Adjacent Agricultural Land Research Articles

Exploring the Spatiotemporal Heterogeneity of Stream Nitrogen Concentrations in a Typical Human‐Activity‐Influenced Headwater Watershed in South China

AbstractStream nitrogen concentrations significantly impact nitrogen loads and greenhouse gas emissions, but their spatiotemporal heterogeneity and human influences remain highly uncertain. This study thoroughly explored the spatiotemporal variations in stream nitrogen concentrations in a typical headwater watershed in South China. Spatially distributed measurements were conducted during 2020–2022, and mathematical modeling was implemented based on incorporating these data. More than 4,400 data points were collected for water temperature and concentrations of ammonium nitrogen (NH4‐N), nitrate nitrogen (NOx‐N), dissolved total nitrogen (DTN), total nitrogen (TN), and dissolved oxygen. Results showed that NOx‐N was the largest component of TN, with average concentrations of 1.20 and 1.66 mg L−1, respectively. The stream N2O concentration could be predicted using NH4‐N and NOx‐N concentrations via the Michaelis‐Menten equation. Significant downstream decreases in NH4‐N, NOx‐N, DTN, and TN concentrations were identified in the largest river in the watershed, and clear spatial differences in these nitrogen concentrations existed among the three main rivers. Clear seasonal and annual variations in stream nitrogen concentrations were observed. NH4‐N, NOx‐N, DTN, and TN concentrations correlated with cumulative precipitation from the preceding 8–12 days, while stream N2O concentrations correlated over 13–20 days. Stream N2O concentrations and emissions averaged 12.77 nmol L−1 and 1.12 nmol m−2 s−1, respectively, and were lower in summer than in other seasons. Upstream tea plantations, villages, and adjacent agricultural lands significantly affected nitrogen concentrations, while overflow dams did not. These findings highlight nitrogen cycle's complexity and the need for high‐resolution data to guide effective watershed management.

Assessment of Landfills and their Impact on the Soil: a Local Study in Ukraine

Landfills are widely utilised for waste disposal due to their economic advantages and ease of implementation compared to alternative methods. However, landfills exert significant environmental and health impacts on adjacent agricultural land. Accumulation of heavy metals in soil is a risk to ecological and food safety. Methodological approaches to assess and mitigate the impact of landfills on agricultural land are essential for ensuring sustainable land use practices and safeguarding human health. In this study, landfills were assessed at the local level, and the hazard level was classified according to it. A set of priority measures for restoring technogenic disturbed areas and minimising their impact on agricultural land was determined. The need to select a set of innovative, ecologically oriented methods for remediation of landfills, depending on the type and degree of soil contamination, was identified in context of ensuring environmental and food security.

Beyond biomass production: Enhancing biodiversity while capturing carbon in short rotation coppice poplar plantations

Biodiversity is essential for the functioning of ecosystems and the provision of services. In recent years, the role of plantations in mitigating climate change through carbon sequestration has been highlighted. In the Mediterranean area, high-density poplar plantations in short-rotation with resprouting management (SRC) have been established for biomass purposes on mostly irrigated agricultural land, coexisting with rainfed and irrigated agricultural crops. This study aims to assess the contribution of these plantations to this type of agroforest ecosystem in terms of biodiversity. For this purpose, both flora and fauna diversity were evaluated both within and outside of the plantation. Additionally, the accumulated carbon in the biomass, as well as in the accompanying vegetation within the plantation, was assessed. Different indices were used to evaluate both the intrinsic diversity of the forest plantation and the degree of substitution and complementarity between the different communities of the landscape. Our findings reveal distinct biodiversity patterns in the land-use scenarios sampled. Specifically, we observed significantly higher flora-species richness in SRC plantations than in the adjacent agricultural land, whereas fauna richness showed a similar but slightly higher level in the forested area. A moderate level of complementarity between land uses was found for insects and mammals (around 45 %), contrasting with high complementarity for birds (87 %) and flora (90 %). This suggests substantial turnover and replacement among these ecological environments. Our results indicate that a second rotation (4 year) plantation could accumulate a total of 61.6 Mg C ha−1, and even though adventitious flora represents <2 % of the total carbon accumulated, its importance in providing ecosystem services is considerable. Hence, these findings evidence the fact that SRC poplar plantations can enhance biodiversity in Mediterranean agroforest ecosystems and actively contribute to various provisioning ecosystem services, including carbon sequestration, reflecting a multi-objective approach that extends beyond biomass production.

