 85 classes, 192 orders, 296 families, 481 genera and 893 species of bacteria were identified, among which Actinobacteriota, Proteobacteria, Acidobacteriota, Chloroflexi and Gemmatimonadota were the dominant phyla, Sphingomonas, norankJ __ norank_o __ Gaiellales, norankJ __ norank_o __ Acidobacteriales, Gemmatimonas, Blastococcus were the dominant genus. The average relative abundance of Actinobacteriota, Proteobacteria and Gemmatimonadota in the rhizosphere soil of susceptible varieties was lower than that of resistant varieties. The relative abundance of Gemmatimonas and Sphingomonas, which were related to disease resistance, was high in the rhizosphere soil samples of resistant variety Liaohong 1 and immunevariety Jihong 9218. [ Conclusion] The bacterial community structure in the rhizosphere soil of different resistant adzuki beans changed under the stress of SCN race 3, and the relative abundance of antagonistic bacterial populations in the rhizosphere soil of resistant varieties was much higher, which indicated that the bacterial community structure in the rhizosphere soil may be correlated with the resistance of adzuki beans to SCN. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to explore the grain production pattern and influencing factors in the major production areas, provided a certain basis for stabilizing the overall situation of national food security and formulating differentiated grain policies. [Method] By means of concentration degree, gini coefficient, logarithmic mean divisia index and cultivated land pressure index, quantitatively analyzed the factors influencing the increase of grain production in major grain producing areas from 2000 to 2020, such as the change of grain production center, variety structure, contribution to increase production, resource bearing capacity and production cost. [ Result] ( i) From the change of grain production center, more than 95 % of the grain increment came from the major grain producing areas, and the major producing areas in the north contributed more to the increase, especially Shandong, Henan and Heilongjiang, which occupied the top three areas of grain output and sown area for a long time. (ii) In terms of the production centers of different food crops, the production centers of wheat, com and beans were stable in the major grain producing areas in the north for a long time, while the production centers of rice and potato were mainly concentrated in the major grain producing areas in the south, but the production centers of rice gradually showed a trend of northward deviation. (iii) From the perspective of contributing factors, the grain increase in the major grain producing areas mainly depended on the increase of yield per unit area, and the contribution rate of yield per unit area to grain increase reached 61. 16%. The grain increase in the major grain producing areas in the north was due to the combined effect of cultivated land area, multiple cropping index, grain crop proportion and yield per unit area. Due to the decrease of cultivated land area in the major grain producing areas in the south had a negative effect on grain increase, the grain yield increase was more dependent on unit yield increase and multiple cropping index. (iv) From the perspective of resource carrying capacity of grain production, the dilemma of uneven distribution of water and soil resources has not been improved for a long time. The constraints of water resources in the major grain producing areas in the north were increasingly strengthened, while the pressure of cultivated land resources in the major grain producing areas in the south was continuously high. ( v) From the change and structure of grain production cost, the average grain production cost in the major grain producing areas was rising continuously. The land cost in the major grain producing areas in the north was higher, and the labor cost in the major grain producing areas in the south was higher. The grain production cost in the major grain producing areas in the north was higher than the whole country and the major grain producing areas in the south for a long time, and the rising rate was slightly faster than that in the major grain producing areas in the south. [Conclusion] Establishing the food security responsibility mechanism shared by the producing and marketing areas, constructing the differentiated compensation mechanism; Strictly observing the grain sown area, adjusting the structure of regional grain varieties; Consolidating scientific and technological support for grain increase, promoting coordinated development of water and soil resources and grain production; Taking multiple measures to improve grain production efficiency, and enhancing the enthusiasm of various subjects to grow grain. [ABSTRACT FROM AUTHOR]

(1) Background--The key state-owned forest areas are unique regions formed under the specific historical periods and special development strategies, and the reform of their governance system is crucial to ecological protection, sustainable development and social well-being in the new era. Although the reform of the state-owned forest areas has lasted for many years, there are still some problems such as dysfunctional institutional reform, stagnant industrial development and imperfect livelihood guarantee. (2) Methods--Taking Yichun Forest Industry Group in Heilongjiang Province as an example, this paper integrated resources, systems and social capitals into the analysis framework, and used the method of multiple case studies to compare and analyze the two reform modes of complete integration of the government and enterprises with the incomplete integration of the government and enterprises. The reform mechanisms and realistic dilemmas in the process of separating the government from enterprises were explored by setting SES (Social-ecological System) key variables in eight typical cases extracted from the four forestry bureaus. (3) Results--First, although the two reform modes of separating the government from enterprises had their own characteristics, in general, the reform of separating the government from enterprises led to the reshaping of the institutional environment and the changes in the authorities and responsibilities of the local governments and forest industry enterprises. However, the deep-rooted "system of units" and the deepening of path dependence limited the smooth implementation of the reform. Second, the reform process of separating the government from enterprises was externally influenced by the completeness of the supporting policies for reform, and internally constrained by the resources allocation rights, relative discourse rights and interdependence of the actors and governance systems, which affected the action stages by affecting the allocation mechanism of the reform costs. Third, the separation of the government from enterprises involved multiple stakeholders, including the government, enterprises, employees, etc., which would inevitably lead to the reconstruction of interest relations. In the post-reform period, it also faced the dilemmas such as unclear boundaries of the government and enterprises functions, insufficient support of the reform-related supporting policies, and difficult balance in the resettlement of the forest employees, which restricted the release of reform dividends. (4) Conclusions and Discussions--First, the local governments need to adjust their roles and responsibilities from those of administrators in the past to those of market regulators and service providers. At the same time, we should establish the value concept of overall co-governance and shape a mature cooperative governance structure. Second, since the reform of separating the government from enterprises affects the action stages of the local governments and forest industry enterprises, it is necessary to reasonably determine the sharing mechanism of reform costs and coordinate funding channels. For the public services undertaken by the enterprises in the transitional period, the government can share the relevant costs by purchasing socialized services. Third, after the separation of the government from enterprises, the forest workers have changed from the original "unit people" to enterprise employees. In the face of the rapidly changing development situation, the forest employees should continue to carry forward the forest industry spirit of hard work and daring to venture, actively face the market, go to the market and integrate into the market, constantly learn new vocational skills, and create "gold mountains and silver mountains" through diversified channels while managing and protecting the "clear waters and green mountains". [ABSTRACT FROM AUTHOR]

