Agricultural Land Use Types Research Articles

Characteristics and Influencing Factors of Soil Particulate and Mineral-associated Organic Carbon in Cropland Soil across Sichuan Basin

Exploring the composition of regional soil organic carbon （SOC） components and identifying their influencing factors are of utmost importance to deeply understand the potential mechanisms of SOC change in cropland soil. Based on data from 871 soil sampling points, this study explored the characteristics of soil particulate and mineral-associated organic carbon （POC and MAOC） in the surface soil of cropland and the relationships with climate, terrain, soil texture, agricultural land-use type, and fertilization across the Sichuan basin using analysis of variance, correlation analysis, and a random forest model. The results showed that the average content of POC and MAOC in the surface soil of cropland was 5.01 g·kg-1 and 9.79 g·kg-1, respectively, accounting for 32.5% and 67.5% of the total SOC； the proportion of POC increased with SOC. The two SOC fractions showed a similar spatial distribution pattern, with the content being higher in peripheral areas and lower in the middle of the basin, which were determined together by structural and random factors. The results of the random forest model showed that the relative importance of agricultural land-use type was much more important than other factors. NPP, mean annual temperature, and soil texture showed the largest correlations with the two SOC fractions in dryland； mean annual temperature and slope had larger correlations with POC and mean annual temperature and soil texture in the dryland-paddy rotation land； and soil texture was the most relevant factor to POC and MAOC in the paddy field. The above results suggested that MAOC was the main component of SOC, and agricultural land-use type was the dominant control and regulated the effects of other factors on the two SOC fractions.

Assessment of Impact of Agricultural Land-Use Types on Some Soil Physical and Chemical Properties in Abeokuta, Southwestern Nigeria

Agricultural land-use practices play a pivotal role in shaping the physical and chemical properties of soil, which in turn influence crop productivity, environmental sustainability, and overall ecosystem health. Understanding the impact of different agricultural land-use types on soil properties is crucial for sustainable land management and effective agricultural practices. This study utilized electrical resistivity technique (ERT) and geochemical methods to assess the impact of different land-uses (mineral farms, organic farms, thick plantations, and cattle stations) on soil physicochemical properties. The research aimed to explore the correlation between soil resistivity and fertility, as well as evaluate the influence of specific land-use types on soil characteristics. Four resistivity traverses were conducted, each corresponding to a different land-use type, and soil samples were collected from various depths. Laboratory analysis revealed high clay content in the cattle station, while all land-use types showed high sand content. Available phosphorus was significantly affected by both land-use and soil depth, negatively correlating with electrical conductivity. Exchangeable bases were generally low across all land-use types. The study recommends promoting site-specific, sustainable land management practices within different agricultural land-use systems.

Soil oribatid mite community structure and its relationship with environmental factors in different agricultural land-use types in Shibing Karst

The karst world natural heritage site is characterized by fragility due to severe rocky desertification. Buffer zone functions as the ecological barrier of the core area of the heritage site, and can play an ecological filtering role in the core area. Therefore, buffer zones are of great ecological significance. In order to reveal the community characteristics of soil oribatid mites in different agricultural land-use in the buffer zone of Shibing Karst World Natural Heritage and their relationship with environmental factors, soil oribatid mites in the buffer zone of corn field (CF), golden pear garden (GP) and tobacco field (TF) were collected in September 2021. A total of 1220 oribatid mites belonging to 79 genera and 41 families were found in the study. Our key results include (1) The family number, genus number, individual number, and individual density of GP are higher (2) Scheloribates is the dominant group, 22 genera such as Oppiella, Tectocepheus, and Xylobates are common groups, and 56 genera such as Neoribates and Protoribates are rare groups. (3) The Diversity index of GP is higher than that of other cultivated land types. Community similarity analysis shows that the similarity between GP and CF is high, but all habitats are at a medium level of dissimilarity. (4) Analysis of the ecological group of oribatid mites shows that Poronota is more abundant than Macropylina and Gymnonota. (5) The Diversity index, richness index, family and genus level of oribatid mites were significantly positively correlated with soil humidity (SH) and the number of genera, individuals and individual density were significantly positively correlated with total phosphorus (TP). Redundancy analysis indicates that total phosphorus (TP), total potassium (TK), and soil organic matter (SOM) are the main environmental factors affecting the distribution of soil oribatid mites communities. Based on the above research results, it can be seen that there are differences in the community structure of soil oribatid mites in different agricultural land-use in the study area. The use of dominant genera of mites can preliminarily indicate the soil ecological environment of different agricultural land-use. The research results provide basic data for the biodiversity protection of soil animals in different agricultural land-use in the buffer zone of Shibing Karst World Natural Heritage.

