Soil Bulk Density Research Articles

Assessing the impact of climate and crop diversity on regional greenhouse gas emissions and water demand of cropland

To tackle the challenges of climate warming and freshwater scarcity, evaluating greenhouse gas (GHG) emissions and water demand in agricultural production can contribute positively to sustainable agricultural practices. This study aims to quantify the GHG emissions and water requirements of three major grains in diverse environmental regions in China, with a specific focus on exploring their spatial heterogeneity due to regional differences. The parameterized DNDC model was used to quantify crop GHG emissions, while the Penman-Monteith equation was utilized to assess crop water demand. The result showed that the total GHG emission of major grain in China was 372.43 Tg/yr (CO2), 11.68 Tg/yr (CH4), 475.56 Gg/yr (N2O) respectively; and the water demand was 473.60 Gm3, in 2015. The Middle-lower Yangtze Plain (MLYP) had the highest emission and water demand. High-temperature and high-precipitation regions had greater GHG emission intensity; the intensity of different GHG emissions was significantly influenced by the type of crops. Late rice had the highest emission intensity. The geospatial distribution of GHG emissions and water demand displayed opposite patterns, with meteorological conditions and crop types as the main reasons. Soil bulk density was the most significant soil element influencing regional emissions. These results will help to assess the spatial heterogeneity of agricultural “water and carbon”, and the quantitative results can be used as evaluation indicators to establish resource- and environment- friendly agricultural cropping patterns suitable for different cropping regions.

Effect of Coal Mining Subsidence on Soil Enzyme Activity in Mining Areas with High Underground Water Levels

In order to investigate the changes in soil enzyme activity and their influencing factors in coal mining subsidence areas with high underground water levels, in this study, we collected soil samples at different depths (SL: 0–20 cm; ML: 20–40 cm; DL: 40–60 cm) in a deep coal seam subsidence area (T1), a shallow coal seam subsidence area (T2), and control non-subsidence areas (W1 and W2) in eastern China. Soil physicochemical properties and enzyme activities were determined, and the mechanism of the latter’s response to coal mining subsidence was investigated based on correlation analysis, redundancy analysis, and structural equation modeling. The results show the following: (1) In the coal mining subsidence areas, the soil pH value (pH), soil available nitrogen (AN), available phosphorus (AP), available potassium (AK), and soil organic matter (SOM) contents were lower than those in the non-subsidence areas, while the soil water content (SWC) and bulk density (BD) were higher than those in the non-subsidence areas and increased with depth. (2) The activities of soil urease (URE), sucrase (SUC), alkaline phosphatase (ALP), and catalase (CAT) gradually decreased with depth and were all lower than those in the non-subsidence areas; the largest decreases with respect to the latter were 24.33%, 18.73%, 38.89%, and 5.88%, respectively. (3) The soil nutrient environment had a highly significant and direct positive effect on enzyme activity, with AN, AP, and SOM contents having the greatest impact. (4) Soil BD had a highly significant and direct negative effect and an indirect negative effect (by affecting nutrients) on enzyme activity. The results of this study on the effects of soil physicochemical properties on enzyme activity provide a basis for the ecological restoration of mines.

Effect of Aminating Lignin Loading with Arbuscular Mycorrhizal Fungi on Soil Aggregate Structure Improvement.

Lignin is an important component of plant fiber raw materials, and is a three-dimensional network structure aromatic polymer with abundant resources and a complex structure in nature. Lignin is generally used as industrial waste, and its potential value has not been fully utilized. Modern agriculture extensively uses chemical fertilizers, leading to the gradual degradation of soil fertility and structure, which seriously affects crop growth, nutrient transport, and root respiration function. Based on soil bulk density, porosity, aggregates, and their stability indicators, this study analyzed the effects of aminated industrial lignin and its loading with arbuscular mycorrhizal fungi on soil structure improvement and plant growth. It was hoped that resource-rich lignin could play a beneficial role in improving soil structure and promoting crop growth. The phenolic hydroxyl group of lignin was epoxidized and further aminated to load with arbuscular mycorrhizal fungi. The results indicated that amine-modified lignin could effectively load with arbuscular mycorrhizal fungi. The application of arbuscular mycorrhizal fungi-supported aminated lignin to soil aggregate structure improvement greatly reduced the bulk density of soil, and increased the porosity of soil and the content of large granular soil. Compared with unmodified soil, soil bulk density decreased by 73.08%, the porosity of soil increased by 70.43%, and the content of large granular soil increased by 56.38%. Using the improved soil for corn cultivation efficiently increased the biomass of corn. The plant height was increased by 72.16%, the root-shoot ratio was increased by 156.25%, and other indexes were also improved to varying degrees. The experimental method provides an important basis for the effective utilization of lignin materials in agriculture in the future.