(1) Background--Global land use changes from 1960 to 2019 have affected nearly 32% of the earth's land area and these changes have obscured different trajectories of policy responses in many regions. Assessing the dynamic changes of land use types in 40 state-owned forest industry enterprises in Heilongjiang Province in different periods is helpful to understand the logical law between land use dynamics and economic and social policy development of state-owned forest industry enterprises, and is helpful to rationally adjust the ecological land layout based on the ecological and resource advantages of state-owned forest areas. (2) Methods--The land cover data of 40 state-owned forest industry enterprises affiliated to China Longjiang Forestry Industry Group Co., Ltd. and Heilongjiang Yichun Forestry Industry Group Co., Ltd. from 2006 to 2020 used in this paper came from European Space Agency Climate Change Institute (ESACCI). Six main types of land use were identified and their respective areas were extracted by using ArcGIS tool for supervision classification and visual interpretation. On this basis, the land use transfer matrix was used to calculate the area change of land use type conversion of the state-owned forest industry enterprises from 2006 to 2020, and the current situation of land use in the state-owned forest areas was analyzed according to the spatial and temporal differences of the scale and direction of land use transfer change in different regions. (3) Results--Forest resources in the state-owned forest areas have been effectively protected under the background of ecological civilization construction. From 2006 to 2019, the ecological protection and restoration of natural forests in the state-owned forest areas in Heilongjiang Province have achieved remarkable results. The area of forestland increased by 33 791'85hm², and the proportion of new dynamic forestland area reached 29'48%. However, the area transferred from ecological land to construction land from 2006 to 2020 was about 2'10 times that of construction land to ecological land. Especially from 2014 to 2018, the transfer between various land use types was the most frequent, and the policy of completely stopping commercial logging in natural forests had a direct impact on the change of land use structure in the state-owned forest areas. In addition, there were significant differences in land use competition and tradeoff between Longjiang forest industry and Yichun forest industry. The degree of land use transfer change of the state-owned forest industry enterprises affiliated to Yichun forest industry was relatively stable, while the transfer and change of land use types of Longjiang forest industry were more frequent. There were great differences in the direction and quantity of land use transfer in different regions. The total output value of the state-owned forest industry enterprises with a higher proportion of ecological land use was relatively high. (4) Conclusions and Discussions--First, clarify the function of land use through detailed spatial and temporal layout in the planning, improve the efficiency of land use and the quality of land use system through policy guidance. Second, fully consider the transition stage of land use in the regions where the forest industry enterprises are located, and strengthen and highlight the integration relationship between the main land use types and the regional ecosystems. Third, pay high attention to the land use types represented by grasslands that are significantly reduced in the short term, and take reasonable measures to protect and restore them. Fourth, ecological land should not be excessively occupied, and the governance and distribution efficiency of all land use factors should be considered as a whole to maximize the overall and long-term interests. [ABSTRACT FROM AUTHOR]

(1) Background--With the blurring and disappearing of industrial boundaries, industrial integration has become an important direction of industrial development and transformation. The integrated development of agriculture and forestry has played an important role in promoting the transformation and economic development of the key state-owned forest areas. (2) Methods--The research data was collected from the "China Forestry and Grassland Statistical Yearbook" from 2011 to 2020 and the "Heilongjiang Statistical Yearbook" from 2012 to 2021. Based on the statistical data from 2011 to 2020, this paper used the industrial coupling model to measure the integration degree of agriculture and forestry in the key state-owned forest areas in Heilongjiang and analyzed the factors influencing the integration degree of agriculture and forestry by principal component analysis. (3) Results--First, the industrial scale of agriculture and forestry integration was the most important factor to promote the integration of agriculture and forestry in the key state-owned forest areas. Second, the technical level could promote the integration of agriculture and forestry in the key state-owned forest areas to a certain extent. Third, the effect of forestry industry structure on the integration of agriculture and forestry in the key state-owned forest areas was limited. (4) Conclusions and Discussions--According to the research results, the following conclusions are drawn: First, the industrial contribution of agriculture and forestry integration in the key state-owned forest areas in Heilongjiang showed an increasing trend year by year from 2011 to 2017, reaching a maximum of 26.001 in 2017, and a decreasing trend year by year from 2017 to 2019. The degree of agriculture and forestry integration in the key state-owned forest areas in Heilongjiang increased year by year from 2011 to 2018, reaching a maximum of 16.101% in 2018, and showing a downward trend year by year from 2019 to 2020. Second, the industrial scale of agriculture and forestry integration in the key state-owned forest areas in Heilongjiang had the greatest impact on the integration degree of agriculture and forestry. This was because the forest-related industries had a good foundation and positive externalities. The agglomeration effect produced by the development of these industries made the integrated development of agriculture and forestry in the key state-owned forest areas in Heilongjiang increasingly obvious. Third, the technical level of forestry workers played a certain role in deepening the integration of agriculture and forestry in the key state-owned forest areas in Heilongjiang Province. Forestry itself includes primary, secondary and tertiary industries. The key state-owned forest areas in Heilongjiang were ahead of agriculture in technological progress, and the degree of technological progress determined the level and scale of industrial development, and also determined the integration degree of agriculture and forestry. Fourth, the promotion effect of forestry industry structure on the integration of agriculture and forestry in the key state-owned forest areas in Heilongjiang was not obvious. The implementation of some national policies, such as the restoration plan of natural forests and the cessation of commercial logging of natural forests, had a great impact on the change of forestry in- dustry structure. It took a long time for these impacts to reflect the changes of industrial structure, thus affecting the promotion of agriculture and forestry integration. Based on the above research conclusions, the following policy recommendations are put forward: First, increase the proportion of agriculture and forestry integration industry in the key state-owned forest areas to promote the development of agriculture and forestry integration. Second, improve the vocational skill level of the forestry workers to promote regional economic development. Third, promote the integrated development of agriculture and forestry through top-level design. [ABSTRACT FROM AUTHOR]

In order to construct a high-precision prediction model of forest surface litter moisture content, this paper takes three typical forests in Harbin City, Heilongjiang Province as the research object, and uses a self-made portable meteorological factor detector for real-time detection. Three representative machine learning methods of RF ( Random Forest ), BP ( Back Propagation ), and LSTM ( Long Short Term Memory ) were used to construct litter moisture content prediction models for the three stands. Results showed that, the prediction accuracy of the prediction model constructed by different forest stands under different machine learning methods was different. The prediction accuracy of the three stands in different machine learning models was LSTM > BP > RF. LSTM had the best effect in the study of surface litter moisture content prediction model. The results of this study indicated that LSTM was outstanding in the prediction of surface litter moisture content, which had important theoretical significance and practical guiding value for improving the accuracy of surface litter moisture content model based on meteorological element method. [ABSTRACT FROM AUTHOR]

