Soil Organic Carbon Stocks in Afforested Agricultural Land in Lithuanian Hemiboreal Forest Zone

In the context of the specificity of soil organic carbon (SOC) storage in afforested land, nutrient-poor Arenosols and nutrient-rich Luvisols after afforestation with coniferous and deciduous tree species were studied in comparison to the same soils of croplands and grasslands. This study analysed the changes in SOC stock up to 30 years after afforestation of agricultural land in Lithuania, representing the cool temperate moist climate region of Europe. The SOC stocks were evaluated by applying the paired-site design. The mean mass and SOC stocks of the forest floor in afforested Arenosols increased more than in Luvisols. Almost twice as much forest floor mass was observed in coniferous than in deciduous stands 2–3 decades after afforestation. The mean bulk density of fine (<2 mm) soil in the 0–30 cm mineral topsoil layer of croplands was higher than in afforested sites and grasslands. The clear decreasing trend in mean bulk density due to forest stand age with the lowest values in the 21–30-year-old stands was found in afforested Luvisols. In contrast, the SOC concentrations in the 0–30 cm mineral topsoil layer, especially in Luvisols afforested with coniferous species, showed an increasing trend due to the influence of stand age. The mean SOC values in the 0–30 cm mineral topsoil layer of Arenosols and Luvisols during the 30 years after afforestation did not significantly differ from the adjacent croplands or grasslands. The mean SOC stock slightly increased with the forest stand age in Luvisols; however, the highest mean SOC stock was detected in the grasslands. In the Arenosols, there was higher SOC accumulation in the forest floor with increasing stand age than in the Luvisols, while the proportion of SOC stocks in mineral topsoil layers was similar and more comparable to grasslands. These findings suggest encouragement of afforestation of former agricultural land under the current climate and soil characteristics in the region, but the conversion of perennial grasslands to forest land should be done with caution.

Soil Organic Carbon Stocks and Its Driving Factors Under Different Land-Use Patterns in Semiarid Grasslands of the Loess Plateau, China

Fencing for grazing exclusion and grazing are common land-use methods in the semi-arid areas of the Loess Plateau in China, which have been widely found to change grassland soil organic carbon (SOC); however empirical studies that evaluated driving factors of soil carbon (C) stocks under the different land use are still weak. In this study, we investigated soil physicochemical and soil respiration (Rs) in the fenced and grazed grassland, to study the soil C stock variations and the main driving mechanism of soil C accumulation. The results showed that bulk density (BD), soil moisture content (SMC), and soil porosity (SP) had no significant difference between fenced and grazed grassland. Fencing increased the SOC, total nitrogen (TN), and C/N ratio, and significantly increased the aboveground biomass (AGB), belowground biomass (BGB), and the amount of soil large macro-aggregates in the topsoil layer (0-10 cm), and the soil stability was improved. Meanwhile, grazing increased soil temperature (ST) and Rs. The soil C stock in the topsoil layer (0-10 cm) of fenced grassland was significantly higher than that of grazed grassland. The soil C/N ratio, BD, and MWD explained large proportions of the variations in soil C stocks. Our results indicate that fencing can improve the stability of soil structure, and reduce Rs, then increase soil C stocks, which is an effective way to improve soil C stocks of grassland ecological in semi-arid areas of northwest China.

Unraveling the Influence of Land-Use Change on δ13C, δ15N, and Soil Nutritional Status in Coniferous, Broadleaved, and Mixed Forests in Southern China: A Field Investigation

