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Against the background of increasing salinisation of land, the use of environmentally friendly plant growth-promoting bacteria (PGPB) resources for soil improvement is particularly important. The aim of this study was to investigate the effects of Pseudomonas cedrina DY1-3 on maize seedling growth, soil physico-chemical properties, and bacterial community structure. The study also evaluates the effects of this microbial agent on plant growth and saline soil improvement, providing theoretical references for microbial agents in promoting plant growth and improving saline soils. We found that there were significant differences between arable and saline soils in terms of soil physico-chemical properties and bacterial community structural composition, and that total salt was the main environmental factor influencing microbial communities. In both arable and saline soils, the application of DY1-3 bacterial suspension had a significant positive effect on the growth of maize plants and bacterial community richness. In arable soil, it could promote the growth of maize seedlings and significantly increase the Shannon and Simpson index, and AK was a key factor influencing the bacterial community. In saline soil, it could alleviate the mitigation stress and promote the growth of maize seedlings and cause a significant increase in Shannon's and Chao1 index, and the application of DY1-3 and potting could cause a significant decrease in total salt. In addition, DY1-3 and maize plants acting together in the soil can better improve the saline soil. The above results indicate that DY1-3 has potential for saline soil improvement and crop yield enhancement. [ABSTRACT FROM AUTHOR]

Natural and anthropogenic changes in the composition of tropical forests are expected to alter soil properties. Thus, an understanding of the effects on changes in crop/plant composition on soil properties is needed to choose better land-use options. So, the primary goal of this study was to examine the impacts of land-use change (from shifting cultivation to teak and rubber plantation) on some physico-chemical features (available P, K, N, pH, moisture content (MC), bulk density, organic matter (OM)) of soil. Soil physico-chemical properties were compared to a shifting cultivation land with a 14-year-old teak plantation and a 16-year-old rubber plantation that had previously been used for shifting cultivation. Results showed that soil properties change with the changes of crop/plant composition, such as phosphorus (P), K, and OM was significantly high in teak and rubber plantation than the shifting cultivation area both in surface (0–10 cm) and sub-surface (10–20 cm) soil layers. Teak (3.5689 mg/kg) and rubber (3.5478 mg/kg) plantations exhibited significantly higher mean P content (p < .01) compared to shifting cultivation (3.4678 mg/kg). Shifting cultivation had the maximum K levels (0.2233 meq/100 g), while teak (0.2833 meq/100 g) and rubber (0.2733 meq/100 g) plantations showed significantly higher values (p < .05). Moisture content was 1.13% higher in teak and 1.2% higher in rubber plantations than in shifting cultivation. Furthermore, OM content was significantly higher in teak and rubber plantations (5.2744%, 5.2567%) compared to shifting cultivation (4.5067%). On the other hand, total nitrogen (N) and pH levels showed no significant difference among the land-use types. Finally, the study showed that conversion to teak and rubber plantation could lead to positive change in the soil properties. Hence it suggested that this can be undertaken/chosen as a better land cover option for shifting cultivated land in Chittagong Hill Tracts (CHTs) from soil conservation point of view. [ABSTRACT FROM AUTHOR]

Land degradation in the form of soil erosion and fertility reduction is a major environmental problem in Ethiopia. Various efforts to control soil erosion through the introduction of soil and water conservation measures have been underway for nearly five decades in Ethiopia. The purpose of this research was to assess the effects of soil bunds on selected soil physical and chemical properties in the Anole watershed of Rift Valley of Ethiopia. A reconnaissance survey was conducted to identify a representative soil sampling site. 18 composite soil samples were collected from soil bund and no conservation practice (control) with three replications at three slope positions from 0 to 30 cm depth, whereas, 18 undisturbed soil samples were collected for bulk density analysis from both land uses. The analysis was carried out using analysis of variance (ANOVA). Clay, sand, BD, CEC, TN, and OM showed significant variation (P < 0.05) between the soil bund and control plots. Whereas, for slope positions, sand, clay, BD, CEC, TN, and available phosphorus in the Anole watershed were found to be statistically significant (P < 0.05). In steep, middle, and lower slopes, contents of OC and exchangeable potassium were greater in fields with soil bunds than without. Lower slope fields showed greater clay, OM, and nutrients than steep slopes. Because of the implementation of soil bund in the study watershed, the majority of soil’s physical and chemical characteristics have shown improvement. Proper implementations of soil bunds in the study area have a pronounced positive impact and should be practiced and applied in adjacent watersheds and similar agroecologies in the Rift Valley of Ethiopia.

Against the background of increasing salinisation of land, the use of environmentally friendly plant growth-promoting bacteria (PGPB) resources for soil improvement is particularly important. The aim of this study was to investigate the effects of Pseudomonas cedrina DY1-3 on maize seedling growth, soil physico-chemical properties, and bacterial community structure. The study also evaluates the effects of this microbial agent on plant growth and saline soil improvement, providing theoretical references for microbial agents in promoting plant growth and improving saline soils. We found that there were significant differences between arable and saline soils in terms of soil physico-chemical properties and bacterial community structural composition, and that total salt was the main environmental factor influencing microbial communities. In both arable and saline soils, the application of DY1-3 bacterial suspension had a significant positive effect on the growth of maize plants and bacterial community richness. In arable soil, it could promote the growth of maize seedlings and significantly increase the Shannon and Simpson index, and AK was a key factor influencing the bacterial community. In saline soil, it could alleviate the mitigation stress and promote the growth of maize seedlings and cause a significant increase in Shannon’s and Chao1 index, and the application of DY1-3 and potting could cause a significant decrease in total salt. In addition, DY1-3 and maize plants acting together in the soil can better improve the saline soil. The above results indicate that DY1-3 has potential for saline soil improvement and crop yield enhancement.