Taking six kinds of arbors in Maoershan area of Heilongjiang Province as the research object, this paper provides theoretical data for forest fire prevention. The pyrolysis stage of holocellulose was studied by thermogravimetric analysis, the mechanism function was selected by Coats Redfern integral method, and the data were processed by Origin software to obtain the corresponding activation energy and frequency factor. The pyrolysis stage data of holocellulose were extracted, and the principal component analysis was carried out by SPSS software to rank the combustibility. The results showed that the pyrolysis process of 6 kinds of arbors’ trunk samples can be divided into water loss stage, holocellulose pyrolysis stage, lignin pyrolysis stage and carbonization stage. The descending order of activation energy in the pyrolysis stage of holocellulose in the branches and stems of 6 kinds of arbors was: Tilia amurensis Rupr., Pinus sylvestris var. mongolica Litv., Fraxinus mandshurica Rupr., Betula platyphylla Suk., Larix gmelinii Kuzen., Pinus koraiensis Sieb. et Zucc., The descending order of principal component analysis was: Tilia amurensis Rupr., Pinus koraiensis Sieb. et Zucc., Fraxinus mandshurica Rupr., Larix gmelinii Kuzen., Pinus sylvestris var. mongolica Litv., Betula platyphylla Suk. . The two orders were different, indicating that the flammability cannot be evaluated only from the micro point of view, but should be considered from many aspects. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to study the spatial-temporal characteristics and influencing factors of carbon emission from cultivated land use transformation in Heilongjiang province, in order to provide reference for achieving carbon peak and carbon neutrality.【Method】Based on the carbon emission coefficient and spatial autocorrelation analysis, the temporal and spatial differentiation characteristics of carbon emission from cultivated land use transformation in Heilongjiang province in 1990—2020 were revealed, and the influencing factors of carbon emission from cultivated land use transformation in Heilongjiang province were detected by geographical detector model.【Result】（i） The cultivated land area increased in Heilongjiang province in 1990—2020, and the conversion between cultivated land and forest land, grassland was the most significant. The carbon emission of cultivated land use transformation decreased from 1126 531 t in 1990—2000 to 125 292.3 t in 2000—2010, and then increased to 1793 129.5 t in 2010—2020. The carbon emission of cultivated land use transformation decreased first and then increased, but it was the carbon source region.（ii） The carbon emissions from cultivated land use transformation had a spatial agglomeration effect, and the hot spots moved from southwest to east and then to northwest, and from plain to hilly. The cold spot area showed a trend of extending from northwest to southeast in 1990—2020.（iii） Carbon emissions from cultivated land use transformation were mainly dominated by natural environment factors, and elevation factor had the strongest explanatory power in 1990—2020. The carbon emission from cultivated land use transformation was the result of the comprehensive effects of natural environment, social economy and policy factors. The interaction between natural environment and social economy factors was the strongest, and the interaction between natural environment and social economy factors was mainly nonlinear, and the interaction between slope and land use degree was the strongest. 【Conclusion】The spatial-temporal characteristics and influencing factors of carbon emission from cultivated land use transformation in Heilongjiang province were analyzed, which provided theoretical support for regional low-carbon sustainable utilization of cultivated land. The next research should focus on the carbon emission from the transformation of land property rights, operation mode and input and output under the hidden form of cultivated land use. [ABSTRACT FROM AUTHOR]

To coordinate the relationship between forest protection and utilization, give full play to the ecological, economic and social benefits of forests, and lay a solid foundation for sustainable economic and social development is a concrete action to implement Xi Jinping thought on ecological Civilization and implement the overall strategy of comprehensive, systematic and source governance of mountains, rivers, forests, farmland, lakes and grasses. Compared with the previous round of forest land protection and utilization planning (“original forest protection”), the new round of forest land protection and utilization planning (“ new forest protection”) is different in many aspects, such as the preparation background, positioning, indicators and requirements. It is very important to correctly understand the “new forest protection”, master the key points of the establishment of the “new forest protection” and learn from the experience and lessons of the “original forest protection”. Based on the last round of forest land protection and utilization planning in Heilongjiang Province, this paper discusses the positioning, technical basis, characteristics, and key links of preparation of the new round of forest land protection and utilization planning, expounds opinions and puts forward opinions, so as to lay a good foundation for the preparation of the new round of forest land protection and utilization planning. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to explain the changes of hydrothermal resources in the growth period of foxtail millet and maize in Heilongjiang region, and to provide theoretical basis for crop safety production.【Method】Based on the daily weather data from 1957 to 2013 in Raoyang County and Penman-Monteith formula, precipitation anomaly percentage and growth length day（GDD）, this paper analyzed the changes of hydrothermal resources in Raoyang County from June to September.【Result】（i） The size of ET0 was June > July > August > September, and the climatic tendency rates were-5.85,-1.96,-2.59 and-1.46 mm 10 a-1, respectively. The decrease of ET0 in different months was affected by different ten days, June was mainly affected by mid-late days, July was affected by mid-late days, August and September were affected by early and mid-late days, respectively.（ii） The frequency of drought from June to September was 33.33 %, 19.30 %, 31.58 % and 38.6 % respectively. Light drought was dominant in June and July, light drought was dominant in August and moderate drought was dominant in September.（iii）From June to September, the growth degree days were 459.58, 516.49, 470.40 and 301.64 ℃·d, respectively. The climatic tendency rates were 1.19, 3.28, 0.46 and 3.10 ℃·10 a-1, respectively. The increase of growth duration in June and August was affected by the first and middle ten days, July by the first and second ten days, and September by all stages, with the greatest increase in the latter ten days. 【Conclusion】In the future interannual changes, for crops such as millet and maize growing in Heilonggang from June to September, the heat resources were abundant and increasing, but the drought risk will increase in July and August. Therefore, in agricultural production, we should improve the irrigation system in July and August, and strengthen the measures of water conservation and drought resistance in this stage. [ABSTRACT FROM AUTHOR]

