Dynamics of Saline-alkali Land and Its Ecological Regionalization in Western Songnen Plain, China

As the important reserve land resources for food production,saline-alkali land should play a significant role to ensure the national food security in the context of global food crisis. The western Songnen Plain is one of main distribution regions of saline-alkali land in China,with great potential in agricultural development. In this study,the extent,transformation,spatial distribution and temporal change of saline-alkali land in the western Songnen Plain during 1954–2005 were investigated by using remote sensing and GIS spatial analysis methods. Saline-alkali land change was detected from a temporal series of topographic maps in 1954,satellite images of Landsat MSS in 1976,Landsat TM/ETM in 1988,2000 and 2005 through artificial visual interpretation. The results indicated a significant expansion in saline-alkali land area and aggravation in salinization. The area of saline-alkali land had increased from 401.48×103 ha in 1954 to 1 097.45×103 ha in 2005. While the ratio of light,moderate and serious salinized land areas changed from 6.72︰2.92︰1.00 to 1.25︰1.06︰1.00 in the study period. Grassland,cropland,swampland and water body were the major land use and land cover types from which saline-alkali land transformed. And the secondary salinization occured mainly in Da′an City,Tongyu County,Changling County,Daqing City,Dorbod Mongolian Autonomous County and Zhaoyuan County. Finally,seven large ecoregions and 14 corresponding sub-ecoregions were delineated out based on spatio-temopral dynamic characteristics of saline-alkali land and geo-relational environmental attributes. According to the results,measures of amelioration and ways of development of saline-alkali land in the western Songnen Plain were put forward.

SUSTAINABLE AGRICULTURE DEVELOPMENT IN SALINE-ALKALI SOIL AREA OF SONGNEN PLAIN,NORTHEAST CHINA

There is great potential for agriculture in saline-alkali soil area in Songnen Plain, Northeast China. But the sustainable crop production in this area has been restricted by a few of main factors, such as less precipitation, h igher evaporation and frequent drought, high salinity and alkalinity, high excha ngeable sodium content and poor infiltration of the soil, and insufficiency and low availability in nutrition. It is also considered that there are a few of fav orable conditions for agricultural development in this region, such as sufficien t light and heat resources, rich ground water resources, plenty of manure produc ed by livestock, and so on. At the same time, scientific management and measurem ents have been employed; rational irrigation and drainage system has been establ ished; reclamation, amendment and fertilization of soil, and suitable strategies of cropping practices have been made for the sustainable development of agricul ture. Great progress has been made during 1996-2000.

Land Use/Cover Changes and Environmental Consequences in Songnen Plain,Northeast China

The Songnen Plain in Northeast China,one of the key national bases of agricultural production,went through remarkable land use/cover changes in recent years.This study aimed to explore the long-term land use/cover changes and the effects of these changes on the environment.The Landsat-based analysis showed that,during 1986-2000,cropland,built-up land and barren land had increased,among which cropland had the largest increase of 9,198km2 with an increase rate of 7.5%.Woodland,grassland,water body and swampland had decreased correspondingly,among which grassland had the most dramatic decrease of 6,127km2 with a decrease rate of 25.6%.The transition matrix results revealed that grassland,woodland and swampland were the three main land use types converted to cropland.Climate warming created the potential environment for the conversion of grassland and swampland into cropland.Land resources policy made by central and provincial governments of China affected the pattern and intensity of land use.Land use/cover changes accompanied by climatic variation brought out a series of environmental consequences,such as sand desertification of land,land salinization and alkalinization,grassland degradation,and more frequent floods.Under this circumstance,optimized land use structure and restoration measures are needed.

Effects of land use/cover change(LUCC) on the spatiotemporal variability of precipitation and temperature in the Songnen Plain,China

Understanding the effects of land use/cover change(LUCC) on regional climate is critical for achieving land use system sustainability and global climate change mitigation. However, the quantitative analysis of the contribution of LUCC to the changes of climatic factors, such as precipitation & temperature(P&T), is lacking. In this study, we combined statistical methods and the gravity center model simulation to quantify the effects of long-term LUCC on P&T in the Songnen Plain(SNP) of Northeast China from 1980–2018. The results showed the spatiotemporal variability of LUCC. For example, paddy field had the largest increase(15 166.43 km2) in the SNP, followed by dry land, while wetland had the largest decrease(19 977.13 km;) due to the excessive agricultural utilization and development. Annual average precipitation decreased at a rate of –9.89 mm per decade, and the warming trends were statistically significant with an increasing rate of 0.256°C per decade in this region since 1980. The model simulation revealed that paddy field, forestland, and wetland had positive effects on precipitation, which caused their gravity centers to migrate towards the same direction accompanied by the center of precipitation gravity, while different responses were seen for building land, dry land and unused land. These results indicated that forestland had the largest influence on the increase of precipitation compared with the other land use types.The responses in promoting the temperature increase differed significantly, being the highest in building land, and the lowest in forestland. In general, the analysis of regional-scale LUCC showed a significant reduction of wetland, and the increases in building land and cropland contributed to a continuous drying and rapid warming in the SNP.

