Soil Chemical Properties Research Articles

Bio-based resources: systemic & circular solutions for (agro)environmental services.

The global promotion of decarbonisation through the circular solutions and (re)use of bio-based resources (BBR), i.e. waste streams, notably from the agricultural, forest and municipal sectors has steadily increased in recent decades. Among the transformative solutions offered by BBR, biosolids (BS), biochars (BC), and bioashes (BA) specifically attract scientific attention due to their highly complex organo-mineral matrices, which present significant potential for recovery in the agro-/forest-ecosystems. These materials enhance various soil (i) chemical (pH, macro/micro nutrient concentrations, organic matter content), (ii) physical (porosity, water-air relations, compaction) or (iii) microbial (diversity, activity) properties. Furthermore, some of transformed BBR contribute to a multitude of environmental services such as the remediation of contaminated sites and wastewater treatment, employing cost-effective and eco-friendly approaches that align with circular economy/waste management principles, ultimately contributing to climate change mitigation. However, several challenges impede the widespread utilization/transformation of BBR, including technological limitations in processing and application, concerns about contamination (e.g., PAHs, PCBs, micro/nano plastics present in BS), toxicity issues (e.g., heavy metals in BA or nanoparticles in BC), and regulatory constraints (e.g., non-uniform regulations governing the reuse of BA and BS). Addressing these challenges demands an interdisciplinary and intersectoral approach to fully unlock the potential of BBR in sustainable decarbonisation efforts.

Edaphic Factors Modulating Phosphorus Availability in Lowland Rice Systems, Nigeria

ABSTRACT The low rice production level in Africa is attributed to poor soil fertility despite the potential for rice cultivation in the inland valleys. This study was conducted to evaluate soil characteristics in some lowlands that have been continuously and intensively used for rice production for over two decades in southwestern Nigeria. Soil physical, chemical, and mineralogical properties, as well as phosphorus sorption characteristics, were assessed in soil samples collected from diagnostic horizons of profiles in six benchmark soils. The results show kaolinite, quartz, potassium(K)-feldspars, and mixed-layered smectite as the predominant minerals. The iron oxide fractions indicate that the soils are at varying degrees of development where the soils at the advanced stage of development are predominantly rich in kaolinite and quartz with a high concentration of total pedogenic iron oxide and generally low in soil fertility. Soil phosphorus buffering capacity is low and varies inversely with pH, confirming the deficiency of phosphorus at low pH. Short-range-order (SRO) iron (Fe) oxides show a strong affinity for phosphorus and this is stronger at lower soil horizons and mediated by some redoxomorphic reactions. The SRO iron oxide concentration has more influence on phosphorus retention in soils rather than the absolute concentration of iron oxides. The study concludes that SRO Fe oxides and soil pH are the major edaphic factors playing a prominent role in phosphorus retention and availability in the wetland soils rather than the clay minerals.

Impact of Soil Management Practices on Soil Culturable Bacteriota and Species Diversity in Central European a Productive Vineyard under Warm and Dry Conditions

Sustainable management practices are crucial for the longevity of a monoculture vineyard, especially in the context of a changing climate. Therefore, soil management practices in a vineyard (T: tillage, T+FYM: tillage + farmyard manure, G: grass strips, G+NPK1: grass strips + rational rates of NPK, and G+NPK2: grass strips + higher rates of NPK) were tested in a temperate climate of Slovakia (Central Europe) under specific soil conditions (Rendzic Leptosol). We investigated the influence of continuous cropping on soil chemical properties and microbial communities during the dry and warm year of 2022. The results showed that the soil pH was higher by 19%, 21%, 24% and 13% in T, T+FYM, G and G+NPK1, respectively, compared to G+NPK2. The lowest soil organic matter (SOM) content was found in T, and it increased in the following order: T < T+FYM < G+NPK2 < G+NPK1 < G. Similarly, the lowest abundance of soil culturable bacteriota was found in T and it increased in the following order: T < T+FYM = G+NPK2 < G+NPK1< G. Culturable bacteriota was identified using mass spectrometry (MALDI-TOF MS Biotyper). The most numerous species group was Bacillus, followed by Lactobacillus > Staphylococcus > Pseudomonas. The most frequently isolated species were Bacillus megaterium (16.55%), Bacillus cereus (5.80%), Bacillus thuringiensis (4.87%), and Bacillus simplex (4.37%). Positive relationships between SOM and soil culturable bacteriota were found in the G and G+NPK1 treatments. Temperature also affected soil culturable bacteriota in all soil management practices, most significantly in G+NPK1. Overall, the best scenario for the sustainable management of a productive vineyard is the use of grass strips.

