Agricultural Land Surface Research Articles

Estimation of 100 m root zone soil moisture by downscaling 1 km soil water index with machine learning and multiple geodata

Root zone soil moisture (RZSM) is crucial for agricultural water management and land surface processes. The 1 km soil water index (SWI) dataset from Copernicus Global Land services, with eight fixed characteristic time lengths (T), requires root zone depth optimization (Topt) and is limited in use due to its low spatial resolution. To estimate RZSM at 100-m resolution, we integrate the depth specificity of SWI and employed random forest (RF) downscaling. Topographic synthetic aperture radar (SAR) and optical datasets were utilized to develop three RF models (RF1: SAR, RF2: optical, RF3: SAR + optical). At the DEMMIN experimental site in northeastern Germany, Topt (in days) varies from 20 to 60 for depths of 10 to 30 cm, increasing to 100 for 40–60 cm. RF3 outperformed other models with 1 km test data. Following residual correction, all high-resolution predictions exhibited strong spatial accuracy (R ≥ 0.94). Both products (1 km and 100 m) agreed well with observed RZSM during summer but overestimated in winter. Mean R between observed RZSM and 1 km (100 m; RF1, RF2, and RF3) SWI ranges from 0.74 (0.67, 0.76, and 0.68) to 0.90 (0.88, 0.81, and 0.82), with the lowest and highest R achieved at 10 cm and 30 cm depths, respectively. The average RMSE using 1 km (100 m; RF1, RF2, and RF3) SWI increased from 2.20 Vol.% (2.28, 2.28, and 2.35) at 30 cm to 3.40 Vol.% (3.50, 3.70, and 3.60) at 60 cm. These negligible accuracy differences underpin the potential of the proposed method to estimate RZSM for precise local applications, e.g., irrigation management.

Assessment of soil resources of agricultural landscapes in Turkestan region of the Republic of Kazakhstan based on agrochemical indexes

Abstract Natural and climatic features of the soil cover formation of Turkestan region of the Republic of Kazakhstan are identified by a set of hydrological and bioclimatic factors serving as important environment-forming functions, which are reflected in the landscape organization of the territory. When assessing soil resources of agricultural landscapes, integrated index of soil fertility was applied – the “soil index,” which takes into account the reserves of humus, mineral elements, and hydrolytic acidity. Based on monitoring observations (1996–2019) of soil fertility in agricultural landscapes (agricultural lands) of Turkestan region, assessment of soil resources was performed, which showed that in general, the generalized “soil index” ranges from 1.086 to 4.800 units depending on natural features of the territory. It is found that the “soil index” in agricultural landscapes is significantly less than its maximum value (20.000 units), which suggests a pronounced humus deficiency, showing low soil fertility in all agricultural landscapes. To assess the soil resources of agricultural landscapes in Turkestan region, a new approach was applied, which is based on the assessment of energy costs for the soil formation process, which enables to quantitatively reflect the radiation balance of the earth surface, heat, and moisture supply of agricultural land for 1941–1960 and 2001–2020. The indicators applied are subject to the law of vertical zonation and change from the mountain to the arid zone, where the potential energy costs for soil formation range from 82.2–101.9 to 129.4–135.5 kJ/cm2, and natural energy costs energy costs for soil formation from 17.2–21.7 to 121.7–125.2 kJ/cm2.

STUDY ON THE USE OF AGRICULTURAL LAND IN THE NORTH-WEST DEVELOPMENT REGION OF ROMANIA BASED ON THE SOCIOLOGICAL SURVEY

The paper aims to present the situation of agricultural lands and the effects of their management on the sustainable development of agriculture in the North-West Development Region of Romania, at the level of 2023. The study is based on data taken through the sociological survey method based on a questionnaire, of a number of 276 respondents. The collected data were interpreted for the following indicators: the type of agriculture practiced, agricultural techniques applied, the involvement of agricultural farms in associative forms, the surface of agricultural land, irrigation of agricultural land, fragmentation of agricultural land, types of crops and the use of modern technologies for a digital agriculture. After analysing the data, it is observed that a predominantly conventional and mixed agriculture is practiced, using an average of 150 hectares per farm. Due to the large presence of arable land, the main crops are field crops, represented by cereals and fodder plants. Permanent crops represented in particular by permanent meadows are owned by the majority of farmers (87.3%), and horticultural crops are present in only 27.17% of farms. Modern technologies have a high potential in the development of the region and must be exploited more in the future.

