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Soil enzymes are crucial in mediating ecosystems' responses to environmental drivers, so that the comprehension of their sensitivity to drivers of global change can help make predictions of future scenarios and design tailored interventions of biomanipulation. Drivers of global change usually act in combination of two or more, and indirect effects of one driver acting through modification of another one often occur, yet most of both manipulative and meta‐analysis studies available tend to focus on the direct effect of one single driver on the activity of specific soil enzymes. One of the biggest challenges is, therefore, represented by the difficulty in assessing the interactions between different drivers, due to the complexity of disentangling the single direct effects from the indirect and combined ones. In this review, after elucidating the general mechanisms of soil enzyme production and activity regulation, we display the state‐of‐the‐art knowledge on direct, indirect and combined effects of the main drivers of global change on soil enzyme activities, identify gaps in knowledge and challenges from research, plus we analyse how this can reverberate in the future of biomanipulation techniques for the improvement of ecosystem services. We conclude that qualitative but not quantitative outcomes can be predicted for some interactions such as warming + drought or warming + CO2, while for other ones, the results are controversial: future basic research will have to center on this holistic approach. A general trend toward the overall increase of soil enzyme activities and acceleration of biogeochemical cycles will persist, until an inflection will be caused by factors such as future shifts in microbial communities and changes in carbon use efficiency. Applied research will develop toward the refinement of "in situ" analytical systems for the study of soil enzyme activities and the support of bioengineering for the better tailoring of interventions of biomanipulation. [ABSTRACT FROM AUTHOR]

The purpose of the study was to study the role of soil moisture in the seasonal change of biological activity, which is one of the main diagnostic indicators of soils in the Sheki-Zagatala region of Azerbaijan in 2020-2022. Studied the same relative change in spectral reflectance coefficients is observed with the change of soil moisture of biological activity. In the spring-summer and spring periods, the most total amount of amino acids was found: in mountain-meadow chernozems: in spring - 13.08 mg per 10 g of soil, in summer - 18.92 mg, in autumn - 11.3 mg, in winter at low temperatures and excessive soil moisture, the amount of amino acids decreases to 7.81 mg, while in brown mountain forest soils it is: in spring - 14.9 mg, in summer - 11.91 mg, in autumn - 10.89, in winter - 7.52 mg. In humidity between 2-37%, the integral reflection coefficient varies from 12 to 33% and in 1% humidity in fidelity in the upper horizon reduces the integral reflection coefficient by 0.96%. [ABSTRACT FROM AUTHOR]

Common fertilizers present a low use efficiency caused by nutrient losses (e.g., through leaching, volatilization, adsorption, and precipitation in solution as well as through microbial reduction and immobilization) that create a significant limiting factor in crop production. Inoculation with Plant Growth-Promoting Bacteria (PGPB) is presented as an alternative to increasing fertilizer efficiency. The goal of the study was to test the hypothesis that PGPB (solution with Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus licheniformis, and Bacillus pumilus) can be a strategy to increase the monoammonium phosphate (MAP) efficiency, root growth, and nutrient assimilation of soybean and corn cultivated in arenosol and oxisol. A greenhouse study was developed with the rates of PGPB (rates: 0, 1, 1.33, and 1.66–2.0 L per ton of fertilizer) sprayed on MAP and applied in an arenosol and oxisol cultivated with soybean and corn. Results showed that in both soils and crops, there was a variation in soil biological activity during the experiment. On day 45, PGPB + MAP promoted the beta-glucosidase and ammonium-oxidizing microorganism activities in the arenosol. The PGPB + MAP increased crop root growth in both soils and crops. Plant dry matter was associated with the phosphorous content in the soil, indicating that the phosphorous applied was absorbed by the plants, consequently resulting in a higher accumulation in the plant. Based on the results, the conclusion is that PGPB + MAP increases the growth and phosphorous accumulation of soybean and corn cultivated in the arenosol and oxisol, with a direct effect on crop rooting. [ABSTRACT FROM AUTHOR]

