Land Management Policies Research Articles

Phenomenon of Non-Grain Production of Cultivated Land Has Become Increasingly Prominent over the Last 20 Years: Evidence from Guanzhong Plain, China

Cultivated land is the carrier of food production. As a populous country that regards cultivated land as the most valuable strategic resource, China has faced the challenge of the phenomenon of non-grain production of cultivated land (NGP) in recent years, which has attracted great attention from the Chinese government. Based on the cultivated land and grain data at the plot scale in 2000, 2010, and 2019, this study explored the evolutionary characteristics and spatial pattern of NGP in the Guanzhong Plain of Shaanxi Province from 2000 to 2019 with the Geographic Information System spatial analysis. The study found a clear trend in the spatial expansion of NGP in the past 20 years. In the 54 counties and districts of Guanzhong, there were different degrees of NGP, showing an annual expansion trend. The spatial agglomeration effect of NGP was significant. This study has important scientific value in understanding the phenomenon and patterns of non-grain production of cultivated land in China and provides a scientific basis for the formulation of cultivated land management policies.

Assessing the impact of global initiatives on current and future land restoration scenarios in India

Land degradation across the world has resulted in an unprecedented decline of ecosystem services, affecting the livelihood of 3.2 billion people globally. Sustainable land management is essential to protect our finite land resources from over-exploitation and degradation. Therefore, the present article was aimed to analyze the impacts of various national and international policies on current and future land restoration scenarios in India. A spatially explicit model (CLUMondo) was employed to predict scenarios, i.e., the ‘business as usual’ (BU) and ‘sustainable restoration’ (SR) by 2030. Though the results showed an increasing trend in land degradation , i.e., from 44.28 to 49.74 Mha during the period of 2005–15, a slight decrease was observed in 2019 (49.24 Mha), suggesting a net increase of 11.21% during the 2005–19 period. However, an increase in forest cover by 5.08% under existing policy targets overtook the degradation rate by restoration initiatives. The net decline in degraded land area by 1% with an increased forest cover by 1.83% observed during the 2015–19 periods reflected the positive impact of various national and global policies on existing restoration ventures in India. Our modeled results (weighted AUC = 0.87) also suggested an increase in forest cover by 6.9% and 9.9% under BU and SR scenarios, respectively. Under the BU scenario, degraded land will be restored up to 12.1 Mha; however, 6.27 Mha of these lands will be converted to cropland for food production. Importantly, a decrease in grasslands by 35.1% under the BU scenario warrants the urgency to maintain the integrity of such ecological systems. However, the SR scenario showed an increase in grasslands by 8.9%, with an overall restoration of degraded land up to 18.31 Mha. Moreover, a reduced cropland expansion rate of 1% suggested an effective land management response. While our results may have some uncertainties due to the model limitations, they can still be used for framing suitable land management policies to facilitate sustainable land restoration programs in India.

Temporal and spatial variation characteristics of vegetation coverage and quantitative analysis of its potential driving forces in the Qilian Mountains, China, 2000–2020

• The proportion of vegetation improvement area in QLMs reached 65.06% in the past 21 years, while 52% of the area will be continuously improved in the future. • The distribution of the NDVI in the QLMs maintained a high spatial agglomeration. • Annual sunshine duration is the main meteorological factor affecting vegetation change in Qilian Mountains. • The interaction between different driving factors can improve the explanatory power of vegetation changes compared with a single driving factor. Vegetation is an important indicator reflecting ecological environment stability, and monitoring vegetation change and understanding its potential driving force have important guiding significance for the adjustment and implementation of ecological restoration measures. As an ecological security barrier in northwest China, the Qilian Mountains (QLMs) play an important role in promoting the green development of social and economic development. Currently, the comprehensive driving effects of natural and anthropogenic factors on vegetation change in the QLMs are not clear. Based on the normalized difference vegetation index (NDVI), the spatiotemporal characteristics and trend changes in vegetation in the QLMs were systematically analyzed from 2000 to 2020 in this paper. The effects of natural and anthropogenic driving factors on vegetation change were explored using a geographic detector (GeoDetector). The results showed that the vegetation has improved continuously in the past 21 years, but the overall vegetation coverage was still low. The vegetation distribution was highly clustered, with a decreasing trend from east to west. Annual sunshine duration ( q statistic = 0.3347) and distance to the rivers ( q statistic = 0.2649) had the greatest explanatory power for vegetation change, while slope, aspect, and landform type had the least explanatory power. The interaction between elevation and sunshine duration, temperature and precipitation, temperature and sunshine duration, elevation and precipitation had the most explanatory power for vegetation change. Finally, we determined the ranges or categories of driving factors that were most suitable for vegetation growth by using a risk detector. The results of this study can help us further understand the potential driving mechanism of vegetation coverage variation in the QLMs and provide theoretical guidance for relevant managers to formulate ecological restoration measures and land management policies in the next step. It is of great significance to maintain the stability of the fragile ecological environment and prevent land degradation in arid and semiarid areas of Northwest China.