The impact of bacillus sp. NTLG2-20 and reduced nitrogen fertilization on soil properties and peanut yield

The excessive use of nitrogen (N) fertilizers has led to farmland degradation and reduced crop yields. To address this drawback, reducing the amount of nitrogen fertilizer and Bacillus sp. NTLG2-20 inoculant are the optimal cultivation method. The impact of different N rates (0, 20, and 40 kg ha-1) combined with the Bacillus sp. NTLG2-20 inoculant on soil chemical properties, growth, development, and peanut yield was designed in the field in Phuoc Hung commune, An Phu district from May to August 2023. The field experiment was designed with 6 treatments and 4 replications. The research results showed that different N rates adequately augmented soil chemical traits such as pH, cation exchange capacity (CEC), soil organic matter (SOM), total N, available phosphorous (AP), and exchangeable potassium (EK). Furthermore, different N fertilizers rates combined with Bacillus sp. NTLG2-20 inoculant adequately augmented plant height, number of leaves, total chlorophyll, nodulous number and weight per groundnut plant. Reducing N fertilizer application by 50% (20 kg N ha-1) was the optimal N reduction rate when combined with the Bacillus sp. NTLG2-20, which resulted in 17.6% higher peanut yield compared to no N application and no difference compared to 100% of recommended N application (P<0.01)). Bacillus sp. NTLG2-20 inoculant increased peanut yield by 19.6% when compared to no Bacillus sp. NTLG2-20 inoculant (P<0.01). Nitrogen – fixing ability of Bacillus sp. NTLG2-20 promoted peanut yield and reduced fifty percentage of the N fertilizer application. Bacillus sp. NTLG2-20 is the promising species for the production of biological fertilizer in the future.

Effect of sugarcane bagasse biochar on soybean germination and initial growth

Biochar is known as an excellent soil conditioner and a powerful carbon sequestration tool. However, to expand its use, it is necessary to understand potential adverse effects. To better address this issue, biochar was prepared from sugarcane bagasse. The effect of biochar on the germination of soybean seeds was evaluated, and a greenhouse experiment was conducted to assess the response of soybean seedlings to biochar application at different rates (CK, 0% w/w; BC1, 1% w/w; BC3, 3% w/w; and BC5, 5% w/w). Thirty days after sowing, growth parameters, soil physicochemical attributes, and microbiota were evaluated. The biochar exhibited a low O/C ratio (0.18) and an irregular porous surface, which promoted improvements in the soil's physical, chemical, and biological attributes. It also demonstrated no phytotoxic effects in germination tests for application rates up to 50 t/ha. The results of the soybean cultivation showed that the BC3 and BC5 treatments significantly increased the fresh mass of the aerial part by 64% and 86%, respectively, compared to CK. These treatments also significantly increased the fresh mass of the root system by 23% and 423%, respectively. These results highlight the potential of biochar in promoting early soybean development.