Modeling Land Use and Management Practices Impacts on Soil Organic Carbon Loss in an Agricultural Watershed in the Mid-Atlantic Region

Measuring organic carbon (OC) losses from soils presents a challenge because of the intricate interplay of human-induced and biophysical processes. This study employs SWAT-C to simulate particulate OC (POC) and dissolved OC (DOC) losses from the Upper Maurice Watershed in the Mid-Atlantic Region. Simulation outcomes reveal that surface runoff was the primary contributor to the total DOC load (65%), followed by lateral flow (30%), and then groundwater (5%). Meanwhile, POC load was linked to erosion processes induced by surface runoff. Our findings indicate that agricultural land-use types exhibited the highest annual average DOC and POC loads. Forests and grasslands displayed intermediate loads, while barren land had the lowest load. Concerning seasonal fluctuations, agricultural land-use types exhibited distinct DOC and POC load patterns when compared to forest and grassland types, indicating the dominant role of management practices in determining soil OC (SOC) losses. Additional modeling of management practices’ impact on SOC budgets indicates maximal SOC sequestration with full irrigation, no-till (NT), and full fertilization. In contrast, the largest SOC depletion arises from combining conservation tillage (CT) and no fertilization, irrespective of irrigation. This study shows that SWAT-C can be used to simulate land use and management impacts on SOC dynamics.

Quantitative Evaluation of the Crop Yield, Soil-Available Phosphorus, and Total Phosphorus Leaching Caused by Phosphorus Fertilization: A Meta-Analysis

Phosphorus (P) leaching from excessive P application is the primary pathway of P losses in agricultural soils. Different P fertilizer practices have mixed effects on P leaching. We conducted a meta-analysis of the relevant literature regarding the response of crop yields, soil-available P (AP), and total P (TP) leaching to reduced P input (RP) and an inorganic-organic combination fertilizer (NPKM) for different agricultural land-use types. Compared to conventional P application (CP), RP (10~90% reduction) did not reduce crop yields in vegetable fields (experiments were 1~4 years) but significantly reduced cereal yields by 4.57%. Compared to chemical fertilizer (NPK), NPKM significantly increased cereal yields by 12.73%. Compared to CP, RP significantly reduced AP at 0~60 cm in vegetable and cereal fields. The greatest reduction occurred at 20~40 cm in vegetable fields (40.29%) and 0~20 cm in cereal fields (34.45%). Compared to NPK, NPKM significantly increased the AP at 0~60 cm in vegetable fields, with the greatest increase (52.44%) at 20~40 cm. The AP at 0~40 cm in cereal fields significantly increased under the NPKM treatment, with the greatest increase at 0~20 cm (76.72%). Compared to CP, RP significantly decreased TP leaching by 16.02% and 31.50% in vegetable and cereal fields, respectively. Compared to NPK, NPKM significantly increased TP leaching in vegetable fields (30.43%); no significant difference in leaching occurred in cereal fields. P leaching, in response to RP, was influenced by the P amounts applied (34.49%); soil organic matter (14.49%); and TP (12.12%). P leaching in response to NPKM was influenced by multiple factors: rainfall (16.05%); soil organic matter (12.37%); soil bulk density (12.07%); TP (11.65%); pH (11.41%). NPKM was more beneficial for improving yields in cereal fields with low soil fertility and lower P-leaching risks.