Rice (Oryza sativa L.) yield evaluation comparing two soil preparation methods

Contextualization: Rice (Oryza sativa L.) cultivation, throughout its vegetative process, generates an increase in bulk density and penetration resistance in soil. The most representative component of production costs is management, even so, land preparation and adaptation reach, and exceed, 20% of the costs. Knowledge gap: As it is a high economic yield crop and little technified in the region, the conservation plows implementation that provide economic and environmental benefits to the community is sought. Purpose: With the aim of promoting a more sustainable production and agriculture, it was proposed to evaluate the soil’s physical properties and the rice crop yield, modifying the conventional preparation with plow to the chisel use. Methodology: The experimental area made up of one hectare was divided into experimental plots, T1: One pass with a vibratory chisel, and T2: Two passes with conventional tillage (plow), in which the soil’s physical properties were evaluated (Real Density, Apparent Density, Porosity and Texture) and the phenological follow-up to the crop development (Germination, Maximum Tillering, Maximum Engrossed, Maturity and Harvest). Soil tests were carried out before and after tillage between 15 and 20 cm depth. The statistical analysis was carried out by means of Analysis of Variance (ANOVA) and graphically, and the techno-economic analysis was carried out based on the production and operation costs comparing between the two types of tillage. Results and conclusions: The results showed that after soil preparation the bulk density decreased by 5,0% for T1 and 13,5% for T2; Likewise, these effects led to an increase in porosity of 13,6% and 29,34%, respectively, and production costs to be $1159,9 USD for T1 and 5,37% higher for T2. At the end, it is concluded that, when evaluating the yield at harvest, there were no significant differences in production because of machining, but a statistical difference was observed between the cost of conventional and reduced tillage, the latter being 148,9% cheaper and less aggressive for the soil.

Microplastics positively mediate soil multifunctionality in dryland

Soil multifunctionality (SMF) denotes soil capability to concurrently offer diversified functions. Here, we unveiled the long-term effects of polyethylene microplastics (MPs) on SMF along their physical forms and concentrations in dryland. General linear model showed that eight major function groups (across 21 functions) explained 78.6 % of SMF variation. Direct or indirect productive functions of soil, including plant productivity and its physical property stability, contributed to SMF by 8.65 % and 13.68 %, respectively. Ecological functions, including microbial activity (12.73 %), bacterial composition diversity (10.69 %), bacterial functional diversity (11.71 %), carbon storage (9.98 %), nitrogen storage (3.54 %) and pollutant metabolism function (7.62 %), exhibited positive contributions to SMF. These were somewhat dependent on MPs physical forms and concentrations, and mostly attributed to the foam-modified effects of MPs on soil bulk density, and functional trade-off between conservation and services. Overall, MPs induced positive effects on SMF, challenging the widespread viewpoint that MPs only produced negative impacts in dryland.