Drivers of ammonia volatilization in Mediterranean climate cropping systems

Ammonia (NH3) volatilization is the major source of nitrogen (N) loss resulting from the application of synthetic and organic N fertilizers to croplands. It is well known that in Mediterranean cropping systems, there is a relationship between the intrinsic characteristics of the climate and nitrous oxide (N2O) emissions, but whether the same relation exists for NH3 emissions remains uncertain. Here, we estimated the impact of edaphoclimatic conditions (including meteorological conditions after N fertilization), crop management factors, and the measurement technique on both the cumulative emissions and the NH3 emission factor (EF) in Mediterranean climate zones, drawing on a database of 234 field treatments. We used a machine learning method, random forest (RF), to predict volatilization and ranked variables based on their importance in the prediction. Random forest had a good predictive power for the NH3 EF and cumulative emissions, with an R2 of 0.69 and 0.76, respectively. Nitrogen fertilization rate (N rate) was the top-ranked predictor variable, increasing NH3 emissions substantially when N rate was higher than 170 kg N ha−1. Soil pH was the most important edaphoclimatic variable, showing greater emissions (36.7 kg NH3 ha−1, EF = 19.3%) when pH was above 8.2. Crop type, fertilizer type, and N application method also affected NH3 emission patterns, while water management, mean precipitation, and soil texture were ranked low by the model. Our results show that intrinsic Mediterranean characteristics had only an indirect effect on NH3 emissions. For instance, relatively low N fertilization rates result in small NH3 emissions in rainfed areas, which occupy a very significant surface of Mediterranean agricultural land. Overall, N fertilization management is a key driver in reducing NH3 emissions, but additional field factors should be studied in future research to establish more robust abatement strategies.

Geospatial segmentation of high-resolution photovoltaic production maps for Switzerland

Until last year, most of Switzerland’s photovoltaic (PV) installations were built on roof tops. But the amount added is not enough to reach the country’s energy transition goals. With the adjustments of September 2023, the government incentivizes large-scale, free-standing photovoltaic installations. It is now essential to identify the best installation locations and to accurately estimate their production potential. Past studies have assessed different landcover classes, but much of the efforts have gone into separating out zones that are not suitable for PV plants; for technical, economical and also legislative reasons. All along, the underlying radiation data that was used to compute the local energy yield remained at a spatial resolution > 1 km. Given the complex terrain of the southern half of the country, this resolution is not high enough to capture the local variability in production potential. Our study introduces a new methodology to derive solar irradiance at a very high resolution of 25 m. Satellite data is combined with high resolution terrain information to compute accurate horizons and to account for local shading effects. These base radiation maps are then converted into potential electricity production from a PV panels. A comparison of the production from a typically chosen panel tilt with the production that can be achieved when the tilt is locally optimized based on the high-resolution radiation maps underlines the value of our new method. In a first application, this data set was used to estimate the lumped production potential of two major landcover classes in Switzerland: agricultural land and water surfaces, each of them divided into two subclasses. The geospatial segmentation was based on land use maps and the total available area within each class was calculated. Comparing the results to the production potential from Swiss roofs shows that these newly incentivized installation areas have a much higher production potential than the conventional roofs; both, in an absolute sense of total potential production (roofs: 120 TWh/a, agricultural: 2,250 TWh/a, water: 210 TWh/a), and in a relative sense of energy yield per installed capacity, especially in winter (roofs <50kWh/m2, agricultural >100kWh/m2, water ≈100kWh/m2).

Use of dry bean fields by birds and mammals in Brazil: Insights from a field study and its use in pesticide risk assessment.