In order to explore the suitable technology for the reclamation of erosion gullies in the black soil area of the Northeast China. In this paper, Xinhua farm is selected as the research area which is located in Hegang City, Heilongjiang Province, China. Aiming at the cause of erosion gullies, a new technology of filling and reclamation erosion gully with coal gangue was introduced and the post effect of the new technology was studied, including, the technological process of filling and reclamation, the influence of the thickness change of reclamation filling materials on the drainage characteristics of the gully, the fertility status and heavy metals pollution degree in the reclaimed soil. This paper aimed to explore the feasibility and breakthrough points of the technology of filling erosion gullies with coal gangue. The results showed that: 1) The increase in soil layer thickness could weaken the drainage capacity of the gully, while the increase of mixed size coal gangue thickness and large size coal gangue could increase the drainage capacity of the gully in different degrees. The interaction between the soil layer thickness and large size coal gangue layer thickness obviously influenced the drainage capacity of the gully. When the thickness of soil layer, mixed size coal gangue layer and large size coal gangue layer were 53.42, 38.51, 90 cm respectively, the shortest outflow time was 145.129 s, the drainage capacity of simulated 2 m deep gully was the strongest in this mode. 2) After 4 years of gully reclamation, the soil bulk increased, the soil acidity improved, the content of total potassium was the same as CK, but the total nitrogen, total phosphorus and organic matter content were lower than CK. And then the comprehensive fertility of soil was less than CK, which is 66.71%-80.81% of CK, and the average level only reach to 72.75%. But it was slightly higher than that of the second accumulated temperature zone in Heilongjiang Province. 3) The content of Pb was basically the same as CK and background value of local control soil; however, as for Cr and Cu, they were higher than CK and background value of local control soil in the reclaimed soil of monitoring gully. But the content of Cr, Pb, Cu are not higher than the second level standard value of national environmental quality of China. . There are slight pollution and slight enrichment of heavy metals Cr, Pb and Cu in monitored gully reclamation soil, so coal gangue can be used as a material for filling erosion gully for reclamation. However, in the long term, attention should be paid to the problem of soil heavy metal enrichment during reclamation. [ABSTRACT FROM AUTHOR]

【Objective】 Base ion in soil is an important index to evaluate soil fertility. The problems of different depth of soil nutrient ion concentration, hardening in drought, sticking and decaying in waterlogging, low water storage and soil moisture conservation capacity seriously affect crop constants. 【Method】In the present paper, the calcareous chernozem in a certain area of Heilongjiang province is taken as the research object to study the effect of soil replacement and fertilization on base ion in calcareous chernozem soil; Under the condition of soil replacement and directional fertilization, the distribution and change of soil salt were studied. 0-20 cm soil and 20-40 cm soil were treated with directional fertilization for three consecutive years after one-year soil replacement. Under the premise of normal application of base fertilizer, the soil replacement(T1), soil replacement + straw(T2), soil replacement + 500 kg/667 m~2 were taken as the control without soil replacement.In the experiment group, the treatment methods of M2 dried chicken manure(T3) and soil replacement + 40 % theoretical phosphate fertilizer application(T4) were used to study the effect of different fertilization conditions on directional fertilization after soil replacement. 【Result】Soil replacement + basal fertilizer and application of organic fertilizer(T3) had the best effect, which could increase the content of water-soluble potassium ions, balance the content of sodium ions, bicarbonate ions and pH acidity and alkalinity, and reduce the content of calcium ions, magnesium ions, sulfate ions and chloride ions. 【Conclusion】The results show that the effect of soil layer replacement technology is obvious in the process of improving soil cation and anion. It can balance the pH value of soil, among which the effect of drying chicken manure with soil layer replacement + 500 kg/667 m~2 is the best. It can balance the content of anion and cation in soil, improve the pH value of soil, and create a good soil environment for corn, which is suitable for popularization and application. [ABSTRACT FROM AUTHOR]

The purpose of the study was to improve the pertinence and accuracy of salinization monitoring and control. The main data sources for this paper include agricultural land classification database, 1:500 000 spatial distribution data of saline-alkali land, China earth international exchange station climate data daily value sata set (V3.0), 1:1 000 000 soil database data, 1:1 000 000 spatial distribution data of soil texture in China, land change survey database and other data of Heilongjiang Province. With the support of the above data, on the one hand, research starts from the connotation of land salinization, filtered out land risk assessment factor from numerous factors, include landform, soil texture, evaporation and precipitation ratio, groundwater mineralization, regional sensitivity, land use level, the relationship between land salinization and its correlation was analyzed by the grey correlation model, and used the grey correlation model to analyze the correlation between these factors and land salinization, in order to verify the rationality of the selection of indicators, based on this, carry out grid training and accuracy test, formed land salinization assessment model. On the one hand, started from the extension of land salinization, screened out the resistance factors of soil salinization diffusion or migration, and constructed a resistance surface, used the minimal cumulative resistance model to evaluate the risk pattern of land salinization landscape. After the above work was completed, then with the help of ArcGIS spatial analysis function, superimposed the evaluation results of land salinization danger and land salinization landscape risk pattern, Formed land salinization type zones and monitoring levels. This paper takes Heilongjiang Province as an example to apply the method, the main research results were summarized as follows: 1) In terms of the salinity danger of the land, the land salinization danger of the salinity risk of severe and above land were mainly distributed in the southwestern part of the Songnen Plain, moderately distributed in the north-central part of the Songnen Plain and the northeastern part of the Sanjiang Plain. The light and below were mainly distributed in the great and small xing'an ridge and the southeastern mountainous areas. Eastern Songnen Plain and Southern Sanjiang Plain. 2) In terms of risk pattern, the severe and above were not only distributed in the central and northern parts of the Songnen Plain, but also in the central and northern parts of the Songnen Plain. In addition, there were also a small distribution in the northeastern and southeastern mountain areas of the Sanjiang Plain; moderately except in the Songnen Plain. The northern part and the northeastern part of the Sanjiang Plain were distributed, in the Middle and Central South of the Songnen Plain, the central and western parts of the Sanjiang Plain, and the southeastern mountain areas were also distributed; the mild and the following risk patterns were mainly distributed in the great and Small Xing’an Ridge, in addition to Sanjiang there is a small distribution on the southern edge of the plains and southeastern mountains. 3) The monitoring level of salinization in Heilongjiang Province showed the overall pattern of the west > east > central, northern and southern regions, the high-level and medium-level monitoring areas were mainly distributed in the western, southwestern, northern parts of the Songnen Plain, and the northeastern part of the Sanjiang Plain, the low-level monitoring areas were mainly distributed in the eastern part of the Songnen Plain, in the south of the Sanjiang Plain, and in the southeastern mountain areas, non-monitoring areas were mainly distributed in the large and Small Xing'an Mountains. The conclusion is that the land salinization monitoring area identification technology based on the risk and landscape ecological risk pattern takes into account the connotation of salinization and the extension of salinization, which provides scientific basis for the monitoring and prevention of land salinization. [ABSTRACT FROM AUTHOR]