Vertical changes in P-acquiring enzyme activities and microbial biomass in Luvisols – The effect of different types of agricultural land use and soil-forming processes

The activities of enzymes involved in the transformation of soil organic P are rarely measured in soils below a 30 cm depth, even though substantial amounts of P are also stored in deep soils. Changes in soil microbial biomass and the activities of P-cycling enzymes with depth were determined across the eight Luvisol profiles in four agricultural land uses including lucerne, winter wheat, vineyards and orchards. The activities of acid phosphatase (AcP), alkaline phosphatase (AlP) and phosphodiesterase (PDE) were assessed, as was the microbial biomass carbon (MBC) and phosphorus content (MBP) as well as some physico-chemical properties (e.g. total organic carbon – TOC, total nitrogen – TN, available phosphorus – Pavail, bulk density, pH in CaCl2). Additionally, mass and morphological parameters of the plant roots were also determined. The highest enzymatic activity and microbial biomass C and P content were found in the surface and sub-surface horizons and decreased with depth to varying degrees in parallel to the changes in TOC and TN. The studied properties were primarily determined by means of the organic C content and availability in all genetic horizons, while the influence of the lessivage (clay content) was only clearly pronounced for AcP activity, which was significantly higher in the illuvial layers (E) as compared to the eluvial horizons (Bt) in most of the considered profiles. What is more, only AcP activity was significantly and positively related to the root biomass and the number of small roots in the plants. Although it was revealed that the particular plants being cultivated had a significant impact on AcP activity, the data should be interpreted with caution because other factors (e.g. mineral fertilization) may also contribute to this.

Effects of Different Types of Agricultural Land Use on the Occurrence of Common Aquatic Bugs (Nepomorpha, Heteroptera) in Habitats with Slow Flowing Water in Bulgaria, Southeast Europe

Agricultural activities can have a significant impact on aquatic organisms, including aquatic insects. Most of the aquatic Heteroptera are known as moderately tolerant to low oxygen and high nutrient concentrations. Nevertheless, the complex effects of agriculture (source of both pesticides and nutrient loads) on this group are still unclear. Therefore, the relationship between six agricultural land use classes and the occurrence of common aquatic bugs in Bulgaria was studied. In order to avoid detection bias, presence-only models were applied; Maxent algorithm was used. According to the results, land use practices connected to arable land (annual crops) have stronger influence on the occurrence of the selected aquatic Heteroptera species than those connected to perennial crops (vineyards and fruit trees). Higher sensitivity to the effects of agriculture was indicated for species preferring microhabitats without macrophyte vegetation, Aphelocheirus aestivalis (Fabricius, 1794) and Micronecta griseola Horváth, 1899, compared to species preferring macrophyte dominated sites, Nepa cinerea Linnaeus, 1758, Ilyocoris cimicoides (Linnaeus, 1758) and Sigara striata (Linnaeus, 1758).

Temporal and Spatial Variations in Soil Elemental Stoichiometry Coupled with Alterations in Agricultural Land Use Types in the Taihu Lake Basin

Soil elemental stoichiometry, expressed as the ratios of carbon (C), nitrogen (N), and phosphorus (P), regulates the biogeochemical processes of elements in terrestrial ecosystems. Generally, the soil C:N:P stoichiometry characteristics of agricultural ecosystems may be different from those of natural ecosystems, with distinct temporal and spatial variations along with the alterations of agricultural land use types (LUTs). The balance of soil C, N, and P reflected by their stoichiometry is primarily important to microbial activity and sustainable agricultural development. However, information on soil stoichiometric changes after long-term alterations in land use is still lacking. We characterized the temporal and spatial changes in soil elemental stoichiometry coupled with alterations in agricultural LUTs in the Taihu Lake basin. By using the ArcGIS method and meta-data analysis, our results showed that the C:N, C:P, and N:P ratios of agricultural soil in the Taihu Lake basin were much lower than the well-constrained values based on samples from forest, shrubland, and grassland at a global scale. Generally, these elemental ratios in soils increased from the 1980s to the 2000s, after experiencing changes from agricultural to other land use. The soil C:N:P stoichiometry may have maintained the increasing trend according to the meta-data analysis from the 341 peer-reviewed publications since 2010. Nevertheless, different regions showed inconsistent change patterns, with the Tianmu Mountain area surrounding the downstream of the Taihu Lake basin experiencing a reduction in those ratios. The changes in LUTs and their corresponding management practices were the major drivers shaping the spatial and temporal distributions of soil C:N, C:P, and N:P. Paddy soil generally achieved higher C sequestration potential due to more straw input and a more rapid transfer of straw C into soil C in the upstream of the Taihu Lake basin than other land use types. These results provide valuable information for the agricultural system of intensive cultivation on how their soil elemental stoichiometry characteristics vary temporally and spatially due to the alteration of agricultural land use types.