Comparative Assessment of Physical and Chemical Properties of Soil of Industrial and Non-industrial Area’s Farmers Field of Nalagarh Tehsil, District Solan, Himanchal Pradesh, India

Comparative Assessment of Physical and Chemical Properties of Soil of Industrial and Non-industrial Area’s Farmers Field of Nalagarh Tehsil, District Solan, Himanchal Pradesh, India

Physical and Chemical Properties of Soils Derived from Different Parent Rocks Mediate Microbial Carbon Cycling

Physical and Chemical Properties of Soils Derived from Different Parent Rocks Mediate Microbial Carbon Cycling

Soil chemical attributes and okra productivity under organic fertilizer in two cultivation cycles

Os solos nas regiões semiáridas geralmente apresentam baixos níveis de matéria orgânica, devido a factores pedogenéticos do solo, e é notável que a aplicação de fertilizantes orgânicos ao solo aumenta a sua fertilidade e o rendimento das culturas. Assim, o objetivo desta pesquisa foi avaliar os efeitos da adubação orgânica do solo nos atributos químicos de um Neossolo Flúvico e na produtividade do quiabeiro em dois ciclos de cultivo. Os tratamentos foram distribuídos em blocos casualizados no esquema fatorial 5 x 2, referente a cinco doses de esterco bovino com relação C/N de 18:1 para aumentar o teor de matéria orgânica no solo de 1,8% para 2,8; 3,8; 4,8 e 5,8% e dois ciclos de cultivo (1º e 2º ciclos) com quatro repetições. As variáveis ​​analisadas foram pH do solo, P, Ca2+, Mg2+, K+ no solo, S.O.M e produtividade de quiabo. Os resultados foram submetidos à análise de variância por meio do teste F para verificar a homogeneidade entre os resíduos. Posteriormente, foi realizada análise conjunta para diagnosticar efeitos significativos por meio do teste F e regressões lineares e polinomiais foram aplicadas para desdobrar o S.O.M em um ciclo. A adubação orgânica com esterco bovino aumentou os teores de P, K+, Ca2+, Mg2+, Na+ e matéria orgânica do solo (S.O.M) e a produtividade dos frutos comerciais de quiabo.

Clay mineral composition drives soil structure behavior and the associated physical properties in Brazilian Oxisols

Soil aggregation controls several physical, chemical, and biological processes. Soil organic matter (SOM) and its stabilizing agents are regarded as the most important factors driving formation and stabilization of soil aggregates. However, aggregate stability in highly weathered soils may also be related to clay mineral composition and soil chemical properties. This study aims to evaluate the processes controlling soil aggregate stability and to understand the influence of soil chemical and clay mineral composition on the structural stability of highly weathered soils. Four Brazilian Oxisols were investigated: (P1) Xanthic Kandiustox, (P2) Rhodic Haplustox, (P3) Anionic Acrustox, and (P4) Typic Hapludox. Undisturbed and disturbed soil samples were collected from the Bw horizon under a native forest. Soil structural stability was evaluated using a variety of techniques and indices, including mean weight diameter (MWD) by hydraulic stress, mechanically-dispersible clay (MDC) by turbidimetry, tensile strength (TS) by crushing aggregates, and soil structural stability index (SSI) taking into account soil organic carbon (SOC). In general, P1 exhibited the highest MDC content (3.05 ± 0.54, Nephelometric Turbidity Unit, NTU/g L‐−1), while P4 had the highest MWD (10.26 ± 0.24 mm) and the highest TS (80.42 ± 18.54 kPa) within the 8–4 mm aggregate size class. The TS for the 4–2 mm and 2–1 mm aggregate size classes was found to be equal for P2 and P4, with values ranging from 158.17 ± 24.70 kPa to 148.04 ± 38.50 kPa in the 4–2 mm class, and from 459.51 ± 189 kPa to 328.35 ± 78.22 kPa in the 2–1 mm one. The SSI was found to be inadequate for evaluating the structural stability of the Oxisols. In general, SOC was found to be the main stabilizing agent of larger aggregates, while clay mineral composition determined the stability of smaller aggregates. Goethite associated with gibbsite was more effective in increasing the structural stability of P2 and P4. Furthermore, kaolinites with low crystallinity, which are found in clayey Oxisols, resulted in a high specific surface area, particularly in Rhodic Haplustox and Typic Hapludox soils, which promoted more interactions with other clay minerals (e.g., goethite and gibbsite) and SOC, thereby increasing the tensile strength in these Oxisols. In fact, the formation and stabilization of aggregates in highly weathered soils depends on several factors, but the influence of clay mineral composition stands out as the most pronounced.

