Soil Nutrient Content Research Articles

The Effect of Soil Heterogeneity on the Content of Macronutrients and Micronutrients in the Chickpea (Cicer arietinum L.)

Chickpea (Cicer arietinum L.) is one of the most important legumes currently grown. It is an important source of proteins and nutrients, such as calcium, potassium and iron. As a result, precise crop management is necessary for maximizing its production. The presented study deals with the effect of soil heterogeneity caused by variable contents of macro- and micronutrients on the uptake of nutrients by chickpea. The values measured (contents of macro- and micronutrients in plant samples) indicate that soil heterogeneity is an important factor for the contents of nutrients and soil reactions, which strongly affect the growth of chickpea. We investigated the soil heterogeneity in a chickpea field. Two zones (A and B) with different stand development were found in the model plot. Zone A showed a healthy (green) growth, while Zone B exhibited a yellow-coloured growth, indicating deficits in nutrient uptake. The contents of selected nutrients (P, K, Ca, Mg, Fe, Cu, Zn and Mn) in the soil and in the plant biomass (i.e., stems, leaves, pods and seeds) were analyzed. In the zone with the yellow-coloured biomass, the results showed significantly (p < 0.05) reduced contents of N, P, K, Mg, Fe, Mn, Cu and Zn in the leaves; higher values of soil reaction (pH); and higher contents of calcium and calcium carbonate in the soil. The uptake of nutrients by the plants and their translocation were affected by the above-mentioned soil parameters and by their mutual interactions. Therefore, it is possible to state that soil heterogeneity (caused by variable contents of nutrients in soil) should be taken into account in the precise crop management of chickpeas.

Drought and nitrogen deposition regulate plant nutrient resorption in a typical steppe

The impending rise in drought events in grasslands of northern China over the next few decades, coupled with escalating nitrogen (N) deposition, will have an important impact on nutrient resorption. Previous research has mostly focused on examining the individual effect of specific drought scenario or N enrichment on nutrient resorption. Nonetheless, the impacts of different drought regimes on the resorption of nutrients have rarely been distinguished, especially under the scenario of N enrichment in temperate typical steppe in Inner Mongolia, we studied how intense drought (excluding 100 % rainfall in June), chronic drought (excluding 50 % rainfall during June-August), reduced rainfall frequency (reducing half rainfall events without changing rainfall amount in June-August), and N deposition (0 and 10 g N m−2 yr−1) affected the efficiency of plants in reabsorbing N and phosphorus (P). Both intense and chronic drought significantly reduced N (by 9.41 % and 9.53 %, respectively) and P resorption efficiency (by 6.71 % and 6.62 %, respectively) in plant communities (defined as the proportion of N and P nutrient resorption from senescing leaves), however reducing rainfall frequency had less effects on plant community N and P resorption efficiency. Nitrogen deposition had no effects on N and P resorption efficiency. Drought and N addition interacted to affect plant community P resorption efficiency. Structural equation modeling (SEM) showed that drought reduced N and P resorption efficiencies in plant communities by directly decreasing soil moisture, suppressing nutrient concentrations in green leaves, and enhancing soil nutrient content. Nitrogen deposition reduced P resorption efficiency by reducing P concentration in green leaves, but this effect was offset by the reduction of soil P availability. These results imply that rainfall amount is more important than rainfall frequency in determining the nutrient resorption efficiency of plant communities in the typical steppe. This study highlights the importance of soil water and N availabilities as well as nutrient concentrations in green leaves in modulating the responses of plant nutrient resorption to global change in the typical steppe.

Study on Associations between Root and Aboveground Growth of Mixed-Planting Seedlings of Populus tomentosa and Pinus tabuliformis under Soil Nutrient Heterogeneity

