Application of GIS in Ecological Land Type(ELT)mapping--A case in Changbai Mountain area

This paper depicted the physiographic landscape features and natural vegetation situation of study area (the eastern Jilin Province), and expatiates the definition, basic characters and its development of Ecological Land Classification (ELC). Based on the combination of relief map, satellite photography for study area and vegetation inventory data of 480 sample sites, a 5-class and a 15-class ecological land type map was concluded according to 4 important factors including slope, aspect, vegetation and elevation. Ecological Classification System (ECS) is a method to identify, characterize, and map ecosystems. The Ecological Land Type (ELT) was examined and applied initially in eastern Jilin Province.

Effects of Different Land Use Types on Soil Organic Carbon and Carbon Management Index in Karst Area

[Objective] The aim was to reveal changes of soil organic matter fraction and their corresponding carbon management indexes as affected by different land use types.[Method]Soil organic carbon,active soil organic carbon and soil carbon management index（CMI）of different land use types in Guilin Maocun karst area were studied.Sampling with field investigation and laboratory testing was carried out.Heavy potassium chromate method was adopted to determine soil organic matter.333 mmol/L KMnO4 oxidation method was used to determine active organic carbon.[Result]With active soil organic matter increasing,the differences of CMI between different land use types were bigger.The CMI value of different land uses was shrubforest paddy fielddry farmland.The statistical analysis showed that labile organic matter was related with major soil properties at a significant level.[Conclusion]Labile organic matter could be used to reveal the influence of different land use types on soil organic matter and carbon management index in karst area.

Study on Influences of Different Land Use Types on Soil Qualities in Plateau Karst Depression

[Objective] The aim was to study influences of different land use ways on soil qualities in plateau karst depression.[Method] Different land use types were divided by topographic map of 1∶10 000 scales and soil properties of physics and chemistry were analyzed.[Result] The results showed that the variation trend of soil depth(A+B stratum)was slope plough(include returning farm to forest)land>natural forest land>planted forest land>shrub forest land,and relative indexes changing regularities of soil...

Soil Moisture Characteristics in Karst Area with Different Land Use Types

Ecological efficiency changes of soil moisture were researched in karst areas with different land type uses, including farmland, abandoned farmland （1 y） and shrub land （1 y）, sparse wood land （15 y）, secondary forest （25 y） and the re- sults showed that physical property of soil was not a simple ＂improvement＂ process during land type evolution. Specifically, from farmland to secondary forest, the con- tent of topsoils changed from being washed away to accumulation and soil bulk density changed from increasing to decreasing. For example, soil bulk densities of abandoned farmland and shrub land increased by 6.6% and 11.57% compared with farmland, and of sparse wood land and forest land decreased by 5.0% and 10.0%. The change trend of soil bulk density was just in contrary to total porosity. Available water capacity was the lowest of shrub land, but increased in rest land types. The increase tended to be volatile in 5.1%-12.5% of different land types and water-sta- ble aggregate content （〉0.25 mm） reached the highest of sparse wood land. The destruction rate, however, was declining in the process of land type evolution and the increase was in the range of 34.0%-64.7% compared with farmland. The de- struction rate of aggregate was of negative correlation with organic matter. Water- holding capacity was the best of forest land and abandoned farmland and the poor- est of shrub land, close to sparse wood land. Water-supplying capacity from high to low was as follows： farmland〉sparse wood land〉secondary forest〉shrub land〉a- bandoned farmland. It is obvious that water-holding capacity and water-supplying capacity are not consistent, but both are closely related to the content of soil clays, porosity, and aggregate stability.

