Evaluation and Driving Force Analysis of Cultivated Land Quality in Black Soil Region of Northeast China

Cultivated land is an important natural resource to ensure food,ecological and economic security.The cultivated land quality evaluation(CQE)is greatly significant for protecting and managing cultivated land.In this study,320 counties in the black soil region of Northeast China(BSRNC)represent the research units used to construct the CQE system measuring the soil properties(SP),cultivated land productivity(CLP),ecological environment(EE)and social economy(SE).The total of 19 factors were selected to calculate the integrated fertility index(IFI)and divided into grades.Simultaneously,we used the coupling coordination degree model to comprehensively analyze the spatial pattern of the cultivated land quality(CLQ)in the BSRNC,and use the structural equation model(SEM)to analyze the driving mechanism.The results show the following:1)The CLQ of 262 counties in the BSRNC is in a state of coupling and coordination,and the coupling and coordination degree presents a spatial distribution pattern of‘high in the southwest and northeast,low in the northwest and southeast’.The coordinated development degree of 271 counties is between 0.4 and 0.6,which is in a transitional state between coordination and disorder.2)The CLQ in the BSRNC is generally good,with an average grade of 3.High-quality cultivated land accounts for 58.45%of all counties,middle-and upper-quality cultivated land accounts for 27.05%,and poor-quality cultivated land accounts for 14.49%.3)The SEM analysis shows that the SP,CLP,EE,and SE all influence the CLQ.Among them,the SP has the largest driving force on the CLQ,while the SE has the smallest driving force on it.The results confirm that the main factors affecting the evaluation results are crop productivity level,normalized difference vegetation index,ratio vegetation index,difference vegetation index,and organic carbon content.When implementing protection measures in counties with a low CLQ,considering a balanced coordination of multiple systems and reasonably controlling the quality degradation are important.This study provides the current situation and driving factors of the CLQ in the BSRNC and will play an important role in black soil governance and utilization.

Study on the Method of Soil Productivity Assessment in Black Soil Region of Northeast China

The objective of this paper is to investigate a simple and practical method for soil productivity assessment in the black soil region of Northeast China.Firstly,eight kinds of physicochemical properties for each of 120 soil samples collected from 25 black soil profiles were analyzed using cluster and correlation analysis.Subsequently,parameter indices were calculated using physicochemical properties.Finally,a modified productivity index(MPI) model were developed and validated.The results showed that the suitable parameters for soil productivity assessment in black soil region of Northeast China were soil available water,soil pH,clay content,and organic matter content.Compared with original productivity index(PI) model,MPI model added clay content and organic matter content in parameters while omitted bulk density.Simulation results of original PI model and MPI model were compared using crop yield of land block where investigated soil profiles were located.MPI model was proven to perform better with a higher significant correlation with maize yield.The correlation equation between MPI and yield was:Y = 3.2002Ln(MPI) + 10.056,R2 = 0.7564.The results showed that MPI model was an effective and practical method to assess soil productivity in the research area.

Relationship Between Soil and Water Conservation Practices and Soil Conditions in Low Mountain and Hilly Region of Northeast China

The soil and water conservation practices of ecological restoration(ER),fish scale pit(FP),furrow and ridge tillage across the slope(FR),shrub strips(SS),and vegetation-covered ridge(VR)are characteristic of the Jixing small watershed of the low mountain and hilly region of Jilin Province,Northeast China.This study aims to elucidate the effects of soil and water conservation practices on soil conditions after the short-term implementation of practices.Soil samples were collected from five soil and water conservation sites(ER,FP,FR,SS,and VR)and two controls(BL and CT)to investigate their properties.To evaluate the influence of soil and water conservation practices on soil quality,an integrated quantitative index,soil quality index(QI),was developed to compare the soil quality under the different soil and water conservation practices.The results show that not all soil and water conservation practices can improve the soil conditions and not all soil properties,especially soil organic carbon(SOC),can be recovered under soil and water conservation practice in short-term.Moreover,the QI in the five soil and water conservation practices and two controls was in the following order:ER>VR>BL>FR>CT>SS>FP.ER exhibited a higher soil quality value on a slope scale.In the low mountain and hilly region of Northeast China,ER is a better choice than the conversion of farmlands to planted grasslands and woodlands early in the soil and water conservation program.