Near-natural transformation can convert artificial monoculture forests into mixed forests with diverse ages, multi-layered structures, and enhanced ecological functions. This transformation optimizes stand structure, improves soil physical and chemical properties, and enhances stand productivity and species diversity. This study aimed to explore the relationship between the underground roots and aboveground growth of Pinus tabuliformis and Populus tomentosa under conditions of nutrient heterogeneity, with the goal of advancing plantation transformation. This research focused on 1-year-old Populus tomentosa and 5-year-old Pinus tabuliformis, employing two planting densities (25 cm and 50 cm) and three fertilization levels, low (50 g·m−2), medium (100 g·m−2), and high (200 g·m−2), using Stanley Potassium sulfate complex fertilizer (N:P:K = 15:15:15). Each treatment had three replicates, resulting in a total of nine experimental groups, all planted in circular plots with a radius of 1 m. Standard major axis (SMA) regression was used to analyze the allometric relationship between underground fine root biomass and aboveground organ biomass. This study further explored correlations between fine root length, root surface area, volume, biomass, and aboveground biomass, culminating in a mixed-effects model. The mixed-effects model quantified the relationships between underground roots and aboveground growth in varying soil nutrient environments. The results indicated optimal root growth in Populus tomentosa and Pinus tabuliformis, characterized by maximum root length, surface area, and volume, under conditions of 200 g·m−2 soil nutrient concentration and 50 cm planting distance; Populus tomentosa fine roots had a vertical center at a depth of 8.5 cm, whereas Pinus tabuliformis roots were centered at depths of 5–7.5 cm, indicating differing competitive strategies. Pinus tabuliformis exhibited competitive superiority in the soil’s surface layer, in contrast to Populus tomentosa, which thrived in deeper layers. The study of the allometric growth model revealed that under conditions where the nutrient gradient was 200 g·m−2 and the planting distance was 25 cm, Populus tomentosa demonstrated its highest allometric growth index (2.801), indicative of positive allometric growth. Furthermore, there was a notable inclination of resource allocation towards the aboveground, which enhances the accumulation of aboveground biomass. The mixed-effects model equation showed a clear linear relationship between underground roots and aboveground biomass. The final fitting coefficient of the model was high, providing a robust theoretical basis for future management practices. The mixed-effects model revealed the following hierarchy of fixed-effect coefficients for root system characteristics affecting aboveground biomass: fine root volume (132.11) > fine root biomass (6.462) > root surface area (−4.053) > fine root length (0.201). In subsequent plantation reconstruction and forest management, increasing soil fertility and planting distance can promote the growth of underground roots and biomass accumulation. Appropriately increasing soil fertility and reducing planting distance can effectively promote aboveground biomass accumulation, achieving sustainable forest development.

Forest and soil fungal community dynamics are fuelled by root rot pathogen‐induced gaps

Abstract Forest dynamics are driven by micro‐disturbances leading to gap formation. Root rot pathogens can cause mortality to adult trees, which die forming gaps. However, little is known about the biotic and abiotic factors that govern gap creation and expansion such as tree infection or drought resilience, and what are the consequences for nutrient cycling and soil microbiota. We studied the dynamics of gaps created by Heterobasidion abietinum in mountain silver fir (Abies alba) forests from the Spanish Central Pyrenees. Tree‐ring width information was used to evaluate growth patterns of trees located within and at the edge of gaps and under closed canopy conditions. We analysed soil nutrient content and microbial structure at different positions with respect to the gap. Soil fungal community was also characterized by sequencing the ITS2 region. Gaps created by H. abietinum ranged 582–1072 m2 and gathered large amounts of standing and laying dead wood biomass amounting to up to 500 m3 ha−1 of coarse woody debris. This indicates that tree mortality had been occurring over decades, and it was preceded by a long‐term growth decline and impaired drought resilience. Root rot affected trees beyond the current limit of the gaps leading to growth decline, preventing canopy closure and allowing the release of suppressed trees within the gap. Gap formation did neither affect soil fertility nor fungal and bacterial biomass and diversity, but long‐distance ectomycorrhizal fungi were more abundant within gaps. Synthesis. Root rot pathogens play key ecological roles in forest dynamics at fine spatial scale. Heterobasidion abietinum infection, and its interaction with drought, creates and expands gaps by killing large trees and preventing surrounding trees from closing the gap. The survival of mycorrhizal networks to gap formation suggests little disruption of soil fungal communities.

Effects of composite soil conditioner on soil properties and corn yield in a saline–alkali soil

AbstractBiochar is widely used in agricultural production because of its ability to improve the physical and chemical properties of soil and promote crop growth. In this study, a combination of different biochar and lake sediments were used to improve saline soils. The four raw materials, including corn stalk and chicken manure liquefaction product (SMLP), rice husk charcoal (RHC) and two types of sediment (S‐1 and S‐2), which was used to improve the saline–alkali soil, respectively. The most significantly effective applied on the soil was when the composite soil conditioner (CSC) prepared by mixing SMLP, RHC, S‐1 and S‐2 at 5:20:6000:500 t·100 ha−1. The results of soil experiments using the above blending levels showed that the spike weight, plant height and root length of corn increased by 12.49%, 47.17% and 22.10%, respectively, and the pH and electrical conductivity (EC) of soil decreased by 4.83% and 24.02%, respectively. The contents of soil nutrients, soil organic matter (SOM), water content (WC) and soluble cations (K+, Ca2+ and Mg2+) all presented an increasing trend, and the contents of Na+ and soluble anions (Cl−, CO32−, HCO3− and SO42−) of soil showed a downward trend. Accordingly, the composite soil conditioner with biochar and dredged sediment achieves a synergistic improvement in soil physical structure and an increase in nutrient content, which is beneficial for promoting the growth characteristics and yield of corn.