Land use change and its driving factors in the ecological function area:A case study in the Hedong Region of the Gansu Province,China

Land use and cover change(LUCC)is important for the provision of ecosystem services.An increasing number of recent studies link LUCC processes to ecosystem services and human well-being at different scales recently.However,the dynamic of land use and its drivers receive insufficient attention within ecological function areas,particularly in quantifying the dynamic roles of climate change and human activities on land use based on a long time series.This study utilizes geospatial analysis and geographical detectors to examine the temporal dynamics of land use patterns and their underlying drivers in the Hedong Region of the Gansu Province from 1990 to 2020.Results indicated that grassland,cropland,and forestland collectively accounted for approximately 99% of the total land area.Cropland initially increased and then decreased after 2000,while grassland decreased with fluctuations.In contrast,forestland and construction land were continuously expanded,with net growth areas of 6235.2 and 455.9 km^(2),respectively.From 1990 to 2020,cropland was converted to grassland,and both of them were converted to forestland as a whole.The expansion of construction land primarily originated from cropland.From 2000 to 2005,land use experienced intensified temporal dynamics and a shift of relatively active zones from the central to the southeastern region.Grain yield,economic factors,and precipitation were the major factors accounting for most land use changes.Climatic impacts on land use changes were stronger before 1995,succeeded by the impact of animal husbandry during 1995-2000,followed by the impacts of grain production and gross domestic product(GDP)after 2000.Moreover,agricultural and pastoral activities,coupled with climate change,exhibited stronger enhancement effects after 2000 through their interaction with population and economic factors.These patterns closely correlated with ecological restoration projects in China since 1999.This study implies the importance of synergy between human activity and climate change for optimizing land use via ecological patterns in the ecological function area.

Structural patterns of land types and optimal allocation of land use in Qinling Mountains

The case study based on Qinling Mountains in Shaanxi Province of China, in virtue of the information from TM image, classifies the land types and analyzes their spatial and temporal differential law, and puts forward three structural patterns of land types in mountainous areas, namely, spatial, quantitative and qualitative structures of mountainous land types. Furthermore, it has been noticed that the analysis of structural patterns can disclose the heterogeneity and orderliness of combination of land types, which can lay the theoretic foundation for comprehensively recognizing ecological characteristics and succession law of structure and function of land types. After the all-around comparative analysis, an optimal allocation of land use in Qinling Mountains has been put forward according to the principle of sustainable development and landscape ecology, which can lay the scientific foundation in practice for the structural adjustment and distribution optimization from the macro level to micro level.

Soil Erosion under Different Land Use Types and Zones of Jinsha River Basin in Yunnan Province,China

Severe soil erosion in the middle and upper reaches of Yangtze River has been regarded as a major environmental problem. The on-site impact of soil erosion on agricultural production and the off-site impact on floods and sedimentation in Yangtze Rive are well known. A quantitative assessment of soil erosion intensity is still scanty for developing appropriate soil erosion control measures for different land use types and zones in this region. This article constructs a localized USLE and estimates the average soil loss in the Jinsha River Region in Yunnan Province, one of the priority areas for soil erosion control in the middle and upper reaches of Yangtze River. The estimation is done under different land uses and zones in this basin. The estimation shows that while soil erosion in the cultivated land is the most severe, 36～40% of the garden and forest land suffers from soil erosion of various degrees due to lack of ground cover and other factors. Soil erosion in the pasture is modest when the ground cover is well maintained. It also confirmed that terracing can reduce soil erosion intensity significantly on the cultivated land. Research findings suggest that sufficient attention must be paid to regeneration of the ground cover in reforestation programs. In addition to mass reforestation efforts, restoration of grassland and terracing of the cultivated land should also play an important role in erosion control.

Elevation and Land Use Types Have Significant Impacts on Spatial Variability of Soil Organic Matter Content in Hani Terraced Field of Yuanyang County,China

Soil organic matter （SOM） content is one of the most important indicators of the sustainability of soil. To maintain sustainable soil utilization and management in fragile Hani terraced field, it is meaningful to investigate the effects of topography and land use type on SOM content. Descriptive statistics and geostatistics were used to analyze the data and the kriging method was applied to map the spatial patterns of SOM content. The results showed that the mean SOM content was 32.76 g/kg, with a variation coefficient of 40%. The SOM content was affected by elevation and land use type. As the increase of elevation, the SOM content in Hani terraced field also increased obviously. The SOM content in tea garden, which is almost at high elevation, was the highest in all six land use types, and the SOM content decreased in a following sequence： tea garden 〉 paddy field 〉 corn field 〉 banana garden 〉 cassava field 〉 sugarcane field. In addition, at the same elevation, the paddy field had the highest SOM content compared with other land use types. All these results demonstrate that paddy field is the most efficient and suitable land use type for SOM conservation at high, middle or low elevations in the fragile Hani terraced field. In order to protect soil quality and maintain the sustainable agricultural development, it is necessary to maintain or even to enlarge the area of paddy field in Yuanyang county, Yunnan Province, China.