Soil microorganisms participate in the energy flow and nutrient cycle of soil ecosystem, affecting the geochemical cycle process of organisms. Their diversity and community compositions play an important role in determining the function and sustainability of soil ecosystem. The functional diversity of soil microbial community is one of the important indexes to express the soil microbial community and ecological function. Soil microbial diversities of black farmland under different land use types are of great significance to the rational utilization and protection of soil resources. This paper explored the diversity of black soil microorganisms under different land use patterns of farmland, including maize, rice, soybean and potato, and taking the wasteland as the control. The Biolog Eco microplate method and pure culture of bacteria were used to study the changes of soil microbial diversity under four different land use patterns in the black soil area of central and southwest Heilongjiang province. The results showed that: 1) The number of culturable bacteria from more to less were potato, rice, soybean, maize, wasteland, but the variation of Shannon-Wiener diversity index from high to low was: wasteland (2.18), maize (2.11), potato (2.00), rice (1.73), soybean (1.49). 2) The utilization degree of carbon source of microorganisms in black soil under different utilization patterns increased with the extension of culture time. We found that amino acids, carbohydrates and polymers were main carbon sources for the metabolism of microorganisms in black soil. The Shannon-wiener index (3.18), McIntosh index (5.96), richness index (24.89) and Simpson index (0.95) of maize soil microorganisms were higher than those of other land use patterns, among which the diversity index of rice soil microorganisms was the smallest. There was no significant difference between the diversity index of potato, soybean and wasteland. Maize was better suited to the soil environment of farmland in the black soil area of Heilongjiang Province. 3) Principal component analysis identified two principal component factors that were related to carbon sources and explained 54.43% and 7.95% of the variance, respectively. Principal component analysis showed that different land use patterns significantly affects the metabolic diversity of carbon sources in the soil microbial community, and the main types of carbon sources that differentiated the metabolic characteristics of the soil microbial community were carbohydrates, amino acids and carboxylic acids, among which carbohydrates were particularly prominent. It showed that different land use patterns can affect the functional diversity of soil microorganisms. The results of this study is helpful to understand the relationship between soil microbial diversity and land use patterns of farmland in black soil area and provides certain scientific basis for agricultural development and scientific and rational utilization of black soil resources. [ABSTRACT FROM AUTHOR]

Technology of straw bale combustion is one of the effective ways to realize the clean utilization of agricultural residue, which has caused widespread concern. In this paper, the latest research progress of straw bale combustion was reviewed, the reaction principle and combustion characteristics of straw bale combustion were described, the generation and emission of particulate matter in the process of straw bale combustion were analyzed, such as NOx, CO and particle. And the research of straw bale combustion types, principles and characteristics were systematically summarized. Researchs showed that the combustion process of straw bale is mainly divided into two stages: volatile combustion and straw charcoal combustion. The heat released by volatile combustion accounted for more than 67% of the heat in the whole combustion process, which affected the combustion state of the whole straw bale.According to the technical characteristics and heating scale, we divided straw bale combustion into two types, one was continuous bale combustion, which can realize continuous feeding and ash cleaning in the combustion process, maintain a stable combustion state in the combustion chamber, and was suitable for the central heating area with large heating area, that mainly included cigar-bale combustion and reciprocating grate combustion. The other was batch combustion technology, which had advantages in small floor area, simple and convenient operation, usually used for small heating mechanism, and it included forward combustion technology and reverse combustion technology. Based on the global literature search, the research hotspot, institutions and development trend of straw bale combustion were analyzed. The running cost of straw baled heating was evaluated. It was found that the straw bale combustion has the characteristics of simple heating process and low operation cost. The operation cost was 19.8 yuan/m2, which was suitable for the industrialization promotion of clean heating in villages and towns. In addition, straw baled heating instead of coal heating can reduce the emission of SO2 by 0.38 kg per square meter and the emission of CO2 by 1.54 kg per year, which has a better benefit of environmental protection. In terms of technology popularization, the industrial system of straw bale combustion in developed countries in Europe is relatively mature, by contrast, the industrial system of straw bale combustion in China is still in the early stage, there are also some large-scale straw bale combustion projects in Liaoning province, Heilongjiang province, Hebei province and other areas, which have achieved good results. Straw bale combustion technology had gradually attracted the attention of scientific researchers. Developed countries in Europe had made some progress in the field of straw bale combustion, such as combustion mechanism, boiler structure, reduction of flue gas emission, etc. And at present, the research of combustion technology focuse on flue gas emission reduction and environmental impact assessment. The existing straw bale combustion technology still has some problems, such as insufficient combustion, unclear generation mechanism of flue gas pollutants, higher NOx and particle emission. It is suggested that we should pay more attention on research of characteristics of pollutant emission, and it is encouraged to reduce the generation of flue gas pollutants from the source. [ABSTRACT FROM AUTHOR]