The relationship between agriculture and wildlife can be both synergetic and challenging, as the increased surface of agricultural land makes it increasingly important for agriculture and wildlife to coexist. This study aims to describe the use of freshly drilled dry bean fields by birds and mammals in Brazilian Cerrado and Atlantic Forest sites and their diversity and abundance within in-crop and off-crop areas (with native permanent vegetation and other surrounding crop fields) at four different farms. A comprehensive survey was conducted, using various sampling methods, including point counts, foraging counts, trail cameras, and occasional encounters. In all, contacts for 12 518 birds across 306 species and 313 mammals across 34 species were registered. The off-crop areas exhibited greater species richness, abundance, and diversity than the in-crop areas on all farms. For birds, 47 species were recorded in-crop, of which 15 were classified as insectivores, 15 as granivores, seven as omnivores, seven as carnivores, and three as frugivores. The number of in-crop observations per species was small. The abundance off-crop was greater for 31 species observed in-crop, indicating that dry bean fields are probably not a preferred habitat for those species. Species classified as granivorous are most likely to feed on dry bean seeds. However, almost all granivorous species observed in-crop areas are too small to be able to feed on dry bean seeds. For mammals, nine species were recorded in-crop, of which four were classified as carnivores, three as omnivores, one as insectivore, and one as granivore. Additionally, despite the considerable effort in this study, no evidence was found that birds and mammals feed on dry bean seeds. The results highlight the importance of off-crop areas in dry bean fields, characterized by a more diverse and abundant bird community than in-crop. Integr Environ Assess Manag 2024;20:864-874. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

STUDY REGARDING CHOOSING THE OPTIMAL TERRITORIAL PLANNING OF AN ARABLE LAND

The main objective pursued in this work was the concentration of agricultural land surfaces in optimally sized units in order to efficiently exploit natural and material resources. Thus, through this work, the organization and development of the territory for the area of ​​126.47 ha, arable use category, related to the locality of Amăraștii de Jos, Dolj county, located in the outskirts and under private administration, was carried out.

Effect of Drip Irrigation Under Mulch on Nitrogen Transport in Deep Soil Layers in an Agricultural Region of the Xiliao River Plain, China

In the agricultural region of the Xiliao River Plain, drip irrigation under mulch has been widely implemented. It not only saves irrigation water, but also changes the structure of the underlying surface of agricultural land, which affects the local hydrological cycle to a certain extent, and makes the process of nitrogen transportation in soil with new characteristics. This study analyzed the distribution of NH4-N, NO3-N, and NO2-N in different soil depths during the whole growth period under three underlying surface conditions, including drip irrigation under mulch, border irrigation, and bare area through field in-situ observation experiment, and analyzed the influence of drip irrigation under mulch on nitrogen transport in deep soil layers. The results showed that under the soil properties of the experimental area, drip irrigation under mulch creates more water to enter the deep soil layers, which was beneficial to alleviate the downward trend of local groundwater level to a certain extent. The average content of NH4-N and NO3-N under drip irrigation under mulch was higher than that under border irrigation. The average content of NH4-N under drip irrigation under mulch was 1.24 mg.kg-1 in soil depths of 80-300 cm, and 0.97 mg.kg-1 under border irrigation. The average content of NO3-N under drip irrigation under mulch was 2.73 mg.kg-1 in soil depths of 80-300 cm, and 1.99 mg.kg-1 under border irrigation. The increment of NH4-N and NO3-N distribution in deep soil layers under drip irrigation under mulch was greater than that under border irrigation, and the increment of NO3-N content is significantly greater than that under border irrigation. Soil water content has a significant impact on the contents of NH4-N and NO3-N. It indicated that compared with traditional border irrigation, drip irrigation under mulch was beneficial to alleviate the downward trend of local groundwater, but it would increase the risk of nitrogen pollution in local groundwater.

