Search Results (3,590)

The accurate prediction of soil organic matter (SOM) content is important for sustainable agriculture and effective soil management. This task is particularly challenging due to the variability in factors influencing SOM distribution across different cultivated land types, as well as the site-specific responses of SOM to remote sensing data and environmental covariates, especially in the black soil region of northeastern China, where SOM exhibits significant spatial variability. This study evaluated the variations on the importance of different remote sensing imagery and environmental covariates in different cultivated land zones. A total of 180 soil samples (0–20 cm) were collected from Youyi County, Heilongjiang Province, China, and multi-year synthetic bare soil images from 2014 to 2022 (focusing on April and May) were acquired using Google Earth Engine. Combining three types of environmental covariates such as drainage, climate and topography, the study area was categorized into dry field and paddy field. Then, the SOM prediction model was constructed using random forest regression method and the accuracy of different strategies was evaluated by 10-fold cross-validation. The findings indicated that, (1) in the overall regression analysis, combining drainage and climate variables and multi-year synthetic remote sensing images of May could attain the highest prediction accuracy, and the importance of environmental covariates was ranked as follows: remote sensing (RS) > climate (CLI) > drainage (DN) > Topography (TP). (2) Zonal regression analysis was conducted with a high degree of precision, as evidenced by an R² of 0.72 and an impressively low RMSE of 0.73%. The time window for remote monitoring of SOM was different for dry field and paddy field. More specifically, the optimal time frames for SOM prediction in dryland were identified as April and May, while those for paddy fields were concentrated in May. (3) In addition, the importance of diverse environmental covariates was observed to vary with the cultivated land types. In regions characterized by intricate topography, such as dry fields, the contributions of remote sensing images and climate variables assumed a heightened importance. Conversely, in paddy fields featuring flat terrain, the roles of climate and drainage variables played a more substantial role in influencing the outcomes. These findings underscore the importance of selecting appropriate environmental inputs for improving SOM prediction accuracy. Full article

Whilst the potential of fish effluents as nutrient sources for crop production has been demonstrated, their use in the European Union remains prohibited in organic farming. In this study, we investigate the efficacy in greenhouse basil cultivation of two types of fish effluents (filtered ‘fish water’ and unfiltered ‘fish sludge’) from an aquaponic system, and assess their role in maintaining and enhancing soil fertility as well as their potential to create a ’living soil’, which are two of the prerequisites for organic certification in the EU. To evaluate the contribution of fish effluents to plant growth in comparison with soil nutrients, basil plants were grown in pots containing two types of substrate: compost-free (without organic matter) and with compost (with organic matter). The results indicate that fish water and fish sludge demonstrate significant potential as fertilisers and outperform compost in certain parameters, such as plant biomass. The results also align with existing literature by demonstrating the positive impact of compost on soil microbial diversity, underscoring its role in fostering plant health. Although the treatments did not show differences in microbial composition at the genus level, the higher microbial diversity observed following fish effluent application highlights its potential for promoting ’living soil’. This research underscores the need for continued exploration of the implications of compost application in conjunction with fish effluent fertilisation on soil microbial communities and the production of specialty crops such as herbs. Full article

The fluorescence index called the Transit Time index (TTi) is based on the fluorescence of natural organic matter in order to qualitatively assess the transit time of karst groundwater, using springs affected by human activities. This study aims to further evaluate the potential of fluorescent compounds as a natural tracer of transit time when applied to unsaturated zone flows with natural catchments, in contrast to the first study. For this purpose, a bi-monthly sampling of one year of monitoring for organic matter fluorescence, TOC, major elements and water-stable isotopes was performed. A conceptual model of the sources and fates of fluorescent compounds is built, emphasizing the allochthonous origin of humic-like C compounds, and the autochthonous production of humic-like M and protein-like compounds within the unsaturated zone. Fluorescent compound intensity interpretation according to this model reveals consistent relative transit times with flow behavior and also provides complementary information. The results also show the TTi’s ability to summarize fluorescent compounds, its consistency with relative transit time, and its higher sensitivity as compared to other natural tracers. However, prior to its use, a thorough assessment of soil organic matter, microbial activity, and potential anthropogenic contamination is required, encouraging interdisciplinary collaboration between hydrogeologists, microbiologists and soil scientists. Full article