Estimates of loss in ecosystem service values of Songnen plain from 1980 to 2000

Ecosystem services are premises for human beings to exist and develop in the world, and it is of importance to study effects of land use change on ecosystem functions. Songnen plain, located in Northeast China, is one of the national key bases for agricultural production. Because there were remarkable variations in land use in recent years, it can supply specific foundation for protection and restoration of regional eco-environment to explore changes in its values of ecosystem services. This study aims to qualify long-term changes in land use of Songnen plain from 1980 to 2000, and to explore the impact of land use change on ecosystem services. With 2-period land use data using RS and GIS, this paper analyzed changes in land use and in ecosystem service values using the ecosystem service value coefficients (VC) put forward by Costanza et al. Results showed that from 1980 to 2000, area of rangeland, water area and wetlands and area of cropland decreased, but urban area and unused land increased. Due to cropland's comparatively low VC and comparatively high VC of wetlands and water area, increment in cultivated land could not offset the total decrement in regional ecosystem service values because of the decrease in area of wetlands and water area. Meanwhile, city sprawl has also led to loss of ecological values. Total ecosystem service values of the study area reduced dramatically, from 34,926.10×106$ to 31,744.54×106$ in the period 1980-2000. This represents a 9.11% net decline in annual value of ecosystem services in the study area.

2005—2020年黑龙江省松嫩平原耕地低碳利用效率时空格局演变及影响因素

[目的]探究黑龙江省松嫩平原地区耕地低碳利用效率时空演变规律及影响因素,为保障国家粮食安全和低碳减排,实现农业可持续发展提供科学依据。[方法]借助超效率SBM模型测度2005—2020年黑龙江省松嫩平原地区33个县(市)耕地低碳利用效率,利用空间自相关和核密度估计方法分析各县(市)耕地低碳利用效率的时空格局演变特征,进而采用地理加权回归模型探究其影响因素。[结果](1)研究期内黑龙江省松嫩平原地区耕地低碳利用效率呈“升—降—升”演变态势,均值为0.80,未达到最有效生产的前沿。(2)从空间维度看,耕地低碳利用效率存在显著的正向空间相关性,且局部呈较强的高低值集聚分布态势,热点多核极化现象显著,主要分布于区域北部和南部;从时间维度看,耕地低碳利用效率表现出不同程度的极化特征,且内部差异呈逐渐缩小的演变趋势。(3)从影响因素看,人均播种面积、单位耕地面积化肥使用量、农村居民人均可支配收入和涉农支出对耕地低碳利用效率具有正向影响,复种指数、单位耕地面积机械使用量及城镇化率对效率呈负向影响,人均GDP对耕地低碳利用效率在不同年份影响程度和方向存在差异。[结论]黑龙江省松嫩平原地区耕地低碳利用效率整体呈上升趋势,且区域间存在明显差异,未来应优化资源配置效率,建立区域协同机制,发挥热点区域示范作用,助推各区域耕地低碳利用效率的提升。

Determination of land salinization causes via land cover and hydrological process change detection in a typical part of Songnen Plain

Causes of land salinization were determined via land cover and hydrological process change detection in a typical part of Songnen Plain. The area of saline land increased from 4627 km2 in 1980 to 5416 km2 in 2000, and then decreased to 5198 km2 in 2015. The transformation between saline land and other land covers happened mainly before 2000, and saline land had transformation relationship mainly with cropland, grassland, and water body. From 1979 to 2007, groundwater depth fluctuated to increase and was mainly deeper than 3.3 m. Spatially, the area of the region where groundwater depth was deeper than 3.3 m increased from 46.7% in 1980 to 84% in 2000, while the area of the region almost occupied the whole region after 2000. Precipitation and evaporation changed little, while runoff decreased substantially. Shallow groundwater, change of cropland, grassland, and water body induced from human activities and decrease of runoff and increase of irrigation and water transfer from outer basin were the main reasons for land salinization before 2000. After 2000, groundwater with relatively great depth could not exert great influence on land salinization. Protection of grassland and wetland prevented the increase of the area of saline land.