Unreasonable cultivation methods and management measures have led to widespread obstacles in tobacco continuous cropping in planting areas, resulting in reduced tobacco yield and soil degradation. Therefore, intercropping tobacco with other crops is an effective strategy to improve continuous cropping barriers. In this study, flue-cured tobacco NC102 and conventional planting varieties of Salvia miltiorrhiza were used as materials, and four treatments of flue-cured tobacco monoculture (CK), flue-cured tobacco, and Salvia miltiorrhiza at a ratio of 1:1 (TS11), 2:2 (TS22), and 2:3 (TS23), respectively, were set up to study their effects on soil microorganisms, physical and chemical properties, and yield and quality of flue-cured tobacco. The results showed that intercropping Salvia miltiorrhiza increased the number of soil bacteria and actinomycetes, decreased the number of fungi, and increased the activity of urease and sucrase. The content of available nitrogen and available phosphorus in intercropping Salvia miltiorrhiza soil was significantly higher than that of the flue-cured tobacco monoculture, while the content of available potassium was lower than that of the flue-cured tobacco monoculture. The soil environment was more conducive to the growth of flue-cured tobacco. Compared with the flue-cured tobacco monoculture, the proportion of superior tobacco in intercropping Salvia miltiorrhiza increased by 2.2–3.4%, and the ratio of potassium to chlorine in leaves of different parts of flue-cured tobacco increased by 12.3–75.0%. The content of total sugar and soluble sugar in middle and upper leaves of intercropping flue-cured tobacco was higher than that of the flue-cured tobacco monoculture, which improved the quality of flue-cured tobacco. From the analysis of the chemical composition of tobacco leaves, TS11 (flue-cured tobacco and Salvia miltiorrhiza intercropping row ratio of 1:1) had the best treatment effect, potassium content, total sugar, reducing sugar content, and potassium chloride ratio of flue-cured tobacco were the highest, the chlorine content was the lowest, and the quality was better than other treatments. From the analysis of total output value, the total output value of TS22 (flue-cured tobacco and Salvia miltiorrhiza intercropping row ratio of 2:2) was higher than that of other intercropping treatments. In 2018 and 2019, the total output value increased by 21.3% and 22.4%, respectively, compared with the flue-cured tobacco monoculture. The intercropping advantage was obvious, and the treatment effect was the best. [ABSTRACT FROM AUTHOR]

Introduction: The pivotal roles of both abundant and rare bacteria in ecosystem function are widely acknowledged. Despite this, the diversity elevational patterns of these two bacterial taxa in different seasons and influencing factors remains underexplored, especially in the case of rare bacteria. Methods: Here, a metabarcoding approach was employed to investigate elevational patterns of these two bacterial communities in different seasons and tested the roles of soil physico-chemical properties in structuring these abundant and rare bacterial community. Results and discussion: Our findings revealed that variation in elevation and season exerted notably effects on the rare bacterial diversity. Despite the reactions of abundant and rare communities to the elevational gradient exhibited similarities during both summer and winter, distinct elevational patterns were observed in their respective diversity. Specifically, abundant bacterial diversity exhibited a roughly U-shaped pattern along the elevation gradient, while rare bacterial diversity increased with the elevational gradient. Soil moisture and N:P were the dominant factor leading to the pronounced divergence in elevational distributions in summer. Soil temperature and pH were the key factors in winter. The network analysis revealed the bacteria are better able to adapt to environmental fluctuations during the summer season. Additionally, compared to abundant bacteria, the taxonomy of rare bacteria displayed a higher degree of complexity. Our discovery contributes to advancing our comprehension of intricate dynamic diversity patterns in abundant and rare bacteria in the context of environmental gradients and seasonal fluctuations. [ABSTRACT FROM AUTHOR]

Purpose A field study was conducted at Dire Dawa, Eastern Ethiopia, with an objective to find out an optimum combination of inorganic (NP) fertilizer and excreta-based vermicompost for best economic yield and quality of tomato and to assess their effect on selected physicochemical properties of amended soil after crop harvest. Methods The experiment consisted of eight treatments where the mineral (NP) fertilizer and the excreta-based vermicompost were combined in different proportions being arranged in a completely randomized block design replicated three times. Results Growth, yield and quality attributes of tomato as well as the post-harvest soil nutrient status were markedly influenced by the nutrient treatments. The highest values for the various growth, yield and quality attributing parameters were recorded for the treatment combination consisting 75% of the recommended rate of NP fertilizer ? 11.25 ton ha-1 vermicompost (T6), this treatment was also observed to have the highest net benefit with acceptable economic return as well as a fairly high residual soil nutrient status. Following this treatment, is the integration of 50% of recommended rate of NP fertilizer ? 7.5 ton ha-1 vermicompost (T3) which surpassed the sole mineral fertilizer and vermicompost in terms of the cropâs yield and its economic return. Conclusion 25â50% of the recommended rate of chemical fertilizer can be supplemented through vermicompost. However, in order to generate more reliable information, there is a need to conduct more such studies using more integration ratios of these nutrient sources (NP fertilizer and vermicompost) at various soil and agro-climatic conditions.

Agroforestry is one of the land use practices that is perceived to be sustainable and that has beneficial impacts on soil properties. However, as a universal statement, this may not be true as best documented successful agroforestry practices are located largely on good soils. Its impacts on dryland soils have rarely been quantified and studied in detail. This study determined the impacts of selected agroforestry practices on soil properties in Makueni, Eastern Kenya. A total of 252 soil samples were collected along transects located within mixed tree woodlots established in 2007, 2010 and 2013 and adjacent parklands and grazing lands at depths of 0–15 cm, 15–30 cm, 30–45 cm and 45–60 cm. Tree density per agroforestry practice was also determined using the quadrat technique. The soil samples were analyzed using laboratory soil physico-chemical properties techniques. The results showed that Soil Organic Carbon (SOC) and Total Nitrogen (TN) were significantly higher in the woodlots than in the parkland and grazing lands (p ≤ 0.05). SOC was significantly higher in woodlots established in 2007 than those established in 2013 and strongly correlated with the tree density. Phosphorus was significantly higher in parkland as compared to woodlots and grazing lands. Phosphorus and Potassium were significantly higher at 0–15 cm depth compared to other soil depths. bulky density was significantly higher with a corresponding lower total porosity in grazing lands than in the woodlots and parklands. Mixed woodlots positively influenced soil property and could be considered as a strategy to restore degraded dryland soils as well act as important carbon dioxide and nitrogen sinks.