Mycorrhizal symbiosis has been the focus of research for more than a century due to the positive effect of fungi on the growth of the majority of woody plants. The extramatrical mycelium (EMM) of ectomycorrhiza (EMR) accounts for up to one-third of the total soil microbial biomass, whereas litter from this short-living pool accounts for 60% of the total litterfall mass in forest ecosystems. The functioning of EMR improves the nitrogen (N) nutrition of trees and thus contributes to the carbon (C) balance of forest soils. The model presented here is an attempt to describe these EMR functions quantitatively. It calculates the growth of EMM and the subsequent “mining” of additional nitrogen from recalcitrant soil organic matter (SOM) for EMR growth, with the associated formation of “dissolved soil carbon”. The decomposition of EMM litter is carried out by all organisms in the soil food webs, forming available NH4+ in the first phase and then solid-phase by-products (excretes) as a new labile SOM pool. These substances are the feedback that determines the positive role of EMR symbiosis for forest vegetation. A sensitivity analysis revealed a leading role of the C:N ratio of biotic components in the dynamics of EMM. The model validation showed a satisfactory agreement between simulated and observed data in relation to EMM respiration in larch forest plantations of different ages. Model testing within the EFIMOD3 model system allowed a quantitative assessment of the contribution of different components to forest soil and ecosystem respiration. The validation and testing of this model demonstrated the adequacy of the theoretical background used in this model, with a fast EMM decomposition cycle by all soil biota of the food webs and without direct resource exchange between plants and fungi. Full article

Soil degradation caused by mining activities has seriously affected the ecological environment of mining areas. Improving the soil quality is the key to solving this problem. This study examined the impact of adding Effective Microorganism (EM) agents and maize straw to the soil from the dump of the Ordos Rongheng open-pit coal mine. We conducted a two-factor complete experiment, varying the amounts of EM agents (0 g·kg⁻¹, 0.1 g·kg⁻¹, 0.2 g·kg⁻¹, 0.3 g·kg⁻¹, and 0.4 g·kg⁻¹) and maize straw (0 g·kg⁻¹, 5 g·kg⁻¹, 10 g·kg⁻¹, 15 g·kg⁻¹, and 20 g·kg⁻¹). Changes in the soil’s physical, chemical, and biological properties were assessed using a six-month-long potting experiment, and a minimum data set was established for soil quality evaluation. Our results indicated that both EM agents and maize straw improved the soil quality. Both additions reduced the soil’s bulk density and pH while increasing its porosity, organic matter, total available nutrients, enzyme activity, and microbial diversity. However, maize straw had no significant effect on the soil moisture content and total available phosphorus, and EM agents did not significantly impact organic matter. The interaction between the two treatments was not significant for soil moisture content, capillary porosity, and total potassium. Finally, we identified five key indicators affecting soil’s quality: the bulk density, available potassium, alkaline phosphatase, bacterial Chao1 index, and fungal Shannon index. The soil quality index (SQI) ranged from 0.158 to 0.568, with the highest SQI being observed with 0.1 g·kg⁻¹ EM agents and 20 g·kg⁻¹ maize straw, which was significantly higher than those from other treatments. New insights into the improvement of soil quality in open-pit mines are provided by these results, which may help guide future ecological restoration of mines. Full article

Agro-industrial activities generate significant amounts of organic waste and a variety of effluents thus posing environmental challenges. Viticulture in Argentina, which covered 204,847 ha in 2023, faces water scarcity as a limiting factor conditioning its production. This industry produces large volumes of grape marc, sediments, and stalks, which can be valorised into products like alcohol, tartaric acid, and compost. However, these valorisation processes generate effluents with high organic load and salinity, further stressing water resources. This study explores the potential of utilising these effluents to cultivate plant biomass in arid regions (sorghum or perennial pasture), which could serve as bioenergy, animal feed, or composting co-substrates, contributing to circular bioeconomy principles. The combined use of effluent as a water resource and the sowing of sorghum and pasture increased soil organic matter content and led to a slight reduction in pH (depth: 0.30–0.60 m) compared to the control treatment. The sorghum plots showed better establishment and higher dry biomass yield (32.6 Tn/ha) compared to the pasture plots (6.5 Tn/ha). Sorghum demonstrated better tolerance to saline soils and high salinity effluents, aligning with previous studies. Although pasture had a lower biomass yield, it was more efficient in nutrient uptake, concentrating more NPK, ash, and soluble salts. Sorghum’s higher yield compensated for its lower nutrient concentration. For biomass production, sorghum is preferable, but if nutrient capture from effluents is prioritised, summer polyphytic pastures are more suitable. These results suggest that the final selection between plant biomass alternatives highly depends on whether the goal is biomass generation or nutrient capture. Full article