Using a comprehensive model for cropland types in relationships between soil bulk density and organic carbon to predict site-specific carbon stocks

Using a comprehensive model for cropland types in relationships between soil bulk density and organic carbon to predict site-specific carbon stocks

Amount, distribution and controls of the soil organic carbon storage loss in the degraded China's grasslands

More than 80 % of China's grasslands are classified as degraded, and the loss of soil carbon storage due to degradation has a significant impact on China's terrestrial carbon sinks as well as carbon neutrality targets. The loss of soil carbon storage in degraded grasslands can serve as a benchmark for quantifying the carbon sequestration capacity of restored grasslands in the future. Here, above- and below-ground biomass, soil organic carbon (SOC) content at various depths (0–100 cm) and soil bulk density were collected from 226 degradation sequences around China. The above information was integrated and statistically analyzed to quantify the difference of SOC storage between the degraded and natural grassland at national scale. The result showed that grassland degradation led to a significant reduction in SOC storage across different depths. SOC (0–100 cm) of degraded grassland decreased by 39 % compared to that of natural grassland, ranging from 21 % in the lightly degraded sites to 59 % of the extremely degraded sites. 15 potential predictors were used to estimate the national amount of these differences of 0–20 cm depth SOC storage as 5.29 ± 1.59 Pg C. This considerable carbon storage gap implies the necessity of China's grassland restoration project in achieving carbon neutrality goals in the future.

Stormwater runoff calculator for evaluation of low impact development practices at ground-mounted solar photovoltaic farms

Estimating runoff at ground-mounted solar photovoltaic (PV) installations is challenging because of the disconnected nature of impervious solar panels and the pervious ground surface underneath and between panel rows. There is a need for improved tools to estimate how low impact development practices at these solar installations affect stormwater runoff. The objective of this study was to develop an innovative spreadsheet-based runoff calculator that rapidly estimates stormwater runoff from ground-mounted solar PV sites. The calculator is built on a 2-D hydrologic model (Hydrus-2D/3D) calibrated and validated using experimental data from five commercial solar farms in Colorado, Georgia, Minnesota, New York, and Oregon. The Hydrus-2D/3D hydrologic model was then used to generate nomographs for stormwater runoff that were incorporated into an easy-to-use Excel-based solar farm runoff calculator. This calculator allows for rapid estimation of NRCS stormwater runoff curve number (CN) values at solar farms by considering several complex factors unique to PV installations including: soil and topographic characteristics, surface cover, disconnected impervious surface factors associated with various solar panel designs, and climatic factors. The solar farm runoff calculator quickly estimates runoff CN for pre- and post-construction scenarios, and can estimate actual depth of runoff based on a user-specified 24-h design storm depth. Factors that have the most significant impact on stormwater runoff include design storm return frequency, soil texture, soil bulk density, and soil depth. Ground surface cover has a moderate impact on stormwater runoff, and factors that have a lesser impact on stormwater runoff include slope and array size, spacing and orientation on the landscape. The runoff calculator allows for accurate estimates of runoff generated by disconnected impervious surfaces and low impact development practices at solar farms as affected by a wide range of site-specific conditions.

Soil health as a proxy for long-term reclamation success of metal-contaminated mine tailings using lime and biosolids

Mine lands contaminted with heavy metals pose environmental risks, and thus reclamation is paramount for improving soil, plant, animal, and ecosystem health. A metal-contaminated alluvial mine tailing, devoid of vegetation, received 224 ​Mg ​ha−1 of both lime and biosolids in 1998, and long-term reclamation success was quantified in 2019 with respect to soils, plants, and linkages to animals. Reclamation success was quantified using the Soil Management Assessment Framework (SMAF), in conjunction with bioavailable (0.01 ​M CaCl2 extractable) and plant-available (Mehlich-3 extractable) soil metal concentrations, X-ray absorption spectroscopy, plant metal concentrations, and plant quality characteristics. Results showed that all soil indicators were improved in successfully-reclaimed areas as compared to on-site degraded areas, including increases in soil aggregate stability, pH, plant-available P and K, soil organic C, potentially-mineralizable N, microbial biomass C and β-glucosidase activity and decreases in soil bulk density and electrical conductivity. Of indicators, unitless soil health scores were assigned based on the SMAF, with data suggesting that bulk density, wet aggregate stability, potentially- mineralizable N, microbial biomass C, pH, and electrical conductivity should be monitored in the future. The long-term effects of lime and biosolids application have improved soil physical, biological, and overall soil health. Plant metal concentrations have decreased by an order of magnitude since early reclamation, with most plant metal concentrations being tolerable for domestic livestock consumption. From an animal health perspective, feeding grasses from this site during latter parts of a growing season may need supplemental feed to provide greater protein and energy content, and to reduce potentially-harmful Cd concentrations from food chain bioaccumulation. However, a health concern exists based on soil bioavailable Cd and Zn concentrations that exceed ecological soil screening levels. Still, plants have stabilized the soil and acidity remains neutralized, leading to long-term improvements in soil health, with overall improved ecosystem health.