Effect of Insurance Subsidies on Agricultural Land-Use.

This paper investigates the effect of crop insurance-subsidies on agricultural land-use allocation. Since the objective of crop insurance is to help farmers with risk management, the expected profit from crop production under crop insurance might be improved, leading farmers to allocate more land to crop production. In this paper, agricultural land-use type is classified by irrigated/unirrigated farmland and cropland/woodland/pastureland. The data come from counties from all the continental states. Considering the fractional outcome of land-use share, we apply a multinomial-fractional-logit model to estimate the effects. The results show that insurance subsidies have a significant effect on land-use allocation. An increase in insurance subsidies increases farmland-share, indicating insurance subsidies could be an efficient tool to adjust agricultural land-use allocation.

Agroforestry orchards support greater avian biodiversity than monoculture oil palm and rubber tree plantations

The suitability of agricultural matrices to support biodiversity, including birds, varies depending on agricultural land-use. In Southeast Asia, monoculture plantations of oil palm and rubber tree have replaced the native rainforests and displaced forest biodiversity. Compared to such single functionality plantations, agroforestry orchards may provide a more complex habitat for biodiversity via polyculture and less intensive farming practices. However, little is known about the conservation value of agroforestry orchards for biodiversity. Here, we investigated the effects of different agricultural habitats on avian biodiversity in Peninsular Malaysia. Using point count method, we assessed bird community in three focal agricultural habitats (i.e., agroforestry orchards, oil palm, and rubber tree plantations). From 6,248 bird encounters, we recorded 110 species comprising 43 families. Bird species richness and abundance were significantly greater in agroforestry orchards than the other two agricultural habitats. Bird abundance was similar in oil palm and rubber tree plantations, but the latter supported significantly more species. Agricultural land-use type had significant effects on certain bird dietary groups (i.e., frugivores, insectivores, omnivores, and granivores). Overlap in bird species composition between habitats was rather evident, though some bird groups were more represented than others in the different habitat types. Our key findings may imply the importance of habitat heterogeneity in relation to vegetation structural complexity (as commonly found in fruit orchards) on farmland birds. Our data suggest that incorporating diverse native fruit trees into large-scale monoculture plantations could promote habitat heterogeneity and floristic composition, which can improve bird conservation and ecosystem services (e.g., pest insect control).

Impact of Local Grasslands on Wild Grass Pollen Emission in Bavaria, Germany

Meteorological conditions and the distribution of pollen sources are the two most decisive factors influencing the concentration of airborne grass pollen. However, knowledge about land-use types, their potential pollen emission, and the importance of local sources remains limited. In this study, wild grass pollen concentrations from 27 stations in Bavaria, Germany, were linked to potential pollen within a 30 km radius. Agricultural grass pollen sources were derived from the InVeKos database, which contains detailed information on agricultural land-use types and their spatial distribution. Non-agricultural grassland was identified by OpenStreetMap. Further source classification was conducted using a cultivation intensity indicator and wind direction. We show that the grassland percentage and pollen concentrations, specified as annual pollen integral and pollen peak vary strongly between pollen stations. Correlation analyses indicated that the impact of the grassland on pollen concentration was greater within 10 km of the pollen traps. At greater distances, the correlation coefficient between the grassland percentage and pollen indicators steadily declined.

Factors affecting cadmium accumulation in the soil profiles in an urban agricultural area