Desertification severely impacts soil environments, necessitating effective control measures to improve sandy soil. On the alpine sandy land of Gonghe Basin, taking bare land containing mobile sand dunes (LD) as a reference, surface soil undergoing four afforestation measures, namely Salix cheilophila + Populus simonii (WLYY), Salix psammophila + Salix cheilophila (SLWL), Artemisia ordosica + Caragana korshinskii (SHNT), and Caragana korshinskii (NT80), was studied, with soil physicochemical properties and enzyme activity measured and the bacterial community structure analyzed using Illumina high-throughput sequencing. Compared to LD, all four afforestation measures significantly reduced the sand content, while increasing soil total carbon, total nitrogen, organic matter, alkali-hydrolyzable nitrogen, and available potassium. WLYY, SLWL, and SHNT significantly increased the surface soil total phosphorus and total potassium. Catalase, sucrase, urease, and alkaline phosphatase activities significantly increased under all four measures. Among them, the highest improvements were observed under SLWL, followed by WLYY. All treatments increased soil bacterial community richness, exhibiting significantly different bacterial community compositions to those in LD. Total phosphorus was the key physicochemical factor affecting the soil bacterial community structure, while enzyme activity was significantly correlated with the relative abundance of most major bacterial phyla. All measures improved the surface soil environment, with SLWL demonstrating the best improvement. The results provide valuable reference for sand prevention and control strategies in alpine sandy areas and offer a theoretical basis for the ecological restoration of sandy soil microenvironments. Full article

The geological study area is volcano-tectonic in nature. Microscopic observations and mineralogical analyses revealed the presence of allophane and diatom clusters whose mineral compositions coincided with weathered andesites and dacites. Edometric consolidation tests showed a high porosity and a reduction in the void ratio by up to five times. These are highly compressible soils with a Cc/Cs ratio of 12 to 15 and a specific gravity (Gs) of 2.4. Low initial bulk density (1.10 Mg/m³), high plasticity, and SUCS (OH) classification are typical of soft soils, with an effective friction angle (ɸ’C_D) of 25.5° to 30° and effective cohesion (c’_CD) of 11.90 to 47.27 KPa. The shear wave velocity for the first 10 m (Vs10) on average ranged from 78 m/s to 120 m/s, whereas that for the first 30 m (Vs30) was 169 m/s. The permeability, which was calculated indirectly, was between 2 × 10⁻⁷ and 3 × 10⁻⁸ m/s. With an organic matter content between 5% and 25%, the Caupicho soil is an organic mineral sediment that is not considered peat (non-peat). The results of this study serve as a basis for future analyses of soil dynamics, bearing capacity, and consolidation settlements in the medium and long term in an area of high urban growth in southern Quito, Ecuador. Full article

Mangrove swamp rice (MSR) production is critical for the diet of small farmers of coastal Guinea-Bissau. In mangrove swamp agroecosystems, rice is grown during the rainy season when freshwater and nutrients are abundant. However, small-scale farmers face challenges like unpredictable rainfall and rising sea levels, which increase soil salinity and acidity. This study aims to assess soil physical–chemical properties, paired with farmers’ local practices, to evaluate fertility constraints, and to support sustainable soil–plant management practices. This co-designed research contributes to filling a gap concerning the adoption of sustainable agricultural practices adapted to specific contexts in West Africa. In two regions, Oio (center) and Tombali (south), rice yields were measured in semi-controlled trials both in two agroecological settings: Tidal Mangrove (TM) and Associated Mangrove (AM) fields. 380 soil samples were collected, and rice growing parameters were assessed during the 2021 and 2022 rice sowing, transplanting, and flowering periods. Principal Component Analyses (PCA) and Multivariate Regression Analysis (MRA) were applied to understand trends and build fertility proxies in predicting yields. Significant spatial and temporal variability in the soil properties between agroecologies was found. Salinity constraints in Oio TMs limit production to an average of 110 g/m², compared to 250 g/m² in Tombali. Yield predictions account for 81% and 56.9% of the variance in TMs and AMs, respectively. Variables such as organic matter (OM), nitrogen (N), potassium (K), and precipitation positively influence yields, whereas sand content, pH, and iron oxides show a negative effect. This study advances the understanding of MSR production in Guinea-Bissau and underscores the importance of incorporating farmers’ knowledge of their diverse and complex production systems to effectively address these challenges. Full article