Spatial Patterns of Soil Bacterial Communities and N-cycling Functional Groups Along an Altitude Gradient in Datong River Basin

The altitude distribution patterns of soil microorganisms and their driving mechanisms are crucial for understanding the consequences of climate change on terrestrial ecosystems. There is an obvious altitude difference in Datong River Basin in the Qilian Mountains. Two spatial scale transections were set up along the mountain slope (with altitude spanning 1 000 m) and the mainstream direction (with altitude spanning 300-500 m), respectively. The distribution characteristics of the soil bacterial community structure and diversity along the altitude gradients were examined using high-throughput sequencing technology. Based on the FAPROTAX database, the altitude distribution patterns of nitrogen cycling functional groups were analyzed to investigate the major environmental factors influencing the altitude distribution patterns of soil bacterial communities. The findings revealed that:① Soil physicochemical characteristics varied significantly with altitude. The content of total nitrogen (TN) and nitrate nitrogen (NO3-) were positively correlated with the altitude (P < 0.01), whereas the soil bulk density and pH were negatively connected (P < 0.001). ② The abundance of OTU increased significantly along the altitude (P < 0.01), and the richness and diversity indices increased along the altitude, although the trend was not statistically significant (P > 0.05). ③ The predominant bacterial communities were Acidobacteria, Proteobacteria, and Bacteroidetes, and as altitude climbed, their relative abundances varied between increasing, decreasing, and slightly decreasing, respectively. ④ The nitrogen cycling processes involved 13 functional groups, primarily nitrification, aerobic ammonia oxidation, aerobic nitrite oxidation, etc. As the altitude increased, the response law changed, with an increase in the abundance of nitrobacteria (P < 0.01), a slight increase in the abundance of aerobic ammonia-oxidizing bacteria and nitrite-oxidizing bacteria, and a hump-back tendency in bacteria abundance for nitrogen respiration. ⑤ Redundancy analysis revealed that the key determinants influencing soil bacterial populations at the phylum level were altitude, pH, and the content of NH4+. Mantel analysis showed that the dominant groups of soil bacterial nitrogen cycling were all statistically and significantly driven by altitude (P < 0.01). ⑥ The α-diversity of the bacterial community with increasing altitude were both increased along the mountain slope and the mainstream direction, but the soil properties, the abundance of N-cycling functional groups, and the main environmental factors differed. Therefore, it is of great significance to explore the altitude distribution pattern of soil microorganisms at different spatial scales.

Altitude Distribution Characteristics of Farmland Soil Bacteria in Loess Hilly Region of Ningxia

It is of great significance for the conservation of biodiversity in farmland ecosystems to study the diversity, structure, functions, and biogeographical distribution of soil microbes in farmland and their influencing factors. High-throughput sequencing technology was used to analyze the distribution characteristics of soil bacterial diversity, community structure, and metabolic function along elevation and their responses to soil physicochemical properties in farmland in the loess hilly areas of Ningxia. The results showed that:① The Alpha diversity index of soil bacterial was significantly negatively correlated with elevation (P < 0.05) and showed a trend of decreasing and then slightly increasing along the elevation. ② Seven phyla, including Proteobacteria, Actinobacteria, and Acidobacteria, were the dominant groups, and five of them showed highly significant differences between altitudes (P < 0.01). ③ At the secondary classification level, there were 36 metabolic functions of bacteria, including membrane transport, carbohydrate metabolism, and amino acid metabolism, of which 22 showed significant differences, and 12 showed extremely significant differences among different altitudes. ④ Pearson correlation analysis showed that soil water content, bulk density, pH, and carbon-nitrogen ratio had the most significant effects on bacterial Alpha diversity, whereas soil nutrients such as total organic carbon, total nitrogen, and total phosphorus had significant effects on bacterial Beta diversity. ⑤ Mantel test analysis showed that the soil water content, total organic carbon, and carbon-nitrogen ratio affected bacterial community structure at the phylum level, and soil pH, total organic carbon, total nitrogen, total phosphorus, and carbon-nitrogen ratio were significantly correlated with bacterial metabolic function. Variance partitioning analysis showed that soil water content had the highest explanation for the community structure of soil bacteria, whereas soil pH had the highest explanation for metabolic function. In conclusion, soil water content and pH were the main factors affecting the diversity, community composition, and metabolic function of soil bacteria in farmland in the loess hilly region of Ningxia.