Pyrethroids are insecticides most commonly used for insect control to boost agricultural production. The aim of the present research was to determine the effect of permethrin and cypermethrin on cultured and non-cultivated bacteria and fungi and on the activity of soil enzymes, as well as to determine the usefulness of Zea mays in mitigating the adverse effects of the tested pyrethroids on the soil microbiome. The analyses were carried out in the samples of both soil not sown with any plant and soil sown with Zea mays. Permethrin and cypermethrin were found to stimulate the multiplication of cultured organotrophic bacteria (on average by 38.3%) and actinomycetes (on average by 80.2%), and to inhibit fungi growth (on average by 31.7%) and the enzymatic activity of the soil, reducing the soil biochemical fertility index (BA) by 27.7%. They also modified the number of operational taxonomic units (OTUs) of the Actinobacteria and Proteobacteria phyla and the Ascomycota and Basidiomycota phyla. The pressure of permethrin and cypermethrin was tolerated well by the bacteria Sphingomonas (clone 3214512, 1052559, 237613, 1048605) and Bacillus (clone New.ReferenceOTU111, 593219, 578257), and by the fungi Penicillium (SH1533734.08FU, SH1692798.08FU) and Trichocladium (SH1615601.08FU). Both insecticides disturbed the growth and yielding of Zea mays, as a result of which its yield and leaf greenness index decreased. The cultivation of Zea mays had a positive effect on both soil enzymes and soil microorganisms and mitigated the anomalies caused by the tested insecticides in the microbiome and activity of soil enzymes. Permethrin decreased the yield of its aerial parts by 37.9% and its roots by 33.9%, whereas respective decreases caused by cypermethrin reached 16.8% and 4.3%. [ABSTRACT FROM AUTHOR]

Biochar is an important soil amendment that can enhance the biological properties of soil, as well as nitrogen (N) uptake and utilization in N-fertilized crops. However, few studies have characterized the effects of urea and biochar application on soil biochemical traits and its effect on paddy rice. Therefore, a field trial was conducted in the early and late seasons of 2020 in a randomized complete block design with two N levels (135 and 180 kg ha−1) and four levels of biochar (0, 10, 20, and 30 t ha−1). The treatment combinations were as follows: 135 kg N ha−1 + 0 t B ha−1 (T1), 135 kg N ha−1 + 10 t B ha−1 (T2), 135 kg N ha−1 + 20 t B ha−1 (T3), 135 kg N ha−1 + 30 t B ha−1 (T4), 180 kg N ha−1 + 0 t B ha−1 (T5), 180 kg N ha−1 + 10 t B ha−1 (T6), 180 kg N ha−1 + 20 t B ha−1 (T7) and 180 kg N ha−1 + 30 t B ha−1 (T8). The results showed that soil amended with biochar had higher soil pH, soil organic carbon content, total nitrogen content, and mineral nitrogen (NH4+-N and NO3−-N) than soil that had not been amended with biochar. In both seasons, the 20 t ha−1 and 30 t ha−1 biochar treatments had the highest an average concentrations of NO3–-N (10.54 mg kg−1 and 10.25 mg kg−1, respectively). In comparison to soil that had not been treated with biochar, the average activity of the enzymes urease, polyphenol oxidase, dehydrogenase, and chitinase was, respectively, 25.28%, 14.13%, 67.76%, and 22.26% greater; however, the activity of the enzyme catalase was 15.06% lower in both seasons. Application of biochar considerably increased the abundance of ammonia-oxidizing bacteria (AOB), which was 48% greater on average in biochar-amended soil than in unamended soil. However, there were no significant variations in the abundances of ammonia-oxidizing archaea (AOA) or nitrite-oxidizing bacteria (NOB) across treatments. In comparison to soil that had not been treated with biochar, the average N content was 24.46%, 20.47%, and 19.08% higher in the stem, leaves, and panicles, respectively. In general, adding biochar at a rate of 20 to 30 t ha−1 with low-dose urea (135 kg N ha−1) is a beneficial technique for improving the nutrient balance and biological processes of soil, as well as the N uptake and grain yield of rice plants. [ABSTRACT FROM AUTHOR]