Surface Brightness Temperature Variation of Different Land Use Types

[Objective] The aim of this study is to investigate the surface brightness temperature variation of different land use types.[Method] Based on MODIS data in 2008 and IGBP land classification system,the surface brightness temperature in the Yangtze River Delta area was calculated,and its rules and reasons were also discussed in this study.[Result] Different land use types had its own special brightness temperature variation.During the day,the brightness temperature was as follows：grassland or urban and built-up landcropland,forest land and barrenwetland and water.During the night,the brightness temperature was as follows：water,wetland and barrengrassland or urban and built-up landforest land and cropland.Brightness temperature showed the trend of high in summer and low in winter or increasing in spring and decreasing in fall.The characteristics of surface thermal radiation could be reflected better by brightness temperature at night.Solar radiation,mixed pixel,heat capacity,water content were the main reasons for the difference of brightness temperature in different land types.[Conclusion] The brightness temperature variation of different land use types has significance for water content analysis in soil and dynamic monitoring of land use.

Soil Physical Properties of Different Land Use Types in Loess Hilly Region

[Objectives]To explore the impact of land use changes on physical properties of soil in loess hilly region.[Methods]The methods of field sampling and indoor analysis were adopted.Farmland in a small watershed in the middle of the Loess Plateau,grassland that had been abandoned for 7 years,grassland that had been abandoned for 30 years,jujube orchard and ditch were sampled,and the particle composition(clay,silt and sand)and moisture changes of the soil in the top 0-100 cm were studied.[Results]In the small watershed,the top 0-100 cm of the soil was composed of 14%clay,70%silt and 16%sand.The contents of clay,silt and sand in the grassland that had been abandoned for 30 years varied greatly,while varied little in the land of other use types.The soil moisture content of grassland that had been abandoned for 30 years,jujube orchard,grassland that had been abandoned for 7 years,farmland and ditch increased with the increase of depth,with means of 10.29%,11.66%,10.08%,11.43%and 11.34%,respectively.[Conclusions]This study provides a theoretical basis for the growth of crops of different land use types in the loess hilly region.

Efficiency Assessment of Land Use Types in Tan Binh Commune,Dak Doa District,Gia Lai Province,Vietnam

Land resource depletion causes a range of consequences,such as threats to food security,increasing poverty,and social unrest.Therefore,reasonable and effective land use has become a crucial issue of the nation and localities nationwide.Research results in Tan Binh commune,Dak Doa district,Gia Lai Province in Vietnam showed that long-term industrial and agricultural land occupies most of the commune's agroforestry land.The study also had shown that there are six common land use types(LUTs)in the commune.In particular,the LUT of pepper cultivation had the highest economic benefit,whereas the LUT of coffee brought the highest social benefit.However,the LUT of chayote was the highest in overall benefits with Ect of 0.93;thus,this LUT should be widely applied throughout Tan Binh commune.The research results were a crucial scientific basis for proposing a group of suitable plants to local natural conditions to bring effective and sustainable efficiency in land-use types.