Soil Cd pollution is a serious environmental issue associated with human activities. However, the factors determining exogenous Cd dynamics in the soil profile in a complex environment are not well understood. Based on regional observations from 169 soil profiles across the Chengdu Plain, this study explored the key factors controlling Cd accumulation in the soil profile under actual field conditions. Results showed that total soil Cd contents decreased from 0.377 to 0.196 mg kg−1 with increasing soil depth. The effects of phosphate fertilizer rates, road density and precipitation on the difference in total soil Cd content were only observed in topsoil, while agricultural land-use type and topography had no impact. In contrast, significant differences in the total soil Cd content among different parent material types were found in the 0–20, 40–60 and 60–100 cm soil depths. One sample t-tests showed that significant Cd accumulation occurred in the whole soil profile in soils formed from Q4 (Quaternary Holocene) grey alluvium, while soils formed from Q3 (Quaternary Pleistocene) old alluvium and Q4 grey-brown alluvium showed significant Cd accumulation only in the 0–40 cm soil layers. In the topsoil, acid soluble Cd accounted for the largest proportion of the total Cd in soils formed from Q4 grey alluvium, reducible Cd was the main fraction in soils formed from Q4 grey-brown alluvium, while reducible Cd and residual Cd contributed the largest proportion of the total soil Cd in soils formed from Q3 old alluvium. The above results indicated that parent material was the decisive factor determining the magnitudes and depths of exogenous Cd accumulation in the soil profile due to its impacts on the Cd fraction distributions. These findings suggested that the parent material-induced Cd fraction distributions and accumulation should be considered for effectively exploring targeted remediation strategies for Cd pollution.

Why a landscape view is important: nearby urban and agricultural land affects bird abundances in protected areas

Protected areas are one of the primary conservation tools used worldwide. However, they are often embedded in a landscape that is intensely used by people, such as for agriculture or urban development. The proximity of these land-use types to protected areas can potentially affect the ecological effectiveness (or conservation effectiveness) of protected areas. In this article, we examine to what degree adjacent agricultural and urban land uses affect the ecological effectiveness of protected areas over the greater Gauteng region of South Africa. We selected 198 common, resident bird species, and analysed detection/non-detection data for these species collected over regular grid cells (approximately 61 km2 in area). For each species, we estimated abundance per grid cell with the Royle-Nichols model in relation to the proportion of protected area as a covariate. Our study focused on how this relationship between proportion of protected area and abundance (which we term the ‘protection–abundance relationship’) changed as a function of other land-use types in the grid cell. Specifically, we examined the interaction effects between protected area and both urban and agricultural land-use type per grid cell on bird abundance. We assigned each species to one of seven guilds, namely: frugivores, gleaners, granivores, ground-feeders, hawkers, predators and vegivores, and examined how the protection–abundance relationship varied across guilds in relation to agriculture and urban area. As urban area within a grid cell increased, the protection–abundance relationship became more positive for 58% of all species. At the level of guilds, the protection–abundance relationship became more positive for two guilds (granivores and ground-feeders), more negative for frugivores, and remained unchanged for the other four guilds (gleaners, hawkers, predators and vegivores). As agricultural area within a grid cell increased, the protection–abundance relationship became more positive for 49% of all species. At the guild level, the protection–abundance relationship became more positive for six guilds (frugivores, gleaners, ground-feeders, hawkers, predators and vegivores) and remained unchanged for the granivores. Our results show land-use type near protected areas modified the effect protected areas had on bird abundances, and hence the ecological effectiveness of protected areas. Our results suggest that protected areas should be viewed as constituents within the landscape, rather than islands of protection.

Temporal and spatial variations of soil C, N contents and C:N stoichiometry in the major grain-producing region of the North China Plain.

Soil C, N contents and C:N stoichiometry are important indicators of soil quality, the variation characteristics of which have great significance for soil carbon-nitrogen cycle and sustainable utilization. Based on 597 observations along with soil profiles of 0–20cm depth in the 1980s and the 2010s, the temporal and spatial variations of soil C, N contents and C:N stoichiometry in the major grain-producing region of the North China Plain were illustrated. Results showed that there were significant changes in soil C, N contents over time, with increasing rates of 60.47% and 50%, respectively. The changes of C, N contents resulting in a general improvement of C:N stoichiometry. There was a significant decline in nugget effects of soil C, N contents from the 1980s to 2010s, the spatial autocorrelation of soil nutrients showed an increasing trend, and the effect of random variation was reduced. C:N stoichiometry was higher in Huixian City and Weihui City, and lower in Yanjin County, an apparent decline was observed in the spatial difference of soil C:N stoichiometry from the 1980s to 2010s. Soil C, N contents and C:N stoichiometry differed among soil types, agricultural land-use types, and topography in space. The temperature, precipitation, and fertilization structure were considered as the main factors that induce the temporal variations. These findings indicated that the soil nutrient elements in the farmland ecosystems changed in varying degrees in both time and space scales, and the variation was influenced by soil types, land-use types, topography, meteorological factors, and fertilization structure.