Phosphorus (P) in soil is important in the process by which soil microbial communities regulate soil enzyme activity. We aim to explore how short-term P fertilization affects the composition and functionality of the soil fungal community, offering insights into the complex responses of soil fungi to fertilization. Soil samples from a long-term experiment with no P fertilization were collected for pot experiments. The pot experiment included four treatments: non-P fertilizer (NK), chemical P fertilizer (NPK), 1/2 organic fertilizer + 1/2 chemical fertilizer (MNP), and organic fertilizer (M). High-throughput sequencing was employed to analyze the composition, diversity, and functionality of soil fungal communities. Results showed that short-term P addition significantly increased the soil fungal Shannon and Pielou e indices, with increases of 34.48%~59.00% and 29.79%~53.19%, respectively. Ascomycota and Basidiomycota were the most abundant fungal phyla, whereas Cladosporium and Emericellopsis were the most abundant genera. The main factors affecting soil fungal community composition were total nitrogen (TN) and organic matter (OM). A linear discriminant analysis effect size (LEfSe) analysis indicated that Mortierellomycota were significantly enriched under the NPK treatment. A FUNGuild analysis revealed that, compared to the NK treatment, the relative abundance of Animal Pathogen–Endophyte–Lichen Parasite–Plant Pathogen–Wood Saprotroph was reduced by 67.54%, 46.93%, and 44.10% under NPK, MNP, and M treatments, respectively. The relative abundance of Plant Pathogen was less than 1% in the NPK and the MNP treatments. These results indicate that short-term P addition increased soil nutrient levels and soil fungal community diversity. Chemical P fertilizer significantly improved the fungal community structure in yellow paddy soils, enhancing beneficial fungi and suppressing pathogens. Full article

In this study, the biodegradability of poly(lactic acid) (PLA), the most widely produced bioplastic, and poly(3-hydroxybutyrate) (PHB), known for its very biodegradability, was investigated in soil and soil amended with nitrogen sources, such as treatment sludge and vermicompost. Biodegradability was evaluated over 180 days by measuring the amount of carbon dioxide (CO₂) and analyzing samples with scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). PLA showed a low biodegradation (6%) in soil, but this increased to 40% in soil amended with treatment sludge and 45% in soil amended with vermicompost. PHB completely degraded within 90 days in soil; however, this process extended to 120 days in soil amended with vermicompost and 150 days in soil amended with treatment sludge. The organic and microbial content of the amendments enhanced PLA biodegradation, while PHB degradation slowed after 50 days as microorganisms prioritized other organic matter. SEM and FTIR analyses after 60 days showed more intense degradation of both bioplastics in soil amended with vermicompost. These findings highlight the potential of treatment sludge and vermicompost for improving bioplastic degradation, contributing to sustainable waste management and soil enhancement. Full article