Responses of soil aggregate stability and soil erosion resistance to different bedrock strata dip and land use types in the karst trough valley of Southwest China

Soil aggregate stability is an important index that reflects soil quality and anti-erosion ability and strongly affects soil processes and functions.Bedrock strata dips(dip and anti-dip slopes)and land use types primarily influence soil aggregate stability,whereas the detailed mechanisms are unclear in karst trough valley.Therefore,to explore the effects of bedrock strata dip and land use type on soil aggregate stability in karst trough valleys,soils were collected from five major land use types(abandoned land,grassland,pepper fields,corn fields and forest)on dip and anti-dip slopes.The soil was fractionated into macroaggregates and microaggrates using dry and wet sieving analysis.The soil particle size distribu-tions in the macroaggregates and microaggregates were measured in conventional laboratories.The results showed significant differences in soil aggregate stability among different bedrock strata dips,slope positions,and land use types(P<0.05).The variation ranges of macroaggregates and micro-aggregates in the pepper fields of the dip slope were higher than those on the anti-dip slope.Comparing all land use types,the forest of the anti-dip slope had>0.25 mm water-stable aggregates(85.31%)and mean weight diameter(2.67 mm)on the upper slope compared to that in the other slope positions of the dip slope.In addition,the dip slope had a higher percentage of aggregate destruction(35.57%)than the anti-dip slope(29.81%),and the soil erodibility factor value of the natural forest of the dip/anti-dip slope was significantly lower than that of the other land use types(P<0.05).When the content of large macroaggregates was larger,the soil macroaggregate weight was greater.When the failure rate of the soil aggregates was lower,the stability of the soil structure was better.Overall,these results suggest that natural forests can significantly improve the stability of soil aggregates,thereby improving soil erosion resistance.Therefore,natural recovery measures should be implemented on dip/anti-dip slopes of karst trough valleys.

Study on the Remote Sensing of Surface Albedo in the Horqin Sand Land

The surface albedo which is affected by the earth surface coverage or other surface characteristics is one of the important factors impacting remote sensing image information and therefore it can be calculated by integrating land coverage types with information of remote sensing images.Horqin sand land which was taken as an experimental area for study on Landsat-TM topography and atmospheric correction,then the Landsat-TM data inversion formula established by Liang was used to calculate the experimental zone albedo map;correlation analysis was performed to the surface albedo map and the land-use maps which was acquired by supervision and classification.The results revealed significant relations between land-use types and the surface albedo of study area.Additionally,the surface albedo and NDVI of the study area were statistically analyzed to obtain the study area's surface albedo and NDVI dependent equation.

Effect of Reclamation Time and Land Use on Soil Properties in Changjiang River Estuary,China

The objective of this study is to analyze soil physical and chemical properties,soil comprehensive functions and impact factors after different years of reclamation.Based on the survey data taken from 216 soil sampling points in the Fengxian Reclamation Area of the Changjiang (Yangtze) River Estuary,China in April 2009 and remotely sensed TM data in 2006,while by virtue of multivariate analysis of variance (MANOVA),geo-statistical analysis (GA),prin-cipal component analysis (PCA) and canonical correspondence analysis (CCA),it was concluded that:1) With the in-crease in reclamation time,soil moisture,soil salinity,soil electric conductivity and soil particle size tended to decline,yet soil organic matter tended to increase.Soil available phosphorous tended to increase in the early reclamation period,yet it tended to decline after about 49 years of reclamation.Soil nitrate nitrogen,soil ammonia nitrogen and pH changed slightly in different reclamation years.Soil physical and chemical properties reached a steady state after about 30 years of reclamation.2) According to the results of PCA analysis,the weighted value (0.97 in total) that represents soil nutrient factors (soil nitrate nitrogen,soil organic matter,soil available phosphorous,soil ammonia nitrogen,pH and soil particle size) were higher than the weighted value (0.48 in total) of soil limiting factors (soil salinity,soil elec-tric conductivity and soil moisture).The higher the F value is,the better the soil quality is.3) Different land use types play different roles in the soil function maturity process,with farmlands providing the best contribution.4) Soil physi-cal and chemical properties in the reclamation area were mainly influenced by reclamation time,and then by land use types.The correlation (0.1905) of the composite index of soil function (F) with reclamation time was greater than that with land use types (-0.1161).

