Land Units Research Articles

The impact of air pollution on urban land price and willingness to pay for clean air - Evidence from micro level land transactions in China

We investigate the impact of air pollution on land prices by combining Chinese micro level land transaction data and PM2.5 concentrations grid data, and evaluate the marginal willingness to pay (MWTP) for clean air through the hedonic price model. The empirical results show that air quality improvement significantly increases the land unit price, and the MWTP value for clean air is estimated to be USD 32.08–33.13/m2 after controlling for variables related to both parcel characteristics and a series of facilities of general interest. Considering the differences in terms of different land use types and administrative levels of cities, the MWTP for clean air is found to exhibit significant heterogeneity both within and between cities. Specifically, the MWTP value of commercial and residential land is significantly higher than that of industrial land, and the value of ordinary prefecture-level cities is much lower than that of municipalities directly under the central government, cities specifically designated in the state plan and provincial capital cities. In addition, mechanism tests suggest that population mobility is a key channel through which changes in land prices reflect the value of clean air. This study provides a new idea for future use of hedonic price model to estimate willingness to pay for public goods such as clean air from the perspective of China's land transaction market, and also provides a reference for policy makers to formulate relevant policies.

MAPPING OF EROSION HAZARD VULNERABILITY BASED ON GIS AND USLE IN WAIRUTUNG WATERSHED, SALAHUTU DISTRICT, CENTRAL MALUKU REGENCY

This study aims to assess the erosion hazard level in the Wairutung Watershed. This study uses the results of overlaying land use maps, slope maps, and soil types maps to generate the Land unit, which is the unit of analysis. Done using a computer-based Geographic Information System (GIS) with the ArcGIS program integrated with the Universal Soil Loss Equation (USLE) model. The sum of the results of the rating of the parameters then determines the class of vulnerability. The results obtained from this study indicate the division of 4 categories of landslide hazards consisting of a very light course with an area of 2900,865 ha spread over land units with alluvial soil types. The medium type, with a total area of 3683.285 ha, is distributed over land units with podzolic soil types. Heavy type with a total area of 1458.367 ha and the whole place is spread over land units with podzolic and cytosol soil types. The erosion hazard level is hefty, with a total area of 421.97 ha, and is spread over land units with podzolic and cytosol soil types. Keywords: Erosion, Vulnerability, and USLE

Exploring the emergence and changing dynamics of a new integrated rice-crawfish farming system in China

Crop-aquaculture systems are widely adopted around the world as they can provide high protein and energy outputs per unit of land and raise farm incomes, particularly for smallholder farmers. Recently, a new crop-aquaculture system, which combines rice production with crawfish breeding (integrated rice-crawfish farming), has emerged and rapidly expanded in China. However, the spatial extent and temporal dynamics of this integrated farming system largely remain unclear, which prohibits rigorous impact assessments to support its sustainable development. Here we use time series of Landsat satellite data, for the first time, to explore the emergence and the changing dynamics of this rice-crawfish farming system for the period of 2013–2021 in five provinces (805 600 km2) of China, where 90% of the global crawfish are produced. Our analysis reveals that the total area of rice-crawfish farming in these five provinces increased steadily from 0.11 Mha in 2013 to 0.70 Mha in 2019, then sharply contracted by a third in 2020 and rebounded in 2021. Spatially, rice-crawfish system is located primarily in low-elevation plain areas with abundant water resources, where paddy rice cultivation has traditionally dominated agriculture. More concentrated rice-crawfish distribution is observed in Jianghan Plain, and regions around Dongting Lake and Poyang Lake. The spatial distribution of rice-crawfish cultivation experienced considerable expansion towards the east and north from 2013 to 2021, with the largest expansion found in Jiangsu and Anhui after 2018. At the county level, over 6% of counties experienced notable area increases of more than 60 km2 from 2017 and 2019, but 20% of counties have decreased from 2019 to 2021. Among the converted land use types, irrigated cropland is the largest contributor to rice-crawfish expansion with a contribution of 56%, followed by water bodies (25%) and rainfed cropland (13%). The spatial and temporal information provided in this study helps to understand the evolution of rice-crawfish cultivation in China and facilitates more efficient management of land resources under the rapid development of this farming system.