The cultivation of ornamental bamboos in pots and gardens has a higher demand for light and clean cultivation substrates, and the effects of such cultivation substrates on the growth of ornamental bamboos are rarely seen. In this study, we compared the effects of physicochemical properties of different cultivation substrates on the growth physiology of ornamental bamboos and analysed the composition of rhizosphere microbial communities by cultivating Pleioblastus chino f. holocrysa (PC), and Arundinaria fortune (AF), in both common soil (CS) and soilless substrate (SS). In PC and AF, compared to biomass at the start of cultivation the aboveground biomass of CS and SS increased by 13.71% and 0.81%, the root biomass increased by 16.01% and 25.52%, and the bamboo whip biomass decreased by 29.72% and 24.75% at the end of the cultivation. In both PC and AF, the abundance of Proteobacteria in SS (42.28% and 48.42%, respectively) was higher than in CS (38.52% and 34.92%, respectively), the abundance of Ascomycota in SS (76.55% and 87.89%, respectively) was higher than that of CS (72.46% and 68.80%, respectively), the abundance of Bacteroidota in SS (10.35% and 9.16%, respectively) was higher in CS (7.42% and 7.61%, respectively), and was positively correlated with organic matter and available nitrogen, phosphorus, and potassium. The abundance of beneficial microbial genera (Haliangium, Acidibacter, BIrii41, Pseudeurotium) increased in SS, and the abundance of pathogenic fungi Fusarium in SS (1.87% and 0.10%, respectively) was lower than in CS (3.97% and 3.10%, respectively). Taken together, the results reveal that SS increased the growth of aboveground parts of ornamental bamboo, inhibited the growth of bamboo whips, and reduced the allocation of biomass to foraging organs compared with CS. The increase in beneficial microbial genera promoted the development of the root system and the accumulation of nitrogen, phosphorus, and potassium in the leaves of ornamental bamboo, and the decrease in pathogenic genera lowered the risk of disease infection in the ornamental bamboo. Full article

Heavy metals, especially lead (Pb), is the major cause of pollution in the military shooting range soils. Bullets, which are primarily made of Pb, are a substantial source of this pollution. On speciation, this Pb is distributed into its different metal forms. Different physicochemical properties of the soil like pH, moisture content, cation exchange capacity (CEC), and organic matter play a very crucial role in the distribution, transformation, and bioavailability of the Pb. The concentration of Pb found in different shooting ranges is examined. Moreover, bullet weathering and the availability of contaminants in the soil are influenced by the physicochemical properties of the soil. For the management of firing range pollution, a variety of strategies have been investigated, including soil washing, phytoremediation, and chemical stabilization. This review focus on the pollution status of different shooting ranges, the impact of the physicochemical properties of soil on the distribution, speciation, and transformation of Pb, and different mitigation strategies to control Pb pollution in military shooting ranges. Full article

Restoration of the longleaf pine forest ecosystem is critical for biodiversity. However, the mixed hardwood forests can grow naturally in the same area. There are limited studies comparing soil organic matter and nutrient contents for restoring longleaf pine forests from the mixed hardwood forest areas in the southeastern USA. In this study, a comparison of the contents in soil organic matter, macro-nutrients, trace metal elements, and litterfall amount, was conducted on the 16 forest stands (4 treatments including stand stages × 4 replicants) at William B. Bankhead National Forest in Alabama through the space-replace-time approach. The results indicate that longleaf pine forests have lower contents of soil organic matter, macro-nutrients, most trace metal elements, and litterfall amount than mixed hardwood forests. However, longleaf pine forests have higher soil Ca, Ba, and Pb contents than hardwood forests. Soil Fe content has more correlations with the contents of other metal elements than soil Mn. The results suggest that multiple ecosystem functions, including soil ecology, must be considered in the regional restoration of the longleaf pine ecosystem. Longleaf pine forests with a certain amount of mixed hardwood trees may be a good way to maintain soil organic matter and nutrients. Full article

Conservation agriculture (CA) is a sustainable land management approach to improve soil quality while mitigating degradation. Although extensive information regarding the effect of CA on soil properties and microbiome is available, complete studies on the cumulative effect on specific interactions between soil parameters, crop productivity, and microbial communities over time are still lacking, mainly in arid regions. Thus, this study aimed to investigate the effects of no-tillage and residue retention over long- and short-term (24 and 3 years, respectively) periods. Six treatments were established in a maize–oat–triticale system from 1995 in a semiarid region: P + H—plow + harrow; H—harrow; MP—multi-plow (short-term); NT—no-tillage; NT33—NT + 33% residue surface cover (long-term); NT66—NT + 66% residue surface cover. Results indicated that CA improved soil quality by increasing soil organic matter (SOM), total carbon, and glomalin; it also enhanced microbial abundance, particularly fungi, and β-galactosidase activity. Nevertheless, conventional tillage practices led to SOM degradation and reduced crop yields. Principal component analysis revealed distinct groupings of treatments based on soil properties and microbial communities. Furthermore, changes could be detected from the short term. These findings highlight the importance of adopting sustainable agricultural practices to maintain soil health and ensure agricultural productivity in semi-arid regions. Full article