近50年来松嫩平原西部土地利用变化及驱动力分析

在遥感和地理信息系统技术支持下,对松嫩平原西部土地利用方式、景观格局的动态变化进行定量研究。结果表明:过去近50年里,松嫩平原西部耕地净增加29.65×104hm2,其中草地与湿地对耕地的增加贡献最大;草地减少70.29×104hm2,除部分草地转化为耕地外,退化为盐碱地、沙地也是草地大量减少的一个重要原因;松嫩平原西部现有沼泽湿地面积44.88×104hm2,近50年来减少62.54%。景观破碎化严重,不同土地利用类型间频繁转化,表明各种土地景观间存在不稳定因素,自然和人为因子在景观的转化中有不可忽略的作用,但人为因子的作用更显著。

松嫩平原西部盐碱地特点及合理利用研究

松嫩平原西部有盐碱化土地面积 373万 hm2 ,是世界三大片苏打盐碱地集中分布区之一 ,由于区域内独特的地貌条件、成土母质组成、气候条件、地下水水位及其含盐量等因素作用 ,尤其是近几十年人为因素的干扰 ,盐碱地面积增加 ,盐碱化程度加剧 ,重度盐碱化土地面积以每年 1.4 %的速度扩展 ,生态环境恶化 ,成为制约区域农业发展的重要因素。针对盐碱化旱田、盐碱化草地和盐碱化湿地的特点 ,提出采用低洼盐碱地种稻模式 ,盐碱湿地育苇—养鱼模式 ,盐碱湖泡养鱼 ,盐碱化旱田改土培肥、种植耐盐碱作物或牧草、微咸水淋洗和物理化学改良 ,盐碱化草地恢复等多种措施 ,遏制盐碱化的发展 ,改善生态环境 ,实现经济、生态和社会效益的协调发展。

松嫩平原盐碱化土地治理与农业持续发展对策

简介了松嫩平原盐碱化土地资源现状和盐碱化土地治理与改良利用的技术创新要点 ,并提出低洼易涝盐碱地开发水稻、盐碱化低产旱田改良、盐碱化草地恢复、盐碱湿地保育和盐碱泡沼养鱼的盐碱化土地治理对策。

松嫩平原西部土地退化的遥感动态监测研究——以吉林省通榆县为例

以松嫩平原西部土地退化典型地区———吉林省通榆县为例,在RS和GIS集成技术支持下,利用不同时相的TM数据,采用线性光谱混合模型方法,选用植被、盐碱地、裸沙地、沼泽地、苇地作为最终光谱单元进行线性光谱分解,依据盐碱地和沙地加权和分量,将试点区的土地退化划分为未退化、轻度退化、中度退化和重度退化四个等级进行动态监测,并分析土地退化的数量、空间分布与动态过程。

松嫩平原西南部土地碱质荒漠化预警研究

土地荒漠化是一个全球性的环境问题 ,其造成的资源丧失和环境破坏给人类带来了严重的危害 ,成为影响深远的缓发的生态环境灾害。笔者以松嫩平原西南部为例开展荒漠化预警研究 ,将地理信息系统与人工神经网络模型相结合 ,实现了对荒漠化发生的定位。

松嫩平原土地利用变化对区域生态系统服务价值的影响研究

应用遥感和GIS技术,在获取松嫩平原三期土地利用动态数据的基础上,分析了该地区土地利用变化与成因及其所引起的生态价值的变化。结果表明,从1986年到2000年,松嫩平原草地、水域和湿地面积大量减少,耕地、城镇用地和未利用地面积在增加。该地区总生态价值从1986年的34 926.10×106美元减少到2000年的31 744.54×106美元,减少率为9.11%,净损失值为3 181.56×106美元。1995-2000年的5年时间里,生态系统服务价值降低的趋势得到一定程度的缓和。对生态价值变化的空间区域分析表明,黑龙江省部分生态价值损失不大,而吉林省部分,特别是吉林西部环境脆弱带生态价值损失较多。

松嫩平原西部土地整理对盐渍化土壤的改良效果

为了研究松嫩平原西部土地整理对盐渍化土壤的改良效果，以吉林省白城市镇赉县土地整理项目区为研究区域，采用野外采样与室内分析相结合的方法，分析了原耕地、盐碱地和新增耕地土壤电导率、阳离子总量、阴离子总量、碱化度、pH值、有机质以及阳离子交换量等指标的差异。结果表明：在0～20和﹥20～40cm土层上，新增耕地土壤电导率显著低于盐碱地44.9%和37.0%（P＜0.05），显著高于原耕地35.7%和58.6%（P＜0.05）；新增耕地阳离子总量和阴离子总量均显著低于盐碱地（P＜0.05）；盐碱地土壤碱化度在37.0%～38.2%之间，pH值接近10.0，为重度碱化土壤，新增耕地土壤碱化度在18.0%～21.6%之间，pH值低于9.0，为中度碱化土壤，其土壤碱化程度与原耕地接近；新增耕地土壤有机质显著高于盐碱地33.4%和61.3%（P＜0.05），在0～20cm土层上显著低于原耕地21.5%（P＜0.05）；新增耕地阳离子交换量比盐碱地提高16.7%和25.1%（不显著，P＞0.05），同时显著高于原耕地4.8%和11.0%（P＜0.05）。典范对应分析表明，土壤盐渍化、肥力指标和土壤离子组成与样地类型分布存在着空间上的有序关系，样地类型由盐碱地向新增耕地的变化，在土壤理化性质层面是盐渍化指标降低、肥力指标升高的过程；在土壤离子组成层面是HCO3-、CO32-和Na＋等离子含量降低的过程。总体来看，松嫩平原西部土地整理能有效改良盐渍化土壤，但新增耕地土壤质量仍低于原耕地，建议在土地整理中通过完善灌溉与排水系统、将土地平整工程与深耕深松和增施有机肥相结合及采用生物措施等提升盐渍化土壤的改良效果。