As a kind of rural residential regions, scattered residential regions in the fields are the inevitable outcome of large-scale habitat-based regions that cannot meet the needs of agricultural planting activities. The rapid development of scattered residential regions in the fields would reduce the effective cultivated land region and cause waste of land resources. Therefore, in order to clarify the influence mechanism of scattered residence pattern in Heilongjiang reclamation region, taking 859 Farm under the jurisdiction of Jiansanjiang Administration Bureau of Heilongjiang reclamation area as the research region, this paper used spatial analysis, coupling degree model, multivariate statistical analysis to explore the influence mechanism of scattered residence pattern. The results show that: 1) 859 Farm has both large-scale habitat-based regions and scattered residential regions in the fields. The number of habitat-based regions is relatively small and the land use mode is relatively intensive. However, some farmers still own scattered residential regions in the fields while owning large-scale habitat-based regions, and the number is relatively large, about 15 times that of large-scale habitat-based regions. It also shows the spatial differentiation characteristics of dense central region and sparse east and west, resulting in extensive residential land use in the study region, reducing the effective cultivated land region and intensifying the contradiction between supply and demand of farm land resources. 2) The average value, the maximum value and the median value of the coupling degree between scattered residential regions in the fields and agricultural planting activities in the study region are 0.52, 1.00 and 0.60, respectively. The coupling degree between the systems is relatively high. Moreover, the spatial differentiation characteristics of coupling degree between scattered residential regions in the fields and agricultural planting activity system and the distribution state of kernel density show spatial consistency. Agricultural planting activities are related to scattered residential regions in the fields to a certain extent, so cultivated land structure, cultivated land region, field fragmentation, tillage radius and deviation distance are the influencing factors of scattered residential regions in the fields in the study region. 3) The main factors influencing the pattern of scattered residential regions in the study area are the attributes of cultivated land (tillage radius, cultivated land region, fragmentation degree of cultivated land) and the status of cultivated land use (cultivated land structure), while the influence of deviation distance is slightly small and is not the main factor. Cultivated land structure and tillage radius are the direct factors, while cultivated land region and field fragmentation are the indirect influencing factors. The mismatch between cultivated land structure and tillage radius makes the study region show the regional characteristics of gathering in the middle and dispersing in the east and west. [ABSTRACT FROM AUTHOR]

Wheat straw returning is one of the main ways to improve soil fertility. Long-term straw returned to field combined with chemical fertilizer can maintain soil fertility. It should be combined with crop rotation system and fertilization management to maximize advantages and avoid disadvantages. The impact of straw returned to field on crop yield and how to fertilize when straw returning are the issues of great concern to agricultural producers. In order to clarify the effect of long-term straw returned to field in wheat-bean rotation on crop yield and soil nutrient, this paper conducted the experiments in the long-term positioning experimental station in Heihe district of Heilongjiang province, and adopted split-plot test method. The main treatment was straw returning to field and non-returning to field, secondary treatment was different fertilization for low, medium and high level. The experiment started in 1980 with wheat-soybean-wheat and wheat-soybean rotation models. The effects of wheat straw returning to field and different fertilization levels on crop yield under wheat-soybean rotation conditions were investigated for 38 consecutive years (1980-2018). The results showed that there was no significant difference in years of yield of wheat, soybean or wheat planted every other year after wheat straw returning. The medium-fertilizer was 7.42%-10.81% higher than that of low-fertilizer area on soybean with continuous fertilization, achieved significant difference level. The yield of wheat increased by 14.52%-19.33% in high-fertilizer area compared with low-fertilizer area. The effect of wheat straw returning on soybean yield was 5.91% higher than that of non-returning in the early stage (1-6 season) and 7.52% higher in the late stage (7-16 season). The yield of wheat increased by 0.31% and 0.22% in early stage (1-5 seasons) and late stage (6-16 seasons) compared with non-returning to field. Generally speaking, after wheat straw returning to the field, the frequency of crop yield reduction in the early stage is high, while the frequency of yield increase in the later stage is high. In Heihe area, the long-term application of wheat straw to field had no significant effect on soil organic matter, total nitrogen, alkali nitrogen, total phosphorus, available phosphorus and total potassium, while the content of available potassium increased significantly. Long-term fertilization had a significant impact on soil nutrients. High fertilizer level could significantly increase the contents of soil organic matter, total nitrogen, alkali nitrogen and total phosphorus. Long-term fertilization also reduces soil pH value, leading to acidification of soil. [ABSTRACT FROM AUTHOR]

In order to improve the efficiency and accuracy of the quantitative prediction of soil nutrient content in black soil of Heilongjiang province, in this paper, we utilized statistical theory and spectral analysis method, researched the relationship of three kinds of soil nutrient content and soil spectrum to established hyperspectral inversion model of soil total nitrogen, available phosphorus, available kalium content. We acquired the aerial hyperspectral data by using CASI-1500 and SASI-600 linear array push-broom imaging spectrometers. Preprocessing of calibration and atmospheric radiation correction of Airborne Hyperspectral raw radiation data was studied. 96 samples were evenly sampled. In order to increase the representativeness of samples, 96 groups of samples were collected from 3-5 samples collected from 15 meters around the sampling point, and 1.5 kg was retained after mixing. After air-drying, mixing and grindingetc, it is used for the contents of total nitrogen, available phosphorus and available kalium were obtained through laboratory tests. The content of total nitrogen, available phosphorus and available kalium was determined by NaOH diffusion method, NaHCO3 extraction-molybdenum blue colorimetry and NH4OAC extraction-flame photometry. Referring to Kennard-Stone method, 72 groups of representative samples were selected as model samples for nutrient content prediction, and 24 groups were model prediction samples. 96 black soil samples were sorted according to nutrient content, and the spectral transformation in the visible near red range was analyzed. The change rule of total nitrogen is that the reflectance decreases with the increase of content. The first order differential spectra at 580 nm were significantly correlated with total nitrogen and available phosphorus content, with a correlation coefficient of -0.43 and -0.36, respectively. The first-order differential spectra at 1730-2200 nm were significantly correlated with K2O, and the maximum correlation coefficient was -0.31. Compared with the original spectral waveform, the correlation coefficient between the first derivative and three nutrient contents fluctuated sharply, and the positive and negative cross-sections were relatively sharp, with more peak coefficients. After spectral contrast analysis and correlation coefficient calculation, 86 bands with higher correlation coefficient were selected for the study under the first order differential variation. On black soil airborne hyperspectral data processing, the application of partial least squares regression (PLSR) and BP neural network method respectively establish soil nutrient content of high spectral quantitative inversion model. The results showed that RPIQ values (Difference between the third and the first quartile of sample observations ratio to RMSE) of total nitrogen PLSR and BP neural network prediction model were 2.42 and 2.80, respectively. The RPIQ values of effective phosphorus PLSR and BP neural network model were 0.83 and 1.67 respectively. The RPIQ values of the available kalium PLSR and BP neural network models were 2.00 and 2.33 respectively. Experiments showed that the spectral quantitative prediction model of soil total nitrogen and available kalium has good accuracy and prediction ability. Nitrogen, phosphorus and potassium, and the spatial distribution of nutrient content in black soil were obtained. However, the prediction effect of effective Phosphorus was not particularly ideal, which could only meet the requirements of approximate quantitative prediction. At the same time, the BP neural network modeling has better accuracy and prediction ability than the partial least square modeling, and the prediction accuracy increased by 6.5%, 10.1% and 6.6% respectively. Due to the limitation of soil samples and other conditions, more samples are needed to verify the universality of the model. More data mining methods are expected to establish more robust prediction models, which will provide more reliable information for the prediction and evaluation of black soil quality information. [ABSTRACT FROM AUTHOR]