Local social-ecological context explains seasonal rural-rural migration of the poorest in south-west Bangladesh

Bangladesh is one of the countries most affected by climate change. Internal migration is often presented as a response to environmental degradation. Here, using a people-centred perspective, we explore the complexity of the links between climate-induced change, environmental degradation caused by waterlogging and seasonal rural migration. We used an inductive qualitative approach in social sciences, conducting fourteen semi-directed interviews and six focus group discussions in March-April 2022. We related those results to a rainfall analysis on CHIRPS data for 1981-2021and we represented interactions and feedback between changes and livelihoods in a model. A complex picture of the situation is emerging, showing the interweaving effects of non-climatic and climatic changes, their interplay at different scales, their cumulative effects, the interactions between livelihood types and feedback between social and natural systems. Most of the climate-induced changes gradually become noticeable over the past 25 years. Climate data confirm these changes in recent decades, with July being wetter and January being dryer. Villagers reported waterlogging as the most significant change in their community, pointing to its multiple causes, originating in non-local and local, non-climatic anthropic changes, exacerbated by shrimp farm enclosures and worsened by climate-induced changes such as heavier rains, wetter monsoons and cyclones. Tiger prawn farms, reported as a lucrative and local adaptation to waterlogging and salinisation for the ones who can afford it, worsen the situation for the less wealthy, causing waterlogging and salinisation of the adjacent agricultural lands and buildings, the disappearance of traditional fishing and a reduction of the local job market. In addition, erratic rain patterns, droughts and cyclones affect local production and labour markets. COVID-19 lockdowns, by impacting markets and mobilities, further aggravated the situation. Inequality has increased as the range of adaptations of the less wealthy appears limited in this context of multiple crises.

Living at the edge: home range patterns of the Buraiga Chimpanzee Community, Kibale National Park, Uganda

Data on space-use patterns are essential for understanding species ecology and conservation. Individual chimpanzee communities are known to vary in home range size and habitat use dynamics, reflecting site-specific strategies to differences in resource availability on different landscapes. Here we present home range estimates for the Buraiga chimpanzees of Kibale National Park, Uganda, a community of eastern chimpanzees (Pan troglodytes schweinfurthii) living within the largest remaining population fragment in Uganda. The Buraiga chimpanzees are currently undergoing habituation for research and tourism under the direction of the Uganda Wildlife Authority (UWA). We analyzed 15 months of GPS data (August 2019 – March 2020, and January – July 2022), calculating overall and seasonal home range and core area estimates with two methods, minimum convex polygon (MCP) and kernel density estimates (KDE). Home range was estimated to cover an area of 15.77 km2 (95% KDE), and 24.90 km2 (100% MCP). Additionally, we found that 15.82% of the Buraiga chimpanzee’s home range overlaps with community-managed land, primarily the Kanyanchu Swamp corridor and adjacent agricultural land. Seasonally, we found that Buraiga chimpanzees used a larger area during dry season months, compared with rainy season months. Documenting how great ape populations utilize increasingly anthropogenically influenced landscapes is important in order to facilitate long-term survival in the face of climate change, habitat fragmentation, and other ongoing threats.