Analisis Tingkat Erosi dan Perencanaan Konservasi Berbasis Sistem Informasi Geografis di Kecamatan Rendang, Kabupaten Karangasem, Provinsi Bali

Erosion Level Analysis and Conservation Planning Based on Geographic Information Systems in Rendang District, Karangasem Regency, Bali Province. The factor of rapid population growth leads to land conversion and slopes used as agricultural land. In Rendang District erosion can be caused by unaccordance land use with conservation principles and Regosol soil types. This study aims to determine the level of erosion and its distribution, the amount of erosion allowed and appropriate conservation planning in Rendang District. The methods used are surveys and Universal Soil Loss Equation (USLE). The result of this study are Rendang District has erosion levels from very light to very heavy, with values ranging from 0.35-809 tons/ha/year. Land unit 1, 2, 10, and 16 have very light levels with total area of 4,302.43 ha. Light levels are found in land unit 9, 13 and 17 with total area of 429.23 ha. Moderate levels are found in land unit 3, 12, 14, 15 and 18 with total area of 1,369.83 ha. Heavy levels are found in land unit 6, 7 and 11 with total area of 1,829.91 ha. Very heavy levels are found in land unit 4, 5 and 8 with total area of 1,529.32 ha. The allowed erosion value in Rendang District is 11-36.10 tons/ha/year. The recommended conservation planning is the improvement of vegetation factors and land management if the erosion is higher than the allowed erosion, otherwise it needs to be preserved.

STATUS C-ORGANIK DAN KADAR N-TOTAL PADA LAHAN PENGEMBANGAN KELAPA SAWIT DI WAWOLAHUMBUTI KECAMATAN PONDIDAHA KABUPATEN KONAWE

study aims to determine the status of soil organic carbon (C-organic), total nitrogen (N-total), and soil pH in oil palm development areas in Wawolahumbuti Village, Pondidaha Sub-District, Konawe Regency. The research was conducted in Wawolahumbuti Village, covering a research area of 365 hectares. Soil testing was carried out at the Biology Laboratory of the Faculty of Mathematics and Natural Sciences, Halu Oleo University, from January to March 2022. The research was conducted using a survey method. The study location consisted of 6 land units. Soil samples were collected using a composite method. Soil samples were taken at approximately ±25 meters intervals in each cardinal direction, then mixed and homogenized at a depth of 0-100 cm, and approximately 1 kg of composite soil was collected. The variables measured were soil organic carbon (measured using the Walkley & Black method), total nitrogen (measured using the Kjeldahl method), and pH (measured using a pH meter). The research results showed that the status of soil organic carbon in the oil palm development areas in Wawolahumbuti Village, Pondidaha-Konawe ranged from very low (0.87%) to low (1.57%). The status of total nitrogen ranged from low (0.11%) to moderate (0.24%), and the soil pH ranged from very acidic (4.42) to acidic (5.12). Management efforts that can be undertaken to enhance the productivity of oil palm plants in Wawolahumbuti Village include the application of organic materials.

Carbon Footprint offset of a managed Bamboo plantation in temperate regions

Bamboo is a fast-growing plant potentially deployable to offset anthropogenic greenhouse gas (GHG) emissions, when properly managed. This study focuses on Phyllostachys edulis (commonly known as Moso) cultivation managed in a temperate region (Italy) with the aim to assess the Carbon Footprint offset by comparing carbon storage capability with GHG emissions of its cultivation.On one side, a dynamic model based on the allometric equations of International Bamboo and Rattan Organization (INBAR) and the parameters of Intergovernmental Panel on Climate Change (IPCC) is developed and validated, using primary data to estimate the direct carbon dioxide (CO2) uptake in biomass. On the other side, GHG emissions produced by the management of the plantation are quantified through the Life Cycle Assessment (i.e., Carbon Footprint) over a period of 100 years.The Carbon Footprint offset is −26,628 t CO2eq (ha)−1 over the specified time frame. It is “net negative” considering an overall Carbon Footprint of 259 t CO2eq (ha)−1 and a cumulative uptake of −26,888 t CO2 (ha)−1. In particular, the CO2 annually removed is 275 t (ha)−1 from the eighth year onwards; this is embedded as carbon in the harvested above-ground biomass and regenerated in the same year (1/3 of culms annually collected). The potential CO2 sequestration per land unit (1 ha) is about 36 times that of a mixed Italian forest.The carbon model is tested to shed light on the dependance on initial conditions (i.e., the life span and the efficient use of the harvested biomass), showing a reduction of the Carbon Footprint offset (from −10 % to −77 %).This study supports the idea of bamboo plantations as a valuable solution for climate change mitigation as long as they are properly managed and the harvested biomass is transformed in durable goods (e.g., construction materials, furniture, fiber, and art), thus generating a semi-permanent carbon storage.