Quantifying the benefits of reducing synthetic nitrogen application policy on ecosystem carbon sequestration and biodiversity

Synthetic Nitrogen (N) usage in agriculture has greatly increased food supply over the past century. However, the intensive use of N fertilizer is nevertheless the source of numerous environmental issues and remains a major challenge for policymakers to understand, measure, and quantify the interactions and trade-offs between ecosystem carbon and terrestrial biodiversity loss. In this study, we investigate the impacts of a public policy scenario that aims to halve N fertilizer application across European Union (EU) agriculture on both carbon (C) sequestration and biodiversity changes. We quantify the impacts by integrating two economic models with an agricultural land surface model and a terrestrial biodiversity model (that uses data from a range of taxonomic groups, including plants, fungi, vertebrates and invertebrates). Here, we show that the two economic scenarios lead to different outcomes in terms of C sequestration potential and biodiversity. Land abandonment associated with increased fertilizer price scenario facilitates higher C sequestration in soils (+ 1014 MtC) and similar species richness levels (+ 1.9%) at the EU scale. On the other hand, the more extensive crop production scenario is associated with lower C sequestration potential in soils (− 97 MtC) and similar species richness levels (− 0.4%) because of a lower area of grazing land. Our results therefore highlight the complexity of the environmental consequences of a nitrogen reduction policy, which will depend fundamentally on how the economic models used to project consequences.

Multidecadal Land Use Patterns and Land Surface Temperature Variation in Sri Lanka

Agricultural land conversion due to urbanization, industrialization, and many other factors is one of the significant concerns to food production. Therefore, analyzing the temporal and spatial variation of agricultural lands is an emerging topic in the research world. However, an agrarian country like Sri Lanka was given weaker attention to the temporal and spatial variation of the land use, including the agricultural lands. This study presents an extended analysis of temporal and spatial variation of land use patterns in Sri Lanka, specifically looking at the agricultural land conversion and land surface temperature (LST) change. Remote sensing techniques and geographic information system (GIS) were used for the presented work. The satellite images from three Landsat’s were analyzed for 2000, 2010, and 2020 to identify the potential land use conversions. In addition, LSTs were extracted for the same period. Significant and continuous increases can be seen in the agricultural lands from 33.94% (of total area) in 2000 to 43.2% in 2020. In contrast, the forest areas showcase a relative decrease from 38.51% to 33.82% (of total area) during the analyzed period. In addition, the rate of conversion from agriculture to settlements is higher in the latter decade (2010–2020) compared to the earlier decade (2000–2010). Only general conclusions were drafted based on the LSTs results as they were not extracted in the same months of the year due to high cloud cover. Therefore, the results and conclusions of this study can be effectively used to improve the land use policies in Sri Lanka and lead to a sustainable land use culture.

Agricultural land conversion and land surface temperature change in four industrial areas in Bangladesh: results from remote sensing and DPSIR approach

Agricultural land conversion and land surface temperature change in four industrial areas in Bangladesh: results from remote sensing and DPSIR approach

ENGINEERING GEOLOGICAL AND GEOTECHNICAL CHARACTERISTICS OF LANDSLIDE IN GORNJI HRGOVI, MUNICIPALITY OF SREBRENIK

<p>Natural disasters during May 2014 caused a flood of water outside the unregulated bed of the river Tinja in the local area of Gornji Hrgovi. The flood effect affected the undermining and destruction of the foot part of the slope, reactivation and regressive development of the landslide, which was manifested by further secondary “breaking” of the sliding body towards the hypsometrically top part of the slope and intersection of the primary water pipeline. Gravitational displacement of the colluvial material resulted in significant degradation of the agricultural land surface in the central part of the unstable slope, while in the accumulation zone the accumulated slide mass destroyed the earth road communication. Based on the conducted geotechnical researches, determined engineering-geological and hydrogeological composition and properties of the terrain, the zoning of the terrain according to the degree of stability was performed, important recommendations and conditions of the landslide remediation method were presented.</p>

Temperature Dynamics Assessment of Agricultural Objects Based on Unmanned Aircraft Data