Rising agricultural water scarcity in China is driven by expansion of irrigated cropland in water scarce regions

Rising agricultural water scarcity in China is driven by expansion of irrigated cropland in water scarce regions

English

Barriers to successful transfer of contaminated land management policy from one country to another include socio-cultural, economic and environmental differences. While weak contaminated land management regimes desire effective legislation and make efforts to transfer policies from established regimes, contextual differences or characteristics between the two countries involved is a key challenge. These differing characteristics include social values, economic strength, governance structure, and technical know-how. An investigation was conducted through workshop and interviews to determine core social values that are impacted due to contaminated land by oil spills in the Niger Delta region of Nigeria. Workshop was undertaken for participants involving community groups (N=35), while interviews involved contaminated land management regulator (N=8), experts in contaminated land management in the Niger Delta (N=6), and operators in the oil exploration industry (N=7). Water quality, soil quality for agriculture, farming and fishing, and health/wellbeing indicated core social values that influence contaminated land management decisions while stakeholders expressed long-term concern about economic losses, clean-up, environmental degradation and public engagement. It is proposed that policymakers should consider unique conditions and country-specific characteristics in the event of policy adaptation for contaminated land management. An alternative approach to improving contaminated land management is recommended that will account for core social values and accommodate varying perceptions of stakeholders.   Key words: Socio-economic values, stakeholder participation, livelihood, drinking water, oil spills, stakeholders’ perception.

Geosite Assessment in the Beigua UNESCO Global Geopark (Liguria, Italy): A Case Study in Linking Geoheritage with Education, Tourism, and Community Involvement

The inventory and the assessment of geosites plays a very important role in highlighting scientific, geotouristic, and geoeducational potential, as well as the ability to identify any criticalities and vulnerabilities of the geological heritage of a territory. Within a geopark, these assessment activities are also crucial for developing land management strategies and policies that not only meet the need to protect geological and natural heritage, but also to promote sustainable economic development of the area and local communities. The Beigua UNESCO Global Geopark (Liguria, Italy) includes fifty-four sites known for their significant geological values. In this work, we have combined a study aimed at the qualitative and quantitative evaluation of 10 of the 54 sites with the results of an analysis of the educational, touristic, and land management activities that have been developed on these sites from 2011 to 2021. The quantitative assessment of the ten selected sites reveals their high scientific value and considerable touristic and/or educational potential. Thus, they represent not only scientific geological heritage to be preserved but also a significant tourism resource for the geopark territory. This is confirmed by the great success of geotouristic and geoeducational initiatives developed in the park over the last ten years, and by the growing involvement of the local communities, institutions, entrepreneurial activities, as well as environmental, sports, and cultural associations. These results highlight some important aspects for the management of geological heritage and associated values within a geopark.