Purpose: Biochar plays an active role in increasing crop yield and improving soil quality due to its unique properties and structure. However, the physical and chemical properties of biochar also change over time after applying to the soil, which is referred to as aging. The distinction between modifying soil fertility and soil nutrient status is uncertain (especially in soil potassium levels). Materials and methods: We used three approaches to simulate aging progress of biochar, including acidification (AB), dry–wet cycle (DWB), and freezing–thawing cycling (FB). We used element analyzer, BET-N adsorption method, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM) to observe the difference in physical and chemical properties between original biochar (OB) and aged biochar (AB, DWB, and FB). In addition, we undertook pot experiment to assess the impact of original biochar and aged biochar on soil fertility status, soil enzyme activities, and the growth of cabbage, especially in the difference in promoting soil potassium (K) level. Results and discussion: The main results were as follows: Original biochar and aged biochar improved soil fertility and cabbage growth, but the improvement effect of aged biochar on soil environment was weakened. Among all-aged biochars, the AB had the worst effect on the soil environment. Compared to without biochar treatment (CK), the water-soluble K, available K, exchangeable K, and non-exchangeable K were increased by 43.60%, 45.56%, 46.49%, and 44.30%, respectively, under original biochar treatment. However, the promotion effect of soil potassium level was significantly decreased under the AB treatment. Additionally, the C and N content of biochar increased with aged biochar treatment, and the increasing trend was further obvious after applying it to the soil. Moreover, aged biochar treatment affected the surface of biochar, and was more susceptible to erosion in the soil by long-term water leaching. Conclusions: Overall, the impacts of aged biochar on cabbage growth and soil fertility were inhibited compared to original biochar treatment, further providing a basis and reference for the proper application of biochar in agriculture production. [ABSTRACT FROM AUTHOR]

Information regarding relationships between forage yield and soil enzymes of legume–grass mixtures under nitrogen (N) fertilization can guide the decision-making during sustainable forage production. The objective was to evaluate the responses of forage yield, nutritional quality, soil nutrients, and soil enzyme activities of different cropping systems under various N inputs. Alfalfa (Medicago sativa L.), white clover (Trifolium repens L.), orchardgrass (Dactylis glomerata L.), and tall fescue (Festuca arundinacea Schreb.) were grown in monocultures and mixtures (A1: alfalfa, orchardgrass, and tall fescue; A2: alfalfa, white clover, orchardgrass, and tall fescue) under three N inputs (N1: 150 kg ha−1; N2, 300 kg ha−1; and N3: 450 kg ha−1) in a split plot arrangement. The results highlight that A1 mixture under N2 input had a greater forage yield of 13.88 t ha−1 year−1 than the other N inputs, whereas A2 mixture under N3 input had a greater forage of 14.39 t ha−1 year−1 than N1 input, but it was not substantially greater than N2 input (13.80 t ha−1 year−1). The crude protein (CP) content of grass monocultures and mixtures significantly (P < 0.05) increased with an increase in the rate of N input, and A1 and A2 mixtures under N3 input had a greater CP content of 18.91% and 18.94% dry matter, respectively, than those of grass monocultures under various N inputs. The A1 mixture under N2 and N3 inputs had a substantially greater (P < 0.05) ammonium N content of 16.01 and 16.75 mg kg−1, respectively, whereas A2 mixture under N3 had a greater nitrate N content of 4.20 mg kg−1 than the other cropping systems under various N inputs. The A1 and A2 mixtures under N2 input had a substantial higher (P < 0.05) urease enzyme activity of 0.39 and 0.39 mg g−1 24 h−1 and hydroxylamine oxidoreductase enzyme activity of 0.45 and 0.46 mg g−1 5 h−1, respectively, than the other cropping systems under various N inputs. Taken together, growing legume–grass mixtures under N2 input is cost-effective, sustainable, and eco-friendly, which provide greater forage yield and improved nutritional quality by the better utilization of resources.