Spatiotemporal Variations and Regional Transport of Air Pollutants in Two Urban Agglomerations in Northeast China Plain

Characteristics of air pollution in Northeast China(NEC) received less research attention in the past comparing to other heavily polluted regions in China.Spatiotemporal variations of six criteria air pollutants(PM10, PM2.5, SO2, NO2, O3 and CO) in Central Liaoning Urban Agglomeration(CLUA) and Harbin-Changchun Urban Agglomeration(HCUA) in NEC Plain were analyzed in this study based on three-year hourly observations of air pollutants and meteorological variables from 2015 to 2017.The results indicated that the annual mean concentrations of air pollutants are generally higher in the middle and southern regions in NEC Plain and lower in the northern region.Megacities such as Shenyang, Harbin and Changchun experience severe air pollution, with a three-year averaged air quality index(AQI) larger than 80, far exceeding the daily AQI standard at the first-level of 50 in China.The annual mean PM and SO2 concentrations decrease most significantly in NEC urban agglomerations from 2015 to 2017, followed by CO and NO2, while O3 shows a slight increasing trend.All the six pollutants exhibit obvious seasonal and diurnal variations, and these variations are dictated by local emission and meteorological conditions.PM2.5 and O3 concentrations in NEC urban agglomerations strongly depend on wind conditions.High O3 concentrations at different cities usually occur in presence of strong winds but are independent on wind direction(WD), while high PM2.5 is usually accompanied by weak winds and poor dispersion condition, and sometimes also occur when the northerly or southerly winds are strong.Regional transport of air pollutants between NEC urban agglomerations is common.A severe haze event on November 1–4, 2017 is examined to demonstrate the role of regional transport on pollution.

Effect of farmland shelterbelts on gully erosion in the black soil region of Northeast China

The black soil region of northeast China is one of the most important grain-producing areas in China.Increasingly severe gully erosion in this region has destroyed much farmland and reduced grain production.We analyzed SPOT5 imagery from 2007 and TM imagery from 2008 to describe the distributions of gullies and farmland shelterbelts in Kedong County and to assess the effect of farmland shelterbelts on gully erosion. The imagery revealed 2311 gullies with average density of 418.51 m km-2, indicating very serious gully erosion.With increasing slope gradient there was an inverse trend between gully density and shelterbelt density, indicating that farmland shelterbelts can prevent gully erosion. The defense effect of farmland shelterbelts against gullyerosion varied with distance: for distances<120 m, the defense effect was consistent and very strong; for distances of 120–240 m, a weak linear decrease was found in the defense effect; and for distances>240 m, the defense effect of the shelterbelts was significantly weaker. We recommend an optimal planting density of farmland shelterbelts for the prevention of gully erosion at1100–1300 m km-2.

Regional Evolution Features and Coordinated Development Strategies for Northeast China

Northeast China,as the most important production base of agriculture,forestry,and livestock-breeding as well as the old industrial base in the whole country,has been playing a key role in the construction and development of China’s economy.However,after the policy of reform and open-up was taken in China,the economic development speed and efficiency of this area have turned to be evidently lower than those of coastal area and the national average level as well,which is so-called ‘Northeast Phenomenon’ and ‘Neo-Northeast Phenomenon’.In terms of those phenomena,this paper firstly reviews the spatial and temporal features of the regional evolution of this area so as to unveil the profound forming causes of ‘Northeast Phenomena’ and ‘Neo-Northeast Phenomena’.And then the paper makes a further ex-ploration into the status quo of this region and its forming causes by analyzing its economy gross,industrial structure,product structure,regional eco-categories,etc.At the end of the paper,the authors put forward the basic coordinated development strategies for Northeast China,namely we can revitalize this area by means of adjustment of economic structure,regional coordination,planning urban and rural areas as a whole,institutional innovation,etc.