Influence of forest types on soil physicochemical and biological characteristics of associated agroecosystems in the central Himalaya

Forests significantly influence the dynamics of microbial biomass and soil nutrients in neighboring agricultural lands. Little information is available on how forest types affect the physicochemical and microbial dynamics of soil in surrounding agroecosystems. The present study evaluated the influence of forest types on soil physicochemical and biological characteristics of forest and associated agricultural systems in the Himalaya. The study was conducted in three forests Banj-oak (OF), Chir-pine (PF), and Nepalese-alder (AF)) and adjacent agricultural lands (OA, oak-adjacent), (PA, pine-adjacent), and (AA, alder-adjacent). Soil samples were collected from three depths (0–10, 10–20, and 20–30 cm). Using two-way ANOVA, soil variables were tested for their effects, including interactions among land-use types and depths. PCA was used to investigate the relationship between land-use types, soil depths, and soil physicochemical and biological characteristics. ANOVA results showed that soil porosity (Po), organic carbon (Corg), total nitrogen (Ntl), bioavailable phosphorous (Pavl), microbial biomass carbon (Cmic), and nitrogen (Nmic) significantly varied (p < 0.05) across land-use types, soil depths, and land-use types × soil depths (p < 0.001) and followed: AF > AA> OF>OA > PF > PA. The soil moisture (Mo), Corg, Ntl, Pavl, Cmic, and Nmic declined with soil depths: 0–10 > 10–20 > 20–30, although variations between lower-surface depths (10–20 and 20–30 cm) were not significant. PCA analysis showed that soil Corg, Po, and pH were the primary regulators of microbial biomass across land-use types and soil depths. Compared to PF, AF and OF have a greater positive influence on soil nutrients and microbial biomass of adjacent agroecosystems. In conclusion, forest vegetation type influences soil microbial biomass by buffering soil substrate (e.g., Corg, Ntl, pH) in forest and adjacent agricultural lands. The findings may help in developing strategies for sustainable agriculture adjacent to forest ecosystems, by maintaining long-term soil quality in the central Himalaya.

Lowland bamboo (Oxytenanthera abyssinica) deforestation and subsequent cultivation effects on soil physico-chemical properties in northwestern Ethiopia

In Ethiopia, bamboo thickets and woodlands play an important role in soil-water conservation and climate change mitigation in arid and semi-arid regions. However, bamboo mass flowering, rapid demographic changes and expansion of agricultural investments into bamboo dominated areas have led to deforestation and land degradation. This study assessed the effects of deforestation and subsequent cultivation on soil physical and chemical properties along a chronosequence of closely located agricultural lands with different times (1, 3, 5 and 7 years) since conversion from natural lowland bamboo forest. Soil samples (n = 90) were taken from both natural bamboo forests and adjacent agricultural lands at two soil depths (0–20 cm and 20–40 cm). Cation exchange capacity (CEC), K+, Ca2+, Mg2+ and available P varied significantly among cultivation periods and soil depth, while soil pH and Na+ varied with soil depth (P < 0.001). Soil C and total N contents (g/kg) in the 0–20 cm soil layer declined significantly and exponentially with increasing years under cultivation. Conversion of natural bamboo forest to cropland during the past seven-year period significantly increased soil pH with soil depth, while CEC declined throughout the cultivation period and with soil depth. In general, the results revealed that conversion of natural lowland bamboo forest and subsequent cultivation of the soil had negative effects on the measured soil physico-chemical properties.

Heritage contestation in matterscape, mindscape, and powerscape

Landscape heritage is frequently contested as perspectives on heritage and landscape may vary across stakeholders. The present article makes a novel contribution by examining pathways to landscape heritage contestation. We propose a distinction between (a) heritage as object in matterscape, being the physical landscape out-there, (b) heritage as meaning in mindscape, being the landscape as experienced by a subject, and (c) heritage as political act in powerscape, being the landscape as rules that organise behaviour. Contestation, then, might originate in matterscape, mindscape, or powerscape. We illustrate these pathways to contestation upon analyses of semi-structured interviews among stakeholders of Schokland, The Netherlands, a World Heritage site. Findings reveal contestation about matterscape pertaining to the issue whether a water system leads to wet spots on adjacent agricultural land, about mindscape pertaining to the beauty of new nature developed around Schokland, and powerscape pertaining to the rules associated with the World Heritage status.