Edaphoclimatic conditions influence nitrous oxide (N2O) emissions from agricultural systems where soil biochemical properties play a key role. This study addressed cumulative N2O emissions and their relations with soil biochemical properties in a long-term experiment (26 years) with integrated crop–livestock farming systems fertilized with two P and K rates. The farming systems consisted of continuous crops fertilized with half of the recommended P and K rates (CCF1), continuous crops at the recommended P and K rates (CCF2), an integrated crop–livestock system with half of the recommended P and K rates (ICLF1), and an integrated crop–livestock at the recommended P and K rates (ICLF2). The ICLF2 may have promoted the greatest entry of carbon into the soil and positively influenced the soil’s biochemical properties. Total carbon (TC) was highest in ICLF2 in both growing seasons. The particulate and mineral-associated fractions in 2016 and 2017, respectively, and the microbial biomass fraction in the two growing seasons were also very high. Acid phosphatase and arylsulfatase in ICLF1 and ICLF2 were highest in 2016. The soil properties correlated with cumulative N2O emissions were TC, total nitrogen (TN), particulate nitrogen (PN), available nitrogen (AN), mineral-associated organic carbon (MAC), and microbial biomass carbon (MBC). The results indicated that ICLF2 induces an accumulation of more stable organic matter (OM) fractions that are unavailable to the microbiota in the short term and result in lower N2O emissions.

Wood ash is sometimes used as an alternative to mineral fertilizers; however, there is still a paucity of reliable data concerning its effect on plants—and on biological properties of soil. The present study aimed to determine the possible extent of soil pollution with ash from Salix viminalis that does not disturb the growth of Zea mays L., intended for energetic purposes, in order to identify how the increasing ash doses affect biochemical and physicochemical properties of soil and to finally to establish the neutralizing effects of soil additives, i.e., compost and HumiAgra preparation, on this soil pollutant. The study demonstrated that the heating value of Zea mays L. was stable and not modified by the excess content of ash from Salix viminalis in the soil. This finding points to the feasibility of Zea mays L. cultivation on soils contaminated with ash from Salix viminalis and its use in bio-power engineering. The biomass of the aboveground parts of Zea mays L. was significantly reduced after soil contamination with Salix viminalis ash dose of 20 g kg−1 d.m. soil, whereas the smaller ash doses tested (5–10 g kg−1 d.m. soil) did not impair either the growth or the development of Zea mays L. The ash inhibited activities of all analyzed soil enzymes but increased soil pH and sorption capacity. Fertilization with compost proved more effective in neutralizing the adverse effect of ash on enzymatic activity of the soil.

The aim of the study was to determine the impact that three cultivation systems—conventional till (CT), reduced till (RT), and strip-till one-pass (ST-OP)—had on the biological parameters of the soil and their relationships with organic matter properties in the row zone (R) and inter-row zone (IR). For this purpose, a long-term static field experiment was carried out, from which soil samples were taken from a depth of 0–20 cm and the following were determined: TOC; TN content and fractional composition of organic matter; activity of dehydrogenases (DEHs), catalase (CAT), alkaline (AlP), and acid phosphatase (AcP); and the abundances of heterotophic bacteria (B), filamentous fungi (F), actinobacteria (Ac), and cellulolytic microorganisms (Ce). Soil samples for biological parameter tests were collected in summer (July) and autumn (October). RT and ST-OP increase the content of TOC, TN, carbon, and nitrogen in the humic and fulvic acid fractions. For the studied groups of microorganisms, the conditions for development were least favourable under CT cultivation. The results show that in July, the activities of DEH and CAT were the highest in ST-OP, whereas in October, they were the highest under CT. AlP and AcP activity were markedly the highest under ST-OP in both months. Enzyme activity was significantly the highest in the IR zone. The results indicate that, of the calculated multiparametric indicators, (AlP/AcP, GMea, BIF, BA12, and TEI), BA12 is a sensitive biological indicator of soil quality.