Abstract Context In temperate hardwood forests, increased intensity of soil and canopy disturbances tends to increase species richness due to the establishment of numerous early-successional plant species. However, while competitive pioneer species from early stages of succession can become recalcitrant and alter patterns of natural regeneration, very few studies have examined longer-term effects of these treatments on plant biodiversity. Aims In this study, we investigated mid-term (ca. 20 years) effects of different regeneration treatments with varying soil and canopy disturbance intensities. We compared understory plant communities in temperate hardwood forests from all the South of Quebec (Canada). Methods Using circular experimental plots of 1962.5 m2 (radius = 25 m), we measured taxonomic and functional diversity indices and soil properties using four levels of disturbance intensity in six temperate hardwood forests of Quebec distributed along a longitudinal gradient. Reference forests, i.e. control forests with no silvicultural treatment known for ≥ 80 years, were compared to 20-year-old single-tree selection cuts, group-selection cuts and group-selection cuts with soil scarification. Results Species richness in both group-selection treatments was higher than that in reference forests. Plant equitability and beta diversity among sites in both group-selection treatments were lower than in single-tree selection cuts and control forests. More intense treatments contributed to the mid-term persistence of recalcitrant competitor species (e.g. Rubus idaeus L., Prunus pensylvanica L.f.) whereas soil scarification appears to have negative sustained effects on species known to be sensitive to regeneration treatments (e.g. Monotropa uniflora L., Dryopteris spinulosa Kuhn). Conclusions In temperate hardwood forests of Southern Quebec, silvicultural treatments of higher intensities resulted in detrimental effects on soil properties, especially in the surface horizon, 20 years after disturbance. This legacy, in turn, affected the composition and diversity of understory plant communities. The more intense silvicultural treatments contributed to the persistence of pioneer species better adapted to a wider range of environmental conditions and resulted in a decrease in understory plant community heterogeneity among sites. Conversely, single-tree selection cutting appeared to be the most appropriate silvicultural treatment for maintaining soil functions and heterogeneity of understory plant communities after 20 years; composition and structure being similar to long-undisturbed forests.

Trichoderma is a genus of widespread filamentous fungi widely used in agriculture as biofungicides for controlling a wide range of plant diseases. Trichoderma, as is well known, can not only effectively control crop diseases but also improve soil physico-chemical properties and increase soil productivity. However, the effects of its control on crop growth and the soil's ecological environment are unclear. The results of Trichoderma on disease resistance, yield, and crop growth as well as the effects of Trichoderma on the soil ecological environment from the standpoint of soil physical, chemical, and microbial properties were therefore reported in this study. Furthermore, this paper highlighted the shortcomings of the existing research on the impact of Trichoderma on crop and soil properties and emphasised opportunities to address the gaps in the existing research on the effects of Trichoderma on crops and soil attributes. This review will provide a theoretical foundation for further research and application of Trichoderma in agricultural production. [ABSTRACT FROM AUTHOR]

Context: In temperate hardwood forests, increased intensity of soil and canopy disturbances tends to increase species richness due to the establishment of numerous early-successional plant species. However, while competitive pioneer species from early stages of succession can become recalcitrant and alter patterns of natural regeneration, very few studies have examined longer-term effects of these treatments on plant biodiversity. Aims: In this study, we investigated mid-term (ca. 20 years) effects of different regeneration treatments with varying soil and canopy disturbance intensities. We compared understory plant communities in temperate hardwood forests from all the South of Quebec (Canada). Methods: Using circular experimental plots of 1962.5 m2 (radius = 25 m), we measured taxonomic and functional diversity indices and soil properties using four levels of disturbance intensity in six temperate hardwood forests of Quebec distributed along a longitudinal gradient. Reference forests, i.e. control forests with no silvicultural treatment known for ≥ 80 years, were compared to 20-year-old single-tree selection cuts, group-selection cuts and group-selection cuts with soil scarification. Results: Species richness in both group-selection treatments was higher than that in reference forests. Plant equitability and beta diversity among sites in both group-selection treatments were lower than in single-tree selection cuts and control forests. More intense treatments contributed to the mid-term persistence of recalcitrant competitor species (e.g. Rubus idaeus L., Prunus pensylvanica L.f.) whereas soil scarification appears to have negative sustained effects on species known to be sensitive to regeneration treatments (e.g. Monotropa uniflora L., Dryopteris spinulosa Kuhn). Conclusions: In temperate hardwood forests of Southern Quebec, silvicultural treatments of higher intensities resulted in detrimental effects on soil properties, especially in the surface horizon, 20 years after disturbance. This legacy, in turn, affected the composition and diversity of understory plant communities. The more intense silvicultural treatments contributed to the persistence of pioneer species better adapted to a wider range of environmental conditions and resulted in a decrease in understory plant community heterogeneity among sites. Conversely, single-tree selection cutting appeared to be the most appropriate silvicultural treatment for maintaining soil functions and heterogeneity of understory plant communities after 20 years; composition and structure being similar to long-undisturbed forests. [ABSTRACT FROM AUTHOR]

Identifying the primary factors influencing spatial distribution of soil organic carbon (SOC) stock is critical for improving the accuracy of soil organic carbon stock estimation. The primary objective of the current study is to determine the effects of land use-land cover, and some soil characteristics on SOC stock in an area of 111 km2 in Vezirköprü district, Samsun province in the Central Black Sea Region of Turkey. To determine land use and land cover of the study area, Triplesat satellite image was used. Four main land use and land cover that are forest, pasture, settlement, and cultivated land were determined. According to the results obtained, it was determined that some soil characteristics and land use-land cover in the study area had a statistically significant effect on the spatial variation of SOC density. The amount of SOC stock in the study area varies between 4.79- and 94.10-tons ha-1 in surface (0-20 cm) soils and between 5.16- and 8.86-tons ha-1 in subsurface (20-40 cm) soils. Among the different land uses, it was determined that the highest amount of SOC stock in the surface soil was 53.356 tons ha-1 in forest areas, while the lowest amount of SOC stock was in agricultural lands with 34.048 tons ha-1.