Cover crop grazing effects on soil properties in no-tillage dryland cropping systems in the central Great Plains

Integrating ruminant livestock such as beef cattle (Bos taurus L.) to graze cover crops (CCs) could balance goals of short-term profitability and long-term environmental sustainability when CCs are grown in water-limited environments like the central Great Plains (CGP), USA. However, little information currently exists about the effects of CC grazing on soil properties in no-tillage (NT) dryland cropping systems, especially after multiple cycles of grazing. This study was conducted from 2018 to 2021 to evaluate the effects of beef cattle grazing CCs on residue return, soil bulk density (BD) and penetration resistance (PR), water stable aggregates (WSA) and wind-erodible fraction (WEF), as well as soil pH and nutrient concentrations on three producer fields in central and western Kansas. Across sites, CC biomass left as residue post-grazing was similar to pre-grazing and was 60 % of the ungrazed CCs (3704 kg ha−1) because of CC regrowth after the 30–40 day grazing period. Soil BD, PR, WSA, WEF, pH, particulate organic carbon, nitrate-nitrogen, and phosphorus concentration were not different between grazed and ungrazed CCs. However, soil organic carbon (SOC) stocks and potassium concentrations were greater with grazed CCs compared to ungrazed CCs possibly due to substantial CC residue retention following grazing coupled with manure and urine deposition. Regression and correlation analyses showed that increased SOC was associated with decreased soil BD and increased WSA, which suggests decreased soil erosion potential as well as possible improvements in water infiltration and underscores the importance of SOC for overall soil health in this water-limited environment. Based on these results, we conclude that grazing of CCs is a viable management option for producers to intensify NT dryland cropping systems to improve soil health and maintain or increase overall system profitability in the CGP. Longer (>3 years) grazing studies are needed, and results are likely to vary based on grazing animal stocking rate, categories, duration of grazing, and available CC biomass for grazing.

Combining Organic and Inorganic Fertilization Enhances Soil Enzyme Activity, the Bacterial Community, and Molecular Ecological Network Complexity in Coal Mine Reclamation Areas

Combined organic and inorganic fertilization can improve soil fertility in coal mine reclamation areas. However, the contribution of the bacterial community (especially its occurrence patterns) to soil physicochemical properties and enzyme activity needs further evaluation. The objective of this research was to clarify the bacterial community diversity, composition, and intraspecific interactions in response to combined organic and inorganic fertilizer application in coal mine reclamation areas in the Loess Hilly Region, China. Maize rhizosphere soil samples were collected under four fertilization regimes (CK, no fertilization control; NPK, compound inorganic fertilizer; M, organic fertilizer; and NPKM, combined organic and inorganic fertilization) in a 10-year field experiment in Gujiao city, Shanxi Province. Bacterial communities were characterized using high-throughput sequencing of the 16S rRNA gene V3–V4 region. A cross-treatment Spearman correlation network was constructed to explore the bacterial co-occurrence patterns. Compared with CK, NPK, M, and NPKM decreased the pH by 0.59%, 2.27%, and 0.12%; increased the soil organic carbon by 11.25%, 11.69%, and 27.05%; and significantly decreased the bacterial Shannon diversity by 3.68%, 0.14%, and 3.54%, respectively. Compared with CK, NPKM significantly increased sucrase, urease, and alkaline phosphatase activities (p < 0.05). Critically, oligotrophic Acidobacteria were significantly more abundant in CK than in the other treatments. Gemmatimonadetes were more abundant in NPK and M, and Actinobacteria, Bacteroidota, and Patescibacteria were more abundant in NPKM. In addition, network analysis revealed that the keystone taxa in the different fertilization treatments belonged to different network modules and were significantly correlated with soil nutrient content and enzyme activity. Simultaneously, the Actinobacteria enriched in NPKM formed specific clusters through strong symbiosis, and there were significant positive correlations among sucrase, urease, and alkaline phosphatase. In summary, long-term combined organic and inorganic fertilization improved maize rhizosphere soil fertility by regulating enzyme activity, bacterial community composition, and bacterial species interactions in coal mine reclamation areas in the Loess Hilly Region.