The Heterogeneity and Its Influencing Factors of Soil Nutrients in Peak-Cluster Depression Areas of Karst Region

By selecting a typical peak-cluster depression area of karst region in Southwest China, we evaluated the effect of land use types and topographic factors on soil nutrients. Grid and line sampling methods were used to sample soil in depression and slope lands respectively, and classical statistical tools were applied to analyze the spatial variability character of soil organic carbon （SOC）, total nitrogen （TN）, total phosphorus （TP）, total potassium （TK）, available nitrogen （AN）, available phosphorus （AP）, available potassium （AK）, pH, and C/N. It was found that land use type was the dominant factor that effected the spatial heterogeneity of SOC, TN, TP, TK, AN, and AP. The content of SOC, TN, and AN decreased with the increase of land use intensity. Due to high fertilizer input, TP and AP in tillage fields were higher than those in the other land use types. TK had no obvious change trend among various land use types. Topographic factors had a significant effect on SOC, TN, TP, AN, AP, AK, and pH. Habitat factor was the dominant factor that effected AK. Altitude factor was the dominant factor for pH. However, all of these factors had no significant effect on C/N. Tillage practice had important effect on soil nutrients loss and soil degradation in the fragile karst ecosystem, and the input of organic manure should be increased in this region.

Effects of Land Cover on Soil Organic Carbon Stock in a Karst Landscape with Discontinuous Soil Distribution

Land cover type is critical for soil organic carbon （SOC） stocks in territorial ecosystems. However, impacts of land cover on SOC stocks in a karst landscape are not fully understood due to discontinuous soil distribution. In this study, considering soil distribution, SOC content and density were investigated along positive successional stages （cropland, plantation, grassland, scrubland, secondary forest, and primary forest） to determine the effects of land cover type on SOC stocks in a subtropical karst area. The proportion of continuous soil on the ground surface under different land cover types ranged between 0.0% and 79.8%. As land cover types changed across the positive successional stages, SOC content in both the 0-20 cm and 20-50 cm soil layers increased significantly. SOC density （SOCD） within O-lOO cm soil depth ranged from 1.45 to 8.72 kg m^-2, and increased from secondary forest to primary forest, plantation, grassland, scrubland, and cropland, due to discontinuous soil distribution. Discontinuous soil distribution had a negative effect on 8OC stocks, highlighting the necessity for accurate determination of soil distribution in karst areas. Generally, ecological restoration had positive impacts on SOC accumulation in karst areas, but this is a slow process. In the short term, the conversion of croplandto grassland was found to be the most efficient way for SOC sequestration.

Spatio-temporal variations of vegetation carbon use efficiency and potential driving meteorological factors in the Yangtze River Basin

Understanding of the vegetation dynamics is essential for addressing the potential threats of terrestrial ecosystem.In recent years,the vegetation coverage of the Yangtze River Basin(YRB)has increased significantly,yet the spatio-temporal variations and potential driving meteorological factors of carbon use efficiency(CUE)under the context of global warming are still not clear.In this study,MODIS-based public-domain data during 2000–2015 was used to analyze these aspects in the YRB,a large river basin with powerful ecological functions in China.Spatio-temporal variations of CUE in different sub-basins and land cover types were investigated and the correlations with potential driving meteorological factors were examined.Results revealed that CUE in the YRB had strong spatiotemporal variability and varied remarkably in different land cover types.For the whole YRB,the average CUE of vegetated land was 0.519,while the long-term change trend of CUE was obscure.Along the rising altitude,CUE generally showed an increasing trend until the altitude of 3900 m and then followed by a decreasing trend.CUE of grasslands was generally higher than that of croplands,and then forest lands.The inter-annual variation of CUE in the YRB is likely to be driven by precipitation as a strong positive partial correlation between the inter-annual variability of CUE and precipitation was observed in most of sub-basins and land cover types in the YRB.The influence of temperature and relative humidity is also outstanding in certain regions and land cover types.Our findings are useful from the view point of carbon cycle and reasonable land cover management under the context of global warming.