This experiment was carried out during 2019 at Department of Soil Science, University of Sargodha, Pakistan to judge the toxic effect of sodium bicarbonate (NaHCO3) commonly recognized as sodicity on soil chemical characteristics using rice as test crop. There were seven treatments with three replicates applied using completely randomized design (CRD). Various levels of sodicity were developed artificially including 15, 20, 25, 30, 35 and 40 SAR by using sodium bicarbonate (NaHCO3). Sufficient time was given for development of desired level of sodicity. Rice was used as test crop. Practices like irrigation, hoeing and weeds eradication were done as per crop requirement. Recommended doses of chemical fertilizer was applied. Crop was raised for 120 days and then collection of soil and plants samples were carried out from all pots for analysis of sodium (Na) and potassium (K) ion concentrations. Similarly, pH, EC and SAR were also determined from all soil samples. Results revealed that deterioration of soil properties (pH, EC and SAR) occurred by the addition of NaHCO3 as values of these properties were negatively affected by increased levels of sodicity. Numerical values of soil pH raised from 7.78 to 9.35, EC from 1.85 to 6.13 dS/m, SAR from 9.80 to 41.53 and ESP from 11.64 to 37.49 me/ L respectively. Regarding ionic composition of rice, an increase in Na ion and decrease in K ion concentration was observed in all treatments in comparison with control. Potassium content in rice decreased from 2.3 to 1.2% while sodium concentration was raised from 102.26 to 410.14 me/L. Toxic effect of sodicity on soil pH, EC, SAR and ESP as well as Na/K ratio in rice plants were enhanced with increasing levels of NaHCO3. [ABSTRACT FROM AUTHOR]

Simple Summary: Super-high density olive orchards are spreading in Italy to reduce production costs and increase yields per hectare. The objective of this study was to assess the orchards' effect on the soil nematode community in five sites located in the main Italian olive cultivation areas compared to the adjacent traditional olive orchard system. Super-high density olive orchard management combined with conventional tillage and mineral fertilization decreased total organic carbon compared to traditional management. The soil nematode community was affected by the depletion of organic matter, especially for plant-parasitic nematodes, which increased. Moreover, this investigation evidenced that the Super-high density olive orchard management system could change the soil plant-parasitic nematode composition of olive orchards. In fact, the families Telotylenchidae, Paratylenchidae, Meloidogynidae, and Criconematidae were favored in the Super-high density olive orchard system, while Longidoridae, Heteroderidae, and Pratylenchidae were disadvantaged. However, conservative and sustainable soil management might maintain or improve the soil nematode community functionality and reduce plant-parasitic nematodes. The soil nematode community plays an important role in ecosystem services. The objective of this study was to assess the effect of Super-high density (SHD) olive orchards on the nematode community in five sites with different soils, climates, and cultivars. At each site, the SHD management system was compared to the adjacent olive orchard traditional (TRAD) system, in which the same soil management and phytosanitary measures were applied. Soil management was assessed by total organic carbon content (TOC), while the soil nematode community was evaluated using the nematode taxa abundances and soil nematode indicators. TOC was significantly decreased in the SHD olive orchard system compared to TRAD in the sites characterized by conventional tillage and mineral fertilization. The two-way ANOSIM analysis on nematode abundance showed no difference between the two olive management methods, instead showing only a significant difference per site mainly due to variabilities in plant-parasitic nematode assemblage. However, a negative impact of SHD management was evident in environments stressed by summer droughts and conventional tillage: the ratio of obligate plant-parasites to bacterivores and fungivores (Pp/(B+F)) was significantly higher in SHD than in the TRAD olive orchard system, and the prey-to-predator θ mass ratio showed the lowest values in the sites under organic fertilization or green manure. The canonical correspondence analysis showed that the free-living nematodes were only slightly affected by SHD olive orchards; instead, the presence of plant-parasitic nematodes families such as Telotylenchidae, Paratylenchidae, Meloidogynidae, and Criconematidae was favored, in comparison to Longidoridae, Heteroderidae, and Pratylenchidae. [ABSTRACT FROM AUTHOR]

Elevation gradient can reflect the effects of soil physico-chemical properties on plant species diversity. Alpine grassland on the QTP has suffered from a serious decline in plant species diversity. In this study, we investigated 112 sites recording plant community characteristics and collecting soil samples along an elevation gradient (3,500–5,200 m asl) in alpine meadow on the QTP. We analyzed the effects of soil physico-chemical properties on plant species composition and diversity by canonical ordination and spatial regression along an elevation gradient. The results showed that species richness of the overall plant communities decreased with the increasing elevation, and the Simpson dissimilarity index (β sim ) had a maximum at low elevation (3,500–4,000 m) with the value of 0.37. Soil available nitrogen content was the primary soil parameter affecting plant species composition and diversity in alpine grassland. The effect of soil available nitrogen content on plant species richness varied at different elevations. For Gramineae plants (G), plant species richness declined with the increase in soil available nitrogen content at low elevation (3,500–4,000 m), but rose at middle elevation (4,000–4,500 m). Soil available nitrogen content had a more significant limiting effect on species richness at high elevation (>4,500 m). These findings increase our understanding about the drivers of plant species diversity changes in alpine grassland on the QTP, and will provide insights into grassland restoration and sustainable management. [ABSTRACT FROM AUTHOR]

Background: Phosphorous is a limiting crop nutrient in highly weathered tropical soils due to fixation, and its availability for plants’ uptake is influenced by soil physico-chemical characterics, land use type and management practices. Objective: To evaluate the relationship between selected physico-chemical properties and phosphorous sorption characteristics of a humic nitisol (Alfisol) from Tigoni, Kiambu County, central Kenya. Methodology: The soil was sampled from the same area with different land uses that include tea plantation, maize field and natural forest at 0-25, 25-50 and 50-75 cm depths. P solution at the rates of 50, 100, 150, 200 mg P L−1 in a 24 h contact time were used in the study for maximum sorption. The data was analysed by simple regression and Pearson correlation analysis. Results: The adsorption data was fitted more to Langmuir model (R2 = 0.9100-0.9994) compared to Freundlich (R2 = 0.6815-0.9971). The values of P sorption maxima ( ) determined by Langmuir model ranged from 3,333-5,000 mg kg-1 and bonding energies ( ) ranged from 0.2308-1.5385 L mg-1. The buffering capacity of soil ranged from 769-5000 L kg-1 and the external P requirement at 0.2 mg kg-1 ( ranged from 147-1176 mg P kg-1 both increasing with soil depth. P sorption maxima were negatively and significantly correlated with organic carbon (r2 = -0.700*) and Ca2+ (r2 = -0.703*) contents. The pH of soil and clay content were negatively correlated with adsorption parameters ( ) while Al content was positively correlated though none of them was statistically significant. Implication: The data revealed a highly P-sorbing soil particularly tea plantation, a situation that can be alleviated by management practices such as liming and enhancing soil organic matter content. Field experiments are however, recommended to validate the findings of this study. Conclusion: Land use type influences P-sorption capacity of soil hence, fertilizer recommendations should be based on soil physico-chemical characteristics besides crop nutrient requirements.