Extraction of Rural Residential Land from Very-High Resolution UAV Images Using a Novel Semantic Segmentation Framework

Accurate recognition and extraction of rural residential land (RRL) is significant for scientific planning, utilization, and management of rural land. Very-High Resolution (VHR) Unmanned Aerial Vehicle (UAV) images and deep learning techniques can provide data and methodological support for the target. However, RRL, as a complex land use assemblage, exhibits features of different scales under VHR images, as well as the presence of complex impervious layers and backgrounds such as natural surfaces and tree shadows in rural areas. It still needs further research to determine how to deal with multi-scale features and accurate edge features in such scenarios. In response to the above problems, a novel framework named cascaded dense dilated network (CDD-Net), which combines DenseNet, ASPP, and PointRend, is proposed for RRL extraction from VHR images. The advantages of the proposed framework are as follows: Firstly, DenseNet is used as a feature extraction network, allowing feature reuse and better network design with fewer parameters. Secondly, the ASPP module can better handle multi-scale features. Thirdly, PointRend is added to the model to improve the segmentation accuracy of the edges. The research takes a plain village in China as the research area. Experimental results show that the Precision, Recall, F1 score, and Dice coefficients of our approach are 91.41%, 93.86%, 92.62%, and 0.8359, respectively, higher than other advanced models used for comparison. It is feasible in the task of high-precision extraction of RRL using VHR UAV images. This research could provide technical support for rural land planning, analysis, and formulation of land management policies.

Drivers and Implications of Land Cover Dynamics in Muger Sub-Basin, Abay Basin, Ethiopia

Research on the landscape level dynamics of land cover and an understanding of the drivers responsible for these changes are useful for formulations of sustainable land management strategies and policy decisions. The pace and magnitude of the LCCs in Ethiopia are threatening the natural ecosystem and creating vulnerability to environmental hazards. This study used a combination of remotely sensed data, field interviews, and observations to examine the dynamics and identify the driving forces of LCC from 1986 to 2020 in the Muger sub-basin, Ethiopia. Multi-temporal satellite images were classified using supervised and unsupervised methods. Information from focus group discussions and the variable ranking method were used to explain the drivers of the observed changes. The study results showed a decline in forest cover from 11.80% in 1986 to 5.90% in 2020, which indicates a loss of 49.90% of the forest cover that existed in 1986. Bare land declined from 1.15% in 1986 to 0.57% in 2020. Similarly, grazing land declined from 1.52% in 1986 to 0.41% in 2020. Wetland also declined from 1.93% in 1986 to 0.31% in 2020. Conversely, during the same period, the proportions of cultivated land, built-up areas, shrubland, and water bodies have risen from 68.86% to 70.44%, from 0.03% to 1.53%, from 14.39% to 20.27%, and from 0.34% to 0.56%, respectively. Population growth and poor agricultural practices were identified as the main causes of LCC in the sub-basin. Therefore, the findings of this study suggest that implementation of comprehensive and integrated basin management policies and strategies will be indispensable to managing the risks and ensuring sustainable development in the larger Abay basin.

Fire and forest loss in the Dominican Republic during the 21st Century

Forest loss is an environmental issue that threatens ecosystems in the Dominican Republic (the DR). Although shifting agriculture by slash-and-burn methods is thought to be the main driver of forest loss in the DR, empirical evidence of this relationship is still lacking. Since remotely sensed data on fire occurrence is a suitable proxy for estimating the spread of shifting agriculture, here I explore the association between forest loss and fire during the first 18 years of the 21st Century using zonal statistics and spatial autoregressive models on different spatio-temporal layouts. First, I found that both forest loss and fire were spatially autocorrelated and statistically associated with each other at a country scale over the study period, particularly in the western and central part of the DR. However, no statistical association between forest loss and fire was found in the eastern portion, a region that hosts a large international tourism hub. Second, deforestation and fire showed a joint cyclical variation pattern of approximately four years up to 2013, and from 2014 onwards deforestation alone followed a worrying upward trend, while at the same time fire activity declined significantly. Third, I found no significant differences in forest loss patterns between the deforested area of small (<1 ha) and large (>1 ha) clearings of forest. I propose these findings hold potential to inform land management policies that help reduce forest loss, particularly in protected areas, mountain areas, and the vicinity of tourism hubs.