During the study, the spatial and temporal distribution of radiant temperature of agricultural fields has been made. The object of the study is agricultural fields (barley, oats, fallow field, perennial grasses (Onobrychis)), located on the territory of the Krasnoyarsk Research Institute of Agriculture of the FRC KSC SB RAS near the village of Minino (Central Siberia, Krasnoyarsk region). The radiant temperature measurement of objects surface was taken by the ZENMUSE XT2 camera installed on the unmanned aircraft DJI Matrice 210 RTK V2. The spatial resolution of the obtained thermal maps is 12 – 14 cm. The state of the objects (the presence of vegetation cover) was assessed using the NDVI values obtained from the PlanetScope satellite data with a spatial resolution of 3 meters. It was established that the presence of plants and the size of their projective cover are decisive in the formation of soil cover temperature conditions. The growth and development of the vegetation cover, its height and closeness, change the temperature regime conditions. Instead of a soil, vegetation cover becomes an active surface. The thermal maps (spatial distribution of radiant temperature) of the agricultural land surface has been carried out, which makes it possible to assess the in-field temperature heterogeneity of the objects

Land use-land cover (LULC) transformation and its relation with land surface temperature changes: A case study of Barrackpore Subdivision, West Bengal, India

Unplanned urban growth and changes of Land-use land cover (LULC) is the warning scenario for towns and cities in world wide. The transformation of natural land to impervious areas has induced in local microclimate variations and changes the surface energy budget. The main objective of the present study is to delineate land-use/land-cover changes and its relation to increases Land Surface Temperature (LST) in Barrackpore Subdivisional area, West Bengal using multi-spectral satellite data. Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM+) data were used in seasons wise (January, April, and November) to analyze LST variations for two different periods of 1990 and 2016. According to the current census report, 40 lakh people live in the study area, out of which 95% of people habitat in urban areas. The growth rate of urban land was 162% during 26 years of the time period. Non-built-up lands have encroached by more than 50% of land loss. The outcome result shows that mean LST has growth 3 °C and 4 °C in winter and summer seasons as well. It is founded that built-up areas are radiated the highest temperature in all seasonal phases which is followed by fallow land, agricultural land, vegetation, and water surfaces. Urban land converted from other evaporating land has raised in mean LST with 3.1 °C–3.2 °C in winter seasons; 4.22°C- 4.4 °C in summer seasons; and lastly 4.36 °C–4.57 °C in autumn season. Different indices, e.g. Normalized Difference Vegetation Index (NDVI), Normalized Difference Built-up Index (NDBI), Normalized Difference Moisture Index (NDMI), and Normalized Difference Water Index (NDWI) were derived to analysis and validate the relationship between LST and different land-use classes. The liner negative regression slope has found between NDVI and LST with a correlation coefficient (R2) varies from 0.429 to 0.67 from 1990 to 2016. R2 values have increased from 1990 to 2016 for every season that indicates the control of vegetation on LST. Seasons statistical relationship between LST and NDBI has exhibited a positive correlation that confirmed impervious surface has strongly influenced to upsurge the surface temperature. Water Surfaces are radiated mean 1 °C less temperature than other land use categories. The regression line is showing the negative relationship between LST-Wetland and Water Bodies which shows the LST effects are very less over extreme humid or moisture areas. The concentration of hotspot and cold spot areas was delineating using the spatial autocorrelation method of Getis-Ord Gi* formula, as the result shows that increased of hotspot areas from 19.9% to 35.3% in January month, 10.25%–16.40% in April month and 15.38%–37.4% in November month during the entire study periods. So, the municipal authority can take new decision policies and management to reduce the effects of LST for sustainable development in the further future.