Biogeochemical and physiological adaptability of winter wheat (Triticum L.) under the influence of heavy metals in the Forest-Steppe of Ukraine

In recent decades, the main objects of biogeochemical research have become the territories of agroecosystems, industrial cities and adjacent agricultural lands. The problem of environmental pollution with pollutants, chemical compounds of microelement composition is one of the most important problems of environmental safety. At present, modern studies of scientists consider toxic heavy metals as the most dangerous pollutants of soil, water and plant products of agriculture. In addition, the most active agents of pollution are their mobile chemical forms, which are able to pass from solid phases into soil and water solutions and be absorbed by plants and other organisms. Cereal crops have the ability to absorb nutrients both through the root system and the leaf apparatus, the surface of the stem. Also, trace elements are involved in many physiological and biochemical processes in plants, including acceleration of development, flowering, fertilization and fruiting, metabolism, etc. Quantitative characteristics of the migration of heavy metals from soil to plants during 2022 were evaluated for the studied territories of the Forest Steppe of Ukraine, in particular in Kyiv and Vinnytsia regions. Complex studies were carried out to determine the influence of Zn2+ and Cu2+ on phytocomponents of ecosystems. At the same time, data were obtained on the effect of zinc and copper salts on seed germination and growth of winter wheat seedlings. It is shown that, depending on the concentration of salts, there is a different effect on seed germination. As you know, heavy metals have a mutagenic, toxic effect and affect the intensity of biochemical processes. The authors established that according to the ecotoxicological criterion of bioaccumulation in the «soil — plant» system, the studied trace elements can be arranged in the following order: Cu2+ &gt; Zn2+. Based on the results of experimental and theoretical research, a comparative analysis of the accumulation of heavy metals in the organs of Triticum aestivum (vulgare) L. (common wheat) is presented. According to the results of field experience, differences in the distribution of Zn 2+ and Cu 2+ in the organs of winter wheat have been established, grown on typical chernozem and gray podzolized soils. It was found that the main barrier function of the inactivation of the investigated heavy metals is performed by the roots of plants.

Soil carbon dioxide (CO2) fluxes in permanent upslope pasture and downslope riparian buffers with varying vegetation

AbstractBackgroundRiparian buffers are primarily implemented for their water quality functions in agroecosystems. Their location in the agricultural landscape allows them to intercept and process pollutants from immediately adjacent agricultural land. Vegetated riparian buffers recycle soil organic matter, which elevates soil carbon (C), which upon processing, processes and releases carbon dioxide (CO2). The elevated soil C and seasonally anoxic environments associated with riparian buffers promote denitrification and fermentation, further increasing soil CO2 production.AimAgainst this context, a replicated plot‐scale experiment was established at North Wyke, UK, to measure the extent of soil CO2 emissions in permanent pasture served by grass, willow, and woodland riparian buffers, as well as a no‐buffer control.MethodsSoil CO2 was measured using the static chamber technique in conjunction with soil and environmental variables between June 2018 and February 2019.ResultsCumulative soil CO2 fluxes were in the descending order: woodland riparian buffer; 11,927.8 ± 1987.9 kg CO2 ha–1 &gt; no‐buffer control; 11,101.3 ± 3700.4 kg CO2 ha–1 &gt; grass riparian buffer; 10,826.4 ± 2551.8 kg CO2 ha–1 &gt; upslope pasture; 10,554.6 ± 879.5 kg CO2 ha–1 &gt; willow riparian buffer; 9294.9 ± 1549.2 5 kg CO2 ha–1. There was, however, no evidence of significant differences among all treatments of the current study.ConclusionsDespite the lack of significant differences, the results from our short‐term study show that the woodland riparian buffer had relatively larger soil CO2 emissions than the remainder of the other riparian buffers and the upslope pasture it serves. Our short‐term findings may be useful in developing soil CO2 mitigation strategies through careful selection of riparian buffer vegetation and may be useful in calibrating mechanistic models for simulating such emissions from similar agro systems.