松嫩平原西南部土地利用动态变化的分形研究

根据分形理论,采用二维欧氏空间分形维模型的计算方法,以TM卫星影像为主要数据源,在GIS支持下,计算出松嫩平原西南部地区在1989年、1996年和2001年主要土地利用类型的分形维数值、稳定性指数和相关景观指数。并根据分形维数和稳定性指数的物理意义及其与景观指数的关系,综合分析了研究区土地利用的动态变化规律。研究表明,水域、草地和湿地的稳定性相对较差,是较脆弱的土地利用类型;除林地外,其它各土地利用类型的稳定性均呈下降趋势,气候干旱和人类不断强化的经济活动对生态环境系统的影响显著,需加大对研究区生态环境修复和重建工程研究和投资的力度。

松嫩平原西部生态脆弱区土地利用时空变化研究

基于 1 986年和 2 0 0 0年 2期TM影像资料 ,在空间图形库系统支持下 ,分析了该区土地利用数量变化、土地利用空间组成变化、空间邻接关系变化和变化主导类型 ,揭示了 1 986～ 2 0 0 0年间松嫩平原西部生态脆弱区土地利用时空变化特征 .结果表明 ,此间林地、草地不断破碎化 ,耕地、盐碱地从整体上呈现集中化特征 .耕地与草地、草地与盐碱地空间相邻度增大 ,草地开垦过快和土地盐碱化日益严重 .土地利用空间变化内在过程基本以旱地 -水田 ,草地 -旱地 ,草地 -未利用地相互转化为主导 .

松嫩平原近20年土壤盐渍化动态变化及驱动力分析

利用1986年(TM)和2001年(ETM)卫星遥感影像数据和RS-GIS集成技术,对松嫩平原盐渍化土地的现状、程度和发展趋势进行了量化分析.结果表明,这15年中,松嫩平原盐碱地面积增加了21.7112×104hm2,每年增加1.45×104hm2,年平均增长率为1.4%.其中轻度盐渍化土地增加8812hm2,年平均增长0.16%;中度盐渍化土地增加3.8306×104hm2,年平均增长0.64%;重度盐渍化土地面积增加了16.9994×104hm2,年平均增长了4.2%.气候变暖,降水减少,人为活动增强是盐渍化程度加重的主要驱动力.

松嫩平原西部地区土地利用/覆被变化的驱动力分析

利用1986年和2000年两期TM影像资料,在空间图形库系统支持下全面分析了松嫩平原西部地区土地利用/覆被数量变化和土地利用空间格局变化,揭示了近15年来研究区土地利用时空变化特征。表现为耕地、盐碱地从整体上呈现集中化,林地、草地不断破碎化。耕地与草地、草地与盐碱地空间相邻度增大,草地开垦和土地盐碱化日益严重。对不同经济类型区即农区、半农半牧区和牧区土地利用变化的社会经济因素的区域相似性和差异性分析表明,人口的压力、落后的畜牧业和经济利益驱动是近15年该区土地利用变化的主导因素。

松嫩平原土地盐碱化动态研究——以农安县为例

结合地形图、遥感影像以及土壤专题图,提取松嫩平原典型代表区域——农安县近40年盐碱化土地面积动态变化信息,结合土地动态度模型和质心移动模型,对农安县近40年来盐碱化土地动态变化进行了较为全面的研究,分析了土地盐碱化动态的自然和人为驱动力因素,提出合理利用土地的建议。

土地利用变化对松嫩平原腹地生态系统服务价值的影响

应用1989年和2000年Landsat TM影像解译数据分析松嫩平原腹地土地利用变化情况,制定单位面积生态系统服务价值系数,计算松嫩平原腹地生态系统服务价值,研究土地利用变化对生态系统服务价值的影响。结果表明,在11 a间,松嫩平原腹地土地利用变化呈现耕地、城镇用地、碱地、林地、沙地迅速增加,草地、水域和湿地大幅度减少的“5增3减”趋势。土地利用景观格局的变化降低了生态系统的服务功能,使其生态系统服务总价值从1366.070亿元/a下降到1017.044亿元/a。