Natural isotopic abundance in soil and foliar can provide integrated information related to the long-term alterations of carbon (C) and nitrogen (N) cycles in forest ecosystems. We evaluated total carbon (TC), total nitrogen (TN), and isotopic natural abundance of C (δ13C) and N (δ15N) in soil and foliar of coniferous plantation (CPF), natural broadleaved forest (NBF), and mixed forest stands at three different soil depths (i.e., 0–10, 10–20, and 20–40 cm). This study also explored how soil available nutrients are affected by different forest types. Lutou forest research station, located in Hunan Province, central China, was used as the study area. Results demonstrated that the topsoil layer had higher TC and TN content in the mixed forest stand, resulting in a better quality of organic materials in the topsoil layer in the mixed forest than NBF and CPF. In general, soil TC, TN, and δ15N varied significantly in different soil depths and forest types. However, the forest type did not exhibit any significant effect on δ13C. Overall, soil δ13C was significantly enriched in CPF, and δ15N values were enriched in mixed forest. Foliar C content varied significantly among forest types, whereas foliar N content was not significantly different. No big differences were observed for foliar δ15N and δ13C across forest types. However, foliar δ13C and δ15N were positively related to soil δ13C and δ15N, respectively. Foliar N, soil and foliar C:N ratio, soil moisture content (SMC), and forest type were observed as the major influential factors affecting isotopic natural abundance, whereas soil pH was not significantly correlated. In addition, forest type change and soil depth increment had a significant effect on soil nutrient availability. In general, soil nutrient availability was higher in mixed forest. Our findings implied that forest type and soil depth alter TC, TN, and soil δ15N, whereas δ13C was only driven by soil depth. Moreover, plantations led to a decline in soil available nutrient content compared with NBF and mixed forest stands.

Evaluating application of fractal analysis of environmental radiation monitoring data for description of characteristics of radionuclides migration in the topsoil of the observation area of JSC "SSC RIAR"

The authors present their technique to describe characteristics of radionuclides migration in the topsoil. The developed method is based on the fractal analysis of spatial patterns. For the qualitative analysis Cs-137 and Sr-90 in the topsoil layer was measured. These radionuclides were selected for analysis due to their long half-life and the ability to be easily included in the food chain, that can cause internal or external exposure of the public to the radionuclides. Abnormal diffusion of the radionuclides detected with the use of the fractal analysis speaks on non-classical spatial distribution of the radionuclides. The technique allows improvement of radioenvironmental monitoring program.

Fate of glyphosate and AMPA in the vadose zone: dissipation, transport and adsorption

&lt;p&gt;Broad contamination of systemic herbicide glyphosate &amp;#8211;GLP&amp;#8211; (N-(phosphonomethyl) glycine) and its metabolite aminomethylphosphonic acid (AMPA) in soil and water has become one of the main environmental issues worldwide, raising awareness of the potential harmful effects to human health and ecosystems. Physical, chemical, and biological soil properties contribute to the complex interaction between GLP and the environment, that makes any prediction of adsorption, transport, and degradation dynamics still challenging.&lt;/p&gt;&lt;p&gt;Within a wide project &amp;#8211;SWAT&amp;#8211; that tries to link GLP and AMPA dynamics through the vadose zone with groundwater contamination, the specific goals of this work are: 1. monitoring soil and water contamination of GLP and AMPA in agricultural lands; 2. identifying the driving factors leading to site-specific soil-water contaminant interactions.&lt;/p&gt;&lt;p&gt;Two experimental sites were located in northeastern Italy (Conegliano and Valdobbiadene municipalities) in the winegrowing terroir of the Prosecco wine production, recently included in the UNESCO&amp;#8217;s World Heritage List. Each site was equipped with two soil-water monitoring stations (25 m&lt;sup&gt;2&lt;/sup&gt; each), multi-sensor soil probes (temperature and water content) and suction lysimeters to monitor the full soil profile. Undisturbed soil cores were also collected and later analyzed for hydraulic, physical and chemical properties down to 70 cm. After GLP field contamination on November 2018 (0.188 g m&lt;sup&gt;-2&lt;/sup&gt;), soil and water were systematically sampled from each site, starting immediately after contamination and thereafter at each rain event for 6 months. Adsorption coefficients (K&lt;sub&gt;f&lt;/sub&gt;) were estimated in laboratory in order to get information about GLP sorption to soil particles at different soil layers along the full soil profile. Site-specific dissipation kinetics (DT&lt;sub&gt;50&lt;/sub&gt;) were also evaluated to better understand its decay rate.&lt;/p&gt;&lt;p&gt;First results revealed that GLP transport was highly site specific and locally affected by preferential flows when intense rainfall events occurred (12 mm h&lt;sup&gt;-1&lt;/sup&gt; max rainfall intensity): GLP showed strong binding affinity to soil particles in the topsoil layer and it likely bypassed the porous matrix towards the deepest layers, where it was detected as in the surface one. The GLP dissipation dynamic was completed after 6 months of experimentation, whereas AMPA was still detected in the topsoil layer, attesting the full degradation after almost 300 days. Site-specific laboratory and field data will be integrated and further discussed to better understand the fate of glyphosate and AMPA in the vadose zone.&lt;/p&gt;