Lodging has been regard as one of the major destructive factors for crop quality and yield, resulting in an increasing need to develop cost-efficient and accurate methods for detecting crop lodging in a routine manner. Nowadays, rapid evolvement in unmanned aerial vehicle (UAV) and sensor technology has allowed high accurate and more accessible in monitoring crop development and health status with adequate temporal, spatial, and spectral resolutions. Compared with satellite and airborne photogrammetry, UAV with proper sensors offer a flexible, convenient, and cost-effective way to provide desired and customized observations on crop fields. Previous studies have extensively examined and verified the potential of UAV-based lodging recognition by leveraging photogrammetric algorithms, geospatial computing analysis, as well as pertinent agricultural expertise. As a substantive extension of previous published proceeding papers, this work presents a complete UAV-based survey methodology for monitoring lodging maize. Multispectral images of lodging mature maize in Youyi farm of Heilongjiang Province were collected to extract the lodging area. There were 4 crop forms in the research area: not-lodging maize with green leaves, not-lodging maize with yellowish leaves, lodging maize with yellowish leaves, and black shadows, based on the multispectral image. The 2 vegetation indexes and 8 co-occurrence measures texture features were calculated, and the feature sets of maize lodging area extraction was constructed on the basis of the above 2 kinds of predictors and spectral reflectivity features. 5 types of maize lodging identification feature sets were sifted, which included spectral feature set, normalized difference vegetation index (NDVI) feature set, red edge normalized difference vegetation index (NDVIR-edge) feature set, single-class texture feature set and multi-class texture feature set. The maximum likelihood method was used to identify maize lodging for all feature sets. Finally, we analyzed the classification error of 4 crop morphology, extraction error and Kappa coefficient of lodging area under different features. The results showed that maize lodging area extracted by spectral feature set and NDVI feature set was larger than measured lodging area, which mainly because the wrong classification of not-lodging B pixels into lodging pixels, while the main reason for the inaccurate maize lodging area obtained by NDVIR-edge feature was that the not-lodging B maize and the not-lodging maize affected by edge effect were classified into lodging. Extraction area of lodging maize by single texture feature set was smaller because some of the not-lodging B maize pixels were classified as lodging pixels, but more lodging pixels was misclassified as not-lodging pixels. Single and multi-class texture feature sets could remove the shadow of blade gap well with appropriate texture filtering window selected, but multi-class feature set had higher extraction accuracy. It was difficult to distinguish the lodging maize from the not-lodging maize with yellowish leaves in mature period, and there was no significant difference in spectral reflectance feature between the 2 crop morphology. Therefore, when we identified these 2 types of crop morphology, a large number of misclassification pixels would be generated. The multi-class texture features extracted from UAV multispectral images could accurately extract maize lodging area. The average error of 4 crop morphology was 9.82%, the extraction error of lodging area was 3.40%, and the Kappa coefficient was 0.84. [ABSTRACT FROM AUTHOR]

Net Primary Productivity( NPP) plays an important role in the study of carbon storage and carbon sinks. In order to understand the changing trend and characteristics of forest vegetation NPP,and realize the dynamic research on the NPP of forest vegetation,this paper took the Dailing District,Yichun City,Heilongjiang Province as the research area,and studied the coniferous forest,broad-leaved and coniferous and broad-leaved mixed forest in the Dailing District the annual growth of forest NPP in 2014-2044 and monthly growth of forest NPP in 2014-2019 based on the 3-PG( Physiological Principles Predicting Growth) model. The results showed that the forest NPP in the Dailing District showed an increasing trend in 2014-2044,but the growth rate gradually decreased with the year. The monthly growth change of NPP in 2014-2019 was cyclical. The total amount of forest NPP in the Dailing District from May to September was 30. 725 × 105 t in 2015. And the annual and monthly values of NPP were expressed in the three forest stands: young forest > middle-aged forest > near-mature forest > mature forest > over-mature forest. The research results make an attempt to apply the 3-PG model in Northeast China,and provide decision support and scientific reference for forestry managers. [ABSTRACT FROM AUTHOR]

In order to study the carbon sequestration of forests and its influencing factors such as tree species,mean DBH,average tree height,stems per hectare,altitude,slope and so on,this paper used two types of the forest resources permanent sample plot survey data from three typical forest farms in Muling City,Heilongjiang Province in 2012 and 2016. The carbon storage capacity of each forest farm was estimated by combining the biomass compatibility model and the carbon content of different tree species. Using ArcGIS’s ordinary Kriging interpolation method,spatial interpolation was used to obtain and analyze the spatial distribution pattern and dynamic changes of the two phases of carbon storage. The relationship between carbon storage and topographic factors such as elevation and slope,and forest stand factors such as tree height and DBH were analyzed,and a carbon storage estimation model was obtained. The results showed that the total carbon storage in the study area was on the rise,the forest carbon sink function was strengthening,the carbon storage in the central and western regions was significantly higher than those in other regions,and the carbon storage in the southeast was relatively low,the broad-leaved mingled forest,oak trees and artificial larch all played an important role in the carbon sink function of forest vegetation in this region. Conclusion: forest carbon sequestration was in good condition,and more attention should be paid to the protection and distribution balance of forest resources. [ABSTRACT FROM AUTHOR]

[Objective]The present paper is about analysis of high density resistance of 36 maize varieties suitable for the third and fourth accumulated temperature zones in the eastern humid region of Heilongjiang province. [Method]The agronomic characters, stem mechanical indexes and yield of maize were analyzed by cluster. It also further confirms the important indexes of lodging resistance of maize. [Result]The results showed that the varieties were classified into three groups by systematic cluster statistics, among which 21 cultivars were highly inverted（Ⅰ）, 10 were moderately resistant（Ⅱ）and 5 were low resistant（Ⅲ）. Rind penetration strength, break strength, dry matter weight per stem length and stem node diameter were significantly positively correlated with stem lodging resistance index(0.597 **, 0.948**, 0.677** and 0.419**, respectively), which could be used as important indicators for evaluating lodging resistance of varieties. [Conclusion]The lodging resistance of Class II varieties is less variable after densification and the yield is higher, so it can be considered to be planted at high density. The results provide quantitative reference for breeding new varieties in main planting area of Heilongjiang province. [ABSTRACT FROM AUTHOR]