Degradation of Adjacent Agricultural Land with Leachates of Packaged and Waste Food Dumped Near It

Physico chemical parameters of dumped food leachates at dump site adjacent agricultural soil at Chapra city, Bihar were investigated for possible pollution impacts. Soil samples were collected in three replicates from two sampling points within the dump site and for control soil samples were collected about 200m. Standard methods were used to determine the following parameters. The pH of leachate affected soil ranged between 7.3 to 7.5 while in control it was 7.6 to 7.8. The electric conductivity 3.6 to 3.82 while in control 1.89 to 1.91, sodium % 5.62 to 7.86 in LAS and 4.25 to 4.68 in control, organic matter g/kg = 16.7 to 20.5 in LAS and 14.30 to 17.64 in control. Calcium carbonates (g/kg) 288.6 to 305.4 in LAS and 264.6 to 280.2 in control. Total nitrogen % in LAS 0.36 to 0.42% and 0.2 to 0.24 in control available phosphorous in mg/kg in LAS. 14.5 to 11.6 mg/kg and 8.62 and 9.15 mg/kg in control. Available potassium in LAS required between 432.4 to 451.6 mg/kg and 332.3 to 362.7 mg/kg in control amount of calcium 14.2 to 16.5 Cmol/kg in LAS and 12.2 to 12.8 Cmol/kg in control. The magnesium contents ranged between 4.2 to 4.6 Cmol/kg in LAS and 3.60 to 3.90 C mol/kg in control.

Deforestation for agriculture leads to soil warming and enhanced litter decomposition in subarctic soils

Abstract. The climate-change-induced poleward shift of agriculture could lead to enforced deforestation of subarctic forest. Deforestation alters the microclimate and, thus, soil temperature, which is an important driver of decomposition. The consequences of land-use change on soil temperature and decomposition in temperature-limited ecosystems are not well understood. In this study, we buried tea bags together with soil temperature loggers at two depths (10 and 50 cm) in native subarctic forest soils and adjacent agricultural land in the Yukon Territory, Canada. A total of 37 plots was established on a wide range of different soils and resampled after 2 years to quantify the land-use effect on soil temperature and decomposition of fresh organic matter. Average soil temperature over the whole soil profile was 2.1 ± 1.0 and 2.0 ± 0.8 ∘C higher in cropland and grassland soils compared to forest soils. Cumulative degree days (the annual sum of daily mean temperatures &gt; 0 ∘C) increased significantly by 773 ± 243 (cropland) and 670 ± 285 (grassland). Litter decomposition was enhanced by 2.0 ± 10.4 % and 7.5 ± 8.6 % in cropland topsoil and subsoil compared to forest soils, but no significant difference in decomposition was found between grassland and forest soils. Increased litter decomposition may be attributed not only to increased temperature but also to management effects, such as irrigation of croplands. The results suggest that deforestation-driven temperature changes exceed the soil temperature increase that has already been observed in Canada due to climate change. Deforestation thus amplifies the climate–carbon feedback by increasing soil warming and organic matter decomposition.