Classification of Soil Distribution on the Island of Saparua Based on the Soil Classification System National and the Equivalent to Soil Taxonomy

This research aims to classify the distribution of soils on Saparua Island, Central Maluku Regency, based on the Subardja, D, et al, (2016) and soil taxonomy (SSS, 2022). The benefit of this research is to find out the distribution of soils on Saparua Island to support the regional development plan. The method used is the survey method, with a semi-detailed survey level of a 1:50,000 scale. The pattern of the approach used is a physiographic analysis approach to landscapes, in which the research area is divided into terrestrial units based on the similarity of the properties of the variables that influence soil formation. The base map used in this study is a land unit map with a scale of 1:50,000. The results showed that the factors and processes involved in soil formation in the study area were parent material and topography, leaching, and eluviation processes. The soils found consisted of seven types of soil with 11 subgroups, namely: Regosol Eutric (Typic Udipsamments and Lithic Udipsamments), Litosol (Lithic Udorthents), Kambisol Distrik (Typic Dystrudepts), Kambisol Litik (Lithic Eutrudepts), Gleisol Eutrik (Typic Endoaquents and Aquic Eutrudepts), Gleisol Distrik (Typic Haplaquepts), Podsolik Kandik (Typic Hapludults and Typic Kandik), and Organosol Hemik (Hydric Tropohemists) were also found.

Recognition of the Interaction Mechanisms between Water and Land Resources Based on an Improved Distributed Hydrological Model

Conflicts between humans and land use in the process of using water and conflicts between humans and water resources in the process of using land have led to an imbalance between natural ecosystems and socio-economic systems. It is difficult to understand the impact of the processes of water production and consumption on land patches and their ecological effects. A grid-type, basin-distributed hydrological model was established in this study, which was based on land-use units and coupled with groundwater modules to simulate the water production and consumption processes in different units. By combining land use and net primary productivity, the runoff coefficient and the water use efficiency (NPP/ET) of different land units were used as indicators to characterize the interaction between water and land resources. The results showed that the average runoff coefficients of cultivated land, forest land and grassland were 0.7, 0.5 and 0.9, respectively. Moreover, the average runoff coefficients of hills, plains and basins were 0.7, 0.7 and 0.8, respectively. The NPP produced by the average unit, evapotranspiration, in cultivated land, forest land and grassland was 7 (gC/(m2•a))/mm, 0.7 (gC/(m2•a))/mm and 0.2 (gC/(m2•a))/mm, respectively. These results provide quantitative scientific and technological support in favor of the comprehensive ecological management of river basins.

Characteristics of Soil Chemical Properties Associated with Inceptisols in Various Land Use in Jasinga, Bogor

Inceptisols are soils with low to moderate fertility and have not experienced further development. This study aims to characterize the chemical properties of inclusions and base exchange fractionation of P of soil on Inceptisol soil map units of forest land, dry land, and paddy fields in Jasinga. Soil samples were taken at three horizons (Ao or Ap, AB/B1, and B/Bt) on forest soil profiles and dry land, while on paddy fields, they were taken at a depth of 0-20 cm, 20-40 cm, and 40-60 cm from the surface land. The chemical properties of the soil analyzed were soil pH, C-organic, soil bases, P-total, CEC, base saturation, and P fractionation. The results showed that the chemical properties of inclusions in the Inceptisol Jasinga soil map unit included high CEC and BS and low Mn-dd. The dominant soil inclusions are in paddy fields, followed by forests, and the lowest is in dry land. The chemical properties findings did not significantly differentiate the available inorganic P, Al-P, (Fe, Mn)-P, and (Ca, Mg)-P fractions. The inclusion of chemical characteristics did not result in a reversal of the correlation with the inorganic P fraction.