Effects of Cascara Cherry and Other Coffee Litter Mulching on Soil Properties, Photosynthesis, and Water Use Efficiency of Coffea Canephora Pierre ex A. Froehner cv. Reyan No.1 Seedling

Mulching cultivation with agricultural wastes is the main production pattern of coffee at present, but the effect of mulching cultivation on photosynthetic physiological processes of coffee plants is still not clear. Therefore, a randomized block design was adopted to establish a field experiment by one-year-old Coffee Canephora seedlings in this study. There were four types of mulch treatments, including non-mulch coffee waste (C), mulching coffee litter (L), mulching coffee cascara (cherry pericarp, P), and mulching coffee litter and cascara (LP) in this field experiment. Soil properties and microenvironment (e.g., moisture, temperature, pH, bulk density, organic matter content, alkali-hydrolyzed nitrogen content, available potassium content, and available potassium content), agronomic traits (e.g., specific leaf area, leaf area index, plant height, and relative chlorophyll content), and photosynthetic indices (e.g., photosynthesis, transpiration, respiration, stomatal conductance, intercellular CO2 concentration, water use efficiency, and carbon use efficiency) were investigated to determine the effects of different coffee waste mulches on the photosynthetic physiology of coffee seedlings. The results show that coffee litter and cascara mulch significantly reduced soil temperature by 0.42 or 0.33 °C, respectively, and coffee litter rather than cascara mulch significantly increased the soil’s available potassium content by 46.28%, although coffee waste mulch did not affect other soil properties or microenvironment indices; coffee cascara mulching significantly increased the specific leaf area and net and gross photosynthesis of coffee by 45.46%, 78.33%, and 91.72%, respectively, but the mulching treatments did not affect stomatal conductance, transpiration, or carbon use efficiency in this study. Additionally, coffee cascara mulching increased leaf respiration and net and gross water use efficiency by 109.34%, 80.54%, and 104.95%, respectively. The coffee cascara mulching alone had the most significant positive impact on the photosynthetic index, followed by a combination of litter and cascara, litter alone, and the control treatment. The observed variations in the coffee photosynthetic index may be attributed to the reduction of soil temperature caused by mulching treatments rather than the increase in soil nutrients content. These results indicate that coffee cascara mulching could effectively promote photosynthesis and the growth of coffee seedlings by improving the soil microenvironment.

Isotope-Based Techniques to Investigate Factors Influencing Water Use Efficiency in Pinus koraiensis Leaves during Plant Growth.

Plant water use efficiency (WUE) is a comprehensive physiological indicator of plant growth and ability to adapt to drought. However, research on the mechanisms controlling WUE during plant growth and development remains weak. Here, we studied Pinus koraiensis as a typical evergreen conifer species in Northeast China. After collecting 80 tree samples with varying diameters at breast height (DBH), we measured δ13C and δ18O as an indicator of WUE, leaf morphology (volume, dry weight, and total epidermal area), ecological stoichiometry (carbon, nitrogen, and phosphorus content), and abiotic factors (light environment, soil pH, soil water content, and soil nutrient content). Correlational analysis of these variables revealed distinct differences between smaller/younger and larger/older plants: (1) In plants with DBH less than 52 cm, δ13C was positively related to DBH, and δ18O was negatively related to DBH. Plants with DBH greater than 52 cm showed no relationship between δ13C and DBH, and δ18O was positively related to DBH. (2) In plants with DBH less than 52 cm, there was a negative correlation between δ13C and δ18O and between δ13C and leaf phosphorus content (LP), but a positive correlation between δ13C and DBH, leaf mass per area (LMA), and leaf density (LD). The slopes of DBH-δ13C, δ18O-δ13C, leaf nitrogen content (LN)-δ13C, and LMA-δ13C correlations were greater in smaller plants than large plants. (3) Structural equation modelling showed that in smaller plants, DBH had a direct positive effect on δ13C content and a direct negative effect on δ18O, and there was a direct positive effect of light environment on δ18O. In larger plants, there was a direct negative effect of light environment on δ13C and a direct positive effect of DBH on light environment, as well as a negative effect of soil nitrogen content on leaf nitrogen. In smaller plants, DBH was the most important factor influencing δ13C, followed by δ18O and soil moisture, with light and soil pH showing minimal influence. In larger plants, light environment influenced δ13C the most, followed by soil nitrogen content and soil moisture content, with leaf nitrogen and DBH contributing little. The results suggest that water use efficiency strategies of P. koraiensis vary according to growth stage, and the effects of abiotic factors and functional traits vary at different growth stages.