Assessment of water quality with comparative study of soil organic carbon stock in Nagdaha Lake and its adjacent agricultural land of Lalitpur, Nepal

Abstract. Bhatta M, Joshi R. 2023. Assessment of water quality with comparative study of soil organic carbon stock in Nagdaha Lake and its adjacent agricultural land of Lalitpur, Nepal. Intl J Bonorowo Wetlands 13: 9-16. The lakes are an important component of the terrestrial Carbon (C) cycle. Estimates of global C burial by lakes suggest burial rates ranging from 0.03-0.07 Pg C yr?1. In the present study, the water quality of Nagdaha Lake and comparative analysis of Soil Organic Carbon (SOC) in Nagdaha Lake and its adjoining agricultural area has been studied. Water quality was determined following APHA (1998); SOC was determined by the Walkey and Black (1934) Titration Method. The present study results show that the mean N-nitrate and P-phosphate concentration in the waters of Nagdaha Lake is 0.135 mg/L and 0.123 mg/L, respectively, and the mean SOC concentration of Nagdaha Lake (71.39±42.58g kg-1) is higher than the adjacent agricultural land (14.36±8.38g kg-1). The t-test result also shows that there is a significant difference in SOC concentration in lakes (t = 9.18) and agricultural (t = 7.66) for agricultural land (p &lt; 0.0001). Nagdaha Lake's area decreased from 52 ropani to 42 ropani between 1964 and 2022. Despite the decrease in area, Nagdaha Lake has more carbon per unit area than agricultural land. Since the conversion of lake land to agricultural land can release a large amount of carbon into the atmosphere, it is imperative to preserve the lakes to mitigate increasing atmospheric CO2 concentration.

Wetland vegetation regeneration in response to tidal reinstatement on an abandoned sugar cane farm

Supratidal wetlands are threatened by agricultural production and are highly vulnerable to climate change, particularly through sea level rise (SLR). While vegetation structure and composition of supratidal wetlands will likely change under projected SLR with run‐on effects for ecosystem service provision, these changes can provide opportunities for restoration of adjacent agricultural land. Here, we investigated the natural regenerative potential of supratidal wetlands on abandoned agricultural land in Southeast Queensland, Australia, specifically, responses of wetland vegetation communities to simulated SLR, through tidal reinstatement. In 15 years since crop abandonment, distinct communities of typical supratidal wetland vegetation have naturally reestablished, in predominately freshwater conditions, with minimal management intervention. Reinstating tidal floodwater increased the flooded extent and permanence of brackish water. Four repeat surveys of vegetation composition, structure, and condition were conducted in permanent plots established in Casuarina swamp, Melaleuca swamp, herbaceous marsh, and riparian zone vegetation communities, to observe change over time. Species richness decreased in all regenerating communities (Herbaceous marsh, Casuarina, and Melaleuca) post flood gate removal. Understory vegetation cover also decreased in Melaleuca and Casuarina plots, but increased in herbaceous marsh plots, with increased cover of salt‐tolerant species throughout. Changes in woody vegetation community and structure were not observed during this short study (2.5 years), although the regenerative capacity of woody and herbaceous species was reduced. Supratidal wetland vegetation communities can naturally reestablish in areas of abandoned agricultural land, however, increased saltwater flooding (likely with SLR) will put these communities at risk of transition to salt‐tolerant vegetation.

Trace Metals in Two Geoduck Clams (Panopea generosa and P. Globosa) Exploited for the Regional Market from Two Areas of Northwest Mexico.

Biological and fishery features of Panopea sp. clams have been studied in northwest Mexico because of their importance for human consumption. However, the content of pollutants in their tissues, along with their implications have not been addressed yet. The concentrations of cadmium (Cd), copper (Cu), mercury (Hg), and zinc (Zn) in soft tissues of Panopea generosa and P. globosa clams were examined in this region by atomic absorption spectroscopy. The metal concentrations (µg/g wet weight) ranged from 6.5 to 14.2, 0.97-8.09, 0.60-1.18, and 0.01-0.07, for Zn, Cu, Cd, and Hg, respectively. This study proposes that metal presence is related to weathering, upwelling, and drainage from adjacent agricultural lands to the coast. According to the Official Mexican Standard (NOM-242-SSA1-2009) and the World Health Organization (WHO, 2022), the metal content in siphon tissue indicates safe levels for human consumption.