Natural colonizers effectively restore heavy metal polluted wasteland

In India, ∼30% of total land is degraded due to pollution, salinization, and nutrient loss. Change in soil-quality at urban waste-dumping site prior and after cow-dung amendment was compared with control agriculture soil. The soil at waste-dumping site had elevated pH, EC, temperature and lowered OC and NPK concentrations when compared to control. Polymetallic pollution of Cr, Cd, Pb, and Ni beyond permissible limits was obtained. Cow-dung amendment restored soil physicochemical properties at the waste-dumping site, with increasing soil moisture, CEC and OC; however, a slight change in soil bulk-density and heavy-metal concentration post-amendment was noted. The seven natural colonizers present at the waste-dumping site accumulated more metals in roots than shoots. Datura innoxia had maximum bioaccumulation of Cr, Calotropis procera of Cd and Ni and Parthenium hysterophorus of Pb in roots. All these plants had Bioacccumulation factor (BAfroot )>1 and translocation factor (Tf) <1 for Cd and serve as its phytostabilizer except Calotropis procera which had BAfroot >1 and Tf >1 and is identified as a phytoextractor for Cd. Cow-dung amendment alone appeared to be insufficient and additionally the revegetation of natural colonizers is recommended for effective reduction in heavy metal load and improving overall soil health at wasteland. Such eco-restoration may also minimize risks to biodiversity in India.

Conservation tillage: a way to improve yield and soil properties and decrease global warming potential in spring wheat agroecosystems.

Climate change is one of the main challenges, and it poses a tough challenge to the agriculture industry globally. Additionally, greenhouse gas (GHG) emissions are the main contributor to climate change; however, croplands are a prominent source of GHG emissions. Yet this complex challenge can be mitigated through climate-smart agricultural practices. Conservation tillage is commonly known to preserve soil and mitigate environmental change by reducing GHG emissions. Nonetheless, there is still a paucity of information on the influences of conservation tillage on wheat yield, soil properties, and GHG flux, particularly in the semi-arid Dingxi belt. Hence, in order to fill this gap, different tillage systems, namely conventional tillage (CT) control, straw incorporation with conventional tillage (CTS), no-tillage (NT), and stubble return with no-tillage (NTS), were laid at Dingxi, Gansu province of China, under a randomized complete block design with three replications to examine their impacts on yield, soil properties, and GHG fluxes. Results depicted that different conservative tillage systems (CTS, NTS, and NT) significantly (p < 0.05) increased the plant height, number of spikes per plant, seed number per meter square, root yield, aboveground biomass yield, thousand-grain weight, grain yield, and dry matter yield compared with CT. Moreover, these conservation tillage systems notably improved the soil properties (soil gravimetric water content, water-filled pore space, water storage, porosity, aggregates, saturated hydraulic conductivity, organic carbon, light fraction organic carbon, carbon storage, microbial biomass carbon, total nitrogen, available nitrogen storage, microbial biomass nitrogen, total phosphorous, available phosphorous, total potassium, available potassium, microbial counts, urease, alkaline phosphatase, invertase, cellulase, and catalase) while decreasing the soil temperature and bulk density over CT. However, CTS, NTS, and NT had non-significant effects on ECe, pH, and stoichiometric properties (C:N ratio, C:P ratio, and N:P ratio). Additionally, conservation-based tillage regimes NTS, NT, and CTS significantly (p < 0.05) reduced the emission and net global warming potential of greenhouse gases (carbon dioxide, methane, and nitrous oxide) by 23.44, 19.57, and 16.54%, respectively, and decreased the greenhouse gas intensity by 23.20, 29.96, and 18.72%, respectively, over CT. We conclude that NTS is the best approach to increasing yield, soil and water conservation, resilience, and mitigation of agroecosystem capacity.