Study on the Effect of Magnesium Chloride-Modified Straw Waste Biochar on Acidic Soil Properties.

Soil biochar is a kind of organic matter rich in carbon, which is of great significance in soil fertility improvement, fertilizer type innovation and greenhouse gas emission reduction. In this paper, Mg-modified biochar was prepared by thermal cracking using rice straw and corn straw as raw materials. The Mg-modified biochar and unmodified biochar were fully mixed with prepared soil samples at the addition amounts of 0.5% (w/w), 1% (w/w) and 2% (w/w), respectively, and then simulated indoor soil cultivation experiments were carried out. The effects of magnesium ion-modified biochar and non-modified biochar on soil chemical properties and the effects of different amounts of biochar on soil properties were studied. The results showed that the yield of Mg-modified biochar from rice straw and corn straw, prepared by pyrolysis, was 65%, and the ash content was large. The pH of MG-modified corn stalk biochar (MCBC) is weakly basic (8.55), while the pH of MG-modified rice stalk biochar (MRBC) is basic (10.1), and their internal structures are slightly different. After the application of biochar prepared from rice straw and maize stover, soil indicators were determined. Compared to the control, the chemical properties of the treated soil samples were significantly improved, with an increase in soil pH, an increase in the content of effective nutrients, such as fast-acting potassium, fast-acting phosphorus and alkaline dissolved nitrogen, and an increase in the content of the total phosphorus and total nitrogen, as well as an increase in the content of organic matter. The Mg-modified biochar was generally superior to the unmodified biochar in improving soil fertility, at the same addition level. It was also found that the rice-straw biochar performed better than the corn-stover biochar and had a more obvious effect on soil improvement in terms of fast-acting potassium, ammonium nitrogen, nitrate nitrogen, total phosphorus and total nitrogen contents.

The impact of soil salinity on the chemical properties of soil at Hatiya Upazila, a remote area of Noakhali, Bangladesh

The impact of soil salinity on the chemical properties of soil at Hatiya Upazila, a remote area of Noakhali, Bangladesh

Structure and function role of soil nematode communities in different types of vegetation in Yogyakarta and Central Java, Indonesia

Abstract. Indarti S, Utami SNH, Putra NS, Maharani R. 2024. Structure and function role of soil nematode communities in different types of vegetation in Yogyakarta and Central Java, Indonesia. Biodiversitas 25: 2765-2772. Soil nematodes are crucial parts of the soil organism community and play a significant role in many ecological soil processes. It is necessary to pay greater attention to the lack of knowledge regarding the composition and role of the soil nematode community in different vegetations. Hence, the nematode structure community from minimal to soil stillages have been observed and compared from seven distinct types of vegetation. This study aimed to determine the soil nematode community structure, which includes the dominance, abundance, richness, diversity, and functional role of nematodes, as well as other chemical soil properties. Vegetation type represents soil management and has an impact on the life of soil organisms such as nematodes. A total of approximately 2328 soil nematodes were found, and 18 genera were identified. The Nematode Indicator Joint Analysis (NINJA) revealed that the vegetation type, land use, and soil chemical properties influence the nematode’s abundance, dominance, and structure differently. Through those results, the authors confirmed that soil nematodes in cultivated vegetation are dominated by the trophic groups of plant-parasitic nematodes and bacterivores. Conversely, predator, omnivores, and fungivores nematodes dominate in soil with minimal tillage. Overall, this study highlights the importance of soil nematode analysis in sustainable agricultural soil ecosystems.