Effect of Wild Boar (Sus scrofa L.) on Forests, Agricultural Lands and Population Management in Lithuania

The wild boar (Sus scrofa L., 1758) is one of the most common and widespread game species not only in the Baltic Sea region but also throughout its entire range. However, quantitative population management is required due to the danger of contagious diseases; the census is imprecise, and integrated management and monitoring are still missing in Lithuania. This study focused on the current condition of the wild boar population at the country level, species activity in forests and adjacent agricultural lands, the problem of damage to agriculture and forestry caused by wild boar, and methods for the management of the wild boar population. A methodology for the assessment of the effect of wild boar will help in reducing their impact. For the successful management of wild boar, an increase in the carrying capacity in conformity with animal density should be accomplished.

Assessment of Water Quality Index in Anzali Lagoon using Multivariate Analysis.

&lt;b&gt;Background and Objective:&lt;/b&gt; Water quality in freshwater bodies is involved with multiple aspects such as physical, chemical and biological processes and their interactions. Due to the vulnerability of water resources, quality control of surface water is one of the key issues in environmental conservation programs. The objectives of the present work were to study the water quality in the Anzali Lagoon and to study the classification of water based on the water quality index in different parts of the Anzali Lagoon. &lt;b&gt;Materials and Methods:&lt;/b&gt; In this study, we sampled water from January to December, 2015 in the Anzali Lagoon. All physicochemical parameters were sampled and determined according to standard methods. &lt;b&gt;Results:&lt;/b&gt; The Water Quality Index results showed the Anzali Lagoon water quality had been "medium" in site 1 and "bad" in sites 2, 3 and 4. The result showed a significant difference between sit 1 and sites 2, 3 and 4 (p<0.05). However, there was no significant difference between sit 2, 3 and 4 (p>0.05). The result showed a clear spatial separation among parts in the Anzali Lagoon. The Eastern part of the Anzali Lagoon showed lower water quality compared to the central and western stations. &lt;b&gt;Conclusion:&lt;/b&gt; This study showed that the level of pollution was different on all of the Anzali Lagoons. The water of the Anzali Lagoon has different quality classes according to the aggregation methods employed. Nutrient loadings from the adjacent agricultural lands combined with high mean salinity values affect all organism conditions. The three primary sources of nutrients, including fertilizers used in agriculture, household waste and livestock waste, reduced the water quality of the Anzali Lagoon.

Soil N2O and CH4 emissions from fodder maize production with and without riparian buffer strips of differing vegetation

PurposeNitrous oxide (N2O) and methane (CH4) are some of the most important greenhouse gases in the atmosphere of the 21st century. Vegetated riparian buffers are primarily implemented for their water quality functions in agroecosystems. Their location in agricultural landscapes allows them to intercept and process pollutants from adjacent agricultural land. They recycle organic matter, which increases soil carbon (C), intercept nitrogen (N)-rich runoff from adjacent croplands, and are seasonally anoxic. Thus processes producing environmentally harmful gases including N2O and CH4 are promoted. Against this context, the study quantified atmospheric losses between a cropland and vegetated riparian buffers that serve it.MethodsEnvironmental variables and simultaneous N2O and CH4 emissions were measured for a 6-month period in a replicated plot-scale facility comprising maize (Zea mays L.). A static chamber was used to measure gas emissions. The cropping was served by three vegetated riparian buffers, namely: (i) grass riparian buffer; (ii) willow riparian buffer and; (iii) woodland riparian buffer, which were compared with a no-buffer control.ResultsThe no-buffer control generated the largest cumulative N2O emissions of 18.9 kg ha− 1 (95% confidence interval: 0.5–63.6) whilst the maize crop upslope generated the largest cumulative CH4 emissions (5.1 ± 0.88 kg ha− 1). Soil N2O and CH4-based global warming potential (GWP) were lower in the willow (1223.5 ± 362.0 and 134.7 ± 74.0 kg CO2-eq. ha− 1 year− 1, respectively) and woodland (1771.3 ± 800.5 and 3.4 ± 35.9 kg CO2-eq. ha− 1 year− 1, respectively) riparian buffers.ConclusionsOur results suggest that in maize production and where no riparian buffer vegetation is introduced for water quality purposes (no buffer control), atmospheric CH4 and N2O concerns may result.