Enhanced immobilization of cadmium and lead in contaminated soil using calcium alginate-modified HAP biochar: Improvements in soil health and microbial diversity

A novel adsorbent, calcium alginate-modified HAP (Hydroxyapatite)-wood ear mushroom sticks biochar (CA-HAPMB), was synthesized to enhance the immobilization of Cd and Pb in soil. Over 150 days, applying CA-HAPMB at concentrations of 0%–3% in contaminated soils from Chenzhou City in Hunan Province (CZ) and Shenyang City in Liaoning Province (SY) resulted in decreased effective concentrations of Cd and Pb. Specifically, in CZ soil, Cd and Pb decreased by 30.9%–69.3% and 31.9%–78.6%, respectively, while in SY soil, they decreased by 27.5%–53.7% and 26.4%–62.3%, respectively. Characterization results, obtained after separating CA-HAPMB from the soil, indicate that complexation, co-precipitation, and ion exchange play crucial roles in the efficient immobilization of Cd and Pb by CA-HAPMB. Additionally, adjusting the amount of CA-HAPMB added allows modulation of soil pH, leading to increased soil organic matter and nutrient content. Following treatment with CA-HAPMB for immobilizing Cd and Pb, soil bacteria abundance and diversity increased, further promoting heavy-metal immobilization.

Effects of nitrogen addition and Bothriochloa ischaemum and Lespedeza davurica mixture on plant chlorophyll fluorescence and community production in semi-arid grassland.

Grass-legume mixture can effectively improve productivity and stimulate overyielding in artificial grasslands, but may be N-limited in semi-arid regions. This study investigated the effects of N addition on chlorophyll fluorescence and production in the grass-legume mixtures community. An N addition experiment was conducted in the Bothriochloa ischaemum and Lespedeza davurica mixture community, with seven mixture ratios (B0L10, B2L8, B4L6, B5L5, B6L4, B8L2, and B10L0) according to the sowing abundance of B.ischaemum and L.davurica and four N addition levels, N0, N25, N50, and N75 (0,25,50,75kgNhm-2 a-1), respectively. We analyzed the response of chlorophyll fluorescence parameters of the two species, the rapid light-response curves of chlorophyll fluorescence, as well as aboveground biomass (AGB) and overyielding. Our results showed that the two species showed different photosynthetic strategies, with L.davurica having significantly higher initial fluorescence (Fo), effective photochemical quantum yield of PSII (ΦPSII), and coefficient of photochemical fluorescence quenching (qP) than B. ischaemum, consisting with results of rapid light-response curves. N addition and mixture ratio both had significant effects on chlorophyll fluorescence and AGB (p<0.001). The ΦPSII and qP of L.davurica were significantly lowest in B5L5 and B6L4 under N addition, and the effect of N varied with mixture ratio. The photosynthetic efficiency of B. ischaemum was higher in mixture than in monoculture (B10L0), and ΦPSII was significantly higher in N50 than in N25 and N50 at mixture communities except at B5L5. The community AGB was significantly higher in mixture communities than in two monocultures and highest at B6L4. In the same mixture ratio, the AGB was highest under the N50. The overyielding effects were significantly highest under the N75 and B6L4 treatments, mainly attributed to L.davurica. The partial least squares path models demonstrated that adding N increased soil nutrient content, and complementary utilization by B.ischaemum and L.davurica increased the photosynthetic efficiency. However, as the different photosynthetic strategies of these two species, the effect on AGB was offset, and the mixture ratio's effects were larger than N. Our results proposed the B6L4 and N50 treatments were the optimal combination, with the highest AGB and overyielding, moderate grass-legume ratio, optimal community structure, and forage values.

Biochar Effectively Promoted Growth of Ardisia crenata by Affecting the Soil Physicochemical Properties.

Biochar is regarded as a soil improvement material possessing superior physical and chemical properties that can effectively enhance plant growth. However, there exists a paucity of research examining the efficacy of biochar in supplanting traditional materials and its subsequent impact on the growth of Ardisia crenata, which is currently domesticated as fruit ornamentals. In this study, the mechanism of biochar's effect on Ardisia crenata was analyzed by controlled experiments. For 180 days, their growth and development were meticulously assessed under different treatments through the measurement of various indices. Compared with the references, the addition of biochar led to an average increase in soil nutrient content, including a 14.1% rise in total nitrogen, a 564.1% increase in total phosphorus, and a 63.2% boost in total potassium. Furthermore, it improved the physical and chemical properties of the soil by reducing soil bulk density by 6.2%, increasing total porosity by 6.33%, and enhancing pore water by 7.35%, while decreasing aeration porosity by 1.11%. The growth and development of Ardisia crenata were better when the appending ratio of biochar was in the range of 30% to 50%, with the root parameters, such as root length, root surface area, and root volume, 48.90%, 62.00%, and 24.04% higher to reference. At the same time, the biomass accumulation of roots in the best group with adding biochar also increased significantly (55.80%). The addition of biochar resulted in a significant improvement in the content of chlorophyll a and chlorophyll b (1.947 mg g-1) and the net photosynthetic rate (5.6003 µmol m-2 s-1). This study's findings underpinned the addition of biochar in soil improvement and plant response. Therefore, biochar can favor the cultivation and industrial application of Ardisia crenata in the future, leading to an efficient and environmentally friendly industrial development.