Illegal land use by Italian firms: An empirical analysis through the lens of isomorphism

Illegal land use is an important environmental issue that is attracting increasing attention. Taking the neo-institutional literature as a starting point, this article outlines an approach focusing on illegal land use by firms. The pervasive nature of illegal land use is examined in terms of isomorphism, intended as imitative behaviour, in response to two kinds of environmental pressures: institutional pressure exerted by complementary institutions at local level, and market pressures, particularly the degree of uncertainty affecting certain sectors. Using a database mainly consisting of judgments handed down by the Italian Court of Cassation, this study argues that low quality of the local regulation and enforcement has a significant impact on the incidence and degree of seriousness of illegal land use, though a connection with the low quality of local governance has yet to be proven. In addition, the study highlights the fact that in sectors characterized by a high degree of uncertainty, the spread of illegal land use consists of practices of a more serious nature. An understanding of the extent to which firms replicate illegal land use with a similar degree of seriousness may help in the design of effective land management policies. Due to the complexity of the behaviour of firms a policy mix is suggested, including transparent rules, and fully functioning checks and balances, particularly local enforcement mechanisms. However, it is argued that better outcomes are more likely to be achieved by preventive measures in the sense of more acceptable land-use regulation and industry-specific measures.

Assessing Spatiotemporal Dynamics of Land Use and Cover Change and Carbon Storage in China’s Ecological Conservation Pilot Zone: A Case Study in Fujian Province

Many strategies have been put forward to seek green and low-carbon development, some of which are achieved through land use and cover change (LUCC). A series of land management policies related to LUCC and corresponding changes in carbon dynamics were released with the implementation of the Ecological Conservation Pilot Zone Program (ECPZP) in China. We explored the spatiotemporal dynamics of LUCC and carbon storage in the first ECPZP implementation region (Fujian province) at the time before and after ECPZP implementation using a simplified carbon pools model and quantified the relative impacts of human activities and climate change on net primary productivity (NPP) employing residual analysis. This can fill the gap of land use and vegetation changes and the corresponding carbon dynamics in the ECPZP region and can serve as a reference for future land management policy revisions and ECPZP project extensions. The results showed that: (1) In 1990–2020, woodland, cultivated land, and grassland were the leading land use type in Fujian province. The area of LUCC was 11,707.75 km2, and it was predominantly caused by the conversion from cultivated land to built-up land, and the interconversion between woodland and grassland. (2) An increase of 9.74 Tg in carbon storage was mainly caused by vegetation conversion from 1990 to 2020. (3) The statistically significant increased area of climate change-induced NPP was 2.3% primarily in the northwest, but the decreased area of it statistically significantly was only 0.1%. Correspondingly, the increased area of statistically significant human activity-induced NPP was 8.7% primarily in the southeast, but the decreased area of statistically significance was 6.5%, mostly in the central region. In addition, the statistically significant areas of NPP caused by the combination of human activities and climate change differed by 1.8%. To sum up, ECPZP makes full use of the vertical mountain landscape and property right reform to effectively secure ecological space and local income. Moreover, urbanization-related policies are an essential impetus for LUCC and carbon balance. The impact of other built-up land expansion on environmental change needs to be paid particular attention to. Moreover, land-use activities in the centre of the study region that are not conducive to NPP growth should be judiciously assessed in the future.

Spatial Pattern of Soil Erosion in Relation to Land Use Change in a Rolling Hilly Region of Northeast China

The black soil region in Northeast China is one of the major grain-producing areas of China. Soil erosion in the black soil region caused by natural factors and anthropic activities has attracted much attention, especially in a rolling hilly region. Compared with natural factors, the land use factor of cropland encompasses the most easily optimized measures. Jiutai County of Changchun City, located in the hilly areas of Northeast China, was taken as an example to calculate the soil erosion modulus using the Revised Universal Soil Loss Equation model. The overall soil erosion status of cultivated land in the study area was mainly slight and light, the proportion of cultivated land affected by extremely intensive and severe erosion was relatively small, and the average soil erosion modulus was 7.09 t·hm−2·a−1 in 2019. In view of spatial distribution characteristics of soil erosion revealed by the spatial aggregation and hot spot analysis, the most serious soil erosion intensity was concentrated in the southeast and northeast sloping farmland over 8°. With the increase in elevation and topographic slope, the proportion of slight and light soil erosion gradually decreased, which was closely related to the increase in soil erodibility caused by the space–time migration of soil organic carbon caused by the interaction of hydraulic and tillage erosion in complex topographic areas. The Geographically Weighted Regression model was introduced to explore the driving factors and superposition mechanism of farmland soil erosion in the hilly region of Northeast China. Based on the relationship between soil erosion and landscape fragmentation, landscape fragmentation was an important driving force promoting soil erosion, sediment yield, and sediment transport. This paper is committed to providing a basis for accurately deploying regional soil and water conservation measures and formulating macro land management policies.