Vegetation and seed bank of an open-scrub bush restinga formation in the Southeastern coast of Brazil

Introduction: Restingas are coastal plain ecosystems located along Eastern Brazil, corresponding to about 5 000 km. The restinga vegetation is associated with the Atlantic rainforest biome and comprises four distinct main formation zones: coastal grasslands, shrublands, open-forests and marsh zones. Especially due to coastal urbanization, this is a threatened ecosystem that, through its different shrub formations, exhibits a unique mosaic as a result of the vegetation distribution in nuclei of different covering, physiognomy and floristic composition. Objective: We aimed to characterize the above and belowground composition of a conserved, non-flooded, open-scrub, nuclei (patches of bushes) formation of restinga in Linhares, ES, southeastern Brazil. Methods: The vegetation survey was conducted using the line intercept method. Diameter and height of the first six nuclei were measured in five transects separated by 50 m, totaling 30 nuclei up to 350 m away from the shore line. The phytosociology and Shannon Index of the aboveground vegetation community were calculated. In the same 30 nuclei, leaf litter and topsoil layer (15 x 15 x 10 cm) samples were collected to survey the viable seed bank, which was later placed in a greenhouse for germination and seedling identification. The Sørensen Similarity index (SSi) was used to compare the floristic composition between the leaf litter and topsoil layer seed banks. Nuclei volume and number of species were calculated as well. Results: In the aboveground vegetation, 54 plant species belonging to 32 families were identified, totaling 1 098 individuals. The nuclei showed a diversity (H') of 3.08 nats, and an average diameter of 11.5 m (s = 9.1), area of 526.4 m2 (s = 1 081.7), and height of 2.9 m (s = 1.1). Davilla flexuosa, followed by Smilax rufescens, presented the highest IVI (Importance Value Index). A total of 1 839 seedlings from 32 species and 19 families were identified in the seed bank. Enydra sessilis (Asteraceae) had the highest seed density (544), while the family with highest species richness was Cyperaceae. A low similarity between the vegetation surveyed and the seed bank composition was found (only 5 species in common, SSi = 0.10). Conclusions: The results indicate that a post-disturbance early community, established from the seed bank, would have a substantially different species composition, but with other potential species to restore vegetation over the long-term succession.

EVALUASI SIFAT KIMIA TANAH MENURUT JARAK DARI SUNGAI DI DAERAH PASANG SURUT KECAMATAN KOTA BESI, KOTAWARINGIN TIMUR, KALIMANTAN TENGAH

ABSTRACTThis study aims to determine the effect of the location distance from the river bank and the depth ofsoil layer to the soil chemical properties in the tidal land area. The study was conducted in April untilJune 2016 in the tidal areas of Bajarum village, District of Kota Besi, East Kotawaringin, CentralBorneo Province. The study used survey methods and soil sampling in the field, analysis of soilsamples in the laboratory and continued with analysis and description of data. Soil sampling wasconducted at distances of 250, 500, 750, 1.000, 1.250 and 1.500 meters from the Mentaya river bankat two depth soil layers (0 - 25 cm and 25 - 50 cm). The soil chemistry properties analyzed includedpH, cation exchange capacity (CEC), base saturation, organic C, N total, total P2O5, total K2O,alumunium and hydrogen exchangeable and soil fertility status. The results of study showed that: (1)The further distance of soil from the position of Mentaya river bank there is an increase of organic C,total P2O5, total N, total K2O, pH, CEC, base saturation and soil fertility status, on the contraryshowed a decrease in alumunium and hydrogen exchangeable. The limiting factor of soil fertility ismainly the low base saturation, besides that at some point observation also due to low CEC, totalP2O5 and total K2O. (2) Sub soil layer (25 - 50) cm has a higher pH and base saturation valuescompared to topsoil layer (0 - 25) cm. In contrast, topsoil layer has CEC, alumunium and hydrogenexchangeable, total P2O5, total K2O, total N and organic C values higher than sub soil layer.Keywords: distance from river, tidal soil, soil chemical properties.