Shifts in Microbial Community Structure and Co-occurrence Network along a Wide Soil Salinity Gradient.

The response of microbiomes to salinity has been clarified in different geographic scales or ecosystems. However, how soil microbial community structure and interaction respond to salinity across wide salinity range and climatic region is still unclearly resolved. To address this issue, we examined the microbial community's composition in saline soils from two climatic regions (coastal wetland and arid desert). Our research confirms that soil salinity had a negative effect on soil nutrient content. Salinity decreased the relative abundance of bacteria, but increased archaea abundance, leading to the shifts from bacteria dominant community to archaea dominant community. Low-water medium-salinity soil (LWMS) had the most complex archaeal community network, whereas for bacteria, the most complex bacterial community network was observed in low-water high-salinity soils (LWHS). Key microbial taxa differed in three salinity gradients. Salinity, soil water content, pH, total nitrogen (TN), and soil organic carbon (SOC) were the main driving factors for the composition of archaeal and bacterial community. Salinity directly affected archaeal community, but indirectly influenced bacteria community through SOC; pH affected archaeal community indirectly through TN, but directly affected bacterial community. Our study suggests that soil salinity dramatically influences diversity, composition, and interactions within the microbial community.

Effect of Soil Texture on Soil Nutrient Status and Rice Nutrient Absorption in Paddy Soils

Soil texture affects rice nutrient uptake and yield formation by influencing soil structure, microbial activity, and soil nutrient supply capacity. Analyzing the relationship between soil texture, nutrient content, and rice agronomic traits is of great significance for precise and efficient fertilizer application. The tillage layer (0–20 cm) of 31 paddy fields in China’s main rice-producing areas was collected to perform rice pot experiments, and soil texture characteristics, physicochemical properties, microbial-related indicators, and rice agronomic traits were measured and analyzed. The results showed that these soils could be classified into four types of soil texture: loamy sandy soil, sandy loam soil, silty loam soil, and silty soil. Analysis of variance showed that the available nitrogen (AN), available potassium (AK), and available phosphorus (AP) contents were the highest in silty loam, silty, and sandy loam soils, respectively, and silt loamy soil had the highest CEC. Principal component analysis (PCA) also showed that soil physicochemical properties can be distinguished to a certain extent according to soil texture types. For the relationship of soil texture parameters and soil physicochemical properties, soil organic matter (OM), total nitrogen (TN), AN, ammonium nitrogen (NH4+-N), and microbial carbon (MBC) contents were positively correlated with soil clay content, AK was positively correlated with silt content, and soil phosphorus status was significantly related to pH. Mantel’s test revealed significant correlations between rice N, P, and K nutrient status, dry matter accumulation, and yield, and soil available nutrient content, MBC, pH, and soil texture parameters. Structural equation modeling (SEM) indicated that sand affected soil available nutrients by regulating pH, while clay can positively influence soil available nutrients by affecting soil organic matter mineralization and microbial activity, thus influencing nutrient absorption and yield formation in rice. Overall, in rice production, the silty and silty loam paddy soil with fine texture and higher clay content facilitates the mineralization of soil organic matter and the activity of soil microbes, resulting in more available soil nutrients, which benefits the rice absorption and accumulation of nutrients. Furthermore, a higher content of clay also promotes the distribution of dry matter to the panicle, thereby promoting rice yield formation.

Examining the Effect of Agrochemicals on Soil Microbiological Activity, Micronutrient Availability, and Uptake by Maize (Zea mays L.) Plants