Present-day 3D deformation field of Northeast China,observed by GPS and leveling

A broad view of present-day 3D deformation field around the Northeast China region was derived from GPS and leveling observations.We draw the following conclusions:First,the Northeast China region moved towards northwest with an average velocity of 5 mm /a,with respect to South China.The entire Northeast China region was in a low strain state from the strain rate field.Second,we processed two periods of firstorder leveling data in 1970 s and 1990 s,showing the vertical deformation of the Northeast China region is"uplift in western part and subsidence in eastern part".

Revitalizing Old Industrial Base of Northeast China:Process, Policy and Challenge

Northeast China is the largest old industrial base of China that endured persistent influence of the past planned economy system. This region has lost its leading place since the reform and opening up, and became a backward region by contrast with the coastal areas. This paper elaborates the evolutionary process of the old industrial base of Northeast China, analyses the main reasons for the decline, gives a preliminary evaluation on the revitalizing polices in recent years, and points out major long-term challenges for future revitalization. It concludes that for Northeast China, a relative declining area: 1) it is indispensable to get the long-term policy support from the central government; 2) system reform and structure adjustment are the crucial strategies, particularly the reform of the large and medium state-owned enterprises; and devel-oping new industries is as important as upgrading traditional advantaged industries; 3) the local governments should play an indirect role, avoiding from any unnecessary intervention on economic activity; and 4) social security and investment climate must be improved simultaneously. In addition, the author stresses that the lack of knowledge on the nature of old industrial base had led to failures of the past initiatives, and revitalizing the old industrial base should be treated as a holis-tic regional project including economy growth, society progress and environment improvement.

Sandy desertification trend in western Northeast China Plain in the past 10 years

The west sandy land of the Northeast China Plain is located in the eastern huge sandy belt of mid-latitude in Eurasia and the eastern fringe of desertified land with best bio-climatic conditions in China. With rapid economic development, the deterioration of eco-environment has occurred and the desertification becomes very obvious. The first part of this paper studies the regional differences of landscape patterns and explores the regional differences of desertification. The second part aims to reveal the dynamics of desertification in the 1990s by using NOAA/AVHRR data and thematic data in GIS database. This work lays a scientific basis for the rehabilitation and development of the sandy lands.

The Evolution and Differentiation of Economic Convergence of Resource-based Cities in Northeast China

A key target of the overall strategy implementation for regional development since the 18th Party Congress of China has involved taking measures to narrow regional disparities. This is because resource-based cities' economic development has fallen below general levels due to resource exhaustion and an unbalanced industrial structure, among other factors. Further, an economic gap has long existed between Northeast China's large number of resource-based cities and non-resource-based cities. This article comprehensively studies the economic convergence of Northeast China's resource-based cities and non-resource-based cities from 1996 to 2015 by using a dynamic panel to analyze not only the economic development of different industries and types of cities, but also the main factors that influence economic development. The empirical results demonstrate that economic convergence exists in both resource-based and non-resource-based cities, but the economic gap between them has clearly narrowed since the implementation of a strategy to revitalize the Northeast's old industrial base. Shrinking cities are the fastest to converge, as mature cities are slower and regenerating cities are the slowest; regarding industry structure, the secondary industry dominates the economy in mature and shrinking cities, and the tertiary industry in regenerating cities. The primary stimulus in resource-based cities' economic development involves upgrading the industrial structure and investing in human capital. As China faces a ‘new normal' economy, resource-based cities in Northeast China should restructure the economy and perfect their market system to avoid again widening the economic gap.

Analysis of Small Earthquake Activities before Medium-strong Earthquakes in Northeast China

13 earthquakes with M≥5.0 have been recorded in the northeast region of China since1970,among which eight medium-strong earthquakes are independent in space and time.Studies of seismicity before these eight medium-strong earthquakes show that small earthquake activity was enhanced before the occurrences.Though seismicity increase is a common phenomenon in the northeast China region,we have difficulty in predicting the medium-strong earthquakes by this phenomenon alone.In order to predict medium-strong earthquakes through seismicity increase,this paper tries to propose a new method that calculates small earthquake frequency through the changing pattern of small earthquake activities based on the characteristics of small earthquake activity in the northeast China region.The results show that we can get the obvious anomaly frequency of small earthquakes before medium-strong earthquakes through the new method,and can obtain a medium to short term anomaly index for the northeast China region.