Dynamics of costs of ecosystem services of small towns in Kyiv region

The purpose of the study is to compare the environmental potential of the two small towns Fastiv and Kaharlyk which remote from Kyiv with the total cost of ecosystem services received in their territories. The experimental towns are located in the Kyiv highland province of the Forest-Steppe zone, which have a similar history of development, but differ in area, population and density of settlement, as well as industrial development and land use structure. Despite the benefits of the concept of ecosystem services, its application in urban planning is constrained by the limited or lack of data for evaluation. This research is based on materials of master plans of towns using the transfer method. The cost of ecosystem services in the territory of the researching small towns is calculated according to the categories of the land fund — agricultural land, forest ecosystems and water surfaces. Ecosystem services per unit of each category of land use adjusted by the transfer of US dollars, taking into account the transfer coefficient of cost per purchasing power parity of money for Ukraine.It is found out that the total number of ecosystem services received is almost the same for both towns. At the same time, the towns are significantly different from the relative number of ecostable territories, which affects the specific indicators of the cost of ecosystem services. One resident of Fastiv accounted for three times less ecosystem services, and a unit area — in twice, and this trend will be preserved in the long run. The dynamics of the total cost of ecosystem services on the territory of Kaharlyk indicates that the principle of ecological balance of the territory in the perspective planning is not being complied with, which contradicts the concept of sustainable development.

Mapping urban cold-air paths in a Central European city using numerical modelling and geospatial analysis

The positive trend of global urbanization goes along with the conversion of non-urbanized, e.g. natural or agricultural land surfaces, into urbanized surface types, e.g. impervious surfaces. This generally leads to an increased intensity of the urban heat island and calls for mitigation strategies to ensure thermal comfort of the urban residents. In the present study, we introduce a method to identify, map and asses the efficiency of cold-air paths, which are low-roughness open areas that support cold-air drainage or transport from rural into warmer urban areas. We define that cold-air paths connect cold-air reservoir areas (CARA) with cold-air impact regions (CAIR). The approach combines numerical modelling using the cold-air flow model KLAM_21 with geostatistical analysis using GIS. In our study area Braunschweig (Northern Germany, 250,000 inhabitants) eight cold-air paths of different lengths and surface areas were identified. The identified surface area of cold-air paths varies between 1.7 and 18.0 km2, and the respective cold-air volume between 0.04 and 0.53 km3. The efficiency of cold-air paths was classified according to six criteria taking the size, length, and the cold-air volume and dynamics into account. The method shows promising results, is transferable to other urban areas and offers potential to support decision-making in urban and environmental planning.

Cadmium Health Risk Assessment and Anthropogenic Sources of Pollution in Mount-Lebanon Springs

Cadmium (Cd) is a highly toxic heavy metal with low permissible limits. This study aims at conducting a health risk assessment for Cd and examining potential sources of pollution in springs of the Mount-Lebanon Governorate, a semi-urbanized area in Lebanon. A total of 31 spring samples were collected during the wet and dry seasons and tested for water quality. Graphite furnace atomic absorption spectrometry was used to quantify Cd levels in water. Risk assessment was performed by means of a survey on water consumption and usage, and followed the USEPA Hazard Quotient (HQ) model. Correlations with different human activities were examined using different linear regression models and spatial analysis tools. Results highlight springs within El Metn and Keserwan Districts as posing a non-carcinogenic health risk in (1) Ain Saadeh both in adults (HQwet = 1.94) and iron-deficient children (HQwet = 1.29), and (2) Faraya both in healthy (HQwet = 1.33; HQdry = 1.19) and iron-deficient children (HQwet = 2.67; HQdry = 2.37), as well as in iron-deficient adults (HQwet = 1.57; HQdry = 1.39). In addition, Cd levels increased significantly with proximity to upstream open dumps (Pearson’s r = − 0.511; p = 0.003), agricultural land surface area, increased upstream industrial activity, mainly jewelry and fine stones industries in both bivariate (r = 0.33; p = 0.001) and multivariate analyses (r = 0.41; p = 0.002), plastic industries (Pearson’s r = 0.36; p = 0.05), and furniture manufacturing (Pearson’s r = 0.38; p = 0.038). Our findings constitute the first report assessing Cd health risk and identifying sources of pollution in Mount-Lebanon, and make a strong basis for a risk management strategy.