Agricultural practices profoundly influence soil microbial populations and physicochemical properties, vital for crop growth and quality. This study aims to explore the impact of diverse agrochemical applications on soil microbial dynamics, physicochemical properties, and maize yield and proximate properties. Topsoil samples, collected at depths of 1 to 15 cm, were transported to Jimma University for maize cultivation. Over 120 days, soil and maize samples were collected at specified intervals for analysis, including soil pH, microbial populations, and nutrient content. Statistical analysis using one-way ANOVA (p &lt; 0.05) was conducted. Soil bacterial and fungal populations were measured on days 5, 10, 20, 40, 80, and 120. The highest total mesophilic bacterial count (TMBC) was in compost-treated pots (G) and the lowest in those receiving macronutrient fertilizers and glyphosates (B). The highest total mesophilic fungal count (TMFC) was in pots with glyphosates and compost (F), and the lowest was in pots treated with macronutrient fertilizers and glyphosates (B). Pots treated with macronutrient fertilizers and glyphosates (B), macronutrient fertilizers (A), and micronutrient fertilizers (C) showed the lowest Fe and Zn levels. Maize in pots treated with macronutrient fertilizer combined with glyphosate (B) exhibited the lowest protein, fats, and carbohydrates. Notably, compost-treated soils showed the highest bacterial and fungal counts, Fe, and Zn concentrations, while micro-mineral fertilizer combined with glyphosate (B) depleted the soil. Agrochemical treatments negatively affected maize yield quality, indicating complex treatment-related changes in soil parameters.

Effects of returning peach branch waste to fields on soil carbon cycle mediated by soil microbial communities.

In recent years, the rise in greenhouse gas emissions from agriculture has worsened climate change. Efficiently utilizing agricultural waste can significantly mitigate these effects. This study investigated the ecological benefits of returning peach branch waste to fields (RPBF) through three innovative strategies: (1) application of peach branch organic fertilizer (OF), (2) mushroom cultivation using peach branches as a substrate (MC), and (3) surface mulching with peach branches (SM). Conducted within a peach orchard ecosystem, our research aimed to assess these resource utilization strategies' effects on soil properties, microbial community, and carbon cycle, thereby contributing to sustainable agricultural practices. Our findings indicated that all RPBF treatments enhance soil nutrient content, enriching beneficial microorganisms, such as Humicola, Rhizobiales, and Bacillus. Moreover, soil AP and AK were observed to regulate the soil carbon cycle by altering the compositions and functions of microbial communities. Notably, OF and MC treatments were found to boost autotrophic microorganism abundance, thereby augmenting the potential for soil carbon sequestration and emission reduction. Interestingly, in peach orchard soil, fungal communities were found to contribute more greatly to SOC content than bacterial communities. However, SM treatment resulted in an increase in the presence of bacterial communities, thereby enhancing carbon emissions. Overall, this study illustrated the fundamental pathways by which RPBF treatment affects the soil carbon cycle, providing novel insights into the rational resource utilization of peach branch waste and the advancement of ecological agriculture.

Using organic amendments in disturbed soil to enhance soil organic matter, nutrient content and turfgrass establishment

Disturbed soils, including manufactured topsoils, often lack physical and chemical properties conducive to vegetation establishment. As a result, efforts to stabilize disturbed soils with vegetation are susceptible to failure. Urban organic waste products such as wood mulch, composted leaf and yard waste, and biosolids are widely distributed as organic amendments that enhance sustainability and plant establishment. Correct use can be determined by examining soil properties such as pH; the concentration of soluble salts (SS); and plant available nutrients — particularly N, C and P; as well as root and shoot growth. This research examined the effects of three typical organic amendments on fertility, establishment, and nutrient loss. A manufactured topsoil was used as the base soil for all treatments, including a control unamended soil (CUT), and soil amended with either mulch (MAT), composted leaf and yard waste (LAT), or biosolids (BAT). A 2 % organic matter concentration increase was sought but not achieved due to difficulty in reproducing lab results at a larger scale. Results showed that LAT improved soil fertility, particularly N-P-K concentrations while maintaining a good C:N ratio, pH, and SS concentration. BAT was the most effective at enhancing shoot growth but results suggest that improved growth rates could result in increased maintenance. Additionally, biosolids were an excellent source of nutrients, especially N-P-K and S, but diminished root growth and N leachate losses indicate that N was applied in excess of turfgrass requirements. Therefore, biosolids could be used as fertilizer, subject to recommended rates for turfgrass establishment to prevent poor root growth and waterborne N pollution. To ensure establishment efforts are successful, MAT is not recommended without a supplemental source of soluble N. Altogether, study results and conclusions could inform others seeking to improve specifications for disturbed soil where turfgrass establishment is needed to stabilize soil.