Effects of land use type and tank components on soil properties and sustainability of tank cascade system in the Dry Zone of north central Sri Lanka

CONTEXTVillage tank cascade system (VTCS) is a globally important agricultural heritage system in Dry Zone watersheds of Sri Lanka. Lands in these watersheds have been under changing management conditions in the recent past, hence their sustainability has been suspected. OBJECTIVEObjectives of this study were to determine current status of soil properties in different land uses and tank components of a VTCS with respect to their position in the watershed, and to assess sustainability of this agricultural system using soil organic carbon management index (CMI) as a proxy. METHODSStudy was conducted in Mahakanumulla VTCS in North Central Dry Zone of Sri Lanka. Soil samples (n = 120) were collected from lands under forest, scrub/shrub, paddy and upland crops representing all elevations in two linear transects located in higher and lower positions along the main valley. Soils from components of tanks in upper and lower positions were also collected. Soil texture and some chemical properties were measured. The CMI in different land uses was calculated using total organic carbon (TOC) and permanganate oxidizable carbon contents. RESULTS AND CONCLUSIONSEffect of land use type on soil properties did not vary with position in the watershed (p > 0.05). An increase in available phosphorus and sulphur was observed in agricultural lands. Significant decreases in TOC (33%) and total N (43%) contents were observed in paddy lands compared to those of forest lands (p < 0.01). However, CMI indicated that management practices in paddy lands and upland soils are still sustainable but scrub/shrub lands need improvements to arrest their degradation. Electrical conductivity, pH, available P, K and Zn were significantly higher in lower positions while total N was lower. Thaulla (inundation area) and Perahana (filter) tank components had regulated flow of clay particles while Kattakaduwa (interceptor) has significantly high available P and TOC contents due to high wetness. Principal component analysis revealed factors that control soil erosion, soil organic matter content, water movement, cation availability and P dynamics governed the variability of major soil properties. Accumulation of soluble salts in lands of lower positions and increase of available plant nutrients in agricultural lands suggest that management practices so far adopted have slightly degraded soil fertility in this VTCS. SIGNIFICANCEFurther degradation of soils in lower positions and scrub/shrub lands in the watershed will negatively affect the livelihood of villagers and the environment. Hence, appropriate land management policies should be introduced to this agricultural system to ensure their sustainability.

Climate-Proof Planning for an Urban Regeneration Strategy

This paper deals with the issue of the relationship between climate change and the government’s land management policies, investigating how urban planning regulation may provide responses to the need for planning and designing the coastal urban settings affected by flooding phenomena as a consequence of gradual sea-level rise (SLR).In this frame of reference, comparison among the strategic planning experiences put into play in a variety of national and international settings suggests the urgency for policymakers to implement knowledge frameworks on planning instruments, in order to identify– as a prerequisite for defining site-specific design actions – the territorial settings affected by the phenomenon of flood risk.