Assessing Soil and Land Suitability of an Olive–Maize Agroforestry System Using Machine Learning Algorithms

Exponential population increases are threatening food security, particularly in mountainous areas. One potential solution is dual-use intercropped agroforestry systems such as olive (Olea europaea)–maize (Zea mays), which may mitigate risk by providing multiple market sources (oil and grain) for smallholder producers. Several studies have conducted integrated agroforestry land suitability analyses; however, few studies have used machine learning (ML) algorithms to evaluate multiple variables (i.e., soil physicochemical properties and climatic and topographic data) for the selection of suitable rainfed sites in mountainous terrain systems. The goal of this study is therefore to identify suitable land classes for an integrated olive–maize agroforestry system based on the Food and Agriculture Organization (FAO) land suitability assessment framework for 1757 km2 in Khyber Pakhtunkhwa province, Pakistan. Information on soil physical and chemical properties was obtained from 701 soil samples, along with climatic and topographic data. After determination of land suitability classes for an integrated olive–maize-crop agroforestry system, the region was then mapped through ML algorithms using random forest (RF) and support vector machine (SVM), as well as using traditional techniques of weighted overlay (WOL). Land suitability classes predicted by ML techniques varied greatly. For example, the S1 area (highly suitable) classified through RF was 9%↑ than that of SVM, and 8%↓ than that through WOL. The area of S2 (moderately suitable) classified through RF was 18%↑ than that of SWM and was 17%↓ than the area classified through WOL; similarly, the S3 (marginally suitable) class area via RF was 27%↓ than that of SVM, and 45%↓ than the area classified through WOL. Conversely, the area of N2 (permanently not suitable class) classified through RF and SVM was 6%↑ than the area classified through WOL. Model performance was assessed through overall accuracy and Kappa Index and indicated that RF performed better than SVM and WOL. Crop suitability limitations of the study area included high elevation, slope, pH, and large gravel content. Results can be used for sustainable intensification in mountainous rainfed regions by expanding intercrop agroforestry systems in developing nations to close yield gaps.

Wheat growth, yield, nutrient concentration and soil chemical properties influenced by liming in an acid soil

Soil acidity has negative effects on both plants and soil. Furthermore, liming is the most common and effective management practice used to neutralize the acid produced in the soil and the problems associated with soil acidification. The study evaluated whether liming impacts wheat growth, yield, nutritional status basis exchangeable, and their related soil acidity indices. A greenhouse experiment was performed under a completely randomized arrangement, with four lime application rates equivalent to (0, 4.0, 8.0, and 12.0 Mg ha−1). The results showed that all yield components significantly increased with increasing lime addition rate. The grain yield, shoot and root dry weight, and plant and spike height improved quadratically (R 2 = 0.909, 0.950, 0.976, 0.902, and 0.891, respectively). Additionally, the lime rate influenced P and Mg concentrations in the shoot, and the concentrations of Cu and Zn. With increasing lime rate, the soil exchangeable Ca and Mg concentrations increased quadratically (R 2 = 0.969 and 0.984), while the soil exchangeable K and Al concentrations decreased significantly. The pH of the soil solution increased linearly (R 2 = 0.994) with the lime addition rate. Liming significantly reduced the exchangeable Al3+ and Al + H in the soil. Finally, liming improves wheat yield in acid soil by reducing the negative effects of Al and H by increasing soil pH, Ca2+, and Mg2+ concentration, consequently improving root growth and resulting in wheat yield. Liming increased the grain yield by 188.7, 198.2, and 322.8% following the increase of lime rate, if compared to the control. Furthermore, lime enhances plant resilience by raising pH and improving soil nutrient availability and the root system.

Enhancement of cadmium uptake in Sedum alfredii through interactions between salicylic acid/jasmonic acid and rhizosphere microbial communities