Mechanisms of phosphorus activation in charosphere and non-charosphere: The priming effect of biochar

Biochar is widely used in soil to increase the soil phosphorus content, but a special ecological zone called the “charosphere” zone is formed where biochar comes into contact with soil. The physical and chemical properties of charosphere soil are different from those of the original soil and the biochar itself, leading to uncertainty regarding the effect of charosphere soil on the phosphorus cycle. Hence, we designed a barrier device to separate biochar from soil and analyzed the impact of biochar diffusion on soil nutrient content and microbial activity. Then, the variation characteristics of the community structure of phoD-harboring bacteria and fungi in the carbonosphere (group B) and non-carbonosphere (group C) were explored. Finally, the key factors and potential driving mechanisms of soil phosphorus activation were explored. The results show that biochar improved soil microbial activity and stimulated the soil nutrient recycling, resulting in a 67.28 % greater percentage of the labile P fraction in group B than in group C. The alpha diversity and nutrient transfer efficiency of the phoD-harboring bacterial community in group B were greater than those in group C, while the phoD-harboring bacterial co-occurrence network of group C was more complex. Moreover, the synergy between the co-occurrence networks of the soil fungal community was stronger than that of the bacterial community. Biochar stimulates microbial activation of phosphorus by increasing the DOC content and pH in the charosphere, and the phoD-harboring bacterial community dominates soil phosphorus activation. These findings offer a new perspective on how biochar regulates soil phosphorus cycling, providing crucial information to guide the application of biochar in agroecosystems.

Effect of intercropping and biochar amendments on lead removal capacity by Corchorus olitorius and Zea mays.

Intercropping is a sustainable strategy recognized for boosting crop production and mitigating heavy metal toxicity in contaminated soils. This study investigates the effects of biochar amendments on Pb-contaminated soil, utilizing monocropping and intercropping techniques with C. olitorius and Z. mays. The research assesses Pb removal capacity, nutrient uptake, antioxidant enzymes, and soil Pb fractionation. In monocropping, the phytoremediation ratio for C. olitorius increased from 16.67 to 27.33%, while in intercropping, it rose from 19.00 to 28.33% with biochar amendments. Similarly, Z. mays exhibited an increased phytoremediation ratio from 53.33 to 74.67% in monocropping and from 63.00 to 78.67% in intercropping with biochar amendments. Intercropping significantly increased the peroxidase (POD) activity in Z. mays roots by 22.53%, and there were notable increases in shoot POD of C. olitorius (11.54%) and Z. mays (16.20%) with biochar application. CAT showed consistent improvements, increasing by 37.52% in C. olitorius roots and 74.49% in Z. mays roots with biochar. Biochar amendments significantly increased N content in soil under sole cropping of Z. mays and intercropping systems. In contrast, Cu content increased by 56.34%, 59.05%, and 79.80% in monocropping (C. olitorius and Z. mays) and intercropping systems, respectively. This suggests that biochar enhances nutrient availability, improving phytoremediation efficacy in Pb-contaminated soil. Phyto availability of trace metals (Zn, Mn, Cu, and Fe) exhibited higher levels with biochar amendments than those without. The findings indicate that intercropping and biochar amendments elevate antioxidant enzyme levels, reducing reactive oxygen species and mitigating Pb toxicity effects. This approach improves phytoremediation efficiency and holds promise for soil pollution remediation while enhancing nutrient content and crop quality in Pb-contaminated soil.

Exploring the Impact of Tea (Camellia sinensis (L.) O. Ktze.)/Trachelospermum jasminoides (Lindl.) Lem. Intercropping on Soil Health and Microbial Communities

Intercropping, a well-established agroecological technique designed to bolster ecological stability, has been shown to have a significant impact on soil health. However, the specific effects of tea/Trachelospermum jasminoides intercropping on the physicochemical properties and functional microbial community structure in practical cultivation have not been thoroughly investigated. In this study, we utilized high-throughput sequencing technology on the 16S/ITS rDNA genes to assess the impact of tea intercropping with T. jasminoides on the composition, diversity, and potential functions of the soil microbial community in tea gardens. The results indicated that the tea/T. jasminoides intercropping system significantly increased pH levels, soil organic matter, available nitrogen, phosphorus, potassium, and enzyme activity, ultimately augmenting soil nutrient levels. Furthermore, an in-depth analysis of the bacterial co-occurrence network and topological structure portrayed a more intricate and interconnected soil bacterial community in tea gardens. Remarkably, the abundance of beneficial genera, including Burkholderia, Mesorhizobium, Penicillium, and Trichoderma, underwent a substantial increase, whereas the relative abundance of pathogenic fungi such as Aspergillus, Fusarium, and Curvularia experienced a marked decline. Functional predictions also indicated a notable enhancement in the abundance of microorganisms associated with nitrogen and carbon cycling processes. In summary, the intercropping of tea and T. jasminoides holds the potential to enrich soil nutrient content, reshape the microbial community structure, bolster the abundance of functional microorganisms, and mitigate the prevalence of pathogenic fungi. Consequently, this intercropping system offers a promising solution for sustainable tea garden management, overcoming the limitations of traditional cultivation methods and providing valuable insights for sustainable agriculture practices.