Heathland restoration in the Netherlands

Lowland heathlands dominated by Calluna vulgaris are a characteristic ecosystem of the sandy soils of Northwestern Europe. Many of these heathlands have been converted to agricultural lands in the 20th century, but because increasing recognition of their nature conservation value has led to an increase in restoration efforts. Since about 2005, several experiments were carried out in a number of former agricultural areas in the Netherlands with the aim of accelerating the succession in vegetation and surface-dwelling fauna towards heathland. We discuss two projects in which the monitoring of the beetle fauna using pitfall traps was carried out. In the new reserve “Reijerscamp”, situated in the Central Netherlands, a 10-year monitoring project was carried out in an abandoned sandy field area of ca 200 ha from 2006-2015. The area consisted of a former grain field and a grass seed nursery, with small wooded areas here and there and the aim is to enlarge the area of dry heathland. In 2006, at four 5-10 ha locations, a few hundred meters apart, the nutrient-rich topsoil layer was removed, and the Pleistocene sand exposed. On a part of each of these sites, heather cuttings were deposited to accelerate the formation of dry heathland. The study consisted of five sampling years spread over the entire study period. In each sampling year, 15-25 series of 5 pitfalls were used to sample the reserve during the period April – October, on the untreated, former agricultural parts and on the four parts with removed top soil, both on the bare sand and on the parts with heather deposition. The results for ground beetles, did not support the hypothesis in all respects. From the results, it became clear that creating environmental heterogeneity, generally contributes to the ground beetle diversity in the reserve. However, the period of ten years was too short to show a clear indication that the faunal succession is moving towards a heathland fauna. The first years showed an interesting fauna with a lot of stenotopic, rare and unexpected species and the local diversity was very high. Halfway through the investigation period, the number of species as well as the numbers of individuals declined. After ten years, in general the character of the fauna was significantly more eurytopic and many of the rare species occurring in the first years vanished. On the four sites with removed topsoil, the carabid fauna differed significantly from the former agricultural land, but there was only a minor difference in the fauna of the parts with only bare sand and those with deposit of heath cuttings, although a clear heathland vegetation was visible in the parts with deposits. Because the area is surrounded by agricultural land and a large forested area, there is hardly direct connection to heathland that can serve as a source for immigration of characteristic heathland species with low dispersal power.. The succession to a typical heathland fauna in this reserve will therefore probably take probably several decades. Immediately adjacent to the National park “Dwingelderveld” (in the north of the Netherlands) the “Noorderveld”, consisting of 200 ha of arable field was acquired for nature restoration. Also here, the aim was to convert this area into heathland by removing the nutrient-rich topsoil layer in 2012-2013, to a depth of more than 60 cm, thus creating a seedless sterile substrate, poor in nutrients. After the topsoil removal, a full factorial experiment of pH manipulation and biotic additions at wet and dry sites was set up to accelerate the process of heathland restoration. Each of 27 plots (9 x 9 meters), received either a liming treatment, acidification or neither, in combination with either heathland sods, heath cuttings, or neither, totaling 9 treatment combinations. From 2013 till 2018 the carabid fauna was monitored frequently by pitfall catches in the plot’s centers. In the first years the highest diversity was observed in the plots with lime and sod cuttings and also the most characteristic heathland ground beetle species were found at these plots. Later on, these differences became less significant, which may be due to the relatively small size of the plots, which hardly can be regarded independent of each other. Conclusion is still that adding lime and sods is the best way for heathland restoration, but the differences with the control treatment were small. The striking result of the present comparison is that the Noorderveld was rather quickly inhabited by characteristic heathland species. This may be due to the fact that latter is directly connected to the vast heathland complex of the national park Dwingelderveld, in contrast to the Reijerscamp, which is isolated from the closest heathlands by a railroad, a highway, large forests and a highly agricultural landscape. connectivity therefore seems to be a crucial condition for characteristic species to colonize new territory, especially for species with low dispersal powers.