Assessment of Integrated Poultry Manure and Synthetic Fertilizer Effects on Maize (Zea mays) Growth and Soil Properties: A Study from Bayero University, Kano

The study investigated the effects of organic and inorganic nutrients on crop productivity and soil health, with a focus on maize growth and soil properties. It was conducted at Bayero University, Kano and comprised six treatments laid out in a Completely Randomized Design (CRD) with three replications. The treatments included poultry manure, synthetic fertilizers, and their combination. The research aimed to assess the impact of these treatments on maize growth and their residual effects on soil physical and chemical properties. Various plant growth parameters and soil properties were evaluated, and the data obtained were analyzed using Analysis of Variance (ANOVA) and Student-Newman-Keuls test (SNK). The results indicated that all treatments significantly influenced morphological parameters, including plant height, number of leaves, stem girth, and leaf area, compared to the control. Maize growth was notably higher with the application of integrated poultry and inorganic fertilizer or solely inorganic fertilizers. Additionally, soil organic carbon, total nitrogen, phosphorus, and potassium contents increased when poultry manure was applied alone or in combination with inorganic fertilizer. The application of poultry manure significantly raised soil pH, organic carbon content, total nitrogen, available phosphorus, exchangeable potassium, calcium, magnesium, and effective cation exchange capacity (ECEC) of the soil. Furthermore, the exchangeable acidity of the soil was reduced by the application of poultry manure alone. Soil texture was improved, soil bulk density decreased, and porosity increased due to the application of poultry manure. The study concluded that the combined application of poultry manure and inorganic fertilizer enhanced the growth of maize and could serve as a good soil management practice for tropical soils. It also suggested that integrating inorganic fertilizers with organic manures at optimum rates could improve crop productivity on a sustainable basis. The findings of this study may contribute to the development of sustainable nutrient management programs aimed at enhancing crop productivity with high efficiency and minimal nutrient loss in the future.

Impacts of geography, climate, soil properties and vegetation characteristics on soil C:N:P stoichiometry across the Qinghai-Tibetan Plateau

Soil C:N:P (soil organic carbon: total nitrogen: total phosphorus) stoichiometry can give important information about biogeochemical cycling in terrestrial ecosystems. The spatial patterns and driving mechanisms of soil C:N:P stoichiometry are still poorly understood on the Qinghai-Tibetan Plateau. In this study, we therefore combine data on the geographic position, climate, soil properties and vegetation characteristics of 319 sites across the plateau to investigate their relationship with the horizontal and vertical patterns of soil C, N and P concentrations and the C:N:P ratios. We observed higherSOC (30.5–46.8 mg g-1), TN (2.4–3.4 mg g-1), C:N (14.7–18.0) and N:P (6.9–8.0) in alpine meadows, forests and shrublands, and higher TP (1.6 mg g-1) in croplands. Overall, SOC, TN, TP, C:N and N:P showed decreasing trends with an amplitude of 67%, 64%, 19%, 12% and 54% respectively along the soil profile. Soil cation exchange capacity (CEC) and bulk density were the stronger environmental drivers of SOC and TN. Soil TP showed latitudinal and longitudinal increasing trends in all soil layers. Soil properties explained most of the variations in SOC (67%–90%), TN (67%–87%), C:N (61%–89%) and N:P (64%-85%), with increasing impacts along the soil profile. Geographical position and climate influenced TP both directly and indirectly through soil properties, with geographical position being the predominant driver (46%–65%) along the whole soil profile. The variation in soil C:N was mostly driven by SOC and TN, and the direct and indirect effects of the environmental factors were relatively weak. Geographical position, climate factors, soil properties and vegetation indirectly impacted soil N:P through their effects on soil TN and TP in all the soil layers. Altogether, our findings shed important light on the relative contribution of geography, climate, vegetation and soil properties on soil C:N and N:P, thus providing a better understanding of C, N, and P cycling across the Qinghai-Tibetan Plateau.