Pollution caused by crude oil is one of the most prevalent environmental problems in oil-rich countries. Bioremediation processes usually exploit the ability of microorganisms to degrade and/or detoxify organic contaminants. A widely used bioremediation strategy is bio-stimulation of the soil’s indigenous microbes by the addition of nutrients, as crude oil contamination tends to result in the rapid depletion of the available pools of major inorganic nutrients such as nitrogen and phosphorus. This study examined the bio-stimulation effect of diammonium phosphate and urea fertilizers on crude oil-contaminated soil enzymes. Soils were artificially contaminated with 3000, 5000, or 8000 ppm of crude oil and treated with Diammonium phosphate (DAP) and urea fertilizers. The activities of soil enzymes such as laccase, lipase, catalase, and peroxidase were analyzed every 6th day for 30 days. The results indicated that the activity of laccase for all the treated soils was significantly higher than the untreated group on days 18, 24, and 30, while those of peroxidase and catalase peaked at day 12, with a sharp decline on days 18 to 30 when compared to the untreated soil. However, the activity of lipase continued to increase until the 30th day in all the treated soils, and the increase was higher in contaminated soils treated with DAP and urea. The decreased activities of peroxidase and catalase in the treated soils may be related to a decrease in the microbial load of the soil. Furthermore, the increase in the activities of soil enzymes, especially in the treated soils, suggested that the treatments contributed to enhancing the activities of the enzymes, and hence may help in the bioremediation process through bio-stimulation of the soil enzymes that function in the breakdown of environmental contaminants.

A field study was conducted to compare FM-1 inoculation by irrigation and spraying for promoting Bidens pilosa L. phytoremediation of cadmium (Cd)-contaminated soil. Cascading relationships between bacterial inoculation by irrigation and spraying and soil properties, plant growth-promoting traits, plant biomass and Cd concentrations in Bidens pilosa L. were explored based on the partial least squares path model (PLS-PM). The results indicated that inoculation with FM-1 not only improved the rhizosphere soil environment of B. pilosa L. but also increased the Cd extracted from the soil. Moreover, Fe and P in leaves play vital roles in promoting plant growth when FM-1 is inoculated by irrigation, while Fe in leaves and stems plays a vital role in promoting plant growth when FM-1 is inoculated by spraying. In addition, FM-1 inoculation decreased the soil pH by affecting soil dehydrogenase and oxalic acid in cases with irrigation and Fe in roots in cases with spraying. Thus, the soil bioavailable Cd content increased and promoted Cd uptake by Bidens pilosa L. To address Cd-induced oxidative stress, Fe in leaves helped to convert GSH into PCs, which played a vital role in ROS scavenging when FM-1 was inoculated by irrigation. The soil urease content effectively increased the POD and APX activities in the leaves of Bidens pilosa L., which helped alleviate Cd-induced oxidative stress when FM-1 was inoculated by spraying. This study compares and illustrates the potential mechanism by which FM-1 inoculation can improve the phytoremediation of Cd-contaminated soil by Bidens pilosa L., suggesting that FM-1 inoculation by irrigation and spraying is useful in the phytoremediation of Cd-contaminated sites.

The interactive effects of three non-fodder Indian arid plant species, Tephrosia purpurea, Aerva persica, and Calotropis procera, and four Aspergillus fungal species on soil enzymes (acid and alkaline phosphatase, -glucosidase, dehydrogenase, urease, and amidase activities) were temporally assessed (15 and 30 days withdrawals). The results were statistically analysed using ANOVA, Principal Component Analysis (PCA), and Canonical Correlation Analysis (CCoA). Aside from these, a biochemical soil quality index was created by assigning a weighted score to each enzyme and analysing it using PCA. This study found that various litter-fungal species complexes acted differently and that their effects changed over time, specifically for acid phosphatase, alkaline phosphatase, beta-glucosidase, and amidase. Dehydrogenase and urease activities increased with predictors over time. With temporal backwash, all four fungal species with C. procera inhibit acid phosphatase, alkaline phosphatase, and beta-glucosidase activities (i.e., more at 15 days and lesser after 30 days). Our current findings suggest that (a) urease activities were modulated by A. persica in cooperation with fungi like A. terreus, A. niger, and A. flavus at specific enzyme levels; (b) In assistance with fungi such as A. fumigatus, A. niger, and A. persica, amidase concentration was successfully managed through litter of the legume plant species T. purpuria. (c) When C. procera and A. fumigatus, A. niger, and A. flavus worked together, they were most effective at supporting beta-glucosidase and dehydrogenase (d) Alkaline phosphatase and (e) acid phosphatase was more responsive to T. purpurea-A. terreus complexes than were T. purpurea-A. flavus and C. procera-A. terreus complexes.