Preliminary research on problems of northeastChina's participation in the northeast Asianeconomic cooperation

According to various factors influencing the economic openness, this paper probestentatively into the way Northeast China complies with and participates in the Northeast Asiancooperation, with perticular attention to the analysis and estimation of the advantageousgeographical condition of the extenal cooperation in Northeast China from the present situation ofdeveloping the external economy and cooperation with the adjacent countries.

典型黑土区不同保护性耕作方式对玉米生长发育及产量形成的影响

实施保护性耕作对保护东北黑土和保障国家粮食安全具有重要意义。为明确东北典型黑土区保护性耕作对玉米产量的影响及其关键因素,开展了连续3年大田定位试验,设常规垄作秸秆不还田(CK)、免耕秸秆全量粉碎覆盖(T1)、免耕留高茬全量秸秆覆盖(T2)、少耕秸秆全量条带覆盖(T3)共4个处理,分析了不同处理对土壤理化特性及玉米生长发育、产量及其构成因素的影响。结果表明,与CK相比,保护性耕作处理(T1、T2和T3)0~20 cm耕层土壤有机质含量呈增加趋势;保护性耕作显著提高了播种至出苗期耕层土壤含水量,T1、T2和T3处理分别提高7.8%~30.4%、9.0%~18.7%和17.3%~20.0%,但显著降低土壤温度,分别降低2.56~3.11℃、2.02~2.27℃、0.94~1.93℃;分别延迟玉米出苗时间5~7 d、4~6 d和2 d;T3处理3年平均出苗率较CK增加3.2%,T1和T2处理出苗率分别降低4.3%和4.7%;T1、T2和T3处理均降低了苗期株高整齐度和植株干物质积累,但T3处理降低幅度明显小于T1和T2处理,6叶期之后干物质积累降低幅度逐渐减小;T1和T2处理显著降低玉米产量,降幅分别为7.5%~15.6%和5.5%~12.9%,T3处理产量与CK差异不显著。结构方程模型(SEM)揭示,保护性耕作通过调节土壤含水量和温度,间接影响玉米出苗时间、出苗率、穗数和百粒重,进而影响产量,也可通过直接影响出苗质量和产量构成因素进而影响产量。在东北典型黑土区,少耕秸秆全量条带覆盖(T3)不仅有利于提高土壤有机质含量,而且还有利于平衡土壤水分和温度矛盾,缩短出苗时间、提高出苗质量、高产稳产,是该区域适宜的保护性耕作方式。

区域协调发展与市场统一的法治保障

实现中国式现代化,需要统筹解决区域协调发展与市场统一问题,并加强相应的法治保障,对此有必要在“区域—市场—法治”的框架下展开分析。以东北地区为例,基于该地区在我国的重要地位及其存在的发展问题,应进一步推进市场化改革,并将其区域发展与区域市场建设有机结合,进而促进全国的区域协调发展和统一大市场建设。针对上述领域既往存在的法治问题,应明晰制度优化的重点,加强经济政策与经济法治的有效协调,从而在法治框架下推动区域协调发展与市场统一的相互促进,这有助于持续推进现代化经济体系建设和国家的整体现代化,深化区域经济学、经济法学、发展法学等领域的理论研究。

东北亚国家数字经济快速发展背景下中国数字经济发展的挑战和新路径

当前互联网、云计算、大数据、人工智能等新一代信息技术的创新和数字经济与传统产业的深度融合,使商业结构和行业理念发生了全面变化。全球传统产业加速向数字化、网络化、智能化转型升级,数字经济规模持续扩大。为应对全球数字化发展趋势,东北亚各国抓住数字经济快速发展带来的新机遇,聚焦数字经济发展,扩大合作不断向深度和广度延伸。本文从数字经济总体规模、数字基础设施建设、数字化政府建设转型、数字竞争力和ICT产业发展等五个方面详细梳理东北亚国家数字经济发展现状,分析域内各国数字经贸多领域合作中面临的挑战,在此基础上,探索东北亚国家数字经济快速发展背景下中国数字经济发展新路径,聚焦东北亚跨境数字服务贸易平台建设、中国东北—俄罗斯远东数字自贸区建设,释放高端智库论坛发展效能,抢抓数字时代东北亚区域经贸合作新机遇。