Sustainable land-use patterns for arid lands: A case study in the northern slope areas of the Tianshan Mountains

Sustainable land use patterns are ecological and economic prerequisites of regional sustainable development. This is especially true for arid lands, where the environment is wholly fragile thanks to extremely limited precipitation, and where human activities have greatly transformed natural desert system by clearing natural vegetation, expanding oases and even building dams on inland rivers. However, the current studies on land use patterns are still characterized by field investigations and case studies, with almost no solid scientific basis. This paper holds that land types and their combination patterns are the principal basis for designing sustainable land use patterns, and that GIS and RS-based large-scale land type mapping and the study of their spatial combination structures should be coordinated with the demand of social development. The existing environmental problems induced by irrational land use mostly result from their deviation from the natural properties of land types. Taking the northern slope of the Tianshan Mountains （NSTM） as an example and considering land type patterns as the basis of land use patterns, this paper improves the vertical oa- sis-and-mid-mountain two-belts development model and the sustainable mountain land use model for arid lands put forward in recent years; and in terms of oases patterns, it outlines oasis development models, including intensive land use pattern in alluvial-diluvial fans, moderate agricultural development pattern in alluvial plains, and ecological land use pattern in river-end oases.

Detecting Global Vegetation Changes Using Mann-Kendal(MK) Trend Test for 1982–2015 Time Period

Vegetation is the main component of the terrestrial ecosystem and plays a key role in global climate change. Remotely sensed vegetation indices are widely used to detect vegetation trends at large scales. To understand the trends of vegetation cover, this research examined the spatial-temporal trends of global vegetation by employing the normalized difference vegetation index(NDVI) from the Advanced Very High Resolution Radiometer(AVHRR) Global Inventory Modeling and Mapping Studies(GIMMS) time series(1982–2015). Ten samples were selected to test the temporal trend of NDVI, and the results show that in arid and semi-arid regions, NDVI showed a deceasing trend, while it showed a growing trend in other regions. Mann-Kendal(MK) trend test results indicate that 83.37% of NDVI pixels exhibited positive trends and that only 16.63% showed negative trends(P < 0.05) during the period from 1982 to 2015. The increasing NDVI trends primarily occurred in tree-covered regions because of forest growth and re-growth and also because of vegetation succession after a forest disturbance. The increasing trend of the NDVI in cropland regions was primarily because of the increasing cropland area and the improvement in planting techniques. This research describes the spatial vegetation trends at a global scale over the past 30+ years, especially for different land cover types.

Changes in soil carbon stocks and related soil properties along a 50-year grassland-to-cropland conversion chronosequence in an agro-pastoral ecotone of Inner Mongolia,China

Land use change significantly influences soil properties. There is little information available on the long-term effects of post-reclamation from grassland to cropland on soil properties. We compared soil carbon （C） and nitrogen （N） storage and related soil properties in a 50-year cultivation chronosequence of grassland in the agro-pastoral ecotone of Inner Mongolia. Field surveys on land use changes during the period of 1955-2002 were conducted to build a chronosequence of cropland of different ages since the conversion from grassland. The results showed that soil C and N storage, soil texture, and soil nutrient contents varied with land use types and cropland ages （P〈0.01）. In the 0-30 cm soil layer, the soil organic carbon （SOC） density was significantly lower in the crop- lands （3.28 kg C/m2 for C50 soil） than in the grasslands （6.32 kg C/m2）. After 5, 10, 15, 20, 35, and 50 years of crop planting （years since the onset of cultivation）, the SOC losses were 17%, 12%, 19%, 47%, 46%, and 48%, respec- tively, compared with the grasslands. The soil total nitrogen （TN） density of the grasslands was 65 g N/m2, and TN density of the cropland soil was 35 g N/m2 after 50 years of crop planting. Both the SOC and TN densities could be quantitatively determined by a negative exponential function of cropland age （P〈0.0001, R2=0.8528; P〈0.0001, R2=0.9637）. The dissolved organic carbon （DOC） content, pH value were decreased; and the soil bulk density and soil available potassium （AK） content, clay content, and sand content were increased since the conversion of grassland into cropland during the 50-year period. Our results show soil nutrients were higher in grassland than in cropland. The conversion of grasslands to croplands induced a loss of soil C storage and changes of related soil properties. The reclamation time of cultivated soil （cropland age） had significant effects on soil properties in the study area.