Effects of soil bulk density on respiratory metabolism and medicinal quality of Rehmannia Glutinosa root

As one of the famous "four huai medicines", Rehmannia glutinosa has a longstanding usage history. This study aimed to determine how variations in soil bulk density impact the respiration metabolism of R. glutinosa root tubers and, consequently, the quality of its medicinal components. We evaluated the enzymatic activities and key metabolic compounds of R. glutinosa across a range of soil bulk densities, which included: pyruvate kinase (PK), pyruvate decarboxylase (PDC), alcohol dehydrogenase (ADH), lactate dehydrogenase (LDH), isocitrate dehydrogenase (IDH), succinate dehydrogenase (SDH), malate dehydrogenase (MDH), and the content of pyruvate, ethanol, lactic acid, succinic acid, malic acid, and quality indicators. High soil bulk density increased the activities of PK, PDC, ADH, and LDH, while decreasing SDH, MDH, and IDH in the roots. This shift in enzymatic activities corresponded to elevated levels of ethanol and lactic acid, and lowered levels of succinic and malic acids. In the additionally, the growth and development of aboveground parts of R. glutinosa were seriously hindered under high bulk weight treatment, and the number of root tubers decreased, root coarser and root length shortened, and the contents of catalpa alcohol and mullein were significantly reduced. Our findings suggest an optimal soil bulk density for R. glutinosa growth to be between 1.2 g/cm3 and 1.4 g/cm3. Based on changes in respiratory metabolism and medicinal quality indicators of R. glutinosa under different soil bulk densities, our findings suggest the optimal soil bulk density for R. glutinosa growth is 1.2 g/cm3 to 1.4 g/cm3. Excessively high soil bulk density will affect the growth and quality formation of R. glutinosa by influencing its metabolism. Recognizing this optimal range is crucial for maximizing the medicinal quality of R. glutinosa, offering valuable insights for cultivation practices.

Assessing the Influence of Soil Physical Properties on the Puddling Quality: A Comprehensive Review

Puddling is a crucial step in rice cultivation, extensively practiced by farmers in Asia for its role in softening soil, aiding in transplanting, and enhancing water and nutrient management. However, the alteration of soil properties by puddling raises concerns about its long-term sustainability. This comprehensive review systematically examines the impact of puddling on soil parameters such as soil texture, bulk density, penetration resistance, hydraulic conductivity, puddling index, and percolation rate. By synthesizing existing literature, the review aims to inform sustainable agricultural practices and effective soil management strategies amidst escalating global concerns. The complexities of puddling's influence on soil structure underscore the need to consider variables like soil texture and aggregate stability. Sustainable practices such as organic manure application offer potential solutions to address puddling-induced compaction, thereby enhancing soil quality and rice production efficiency. Optimizing tillage methods and improving hydraulic conductivity are essential components of effective soil management strategies for sustainable rice cultivation. Additionally, assessing puddling quality through indices like the puddling index and optimizing percolation rates are vital steps toward improving water management and overall productivity in rice farming.

Prediction of external corrosion rate for buried oil and gas pipelines: A novel deep learning method with DNN and attention mechanism

Buried pipelines is easily subjected to external corrosion affected by complex underground environment, such as soil resistivity, pH, dissolved ion concentration, water content and coatings condition. Therefore, external corrosion rate prediction is essential to ensure pipelines intrinsic safety. Generally numerous researches focused on mathematical models and degradation analysis are limited to considering comprehensive corrosion factors. In this work, a novel proposed deep learning method involves a deep neural network (DNN) and attention mechanism which has good robust generalization ability. DNN was used to predict external corrosion rate of buried pipelines with extracting corrosion characteristics data, and attention mechanism is carried on weighting operations of corrosion factors furtherly. The results show that main controlling factors are pipeline age and soil bulk density, sulfate ion concentration and redox potential have less effect by analyzing external corrosion factors dataset, and data reduction and standardization of DNN-attention mechanism model are carried out. The external corrosion rate value predicted by the DNN-attention mechanism model is the closest prediction with the real truth, which the evaluation index root mean square error (RMSE) is 0.0064, and prediction accuracy is 91.91 % compared with convolutional neural network (CNN), CNN-residual, DNN. It proves that it is reasonable to predict pipeline external corrosion rate using DNN-attention mechanism based on publicly pipeline corrosion dataset.