Elevation gradient can reflect the effects of soil physico-chemical properties on plant species diversity. Alpine grassland on the QTP has suffered from a serious decline in plant species diversity. In this study, we investigated 112 sites recording plant community characteristics and collecting soil samples along an elevation gradient (3,500–5,200 m asl) in alpine meadow on the QTP. We analyzed the effects of soil physico-chemical properties on plant species composition and diversity by canonical ordination and spatial regression along an elevation gradient. The results showed that species richness of the overall plant communities decreased with the increasing elevation, and the Simpson dissimilarity index (βsim) had a maximum at low elevation (3,500–4,000 m) with the value of 0.37. Soil available nitrogen content was the primary soil parameter affecting plant species composition and diversity in alpine grassland. The effect of soil available nitrogen content on plant species richness varied at different elevations. For Gramineae plants (G), plant species richness declined with the increase in soil available nitrogen content at low elevation (3,500–4,000 m), but rose at middle elevation (4,000–4,500 m). Soil available nitrogen content had a more significant limiting effect on species richness at high elevation (>4,500 m). These findings increase our understanding about the drivers of plant species diversity changes in alpine grassland on the QTP, and will provide insights into grassland restoration and sustainable management.

Vegetation recovery is essential in land restoration after the eruption of Mount Merapi in 2010. Vegetation is a source of organic material that produces root exudate containing organic acids. These acids accelerate the dissolution process of volcanic material so that it affects the soil characteristics. This study was conducted to analyze the effect of four types of perennial plants on soil chemical and physical characteristics. The soil samples were taken on the area planted with cinnamon, albizia, bamboo, and acacia, at depths of 0 – 10 cm, 10 – 20 cm, 20 – 30 cm, 30 – 40 cm, and 40 – 50cm. The soil chemical analysis carried out included pH H2O, pH KCl, pH NaF, C-organic, Humic acid and Fulvic acid, cation exchange capacity, Ca, Mg, K, Na, available P, base saturation, and particle size distribution. The results show that pH H2O, pH KCl, C-organic, humic acid and fulvic acid, CEC, K, Na, Ca, Mg, available P, base saturation, and particle size distribution were significantly affected by vegetation type. Meanwhile, the pH of NaF was not significantly influenced by vegetation type. Cinnamon is a plant that gives the strongest influence in the improvement of soil chemical-physical properties compared to the other three types of vegetation. Therefore cinnamon is quite prospective plant to be developed for post-eruption land reclamation.

The present investigation was conducted at the Research Farm, Khalsa College, Amritsar during rabi season of 2017-18 in order to evaluate the impact of organic manures (FYM, Vermicompost, Poultry manure) and inorganic fertilizers on soil physico-chemical properties and available nutrient status in soil after onion (Allium cepa L.) harvest. The experiment was laid out in randomized block design with twelve treatments and replicated thrice. It was observed that significant variation in organic carbon, bulk density, available macro (N, P, K and S) and micro (Fe, Mn, Zn and Cu) nutrients status was noticed when organic manures were integrated with inorganic fertilizers as compared to sole use of inorganic fertilizers and initial status of soil. The maximum available nutrient status was recorded with treatment T12 {25% RDNF + 25% N (FYM) + 25% N (VC) + 25% N (PM)} whereas lowest was recorded with treatment T1 (control). The soil properties such as pH, EC, particle density and porosity did not showed any significant difference. [ABSTRACT FROM AUTHOR]

Polychlorinated biphenyls (PCBs) belong to the organic pollutants that are toxic to humans and harmful to environments. Numerous studies dealing with the impact of PCBs on soil microorganisms have focused on bacterial communities. The effects of PCBs on fungal communities in three different PCB-polluted soils from former industrial sites were investigated using high-throughput sequencing of the internal transcribed spacer 1 region. Significant differences in fungal alpha diversity were observed mainly due to soil physico-chemical properties. PCBs only influenced the richness of the fungal communities by increasing it. Fungal composition was rather strongly influenced by both PCBs and soil properties, resulting in different communities associated with each soil. Sixteen Ascomycota species were present in all three soils, including Stachybotrys chartarum, Fusarium oxysporum, Penicillium canescens, Penicillium chrysogenum,Penicillium citrosulfuratum and Penicillium brevicompactum, which are usually found in PCB-polluted soils, and Fusarium solani, Penicillium canescens, Penicillium citrosulfuratum and Penicillium chrysogenum, which are known PCB degraders. This study demonstrated that PCBs influence the richness and the composition of fungal communities. Their influence, associated with that of soil physico-chemical properties, led to distinct fungal communities, but with sixteen species common to the three soils which could be considered as ubiquitous species in PCB-polluted soils.

Knowledge of the spatial and temporal variabilities of soil respiration is important in estimating the soil carbon budget and in understanding how soils may respond to global changes. In areas with complex terrain, the topography can modify the hydrological conditions and other biophysical variables, which complicates the spatial and temporal heterogeneity of soil respiration. Herein, we investigated soil respiration along topographic transects with ridge, middle slope, lower slope and valley positions in a humid subtropical mountain forest in China to assess the driving factors of the variations in soil respiration. Our results showed that there were substantial temporal and spatial variations in soil respiration. The temporal variation of soil respiration could be well explained by the dynamics of soil temperature and moisture. Soil respiration rates also showed clear topographic pattern and decreased significantly from the ridge to valley soils, with the mean rates equaled 3.43 ± 0.13, 2.64 ± 0.30, 2.13 ± 0.26 and 1.88 ± 0.24 μmol m−2 s−1 at the ridge, middle slope, lower slope, and valley, respectively. Correlation analyses revealed that the spatial variation of soil respiration could be explained by multiple variables (e.g., soil temperature, basal area of the trees, thickness of the forest floor, root biomass and stock of soil dissolved carbon, soil C/N and soil bulk density). Results from partial least squares path modeling suggested that the topography modified the fine root distribution and the lateral losses of light and dissolved organic materials that created areas of high carbon sources for soil respiration at the ridge. The topographically regulated processes further resulted in a high soil C/N at the ridge that favored SOC decomposition. The higher respiration rate for the ridge soil and its higher sensitivity to soil temperature and moisture changes suggested that the ridge position was a potential hot spot for future environmental changes. Future studies and management practices regarding the soil carbon efflux in forest ecosystems with topographical variations should take into account the topographic effects. [ABSTRACT FROM AUTHOR]