东北亚安全发展问题探析

东北亚各国经济相互依存,产业链供应链向横向与纵向深化,形成地区生产网络,构成了地区安全发展的价值轴。当前全球层面的大国竞争与“阵营化”投射至东北亚,日本和韩国追随美国“去风险”及“脱钩断链”,导致地区合作停滞且信任赤字不断累积,成为制约东北亚地区稳定繁荣的重要因素。以经济发展为中心是“一条和平发展的道路”,地区国家要看到安全发展的史之大、市之大、势之大、实之大、失之大,树立正确的历史观、大局观和角色观,更多从发展角度思考如何用地区新安全格局保障地区新发展格局,探索和重塑地区价值观,构建地区生产力和生产关系大发展的文化根基。

基于高分七号影像自动提取东北黑土区侵蚀沟的方法

东北黑土区沟蚀严重且分布面积广,目前对其进行监测大多基于目视解译,自动化程度低,急需一种快速提取方法。本文选取沟蚀严重的黑龙江省宾县马蛇子河流域,基于高分七号影像,以目视解译结果为参照,比较流向边缘检测、机器学习、深度学习3种方法自动提取侵蚀沟的精度。结果表明:①流向边缘检测方法依赖高精度地形数据,高分七号立体像对生成的地形数据垂直精度低,侵蚀沟整体提取精度仅为6.7%,无法用于切沟和浅沟的自动提取;②机器学习方法需要人为设置分割参数并设计分类特征,自动化程度较低,侵蚀沟整体提取精度可达50.7%,对切沟识别精度可达83.1%,但对浅沟识别精度仅为9.2%;③深度学习方法采用端对端的模式,无须人为设计特征提取器,自动化程度高,整体提取精度可达60.8%,对切沟识别精度可达68.1%,对浅沟识别精度可达69.7%。

中国东北黑土区地表土壤含水量时空分异特征研究

土壤含水量通过影响土壤养分循环进而控制植被分布格局,量化黑土区土壤含水量空间格局对于理解土地覆被特征及生态系统小气候变化等具有重要意义。本研究以Sentinel-1A双极化合成孔径雷达影像数据为基础,辅助同时段Sentinel-2光学影像数据,基于修正水云模型对东北黑土区不同土地覆被类型下复杂地表土壤含水量进行定量反演;借助MOD11A2和MOD13A3产品计算的温度植被干旱指数,挖掘东北黑土区土壤含水量时空变化特征及其控制因素。研究结果表明,借助VV极化的修正水云模型(R^(2)=0.75,R_(e)=0.015)反演东北黑土区土壤含水量精度最高,研究区内的土壤含水量具有较强的空间分异性,整体呈现偏干旱的状态,其中旱地的干旱现象最为严重,但随着时间的变化,干旱有减轻趋势;土壤含水量变化受降雨的影响高于温度,但研究区内复杂的环境致使干旱情况并不是受单一因素控制。

高校强化区域认同:优势、着力点与路径选择

“东北”既是地理概念,也指向超越行政区划的区域认同的存在,强化区域认同,留住人才是影响东北地区发展的重要因素。高校具有人才培养、科学研究、社会服务、文化传承与创新等多元职能,在促进和强化区域认同方面具有得天独厚的优势。高校在强化区域认同的过程中,应以分类协同为办学理念及定位原则,以共同体建设为组织依托,以文化认同为实践主着力点,从而体现自身在促进区域认同与区域发展中的主体地位和行为能力。

近二十年间国内清代东北社会经济史研究状况述评

东北地区作为清王朝的“龙兴之地”,其社会经济发展具有较高的研究意义。改革开放以来学界关于清代东北的矿业开发、商业、交通运输、农业、林业等诸多领域研究取得了巨大的进步。但同时在地区社会经济研究、民族区域间的交流联系研究、史料档案运用等仍需要进一步完善,需要广大学者更加详细的研究。