Study of soil chemical characteristics on citronella cultivation area in the Gayo Highlands

This research tries to identify the chemical state of the soil in the existing citronella planting area in the Gayo Highlands based on altitude, slope, and soil type. The method used in this research is the descriptive method, with data collected through field surveys and laboratory analysis. Soil samples were taken at each observation point by a purposive sampling method, which was determined based on the components forming a homogeneous land unit consisting of six (6) elevation classes, five (5) slope classes, and five (5) soil types. The results of the analysis showed that the highest value of C-organic was found at location Land Unit 6 (LU6) altitude above 1,200 meters above sea level (m asl), which was 7.29%, and the lowest value was found at location LU1 (200-400 m asl), which was 0.81%. While the highest variation of CEC values was found at locations LU6 and LU3 (600-800 m asl) with a value of 56.40 cmol kg−1, the lowest was found at locations LU1. The citronella cultivation area in the Gayo Highlands was studied based on altitude, slope, and soil type at each observation point. It is still suitable to be developed as a citronella cultivation area where the value of soil chemical characteristics found at each research location is in the low to very high criteria and the pH criteria are in the acid to slightly alkaline criteria.

Vulnerability, susceptibility and community preparedness for flood disaster in Banyumas, Indonesia

Banyumas Subdistrict, Banyumas Regency, which is an area prone to flooding, it is proven that five villages were flooded and dozens of people were evacuated due to the overflowing of the Serayu River so which had an impact on socio-economic conditions. Information on flood hazard and vulnerability data is still in numerical form (table) so it has not been mapped spatially. The objectives of this study were: (1) To analyze the level of flood vulnerability in Banyumas District, Banyumas Regency (2) To analyze the level of flood susceptibility in Banyumas District, Banyumas Regency (3) To analyze the level of community preparedness in dealing with flood disasters in Banyumas District, Banyumas Regency. The research method uses a descriptive approach. The sampling technique used was the saturated sample method and the simple random sample method. Data collection techniques using field observations, interviews, questionnaires, and documentation. The data analysis technique used to determine the level of vulnerability and susceptibility to flooding uses spatial analysis and scoring, to determine the level of community preparedness in dealing with flood disasters using descriptive analysis. The results of the study are: (1) The level of flood vulnerability in Banyumas District is dominated by a high level of vulnerability as many as 18 land units with an area of 1.668,53 Ha (39%). (2) The level of flood susceptibility in Banyumas District is dominated by a moderate level of susceptibility in as many as 10 villages with an area of 2.684,72 Ha (83%) and high susceptibility in as many as 2 villages with an area of 1.342,86 Ha (17%). (3) The level of community preparedness in dealing with flood disasters in Kedunguter Village is ready to face flood disasters.

Geomorphological mapping and landform characterization of Semeru volcano after the eruption in 2021

The eruption of the Semeru volcano in 2021 has diverse impacts on the landscape and surroundings. It is essential to detect recent landscape features to promptly evacuate personnel and property near the volcano and take emergency treatment measures in case of sudden danger. This study presents a detailed geomorphological map on a 1:50.000 scale for the Semeru volcano after the eruption in 2021. The analysis of the hybrid approach and the on-screen image interpretation (OSII) method on DEM data, optical satellites, and lithology units was carried out to obtain morphological, morphochronological, and morphoarrangement information. While, morphoprocess information was obtained through field observations. We used DAS Rejali for our study area. The results of identifying geomorphological conditions divide the Rejali watershed area into 32 landforms consisting of landform units from volcanic, structural, fluvial, and marine processes. Twenty-three land units in the research location are landforms from volcanic processes. This condition causes morphological conditions, material availability, and processes that dominantly reflect the characteristics of an active volcano. In addition, the landform units from the fluvial process in the Rejali watershed area were identified as many as six units in the form of floodplains of lahar flows along the main river. Landforms with structural genesis were placed in Mandalika formation and diorite rock breakthrough. The structural formation in the Rejali watershed has retention and rock structures that are not easily eroded by water. It becomes a bottleneck formation as a barrier between the upstream and middle areas