Sugarcane cultivation in Japan has not yet focused on suppressing plant-parasitic nematodes. For proper nematode management, it is essential to know the spatial distribution of economically important plant-parasitic nematodes and free-living nematodes that play important roles in terrestrial ecosystems. We aimed to reveal nematode fauna and soil properties in 85 sugarcane fields of three major sugarcane producing islands in Japan, and to examine their relationship by using the mixed-effect model and by visualizing the spatial distributions using the inverse distance weighting (IDW) approach. The nematode community structures were analyzed by non-metric multidimensional scaling (NMDS). Among plant-parasitic nematodes in sugarcane, the root-lesion nematodes (Pratylenchus sp.) and the stunt nematodes (Tylenchorhynchus sp.) were widely distributed in these islands, yet the abundance and the species varied geospatially. Soil pH was significantly correlated with the abundance of Pratylenchus and Tylenchorhynchus species. The abundance of Pratylenchus and Tylenchorhynchus species were significantly correlated with soil pH. The abundance of Pratylenchus was significantly correlated with the abundance of free-living nematodes, the number of free-living nematode species, and exchangeable cation K+, as were the abundance of Tylenchorhynchus to the clay content and that of non-Tylenchorhynchus. This study also revealed that the three islands had different nematode faunas, which were explained especially by soil pH, texture, and exchangeable basic cations.

Cultivation of legume plants is well known to improve soil N level and net primary productivity; besides, it may deliver other ecosystem benefits such as increasing soil carbon sequestration and soil food web complexity. However, little is known about whether legumes can improve the resistance of soils to ecosystem disturbances. In the present study, we compared the resistance of soils to an ecosystem disturbance (understory removal) in the presence or absence of a legume species (Cassia alata) in mixed tree species plantations in southern China. Soil physico-chemical and biotic properties were employed to quantify the resistance of soils to understory removal. Our results showed that the resistance indices of soil water content, omnivorous-predacious nematode abundance and nematode channel index to understory removal were greater in the presence of legumes than those without legumes in wet season. The resistance indices of fungal to bacterial ratio, fungivorous nematode abundance and total arthropod abundance were greater in the presence of legume than those without legume species in dry season. Our results indicate that legumes may enhance the resistances of soil physico-chemical and biological properties to the ecosystem disturbance. Our findings could provide a better understanding of the myriad ways in which legumes can positively affect ecosystem functioning.

Abstract Soil, is a reclamable and sustainable source. it is the basis of survival and it’s implication, should be performed on the basis of productivity identification according to scientific and technical rules, we can protect this valuable source, and increase it’s productivity and usage. Nowdays, saline soils cover nearly 14.6% of the country area. Study areas (Kashan’ playa) have saline and alkali soils. Identification of these soils and their’s reclamation and implementation for different usage, is very important, especially, they have abundant water resources. They have important influence on establishment and development of plants. Therefore, we started qualitative and quantitative pedological research. First, we prepared cover map as georeference with Ilwis 3.3 software. We overlaied cover map and georeference geological map. We determined 12 working units, and then we took samples from units. Physico-chemical factores such as EC, Gypsum%, soluble cations and anions, organic matter, CaCO3 % and etc, determined from the depths of 0-10, 20-40, 40-80 of plant types(working units, QM, QC) in February and july. Result shows, Na, Mg, SO4, K, pH, Cl, CO3, HCO3, CaCO3, SAR, CEC rates decreased and Gypsum and Ca% rates increased, from the Lake to uplans. Also, the soil’s texture was changed from clay sandy loam to sandy loam. At last, was drew Soil’s salinity map according to the soil taxonomy, it is in entisol order, aquent suborder, endo aquent greatgroup and typic endoaquent subgroup. According to the results, the soil isn’t suitable for dry farming and aquaculture (very bad class (class V)). Study area, covered by halophyte plants and it will be appropriate to develop and improve with other halophytes. It should be protected from animals. Especially camels that conserve soil structure and poor plant cover.

Carbon has an important role in soil fertility; its sequestration is essential for sustainable agriculture. Soil organic carbon of three land uses viz. forest land, grassland, and cultivated land were quantified. These land uses belonged to two soil groups having different soil type and climate. Selected soil groups were Inceptisols (site 1) and Mollisols (site 2). Soil samples were analyzed for bulk density (BD), soil organic carbon (SOC), total nitrogen (TN), available phosphorus (AP), extractable potassium (K) and pH. Statistically (p ≤ 0.05) higher SOC contents of Inceptisols and Mollisols were 14.18 g kg-1 and 23.42 g kg-1, respectively under forest land use. At both sites forest soils had higher SOC and AP while K was higher in grassland use. Forest soils had slightly acidic pH and lower BD than cultivated land uses. Data combined over locations illustrated that Mollisols contained higher SOC and K, whereas, TN, AP, and BD were statistically similar at both sites. The SOC was positively correlated with TN, AP and K of soil, whereas, SOC was negatively correlated with BD and pH of the soil. There is a large difference in SOC storage and physico-chemical properties mainly in relation to climate, soil type and vegetation. [ABSTRACT FROM AUTHOR]

Physico-chemical properties of forest soil depends on a variety of natural factors, the most important are variation in altitude, vegetation cover and microbial activities. The present study was conducted to understand the effect of variation in altitude in the soil characteristics in Tarai Sal forest (TSF) and Hill Sal forest (HSF), of eastern Nepal. Soil samples were collected from thirty plots randomly in each forest from 0-15cm and 15-30cm depths in May 2012. Both forests had sandy loam type of soil texture. However, the percentage composition of soil particles varies within the forest sites. Soil moisture was higher in TSF. It was maximum in the rainy season in both forests. Water holding capacity was slightly higher in TSF. Bulk density was higher in TSF and it increased with soil depth in both forests. The pH value was slightly higher in HSF than TSF however, the value increased in lower soil depth in both forest stands. In the upper soil layer (0-15cm) soil organic carbon (SOC) was higher in HSF (2.09%) than TSF (1.6%). Similarly, total nitrogen (TN) was also higher in HSF (0.173%) than in TSF (0.129%) while total phosphorus (TP) was more or less same in both forest stands. The potassium (K) a soil extractable nutrient also showed higher value in HSF (312.13 µg g-1) than TSF (238.47 µg g-1). The values of SOC, TN, TP and K decreased in lower depth (15-30cm) in both forest stands. In conclusion, variation in altitude causes difference in the microclimatic condition which resulted into the alternation in soil characteristics. [ABSTRACT FROM AUTHOR]