Estimation of Surface Soil Moisture With Downscaled Land Surface Temperatures Using a Data Fusion Approach for Heterogeneous Agricultural Land

AbstractField‐scale surface soil moisture (SSM, 0–10 cm), which is closely linked with land surface temperature (LST), is particularly important to agricultural water resource management. Active and passive microwave remote sensing‐based SSM retrievals on the order of kilometer squared resolutions are difficult to apply to heterogeneous agricultural land surfaces that may need SSM data at a resolution of 30 m. In this study, the High‐resolution Urban Thermal Sharpener and Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model were applied to downscale optical and thermal remote sensing data simultaneously by blending Landsat and MODIS red‐near infrared‐LST data, with the ultimate goal to generate field‐scale SSM values from the trapezoidal approach. To evaluate the performance of the downscaled LSTE (based on the Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model method) and SSM, an irrigation district (Area 1) in Inner Mongolia and an irrigation district in the North China Plain (Area 2) with varying spatial heterogeneity were selected as the testbeds. Results indicated that the downscaled LSTE was highly consistent with synchronous Landsat LSTH and in situ LST measurements in Area 1, with the root‐mean‐square error ranging from 0.73 to 2.75 K. Compared with the MODIS SSM, the average root‐mean‐square error of the downscaled SSM improved from 0.048 to 0.038 cm3/cm3 for both areas. The downscaled LSTE and SSM developed in this study enhance the spatiotemporal resolutions of the SSM estimates, maximizing the potential of remotely sensed information for agricultural water resource management.

ANÁLISIS DEL CAMBIO TEMPORAL Y ESPACIAL DEL USO DEL SUELO EN LA REGIÓN CENTRO-SUR DE CHILE

La investigación estudia el cambio temporal y espacial del uso del suelo en la Región del Bio- Bio (Centro-Sur de Chile), para el periodo 1998 y 2008. Se utilizó la cobertura digital del monitoreo nacional del año 1998 y fotografías aéreas para el año 2008, posteriormente se construyeron matrices que explican el cambio y transiciones entre los diferentes usos del territorio. Las superficies con plantaciones crecieron a una tasa anual de 2,5 %, incremento generado por el consumo de praderas y matorrales en 21 %, terrenos agrícolas 14 %, bosque mixto 8,8 %, humedales en 1,6 % y bosque nativo en menor medida 1,1 %. Las praderas y matorrales presentaron una pérdida a una tasa de 2,5 % anual, la causa principal se debe a la transferencia de este uso a plantaciones con un 21 % y a otros usos como terrenos agrícolas 2 %. Los terrenos agrícolas perdieron superficie con una tasa anual de 1,5 %, terrenos que incrementaron a las plantaciones en 14 %, los humedales perdieron superficie con tasa de 0,4 %, la superficie se trasladó a las áreas urbanas e industriales en 2,6 % y plantaciones en 1,6 %. La principal presión para ocupar superficie, corresponde a las plantaciones, debido a que la Región del Bio-Bio representa la mayor cantidad de superficie (858.592 ha) de plantaciones exóticas del país.

Evaluating water-saving efficiency of plastic mulching in Northwest China using remote sensing and SEBAL

Plastic mulching of agricultural land surfaces has been widely used to cope with growing water shortage, but little research has been done in evaluating its water-saving efficiency at large catchment scale. We evaluate the effectiveness of water use in plastic mulching in a large catchment in Northwest China using remote sensing data and the Surface Energy Balance Algorithm for Land (SEBAL). We use a decision-tree method to delineate the plastic mulching lands (PML) from other croplands (NPML) based on land surface albedo and temperature derived from Landsat images. We use SEBAL and Moderate-resolution Imaging Spectroradiometer (MODIS) data to estimate evapotranspiration (ET) and the water use in PML and NPML. Our study shows that ET from the PML reduced about 6.6% compared with NPML, and the area of PML increased about 84.2% during the 14-year period of 2000–2013 in the catchment. However, the total water use in the area still increased 50.0% as the total cropland area increased about 48.6% in the same period. Our study therefore suggests that the best water management strategy in arid China needs not only to increase water use efficiency but also to control total water usage by limiting reclamation of farmlands.