Analysis of landslide susceptibility in Tirtomoyo Watershed, Central Java, Indonesia

Landslide susceptibility is a measure to express the high or low probability of an area experiencing a landslide disaster which has an impact on the community which is very necessary for disaster mapping of the Tirtomoyo Watershed including Tirtomoyo. From 2014 to 2022, the Tirtomoyo Watershed experienced 147 landslides which caused material losses and casualties. The aspect of landslide disaster assessment in the watershed is very basic to reduce the risk of loss. This study aims to map landslide-prone areas. The research method uses scoring to analyze the level of landslide vulnerability and analysis of land units. The Tirtomoyo Watershed has a low landslide vulnerability potential of 119 hectares, a moderate landslide vulnerability of 2,395 hectares, a high landslide vulnerability of 18,946 hectares, and a very high landslide vulnerability of 373 hectares.

Evaluasi Kesesuaian Lahan Sawah Berdasarkan Status Hara di Kecamatan Seluma Selatan Kabupaten Seluma

The low productivity of rice in Seluma Selatan District is caused by fertilization actions based on general recommendations and not based on site-specific recommendations. In fact, fertilization should be based on soil nutrient status, especially N, P and K. This study aims to determine the nutrient status and evaluate the suitability class of lowland rice in Seluma Selatan District, Seluma Regency. This study used survey methods, soil sampling, and laboratory analysis, then matched it with the soil fertility level classification system and land suitability classification. The results showed that the nutrient status of paddy fields in Seluma Selatan sub-district in low-medium rice fields was categorized. It is characterized by an acidic pH value and low P2O5 in providing nutrients for lowland rice plants. Evaluation of land suitability in Seluma Selatan sub-district shows that the land suitability classes are S2 and S3. The results of the evaluation of the most suitable land suitability for land unit 2 (Au.1.1.1) were quite suitable for S2n with available nutrient limiting factors at the P2O5 level and marginally suitable for S3n on land unit 4 (Hab.1.1.1) with available nutrient limiting factors at P2O5 and K2O levels. Efforts to improve the suitability class S2 (fairly suitable) can be increased to S1 class (very suitable) and the S3 land suitability class (marginally appropriate) can be increased to S2 (quite suitable) . Keywords: Land suitability, lowland rice, nutrient status

On Farm Evaluation of Low-Cost Drip Irrigation on Water and Crop Productivity Compared to Conventional Hand Watering System

The efficient use of water is seen as a key to crop production in semi-arid and arid areas of Ethiopia. For smallholder farmers, low-cost drip irrigation systems provide a means of maximizing return on their cropland by increasing the agricultural productivity per unit of land; and through increasing cropping intensity during the dry season. The experiment was conducted in 2019-2020 cropping seasons in moisture deficit areas of Goro district Nere Negaya peasant association (PA), Southeastern Ethiopia. The study was conducted to evaluate and demonstrate low-cost drip irrigation system in moisture deficit areas and increase the productivity of farmers using harvested water with drip irrigation technology. The runoff water during rainy season was collected stored in the lined farm pond (Capacity of 60m3 ) with geomembrane then the water was lifted manually to water tanker for drip. Low-cost drip set which operates with gravity installed at 1m height above the ground level to supply water for the crop was obtained from Maki Batu Farmer Union. The highest Tomato yield of 40.8 t ha-1 which is 64.8% higher over farmer practice was recorded under drip Irrigation with recommended practice at the study area. Whereas Conventional hand watering with recommended management practice gave the Tomato yield of 31.7 t ha-1 (28%) Over farmer practice. The highest water use efficiency(3.76kg/m3) was obtained from Drip Irrigation with recommended managements and saves 10% water over farmer practice and lowest water use efficiency (2.06 kg/m3) was obtained from farmer practice. Consequently, an economic analysis shows that there is a significant difference, in terms of net income, between the various Irrigation method. Tomato was more valuable with Drip Irrigation, compared to hand watering and farmer practice. It can be concluded that Low-cost drip Irrigation with recommended management practice, saves labour and time and it provides uniform irrigation for Tomato production.