The focus on phytoremediation in soil cadmium (Cd) remediation is driven by its cost-effectiveness and eco-friendliness. Selecting suitable hyperaccumulators and optimizing their growth conditions are key to enhance the efficiency of heavy metal absorption and accumulation. Our research has concentrated on the role of salicylic acid (SA) and jasmonic acid (JA) in facilitating Cd phytoextraction by “Sedum alfredii (S. alfredii)” through improved soil-microbe interactions. Results showed that SA or JA significantly boosted the growth, stress resistance, and Cd extraction efficiency in S. alfredii. Moreover, these phytohormones enhanced the chemical and biochemical attributes of the rhizosphere soil, such as pH and enzyme activity, affecting soil-root interactions. High-throughput sequencing analysis has shown that Patescibacteria and Umbelopsis enhanced S. alfredii's growth and Cd extraction by modifying the bioavailability and the chemical conditions of Cd in soil. Structural Equation Model analysis further verified that phytohormones significantly enhanced the interaction between S. alfredii, soil, and microbes, leading to a marked increase in Cd accumulation in the plant. These discoveries emphasized the pivotal role of phytohormones in modulating the hyperaccumulators' response to environmental stress and offered significant scientific support for further enhancing the potential of hyperaccumulators in ecological restoration technologies using phytohormones.

Effects of Different Microbial Fertilizers on Soil Quality and Maize Yield in Coastal Saline Soil

Microbial fertilizers have the characteristics of high efficiency and environmental protection in improving saline soils, and the application of functional microbial fertilizers is of great significance for the green abatement of saline barriers and the improvement of soil quality in coastal areas. The experiment was based on moderately saline soil in the coastal area of Hebei Province, with corn as the indicator crop, on the basis of conventional chemical fertilizer application. Different microbial fertilizer treatments, namely, T1 （conventional chemical fertilizer 750 kg·hm-2 + compound microbial agent 75 kg·hm-2）, T2 （conventional chemical fertilizer 750 kg·hm-2 + Bacillus megaterium 300 kg·hm-2）, T3 （conventional chemical fertilizer 750 kg·hm-2 + B. mucilaginosus 300 kg·hm-2）, T4 （conventional chemical fertilizer 750 kg·hm-2 + organic silicon fertilizer 600 kg·hm-2）, T5 （conventional chemical fertilizer 750 kg·hm-2 + bio-organic fertilizer 600 kg·hm-2）, T6 （conventional fertilizer 750 kg·hm-2 + active microalgae 15 kg·hm-2）, and CK （only fertilizer 750 kg·hm-2）, were used for these seven treatments, to study the effects of different microbial fertilizers on soil nutrients, salinity, bacterial community, and corn yield and economic efficiency during two critical periods （V12 stage and maturity stage） of corn. The results showed that compared with that in CK, T1 significantly increased soil total nitrogen （TN） and available phosphorus （AP） contents during the whole growth period. Over the whole reproductive period, soil organic matter （OM） at maturity increased by 10.35% over the V12 stage compared to that in CK, but there was no significant difference between treatments. Compared with that in CK, T5 and T6 significantly reduced soil total salinity and Ca2+ content during the whole growth period by an average of 14.51%-18.48% and 24.25%-25.51%. T1 significantly increased the bacterial diversity index over the whole growth period by 45.16% compared to that in CK. The dominant soil phyla were Actinobacteria, Proteobacteria, Acidobacteria, and Chloroflexi, and the dominant genera were Bacillus and Geminicoccaceae. The most abundant functions of the bacterial community in the study area were chemoheterotrophy and aerobic chemoheterotrophy, with average relative abundances of 28.89% and 27.11%, and T3 and T6 significantly improved soil N cycling function. The results of redundancy analysis （RDA） indicated that Na+, SO42-, pH, and EC were important factors driving the structure of the bacterial community, and correlation heatmaps showed that Na+, SO42-, pH, and EC were significantly and positively correlated mainly with the phylum Planctomycetota, whereas soil OM and TN were significantly and positively correlated with Cyanobacteria. Compared with that in CK, T6 increased the relative abundance of Cyanobacteria and optimized the bacterial community structure during the whole growth period. Using recommended dosages of bacterial fertilizers T1 and T6 increased maize yield by 7.31%-24.83% and economic efficiency by 9.05%-23.23%, respectively. The preliminary results of soil chemical properties and yield correlation analysis revealed that EC, AP, HCO3-, and Mg2+ were the obstacle factors limiting soil productivity in coastal areas. In conclusion, the use of the compound bacterial agent （T1） and active microalgae （T6） at the recommended dosage can significantly enhance soil nutrients, reduce salinity, and improve the structural diversity of soil bacterial communities, which not only ensures the increase in maize yield and efficiency but also realizes the efficient use of microbial fertilizers and the improvement of soil quality.