French bean (Phaseolus vulgaris L.) cultivation faces multipronged challenges of low farm productivity, poor economic returns, and soil health deterioration in the hilly ecosystem of India. Hence, the development of a cost-effective and soil-supportive French bean cultivation technology is highly warranted. Thus, a field experiment was conducted for two consecutive seasons in the Sikkim region of the Indian Himalayas to assess the impact of different organic nutrient sources on the production potential, profitability, and soil health of French bean. Eight organic nutrient management practices, viz., farmers' practice, 100% recommended dose of nitrogen (RDN) through FYM, 100% RDN through mixed compost (MC), 100% RDN through vermicompost (VC), 50% RDN through FYM + 50% RDN through MC, 50% RDN through FYM + 50% RDN through VC, 50% RDN through MC + 50% RDN through VC, and 33% RDN through FYM + 33% RDN through MC + 33% RDN through VC, were assigned in a three times replicated randomized complete block design. The results revealed that the supply of 33% RDN through FYM + 33% RDN through MC + 33% RDN through VC 33% recorded the highest pod yield (8.30 and 8.00 Mg ha−1) and net returns (1,831 and 1,718 US$ ha−1). Furthermore, the supply of 33% RDN through FYM + 33% RDN through MC + 33% RDN through VC 33% also had a positive impact on soil health. It was shown that an equal supply of RDN through FYM + MC + VC increases soil pH by 8.35%, SOC by 5.45%, available N by 6.32%, available P by 16%, available K by 9.92%, and micronutrients by 5–7% over farmers' practice. Thus, the supply of RDN through the integration of FYM + MC + VC in equal proportion is an economically robust and soil-supportive nutrients management practice for organic French bean production in the hilly ecosystem of North East India.

The stability of soil organic carbon (SOC) plays a vital role in C sequestration, and largely depends on the availability of soil nitrogen (N) and phosphorus (P). Understanding how different fractions of SOC respond to N and P availability and the underlying microbial mechanism is crucial for mitigating climate changes. Here, we assessed how soil N and P availability modifies different SOC fractions and the soil microbial communities in a tropical forest. We measured soil chemical properties, SOC fractions, microbial PLFA abundance, fungal rDNA and its predicted gene abundance, and extracellular enzyme activities within a field N and P addition experiment. P addition decreased the concentration of recalcitrant SOC and greatly increased the soil oxidative extracellular enzyme activities, while N addition increased active SOC, mainly light fractions, and decreased soil phenol oxidase activity. P addition also induced the greatest abundance of oxidoreductases. Additionally, the transferases, lyases, hydrolases, isomerases, and ligases were also expressed at higher levels after P addition. The results indicate that enhanced soil microbial activities after P addition accelerated recalcitrant SOC decomposition by higher oxidative enzyme activities. Given the increasing N deposition, tropical forests that characterized by a low P have a great potential to sequester more SOC which will mitigate climate change. However, the increase in SOC might be vulnerable to disturbance, because most of the increased C is the active SOC.

The Qinghai-Tibetan Plateau (QTP) is sensitive to global climate change. This is because it is characterized by irregular rainfall and freeze–thaw cycles resulting from its high elevation and low temperature. Greenhouse gases (GHGs) mainly contribute to the warming of the QTP, but few studies have investigated and compared the effects of irregular rainfall and freeze–thaw cycles on GHGs. In this study, we conducted a laboratory experiment under four types of freeze–thaw treatments with three soil water content levels to simulate the irregular freeze–thaw and rainfall conditions. The results showed that both the soil water content and freeze–thaw treatment influenced the soil properties, soil enzyme activities, and the microbial biomass; however, the freeze–thaw treatment had significantly higher influences on GHG fluxes than soil water content. In order to explore other biotic and abiotic factors in an attempt to establish the main factor in determining GHG fluxes, a variation partition analysis was conducted. The results revealed that freeze–thaw treatments were the strongest individual factors in predicting the variance in N2O and CO2 fluxes, and the pH, which was only significantly affected by freeze–thaw treatment, was the strongest individual factor in predicting CH4 flux. Across the water content levels, all the freeze–thaw treatments increased the N2O flux and reduced the CH4 flux as compared to the CK treatment. In addition, long-term freezing reduced the CO2 flux, but the treatment of slowly freezing and quickly thawing increased the CO2 flux. In summary, these results suggest that the freeze–thaw treatments had quite different effects on N2O, CH4, and CO2 fluxes, and their effects on GHG fluxes are more significant than those of soil water content on the eastern edge of the QTP. [ABSTRACT FROM AUTHOR]