Genetic architecture of inter-specific and -generic grass hybrids by network analysis on multi-omics data

BackgroundUnderstanding the mechanisms underlining forage production and its biomass nutritive quality at the omics level is crucial for boosting the output of high-quality dry matter per unit of land. Despite the advent of multiple omics integration for the study of biological systems in major crops, investigations on forage species are still scarce.ResultsOur results identified substantial changes in gene co-expression and metabolite-metabolite network topologies as a result of genetic perturbation by hybridizing L. perenne with another species within the genus (L. multiflorum) relative to across genera (F. pratensis). However, conserved hub genes and hub metabolomic features were detected between pedigree classes, some of which were highly heritable and displayed one or more significant edges with agronomic traits in a weighted omics-phenotype network. In spite of tagging relevant biological molecules as, for example, the light-induced rice 1 (LIR1), hub features were not necessarily better explanatory variables for omics-assisted prediction than features stochastically sampled and all available regressors.ConclusionsThe utilization of computational techniques for the reconstruction of co-expression networks facilitates the identification of key omic features that serve as central nodes and demonstrate correlation with the manifestation of observed traits. Our results also indicate a robust association between early multi-omic traits measured in a greenhouse setting and phenotypic traits evaluated under field conditions.

Artificial intelligence for sustainable development of smart cities and urban land-use management

ABSTRACT The urban land-use allocation problem is a spatial optimization problem that allocates optimum land-uses to specific land units in urban areas. This problem is an NP (nondeterministic polynomial time)-hard problem because of involving many objective functions, many constraints, and complex search space. Moreover, this subject is an important issue in smart cities and newly developed areas of cities to achieve a sustainable arrangement of land-uses. Different types ofMulti-Objective Optimization Algorithms (MOOAs) based on Artificial Intelligence (AI) have been frequently employed, but their ability and performance have not been evaluated and compared properly. This paper aims to employ and compare three commonly used MOOAs i.e. NSGA-II, MOPSO, and MOEA/D in urban land-use allocation problems. Selected algorithms belong to different categories of MOOAs family to investigate their advantage and disadvantages. The objective functions of this study are compatibility, dependency, suitability, and compactness of land-uses and the constraint is compensating of Per-Capita demand in the urban environment. Evaluation of results is based on the dispersion of the solutions, diversity of the solutions’ space, and comparing the number of dominant solutions in Pareto-Fronts. The results showed that all three algorithms improved the objective functions related to the current arrangement of the land-uses. However, the run time of NSGA-II is the worst, related to the Diversity Metric (DM) which represents the regularity of the distance between solutions at the highest degree. Moreover, MOPSO provides the best Scattering Diversity Metric (SDM) which shows the diversity of solutions in the solution space. Furthermore, In terms of algorithm execution time, MOEA/D performed better than the other two. So, Decision-makers should consider different aspects in choosing the appropriate MOOA for land-use management problems.

Effects of complex terrain on the shortwave radiative balance: a sub-grid-scale parameterization for the GFDL Earth System Model version 4.1