Physico-chemical properties of soil of two dominant forest types in Western Himalaya, viz. oak (Quercus leucotrichophora) and pine (Pinus roxburghii) across three soil depths, and winter and rainy seasons were analysed. In general, all the soil parameters, viz. soil moisture, water-holding capacity, organic carbon and total nitrogen decreased significantly with increasing soil depth in both the forests. However, pH did not show any trend with soil depth. All the soil physicochemical parameters were found significantly higher for oak forests compared to pine forests. The topsoil layer (0-30 cm depth) of both the forests had high concentration of soil organic carbon (SOC) and total N. Shallower distribution of the most limiting nutrients for plants such as N was in agreement with earlier reports. A declining nutrient concentration with increasing soil depth may explain that the zone of accumulation of nutrients is not well established in the forest soils of this mountainous region due to strong leaching effect. With regard to nutrient extraction from deeper soil layers, the deep-rooted oak forest has competitive advantage over the shallow-rooted pine forest. Considering that SOC stored in the surface layer is more vulnerable and less stable than that in the deeper layers, the topsoil of these forests should be protected to minimize the risk of large carbon release. The oak forests should be given priority over the pine forests in afforestation and conservation programmes to sequester and stock high amounts of carbon in the soil pool and contribute towards mitigation of climate change impacts. [ABSTRACT FROM AUTHOR]

Flooding can have a major impact on riverside plant communities, and this is likely to be especially important in monsoonal climates, where large floods occur after heavy rain. In urban areas where riparian vegetation remnants are the only vegetation of conservation interest remaining, understanding the impacts that floods have on these ecosystems is needed to inform their future conservation. Accordingly, we assessed the impact of a flood caused by Typhoon "Ewiniar" on the soil seed bank of five plant communities of the only remaining fragment of high-quality riverine habitat within the Seoul city stretch of the Han River (South Korea). We surveyed the seed bank composition of the five dominant plant communities before and after the flood. We also measured selected soil physico-chemical properties in each community. We used univariate and multivariate methods to examine the effect of the flood on both seed bank and soil physico-chemical properties. Flooding resulted in variable deposition of sediment within the plant communities; four communities varied from 14.6 to 18.8 cm but the fifth (dominated by Miscanthus sacchariflorus) had much less sediment (4.8 cm). The physico-chemical properties of the surface soil also changed after the flood, with the sediment particle size being the most affected. The species richness and composition of the seed bank suffered significant changes after the flood. In both cases there was a homogenization process, with was also impinged on species with different life-forms (annuals and perennials). Our results suggest that an extreme flood can affect the riparian vegetation seed bank by removing wetland plant species and allowing common and ruderal species to establish. There may also be different interactions between the different plant communities in terms of sediment capture and this translates into altered soil conditions and seed banks. These results are of use to conservation policy-makers aiming to conserve a native flora within severely modified urban rivers, and these remnant areas can provide an important seed source of wetland plants to aid restoration of riparian ecosystems. [ABSTRACT FROM AUTHOR]

Aims: Little is known about how soil parameters change during early stages of revegetation dynamics on newly-restored coal mines, particularly in a Mediterranean climate. Our aim was to explore the short-term interactions of changes in soil physico-chemical properties and vegetation succession (composition and structure) in these newly-forming ecosystems, and discuss potential functional relationships. Methods: Between 2004 and 2009, we monitored soil and vegetation changes in nine permanent plots (20 m each one) at a restored open-pit coal mine annually; these plots were set up in a structured way to account for site aspect (north, south and flat). We used linear mixed models and multivariate analysis to derive patterns of soil parameters changes through time and to relate soil variables with vegetation structure or floristic compositional changes. Results: Soil variables showed a general trend over time of increasing soil organic matter, total carbon and nitrogen, sand content and exchangeable calcium, but a reduction in soil pH, clay and lime contents, whereas electrical conductivity, P, Mg and K showed no change through time. More importantly, these changes in soil properties were independent of aspect, whereas vegetation functional/structural changes were related to the accumulation of organic matter and sand content, and pH reduction. Surprisingly, floristic compositional changes had little relationship with soil factors. Conclusions: The results indicate that age since restoration was the main driving agent, at least in the short-term, of soil and vegetation compositional changes during ecosystem development through the restoration of a coal mine, whereas vegetation functional/structural changes are involved in the mechanism that induce some soil changes, favouring the increase of plant community complexity in such mined areas. Finally, these results suggest that if soil-forming material is sufficiently good for vegetation development, floristic compositional differences are mainly driven by a combination of abiotic and stochastic factors in the short-term. [ABSTRACT FROM AUTHOR]

Abstract: In order to determine the best combination of the most adaptable shrub, the irrigation frequency (IF) and irrigation amount (IA) in the Tarim Desert Highway Ecological Shelterbelt Project, we investigated the soil moisture (SM), soil electrical conductivity (EC) and shelterbelt shrubs height (SH) where the plants were irrigated with the saline groundwater (5gL−1) bumped from the local wells. And an orthogonal array experiment was set to test the effects of the species, IF and IA on the plants height. When the different irrigation ways were used to irrigate the shelterbelt plants, significant differences in plant species heights, soil moisture, and salt accumulation on the surface were found. All of these findings suggested that the IF 20-day with IA 30mm every time was the better choice in which the soil moisture was above 2%, little salt accumulated on the dune surface and the most plants’ height occurred. Our results indicated that species was the more important factor to concern than IF and IA when the IA was above 15mm with the IF less 30-day. The shrub traits determined greatly the growth status. And Haloxylon ammodendron was the best species selected among the three main shelterbelt shrubs, Tamarix taklamakanensis, H. ammodendron and Calligonum caput-medusae in the ecological shelterbelt project. Multivariate orthogonal array designs provided an effective strategy to determine the optimum irrigation management of individual additive components to the shelterbelt shrubs in the Tarim Desert Highway Ecological Shelterbelt Project. [Copyright &y& Elsevier]