FORECAST EFFECTS OF DROUGHT ON AGRICULTURAL LAND USE BY GIS AND REMOTE SENSING IN BAC TRA MY DISTRICT, QUANG NAM PROVINCE

The phenomenon of prolonged drought as one of the consequences of climate change has significantly affected the agricultural production of rural communities in both mountainous and plain areas of Vietnam. This study, using standardized precipitation index (SPI) combining with the space technologies of Geographical Information Systems (GIS) and Remote Sensing (RS) to simulate and forecast the effects of drought on agricultural land use in Bac Tra My district, Quang Nam province. The data was set up for two scenarios of RCP 4.5 and RCP 8.5 in Bac Tra My district of Quang Nam province. Simultaneously, the research has also applied the focus group discussion, in-depth interview and field survey for data cross-checking to ensure highly reliable predictions. The research result has addressed four levels of drought, including normal, mild, moderate and severe drought appearing in the Summer-Autumn crop in the period 2016 – 2035 of the district. In which, severe drought will appear on large scale for both scenarios of RCP 4.5 and RCP 8.5 for 5 types of agricultural land use including paddy, annual crop, perennial, afforestation and aquacultural land. From these findings, the local authorities can consider and apply the adaptation and mitigation measures to climate change in agricultural land use planning.

The Pyrogenic Archives of Anthropogenically Transformed Soils in Central Russia

Charred materials (anthracomass) stored within a soil constitute a major part of its pyrogenic archive and could provide evidence of past fire events, both natural and anthropogenic. However, the dynamics of man-made contributions to the total anthracomass of soil at different time scales are insufficiently understood. In this study, we determined the anthracomass concentrations, stocks, and particle-size distribution in anthropogenically transformed soils of different genesis and ages. Materials were collected from the following archaeological sites within Central Russia—3 Upper Paleolithic sites (Avdeevo, Khotylevo-2 and Yudinovo-1), 2 Early Iron Age settlements (Khotylevo-2 and Yaroslavl), and 1 Medieval site (Yaroslavl). Samples from different cultural layers (CLs), plough layers, and native soils (control) were studied. We identified anthracomass accumulation over a wide chronological scale starting from the Upper Paleolithic Period. The high degree of preservation of anthracomass in ancient anthropogenically transformed soils was explained by the presence of large fragments of charred bones, which are more durable in comparison to wood charcoal. The anthracomass concentrations and stocks in the Early Iron Age plough layer were lower than those in the Medieval plough layer. CLs were generally more enriched in the anthracomass than plough layers, due to their sedimentational genesis, which is more favorable for anthracomass preservation than the turbational genesis of plough layers. However, the differences between charred particle sizes in synlithogenic CLs and turbational plough layers were less clear than expected, due to the specific conditions of formation of each particular layer, e.g., burial rate, duration of ploughing, and type of agricultural land use.

Spatial variation and driving mechanism of soil organic carbon components in the alluvial/sedimentary zone of the Yellow River

Alluviation and sedimentation of the Yellow River are important factors influencing the surface soil structure and organic carbon content in its lower reaches. Selecting Kaifeng and Zhoukou as typical cases of the Yellow River flooding area, the field survey, soil sample collection, laboratory experiment and Geographic Information System (GIS) spatial analysis methods were applied to study the spatial distribution characteristics and change mechanism of organic carbon components at different soil depths. The results revealed that the soil total organic carbon (TOC), active organic carbon (AOC) and nonactive organic carbon (NOC) contents ranged from 0.05–30.03 g/kg, 0.01–8.86 g/kg and 0.02–23.36 g/kg, respectively. The TOC, AOC and NOC contents in the surface soil layer were obviously higher than those in the lower soil layer, and the sequence of the content and change range within a single layer was TOC>NOC>AOC. Geostatistical analysis indicated that the TOC, AOC and NOC contents were commonly influenced by structural and random factors, and the influence magnitudes of these two factors were similar. The overall spatial trends of TOC, AOC and NOC remained relatively consistent from the 0–20 cm layer to the 20–100 cm layer, and the transition between high- and low-value areas was obvious, while the spatial variance was high. The AOC and NOC contents and spatial distribution better reflected TOC spatial variation and carbon accumulation areas. The distribution and depth of the sediment, agricultural land-use type, cropping system, fertilization method, tillage process and cultivation history were the main factors impacting the spatial variation in the soil organic carbon (SOC) components. Therefore, increasing the organic matter content, straw return, applying organic manure, adding exogenous particulate matter and conservation tillage are effective measures to improve the soil quality and attain sustainable agricultural development in the alluvial/sedimentary zone of the Yellow River.