Soil microorganisms could obtain energy and nutrients during litter decomposition with the help of soil extracellular enzymes. The litter types were among the most critical factors that affect soil extracellular enzyme activities. However, how litter types modulate the soil extracellular enzyme activity with grassland gradation is unclear. Here, we conducted a 240-day experiment of two different types of litter decomposition on soil extracellular enzyme activity and stoichiometry in different degraded grasslands. We found that C-acquiring enzyme activity and the enzyme stoichiometry of C/N were higher in Chloris virgata litter than in Leymus chinensis litter at lightly degraded level and C-acquiring enzyme activity in C. virgata was 16.96% higher than in L. chinensis. P-acquiring enzyme activity had the same trend with litter types in moderately and highly degraded levels and it was 20.71% and 30.89% higher in C. virgata than that in L. chinensis, respectively. The change of the enzyme stoichiometry with litter types was only showed in the enzyme stoichiometry of C/N at lightly degraded level, suggesting that litter types only affected the microbial C limitation in lightly degraded grassland. Almost all soil extracellular enzyme activities and extracellular enzyme stoichiometry, except the enzyme stoichiometry of N/P, decreased with grassland degraded level increasing. All vector angles were less than 45° suggesting that soil microorganisms were limited by N rather than by P during the decomposition process. Enzyme vector analysis revealed that soil microbial communities were co-limited by C and N during litter decomposition. Moreover, based on Random Forest (explaining more than 80%), we found that soil total nitrogen, total carbon, total phosphorus, dissolved organic C, pH and EC were important factors affecting soil enzyme activities by degradation levels. Our results emphasized that degradation levels could modulate the influences of litter types on soil extracellular enzyme activity. Our study enhanced our understanding in resource requirements for microbial communities to litter resources in degraded grassland and helped us to provide new ideas for improving degraded grassland ecosystems. [ABSTRACT FROM AUTHOR]

Interactions between soil fungi and soil environmental factors regulate soil nitrogen (N) mineralization rates on the eastern Qinghai-Tibetan Plateau. Some studies have also illuminated differences in soil N mineralization rate based on different mycorrhizal forests, but the associated effect of soil fungal functional guilds and soil environmental factors underlying this process are not wellunderstood. Three primary forests respectively dominated by Abies fargesii var. faxoniana (ectomycorrhizal, EcM), Cupressus chengiana (arbuscular mycorrhizal, AM) and Rhododendron phaeochrysum (ericoid mycorrhizal, ErM) trees were selected in this area. Meanwhile, soil net N mineralization rate, soil fungal composition and soil enzyme activity among these three mycorrhizal forests were studied. Our results showed that there were significant differences in the seasonal variation of soil net N mineralization rates among three mycorrhizal forests. Soil net N mineralization rate in the AM forest was faster. EcM fungi and saprotroph are the main functional guilds in these three mycorrhizal forests. Meanwhile, the relative abundances of soil fungal functional guilds, soil temperature and soil peroxidase activity could explain 85.0% in the difference of soil net ammonification rate among three mycorrhizal forests. In addition, soil temperature, soil water-filled pore space and soil ammonium content play a central role in controlling the differing soil net nitrification rate among three mycorrhizal forests. Our results suggest differences in soil net mineralization among different mycorrhizal forest types are driven mainly by soil net ammonification. Soil fungal functional guilds and temperature regulate the rate of soil net ammonification by modulating soil peroxidase activity. [ABSTRACT FROM AUTHOR]