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This study was undertaken to develop new pedotransfer functions (PTFs) for the estimation of soil moisture content at field capacity (FC, at −33 kPa) and permanent wilting point (PWP, at −1500 kPa) for South African soils based on easily measurable soil physico-chemical properties. The new PTFs were developed using stepwise multiple linear regressions with the dependent variable (either FC or PWP) against clay, silt, sand and soil organic carbon (SOC) content from a total of 3171 soil horizons as the explanatory variables. These new PTFs were evaluated and compared with five well-established PTFs using a total of 3136 soil horizons as an independent dataset. The coefficient of determination (r2) values for the existing PTFs ranged from 0.65–0.72 for FC and 0.72–0.81 for PWP, whilst those developed in this study were 0.77 and 0.82 for FC and PWP, respectively. The root mean square error (RMSE) values for the well-established PTFs ranged from 0.052–0.058 kg kg−1 for FC and 0.030–0.036 kg kg−1 for PWP, whilst those developed in this study were 0.047 and 0.029 kg kg−1 for FC and PWP, respectively. These findings suggest that PTFs derived locally using a large number of soil horizons acquired from different agro-climatic locations improved the estimation of soil moisture at FC and PWP. Due to the range of conditions and large soil datasets used in this study, it is concluded that these new PTFs can be applied with caution in other regions facing data scarcity but with similar soil types and climatic conditions. [ABSTRACT FROM AUTHOR]

Polychlorinated biphenyls (PCBs) belong to the organic pollutants that are toxic to humans and harmful to environments. Numerous studies dealing with the impact of PCBs on soil microorganisms have focused on bacterial communities. The effects of PCBs on fungal communities in three different PCB-polluted soils from former industrial sites were investigated using high-throughput sequencing of the internal transcribed spacer 1 region. Significant differences in fungal alpha diversity were observed mainly due to soil physico-chemical properties. PCBs only influenced the richness of the fungal communities by increasing it. Fungal composition was rather strongly influenced by both PCBs and soil properties, resulting in different communities associated with each soil. Sixteen Ascomycota species were present in all three soils, including Stachybotrys chartarum, Fusarium oxysporum, Penicillium canescens, Penicillium chrysogenum,Penicillium citrosulfuratum and Penicillium brevicompactum, which are usually found in PCB-polluted soils, and Fusarium solani, Penicillium canescens, Penicillium citrosulfuratum and Penicillium chrysogenum, which are known PCB degraders. This study demonstrated that PCBs influence the richness and the composition of fungal communities. Their influence, associated with that of soil physico-chemical properties, led to distinct fungal communities, but with sixteen species common to the three soils which could be considered as ubiquitous species in PCB-polluted soils. [ABSTRACT FROM AUTHOR]

Plantation forests can influence both plant diversity and soil properties. This study mainly aims to determine and compare the status of plant diversity of ground flora andsome physico-chemical properties of soil under influencing of plantation with conifer and broad leaved species. Three sites (conifer, broad leaved and non-planted site as control) were selected in Sanandaj (Dushan region). These sites were physiographically and climatically similar. Systematic random sampling was used as a method for data collection. To study quantitative characteristics of stands, 20 quadrate sample plots with 400m2 area were selected in each site (60 plots totally). In order to determine the herbal species and their coverage percent, each plot was divided into 4 sections and a microplot (1.5m×1.5m) was selected in each section. To study the physico-chemical properties of soil influenced by planted species, 3 soil samples were selected in the center of each plot in depth of 0 to 20cm and the soils were mixed with each other to obtain mixed soil samples. The data was analyzed using complete randomized design. Results showed that the plant diversity and frequency on ground flora under influence of plantation with broad leaved species was maximum, while the evenness index was minimum. There was significant difference among all sites regarding to porosity, however there was no difference among the sites from view point of other physical parameters. Moreover, there were significantly differences between most chemical parameters of soil in three studied sites.

Sugarcane cultivation in Japan has not yet focused on suppressing plant-parasitic nematodes. For proper nematode management, it is essential to know the spatial distribution of economically important plant-parasitic nematodes and free-living nematodes that play important roles in terrestrial ecosystems. We aimed to reveal nematode fauna and soil properties in 85 sugarcane fields of three major sugarcane producing islands in Japan, and to examine their relationship by using the mixed-effect model and by visualizing the spatial distributions using the inverse distance weighting (IDW) approach. The nematode community structures were analyzed by non-metric multidimensional scaling (NMDS). Among plant-parasitic nematodes in sugarcane, the root-lesion nematodes (Pratylenchus sp.) and the stunt nematodes (Tylenchorhynchus sp.) were widely distributed in these islands, yet the abundance and the species varied geospatially. Soil pH was significantly correlated with the abundance of Pratylenchus and Tylenchorhynchus species. The abundance of Pratylenchus and Tylenchorhynchus species were significantly correlated with soil pH. The abundance of Pratylenchus was significantly correlated with the abundance of free-living nematodes, the number of free-living nematode species, and exchangeable cation K+, as were the abundance of Tylenchorhynchus to the clay content and that of non-Tylenchorhynchus. This study also revealed that the three islands had different nematode faunas, which were explained especially by soil pH, texture, and exchangeable basic cations. [ABSTRACT FROM AUTHOR]

Understanding the variation of soil physico-chemical properties along slope position gradients is essential for vegetation restoration and reconstruction, but how slope positions impact the soil physico-chemical properties in the secondary vegetation of hilly regions is poorly understood. To address these uncertainties, we examined the changes in soil physico-chemical properties and their relationships along the slope position gradient in secondary vegetation of the hilly region in Guilin, southwest China. The results showed that except for the soil water content, soil total phosphorus and soil total potassium which reached the highest value at the footslope, other soil physico-chemical properties reached the highest content in the middle slope, and most of the soil physico-chemical properties showed the lowest content in the upper slope or footslope. Moreover, Pearson's correlation analysis revealed that there were no significant correlations between most of the soil physico-chemical properties and that the correlations between soil physico-chemical properties were not consistent across different slope positions. Additionally, the principal component analysis showed that the first 4 principal components together explained 84.32% of the total variation and might be interpreted as the change of soil total nitrogen, soil organic matter, soil available nitrogen, soil available potassium, soil water content and soil total potassium. Overall, our results strongly demonstrated that slope positions showed significant effects on most of the soil physico-chemical properties and would provide an important reference for the formulation of restoration strategies in different slope positions to facilitate vegetation restoration and reconstruction and the sustainable development of the ecological environment in the hilly region. [ABSTRACT FROM AUTHOR]