Estimation of soil carbon stock in some wetlands of the northeastern region of Bangladesh

An investigation was carried out in some wetland soils of the northeastern region of Bangladesh up to 100 cm depth of both medium high and lowlands to estimate the carbon (C) stock as well as evaluate the impact of anthropogenic activities in these ecosystems. Among these wetland soils, C stock was found to be the highest in Nikli wetland (4.5 Tg), succeeded by Hakaluki (4.0 Tg), Hail (2.8 Tg) and Balai wetland soils (2.5 Tg). The C stock was higher in the medium low land sites in contrast to medium high land sites. The soil reaction, bulk density, nitrogen content, soil carbon-nitrogen dynamics and soil organic carbon (SOC) storage were investigated in the studied sites as well in different vertical scales. Among the investigated wetland soils, Hakaluki wetland stored greater amount of SOC in the deeper soil layers whereas an inverse relationship between soil depth and SOC storage was noted for rest of the wetlands. Moreover, C stock in basin regions was gradually lessening in greater magnitude which may lead to higher carbonaceous gas emissions. Management practices including restoration of the drained agricultural land-use types to flooded conditions, balanced fertilization along with organic manure and water management practices should be adopted to restore these wetland soils as a C sink from the C source.

Assessment of agricultural land loss due to mining in Moscow region

The study discusses the impact of open cuts for the extraction of common minerals on soil resources and agricultural lands in Moscow region (MR). For this, the features of soil cover in Moscow region and the distribution of soil types by their use as agricultural resources were analyzed. Further, it was determined which types of soils are subject to varying degrees of open cut load. As a result, a schematic map of the soil cover with open cut load zones was made. It is shown which agricultural lands exposed to open cuts of varying intensity. A conclusion is made about the types of soil cover, which accounts for the greatest and least open cut load, as well as the degree of impact of open cuts on agricultural land resources and the correlation between the degree of open cut load and type of agricultural land use. It is shown that the most fertile soils, which occupy only 2.9% of the MR area, are not affected by the open cut load at all. The greatest open cut load is associated with agricultural lands, represented mainly by various sod-podzolic soils, which occupy 70.5% of the territory of the Moscow region. If economic trends and population growth rates in the Moscow region continue until 2030, we should expect a further increase in the influence of open cut load on agricultural land towards its intensification.

Potential risks of invasive alien plant species on agriculture under climate change scenarios in Sri Lanka

Invasive alien plant species (IAPS) have had a significant impact on agriculture in many countries in the world. Climatic suitability maps can be used to assess the vulnerability of agricultural areas for potential plant invasions. We used climatic suitability heat maps of IAPS to examine how potential climatic suitability for multiple IAPS invasion changes in eight agricultural land-use types in Sri Lanka under climate change scenarios for 2050. The findings of the study revealed that all evaluated agricultural land-use types are potentially vulnerable to invasion by different numbers of IAPS. In the majority of land-use types, the climatic suitability for multiple IAPS was predicted to increase under climate change scenarios. Out of all land-use types, coconut grown areas are expected to have the greatest suitability increase for more than three IAPS. Nearly all paddy lands were predicted to become suitable for two serious aquatic invaders (Eichhornia crassipes and Salvinia molesta) under current climatic conditions. However, a noticeable reduction in climatic suitability for IAPS was predicted in paddy lands by 2050. The study provides useful information that can be used by policy-makers to develop effective control and management strategies against the establishment of IAPS in agricultural land-uses in Sri Lanka.