Spatial Variability of Soil Chemical Properties of an Undulating Site within a University Farm at Okha, near Benin City in Nigeria

Spatial Variability of Soil Chemical Properties of an Undulating Site within a University Farm at Okha, near Benin City in Nigeria

Fire-deposited charcoal enhances soil microbial biomass in a recently harvested subtropical plantation forest

Charcoal, a byproduct of biomass burning, is widely and heterogeneously distributed in fire-affected ecosystems. However, few field studies have been conducted to evaluate the effects of fire-deposited charcoal on the post-fire soil quality. In this study, we aimed to investigate whether charcoal generated during post timber harvest broadcast burning influenced the recovery of individual soil properties and overall soil quality in subtropical forest plantations. Broadcast burning was conducted on experimental Pinus massoniana plantation timber harvest sites in southern China. Surface soils (0–10 cm) were collected in plots established on the burnt sites five years after the disturbance event. Plots were established immediately after burning with three different levels of charcoal input (C0, removal of all visible charcoal; C1, charcoal retained in-situ; C2, charcoal removed from C0 added to C2) and an unburnt control (UB). Thirty-two soil indicators representing soil physical, chemical, and biological properties were determined. The results showed that 11 indicators exhibited significant differences among the treatments, with significantly lower SOM, microbial biomass carbon (MBC), peroxidase (POD) and leucine aminopeptidase (LAP) activities for the C0 and C1 plots than the UB plots (P < 0.05), while no significant difference was observed between the UB and C2 plot (P > 0.05). The soil available N, P and exchangeable nutrient contents were not significantly different among the treatments (P > 0.05). Our results indicate that SOM and microbial attributes did not recover five years after the disturbance event and that charcoal appeared to play a positive role in the post-fire soil restoration. Whether the accelerated recovery of soil restoration induced by charcoal might contribute to higher forest productivity needs to be testified in combination with plant growth and performance analysis in the future.

Influence of Drought Stress on the Rhizosphere Bacterial Community Structure of Cassava (Manihot esculenta Crantz).

Drought presents a significant abiotic stress that threatens crop productivity worldwide. Rhizosphere bacteria play pivotal roles in modulating plant growth and resilience to environmental stresses. Despite this, the extent to which rhizosphere bacteria are instrumental in plant responses to drought, and whether distinct cassava (Manihot esculenta Crantz) varieties harbor specific rhizosphere bacterial assemblages, remains unclear. In this study, we measured the growth and physiological characteristics, as well as the physical and chemical properties of the rhizosphere soil of drought-tolerant (SC124) and drought-sensitive (SC8) cassava varieties under conditions of both well-watered and drought stress. Employing 16S rDNA high-throughput sequencing, we analyzed the composition and dynamics of the rhizosphere bacterial community. Under drought stress, biomass, plant height, stem diameter, quantum efficiency of photosystem II (Fv/Fm), and soluble sugar of cassava decreased for both SC8 and SC124. The two varieties' rhizosphere bacterial communities' overall taxonomic structure was highly similar, but there were slight differences in relative abundance. SC124 mainly relied on Gamma-proteobacteria and Acidobacteriae in response to drought stress, and the abundance of this class was positively correlated with soil acid phosphatase. SC8 mainly relied on Actinobacteria in response to drought stress, and the abundance of this class was positively correlated with soil urease and soil saccharase. Overall, this study confirmed the key role of drought-induced rhizosphere bacteria in improving the adaptation of cassava to drought stress and clarified that this process is significantly related to variety.

Growth response and changes of soil chemical properties with application of vermichar in bell pepper production

Growth response and changes of soil chemical properties with application of vermichar in bell pepper production