Decoupling Relationship between Industrial Land Expansion and Economic Development in China

Economic expansion has caused increasingly serious land resource problems, and the decoupling of urban industrial land expansion from economic development has become a big topic for intensive development. The current research has mainly concerned industrial land efficiency, a single, static indicator, compared to a decoupling model, which takes into account two variables and gives a full expression of the spatio-temporal dynamic characteristics. However, little attention has been paid to the relationship between industrial land expansion and economic development in China from the perspective of decoupling. Based on a combination of Tapio‘s decoupling model and spatial analysis methods, this paper investigates the decoupling relationship between industrial land expansion and economic development in Chinese cities from 2010 to 2019. On that basis, we divided the study area into three policy zones and made differentiated policy recommendations. In addition, based on the decoupling model, we obtained the decoupling indices of the cities and grouped the cities into eight decoupling types. After the spatial autocorrelation analysis, we further verified the spillover effect of decoupling with the results of urban spatial differentiation. This paper draws the following conclusions: (1) Urban industrial land expansion and economic development exhibit marked and increasingly significant spatial heterogeneity and agglomeration. (2) Industry and economy are in weak decoupling in most cities, but there are a growing number of cities in negative decoupling. (3) Decoupled cities are shifting from the southeast coast to the middle and lower reaches of the Yellow River and Yangtze River, while negatively decoupled cities keep spreading from northeast and south China to their periphery, with clear signs of re-coupling. (4) It is necessary to develop urban industrial land supply and supervision policies according to local actuality and to implement differentiated control of industrial land for cities and industrial sectors with different decoupling types. To some extent, this paper reveals the evolution dynamics, performances, and strategies of industrial land, providing a decision basis for industrial land management policies and industrial planning in China and other countries at similar stages.

Monitoring Changes in Land Use Land Cover and Ecosystem Service Values of Dynamic Saltwater and Freshwater Systems in Coastal Bangladesh by Geospatial Techniques

Assessing and modeling the changes in land use and land cover (LULC) patterns and associated ecosystem service values (ESV) has become an important global agenda for formulating sustainable land management policies. Taking the coastal region of Bangladesh (CRB) as a case study, we utilized remote sensing and GIS techniques to analyze Landsat data of 1999 and 2019 to estimate the effect of LULC changes on the ESVs. The LULC classification, ESV quantification, and spatial variations were performed by semi-automated classification, per-unit value transfer, and spatial autocorrelation techniques, respectively. First, between 1999 and 2019, LULC altered dramatically (agricultural land and coastal wetlands decreased, while all other LULC types increased). Second, the total ESV decreased by 1.87%, which was mostly attributed to a 70% growth in both rural settlement and aquaculture/saltpan, and a 30% decline in both agricultural land and wetlands. Third, significant spatial correlation and moderately high spatial clustering were observed, which consisted mostly of mangrove forests, waterbodies, and wetland zones. Both high-high and low-low values increased, but spatial outliers remained unchanged. Conserving agricultural land should be prioritized in future land use plans of CRB to meet the ever-increasing food demands, control natural land conversion, and make land use sustainable.

Spatiotemporal Patterns in and Key Influences on Cultivated-Land Multi-Functionality in Northeast China’s Black-Soil Region

Cultivated-land multi-functionality has become an important way to achieve sustainable cultivated-land protection, and it has become a hot spot in the field of land-management policy. Taking the cultivated black soils in the grain-producing area of Jilin Province, Northeast China, as a case study, this paper assessed the multi-functions of cultivated land over the past 30 years by applying the improved TOPSIS model. Furthermore, the key limiting factors and influencing factors of the multi-functions of cultivated land were identified through the obstacle-degree model and the Geo-detector. The results show that the level of multi-functionality rose from 1990 to 2020, but an increase in both economic and social functions hindered improvements in the ecological function of cultivated land. There were obvious spatial differences in the functions of cultivated land in different counties, with ecological functions showing the highest degree of differentiation, followed by social and economic functions. The per capita agricultural output, the degree of agricultural mechanization, the average output from cultivated land, and the agricultural-labor productivity had the most restrictive effects on the functions of cultivated land, with barrier-degree values of 15.90, 13.90, 11.76, and 10.30, respectively. Coupling–coordination in the multi-functions and sub-functions of cultivated land showed an upward trend, from “low coupling coordination–antagonistic coupling coordination” to “high coupling coordination-optimal coupling coordination”. The government should include the level of multi-functional utilization in future policies for the management and utilization of cultivated land and take measures to reduce the differences in the functions of cultivated land among regions. Quantifying the multi-functional value of cultivated land and subsidizing land cultivation should encourage farmers to protect the land and help to strengthen multi-functional planning and functional design, improve ecological utilization, and promote the sustainable use of cultivated land.