Straw returning to the filed can not only improve soil fertility, but also alleviate the imbalance of nitrogen, phosphorus and potassium, improve crop yield and quality, and reduce the cost of agricultural production. Rice straw is decomposed gradually by microorganisms in the soil, which can release nitrogen to the soil for rice growth. Nitrogen released from straw can be divided into expended nitrogen and nitrogen retained in soil. Expended nitrogen can be further divided into nitrogen absorbed by plant and lost nitrogen. 15N tracer technology is an effective means to study the nitrogen budget of farmland, by which we can accurately grasp the status of nitrogen utilization and residue, and analyze the nitrogen utilization efficiency of straw. Understanding the utilization rate of straw nitrogen is the premise of fertilization regulation and control. Heilongjiang Province still lacks the utilization rate of nitrogen in rice straw and the technical achievements of nitrogen regulation and control under straw returning conditions. In this paper, we take Qianjin Farm(132°17′E,47°34′N), Sanjiang Plain as test site and the albic soil as the test soil. we conduct a series of experiments during nitrogen regulation and control period including 15N straw labeling tracer test and straw returning nitrogen optimization test, the utilization rate of nitrogen in straw after rice straw returns to the albic soil is defined and the optimized application technology of nitrogen fertilizer after rice straw returns to the albic soil is summarized, so as to provide theoretical basis and technical guidance for optimized application of nitrogen fertilizer after straw returns to the field. The results showed that, according to 15N isotope tracer, the contribution rate of straw nitrogen in the albic soil to rice plant nitrogen accumulation was 6.49%~7.48%, 3.26%~4.16% to stem and leaf nitrogen accumulation, 8.67%~9.74% to seed; the total nitrogen use efficiency of straw was 6.51%~7.65% in the current year, and the adjustment of C/N ratio was beneficial to improving straw nitrogen utilization rate. Field experiments showed that the nitrogen application rate under straw returning was 10% lower than that under conventional nitrogen application for three consecutive years, and the field with good drainage had the effect of increasing yield, with the average yield increase by 6.17% for three years, and the yield with the reduction of nitrogen by more than 20% was low and unstable. Balanced and basal nitrogen reduction was suitable in nitrogen reduction period, and the yield was reduced significantly in case of fertilizer for tillering and panicle with nitrogen reduction; the field with poor drainage was not suitable for nitrogen reduction, otherwise, it led to yield reduction. There are differences in nitrogen regulation and control after straw returns to different kinds of soil. The corresponding measures for nitrogen management should be formulated according to soil conditions. [ABSTRACT FROM AUTHOR]

Based on the systematic description of the economic transformation and development of Heilongjiang forest industry area, thin paper realized the dynamic factors identification and the quantitative study of the driving effects with the dynamic model and the statistical data from 2005 to 2016. The results show that the industrial structure level has the most significant driving effect on the economic transformation and development, which is closely related to the scientific industrial layout and the optimal allocation of resources between industries. The capital and labor factors have positive effects on the economic transformation of forest areas, but lower than the industrial structure level; the driving effect of capital factors is greater than the labor factor, which clarifies the urgent demand for capital investment in the development of alternative industries in the current forest area, and the problems of poor labor resources and unbalanced structure in the forest area are serious. It has restricted its promotion role in the economic transformation and development of forest areas. In summary, the economic transformation and development of Heilongjiang Forest Industry Region is driven and influenced by a series of factors ranging from industrial structure level, capital and labor factor input, and combined with the research conclusions and the objective reality of the forest area, it puts forward a feasible path to accelerate the economic transformation and development of the forest area. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the composition of bacterial diarrhea pathogen spectrum in Heilongjiang Province，explore the variation and epidemic change rules of major pathogens，improve the ability of the laboratory to diagnose，monitor and warn the pathogen of diarrhea，and deal with the outbreak of bacterial diarrhea so as to provide scientific basis for further prevention and control. The sentinel hospital patients with intestinal bacteria in outpatient infective diarrhea feces were collected. Separated culture， biochemical identification， and serotyping method were used to detect Salmonella， SAigella， E'scAericAia coli (c o l i) ， and other intestinal pathogenic bacteria. Among the test specimens of 537 patients with bacterial diarrhea syndrome， the detection rate was 36.69%. The major pathological bacteria were pathogenic coli，SAigella， Vibrioparahaemolyticus，Salmonella， Plesioms sAigelloies，Aeromonas AyropAila， Fersinia enterocolittca， Vibrio cAolerae， Campylobacter ye/uni， and pathogenic coli. The corresponding detection rates were 9. 3 1%， 6. 8 9%， 1. 3 0%， 3. 3 5%， 0.56%，0 . 1 9%， 0.37%， 0.74%， 5.40%， and 16.95%， respectively. There was no significant gender difference， while the age pathogen detection rate and month pathogen detection rate were significantly different among all age groups. Pathogen detection rate had seasonal differences that the detection rates in June， July， August， and September were high，and the detection rate accounted lor 93.40% ol the total detection rate. The sum ol 0〜10 years old age group number ol cases and the detection rate were higher than other age groups. It was lound that the summer and autumn seasons in Heilongjiang Province are the seasons with high incidence ol bacterial infectious diarrhea，and the main pathogens were E. coli，Shigella，Salmonella，and Campylobacter jejuni. [ABSTRACT FROM AUTHOR]

With the application of super high and large-span floor structure, the design of the formwork support system should meet more strict demands. This paper introduced a steel column-tube support system for the formwork of the large-span and multi-layer gymnasium in Heilongjiang University of Chinese Medicine. The steel column-tube support system can not only unload step by step, but also promote productivity of labor and reduce engineering cost evidently. The performance of the support system of large-span floor structure were summarized and analyzed firstly. Then, this paper elaborated the design and construction means of the support system. Finite element model was established to analyze the bearing capability of the structure when the floor was set the steel column in the position of shear pole. The results show the support system has the features of high bearing capacity and security which can meet the requirements of the design code. [ABSTRACT FROM AUTHOR]