Biochar Addition Increased Soil Carbon Storage but Did Not Exacerbate Soil Carbon Emission in Young Subtropical Plantation Forest

Forests play a crucial role in mitigating global warming, contributing approximately 46% of the global terrestrial carbon sink. However, it remains uncertain whether the addition of biochar to forests enhances the ecosystem’s carbon sink capacity. This study aims to address this scientific question by investigating whether biochar application increases carbon storage, potentially leading to an overall rise in carbon emissions by influencing soil respiration and identifying the underlying mechanisms. A controlled experiment was conducted in a young plantation forest that had grown for three years, where soil CO2 efflux rate and physicochemical properties, photosynthesis, and plant growth traits were measured across varying biochar addition rates (0, 5, and 10 t/ha) over five seasons. Then, statistical methods including one-way ANOVA, regression analysis, and structural equation modeling (SEM) were employed to assess differences in biological and abiotic factors among biochar addition gradients and understand the influencing mechanisms of soil CO2 efflux change. The findings revealed that biochar addition significantly increased the contents of soil organic carbon (SOC) and microbial biomass carbon (MBC), consequently promoting photosynthesis and plant growth (p &lt; 0.05). Biochar addition accounted for 73.8% of the variation in soil CO2 efflux by affecting soil physicochemical properties, photosynthesis, and plant basal diameter growth. However, the net effect of biochar addition on soil CO2 efflux was found to be low. The positive effects of biochar addition on soil CO2 efflux via factors such as soil bulk density, total nitrogen (TN), MBC, and photosynthesis were counteracted by its negative impact through soil total phosphorus (TP), water content, pH, SOC, and plant basal diameter growth. Overall, our findings indicate that there was no significant increase in soil CO2 efflux in the short term (totaling 16 months) over the biochar addition gradient. However, we observed a substantial increase in soil carbon storage and an enhancement in the soil’s capacity to act as a carbon sink. Therefore, adding biochar to forests may be a feasible strategy to increase carbon sinks and mitigate global climate change.

Study on Plant-blanket to reduce heavy metal migration caused by precipitation and to improve the soil environment of pyritic tailings

The increasing demand for mineral resources due to industrial development has led to significant tailings pollution during the mineral extraction process. In the southwestern region of China, a large amount of pyritic tailings containing pyrite cinder easily leaches heavy metals and other pollutants when exposed to precipitation, resulting in widespread soil contamination. Effective remediation methods are urgently needed to address this issue. This study utilized naturally occurring Plant-blanket formed by the symbiosis of moss and herbaceous plants on pyritic tailings as restoration material. Through leaching experiments and staining tracer techniques, the study investigated the ability of Plant-blanket to reduce the migration of heavy metals from pyrite cinder to soil under the influence of precipitation and its role in improving the soil environment. The results showed that within 12 h, the Plant-blanket could absorb water equivalent to 206.9 % of its own weight and had good water retention ability. It reduced the stained area ratio of soil horizontal and vertical profiles after precipitation leaching by a maximum of 76.08 % and 46.41 %, respectively, and improved the pH, cation exchange capacity (CEC), bulk density, and water content of soil at different depths. In addition, after being covered by Plant-blanket, the migration of Cd and Cu was reduced by a maximum of 44.35 % and 55.77 % respectively, and it increased the diversity and abundance of bacterial communities, promoting the recovery of soil microbial ecological functions. These findings indicate that Plant-blanket can regulate water and improve soil environment, and has certain control ability on the migration of Cd and Cu produced by pyritic tailings. Meanwhile, Plant-blanket plays an important role in improving the soil environment in mining areas and promoting ecosystem restoration, providing valuable reference for further exploration of ecological restoration of tailings.