China's Rural Areas toward 2035: Vision, Challenges and Strategies

Rural revitalization and development are mainly based on the urban-rural integration, which can be regarded as a key factor for China's rural land-use policy reform. This paper focuses on the research of the theory, technology, and management of rural revitalization from the perspective of the human-earth areal system. Firstly, this paper constructs the regional digital economy development evaluation index system according to the three-step selection process of indicators. Secondly, this research uses land engineering for land capacity building as the technical support to solve rural issues and constructs a framework of rural land management policy reform in China. Finally, the research results show that the consolidation of hollowed villages as well as gullied, degraded, and sandy land for highstandard farmland has been implemented, providing an important approach in improving land productivity. Collaboration among policymakers, multilateral organizations, and the private sector is crucial in filling gaps in solving the current problems.

The Relationship of Environmental Factors and the Cropland Suitability Levels for Soybean Cultivation Determined by Machine Learning

The relationship between cropland suitability and the surrounding environmental factors has an important role in understanding and adjusting agricultural land management systems to natural cropland suitability. In this study, the relationship between soybean cropland suitability, determined by a novel machine learningbased approach, and three major environmental factors in continental Croatia was evaluated. These constituted of two major land cover classes (forests and urban areas), utilized soybean growth seasons per agricultural parcels during a 2017–2020 study period and soil types. The sensitivity analysis in geographic information system (GIS) using a raster overlay method, along with auxiliary spatial processing, was performed. The proximity of soybean agricultural parcels to forests showed a high correlation with suitability values, indicating a potential benefit of implementing agroforestry in land management plans. A notable amount of suitable agricultural parcels for soybean cultivation, which were previously not utilized for soybean cultivation was observed. A disregard of crop rotations was also noted, with the same soybean parcels within the study period in three and four years. This analysis showed considerable potential in understanding the effects of environmental factors on cropland suitability values, leading to more efficient land management policies and future suitability studies.

Terrain Variables Based Spatial Mapping of Soil Properties in a Watershed of Himalayan Landscape Using Random Forest Model

Soil information, including their spatial variability is vital for devising various soil and land management policies and strategies as well as assessing the environmental impact of different land use changes. Among the various soil forming factors, terrain plays a vital role in determining the spatial distribution of soil properties especially in hilly terrains due to its impact on soil processes as well as the redistribution of soil materials. The study was carried out for assessing the applicability and efficiency of various terrain parameters for prediction as well as spatial mapping of different soil properties using Random Forest (RF) modeling approach, in a mid-Himalayan watershed located in Tehri Garhwal district, Uttarakhand. Field data collection was done by collecting soil samples from 0-15cm depth (surface layer) at 68 different locations in the study area, following a transect survey method. Collected samples were pre-processed and analyzed in the laboratory for estimating various soil properties such as sand, silt and clay contents as well as soil nutrients such as Soil Organic Carbon (SOC) and nitrogen (N). Fifteen terrain parameters derived by digital terrain analysis of CartoDEM of 10m spatial resolution were used as predictor variables during RF modeling. Pearson correlation analysis revealed poor linear relationship of soil properties with various terrain parameters. Variable importance ranking revealed that compound topographic index, elevation, heat load index, integrated moisture index and mean curvature are the most important variables, explaining maximum variability in different properties. The performance of RF models for predicting various soil properties were evaluated based on the coefficient of determination (R2), Root Mean Square Error (RMSE) as well as Lin’s Concordance Correlation Coefficient (CCC). The models were found to perform well with R2 and CCC values of 0.47 and 0.50 for sand, 0.52 and 0.55 for silt, 0.44 and 0.57 for clay, 0.41 and 0.36 for organic carbon and 0.55 and 0.34 for nitrogen, respectively. The validated models were further employed for generating the spatial distribution maps of various soil properties. Such attempts combining various environmental variables with machine learning based models may aid us in mapping the spatial distribution of various soil properties in the hilly mountainous terrains with considerable accuracies.