Roadside verges support greater ecosystem functions than adjacent agricultural land in a grassy woodland

Vegetation clearance is the major land use change in agricultural landscape, where woody species are removed to support agricultural production. Native woody species are now largely restricted to the thin strips along the road (roadside verges). Despite the importance of roadside verges as refugia for native species, their impacts on ecological functions and the driving factors have been little explored over extensive areas, limiting our capacity to argue for the retention and improvement of these ‘off-reserve’ habitats within agroecosystems. We compared the magnitude of ecological functions between paired roadside verges and adjacent agricultural land at 111 sites along a vegetation condition gradient in eastern Australia to examine the ecological importance of roadside verges and the potential regulators. Eighty-six percent of our 21 ecological attributes differed between roadsides and adjacent agricultural land, with roadside verges supporting greater carbon stocks, vegetation coverage, plant diversity, habitat complexity and tree recruitment, and were subject to less modification and erosion. These ecological effects strengthened with increasing roadside verge width, particularly for plant cover and diversity, the proportion of native plant species and habitat complexity. Management practices were major regulators of roadside functions, with roadside verge width and site modification negatively associated with tree recruitment and the soil organic carbon pool. Site modification and roadside verge width also indirectly reduced the soil organic carbon pool by either suppressing tree diversity or promoting the proportion of native plant species. Our study provides empirical evidence of the ecological importance of roadside verges in maintaining ecosystem functions and the sustainability of native plant communities in peri-agricultural landscapes. Our study also demonstrates the negative effects of site modification on tree recruitment and soil organic carbon pools, highlighting the importance of mitigating management activities (e.g., tree removal, fire, grazing) in the conservation of roadside verges.

Geophysical and Geochemical Characterization of Solidwaste Dumpsite: A Case Study of Chowa Gujar, Peshawar (Part of Indus Basin)

Open and non-engineered dumping is a typical method for solid waste disposal in most cities of Pakistan. This practice of waste dumping poses a serious threat to the surrounding ecosystem and human population due to the release and transport of decomposed organic matter, i.e., leachate from dumpsite into the groundwater. The present study was conducted over a non-engineered and open dumpsite (Chowa Gujar), located in the outskirts of the highly populated city of Peshawar by using integrated geophysical techniques such as electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) and geochemical techniques. The main goal was to delineate the characterization and depth of buried waste, to map the subsurface extension of contaminant plumes towards agricultural land and groundwater table and the concentration of heavy metals (HMs) in dump and agricultural soil. Geophysical results showed that the thickness of buried waste (predominantly composed of domestic waste) was around 4 m and the leachate plumes have percolated to the adjacent agricultural land. A range of heavy metals (mg/kg) such as Cr (20.5–26.6), Cd (2.6–5.7), Pb (0.35–21.25), Ni (2.5–53.05), Cu (29–68.3), Zn (45.7–77), and Co (18.9–23.2) have been found in the agricultural land adjacent to the dumpsite. The findings demonstrated that combined use of ERT and GPR successfully characterize the buried waste and spread of pollutant plumes spatially and vertically from Chowa Gujar dumpsite. The anomalous geophysical signatures were confirmed by geochemical characterization. The movement of leachate plumes towards agricultural land and groundwater table and the concentration of HMs in soil show that Chowa Gujar dumpsite is a potential source of contamination not only to the surrounding population but also to the agricultural land, surface (Bara River), and subsurface water bodies. In the study region, there is an urgency to take remediation and mitigation measures to reduce the level of pollution created by the dumpsite.