Abstract. Parameterizing incident solar radiation over complex topography regions in Earth system models (ESMs) remains a challenging task. In ESMs, downward solar radiative fluxes at the surface are typically computed using plane-parallel radiative transfer schemes, which do not explicitly account for the effects of a three-dimensional topography, such as shading and reflections. To improve the representation of these processes, we introduce and test a parameterization of radiation–topography interactions tailored to the Geophysical Fluid Dynamics Laboratory (GFDL) ESM land model. The approach presented here builds on an existing correction scheme for direct, diffuse, and reflected solar irradiance terms over three-dimensional terrain. Here we combine this correction with a novel hierarchical multivariate clustering algorithm that explicitly describes the spatially varying downward irradiance over mountainous terrain. Based on a high-resolution digital elevation model, this combined method first defines a set of sub-grid land units (“tiles”) by clustering together sites characterized by similar terrain–radiation interactions (e.g., areas with similar slope orientation, terrain, and sky view factors). Then, based on terrain parameters characteristic for each tile, correction terms are computed to account for the effects of local 3D topography on shortwave radiation over each land unit. We develop and test this procedure based on a set of Monte Carlo ray-tracing simulations approximating the true radiative transfer process over three-dimensional topography. Domains located in three distinct geographic regions (Alps, Andes, and Himalaya) are included in this study to allow for independent testing of the methodology over surfaces with differing topographic features. We find that accounting for the sub-grid spatial variability of solar irradiance originating from interactions with complex topography is important as these effects led to significant local differences with respect to the plane-parallel case, as well as with respect to grid-cell-scale average topographic corrections. We further quantify the importance of the topographic correction for a varying number of terrain clusters and for different radiation terms (direct, diffuse, and reflected radiative fluxes) in order to inform the application of this methodology in different ESMs with varying sub-grid tile structure. We find that even a limited number of sub-grid units such as 10 can lead to recovering more than 60 % of the spatial variability of solar irradiance over a mountainous area.

The importance of land in resource criticality assessment methods: A first step towards characterising supply risk

Land is a key resource for human activities under growing pressure. Resource criticality assessment methods investigate the extent to which a resource may become a limiting factor according to various dimensions, including geological, economic and geopolitical availability. They have been applied to resources like minerals, fossil fuels, biotic material or water, but none consider land resources, i.e. natural land units providing space and support for human activities. Based on two recognised criticality methods developed by i) the Yale University and ii) the Joint Research Centre of the European Commission, this study aims to develop spatialized land supply risk indexes at country level. The accessibility of raw resources can be quantified and compared using the supply risk index. The specific characteristics of land call for certain adaptations of the criticality approach, and are designed to ensure comparability between resources. The main adaptations include the definition of land stress and the internal land concentration index. Land stress represents the physical availability of land, while internal land concentration relates to the concentration of landowners within a country. Finally, land supply risk indexes are computed for 76 countries, including 24 European countries for which the results of the two criticality methods are compared. Comparison points to divergences in the countries ranking for land accessibility, thus underlining the importance of methodological choices in the construction of the indexes. Data quality is discussed for European countries with the JRC method, and the use of alternative data sources reveals that it may lead to differences in absolute values, although the ranking of countries with low or high land supply risk does not change.Finally, this work covers a gap in criticality methods by including land resources. These resources can be critical for certain countries, and are essential for human activities such as food or energy production.

Role of coffee plantation in reducing erosion under coarse textured soil in wet tropical region

Water erosion is one phenomenon causing land degradation in a wet area. The research was aimed to evaluate the total of soil erosion under coffee plantations having coarse textured soil in wet tropical regions. This research was taken out on a coffee plantation in Sibarasok, Maninjau having rather to very steep slope and high annual rainfall, with Inceptisol soil order. Soil samples were taken from 6 land units (Coffee-86 y having 0-8%, 25-45%, and >45%, Coffee 5 y-15-25%, Coffee 8 y-25-45%, and forest >45% as control). The samples of soil were prepared and analyzed in the Laboratory of Soil, Department of Soil Science and Land Resource, Andalas University. The actual amount of soil eroded was predicted using the USLE formula. Then, it was compared to the tolerated (Etol) soil erosion. The result showed that the predicted amount of soil eroded was quite low (<10 T/Ha/y), except under coffee having >45% slope. The highest soil eroded in the very steep slope was due to its low SOM content and permeability, with an erosion hazard level of 1.2. Compared to tolerated erosion (Etol), the actual soil erosion predicted was lower than the Etol. The fiber roots of the coffee dominating the top 5 cm of soil surface as well as high SOM content and hydraulic conductivity rate caused the soil on the top to become tightly held avoiding erosion.