Biochar (BC) is a material that has many applications in agricultural and environmental activities. The aim of the study was to define the influence of BC produced in low-temperature pyrolysis from various organic waste materials, including one-month-old compost (OMOC), pine bark (PB), pine needle mulch (NM), pine cones (PC) and maple leaves (ML), on soil enzyme activity as well as its relation with organic matter properties. A 60-day incubation pot experiment was set up to investigate the influence of BC amendment on soil (S) characteristics. After incubation, we investigated the activity of soil enzymes, the content of available phosphorus (AP), potassium (AK) and magnesium (AMg), total organic carbon (TOC), total nitrogen (TN), dissolved organic matter (DOM) and its fractional composition (content and share of carbon and nitrogen of humic (CHAs, NHAs) and fulvic (CFAs, NFAs) acids and humin fractions). The effect of the amended biochars differed depending on the feedstock material. In general, the use of biochar enriched the soil with AP, AK and AMg increased the soil carbon stock, increased the intensity of nitrogen transformation and influenced the soil enzyme activity. OMOC and ML biochars significantly increased soil fertility, which was expressed by the high value of the CHA/CFA ratio. [ABSTRACT FROM AUTHOR]

The use of fertilizers based on organic waste as a result of microbial biodegradation and biotransformation is becoming increasingly common practice in plant cultivation. This is to limit the chemicals used in agriculture and thus protect the environment and consumer health. The aim of this study was to evaluate a hitherto unexplored effect of hydrolysates obtained after biodegradation of chicken feather waste by a soil strain of the keratinolytic fungus Trichophyton ajelloi on germination, early growth, and development of plants, in particular with high sulfur requirements, and to verify, in model conditions, their impact on soil biological activity and the total pool of soil DNA. Undiluted and diluted keratin hydrolysate generally stimulated seed germination as well as root and shoot growth of the Lepidium sativum L. (garden cress) and Brassica napus L. var. napus (oilseed rape) on sandy soil (Cambisol I), loamy soil (Cambisol II), and Chernozem. In the model experiment, in the variants with and without oilseed rape on sandy soil and Chernozem, the introduction of keratin hydrolysate generally increased the total abundance of microorganisms. In sandy soil, feather hydrolysate mostly increased respiratory activity, dehydrogenase activity, and alkaline phosphatase activity by an average of approx. 38% and the total DNA pool by 15% and 23% in the variant with and without plants. The activity of protease and acid phosphatase increased by an average of 4% and 6% only in the variant without oilseed rape. Respiratory and enzymatic activity in Chernozem, in the variants with and without oilseed rape, tended to show a downward trend, despite periodically recorded increases. The total DNA pool has increased by 8% in the oilseed rape variant. Oilseed rape biomass was almost two-fold higher after adding feather hydrolysate to both soils, and its yield was higher by 98% in Chernozem than in sandy soil. The results have demonstrated that keratin hydrolysate can be used as a biofertilizer. [ABSTRACT FROM AUTHOR]

Purpose: Oxybenzone has received widespread attention owing to its extensive accumulation in the soil and adverse effects on plant growth. The aim of the study was to verify the potential of tobacco (Nicotiana tabacum) combined with the use of adenine and plant growth-promoting rhizobacteria (PGPR) (Methylophilus sp. strain FP-6) to enhance the efficiency of oxybenzone removal from the soil, and investigate the interaction between adenine and strain FP-6 that occurred during the phytoremediation process. Methods: First, we determined whether the presence of adenine stimulated the growth and plant growth-promoting (PGP) traits of strain FP-6, which was isolated in our previous study and demonstrated considerable potential for the degradation of oxybenzone. The combined effects of strain FP-6 and adenine on the growth of tobacco and the efficiency of oxybenzone removal from the soil were then investigated. Furthermore, we evaluated the soil enzyme activities and microbial community composition in tobacco-growing soil containing oxybenzone. Results: The adenine-FP6 amendment significantly improved photosynthetic efficiency and maintained the ion homeostasis of tobacco, which was destroyed by oxybenzone, thereby promoting the efficiency of phytoremediation of oxybenzone by tobacco (97.99%). Furthermore, a series of hydrolases involved in nutrient cycles and oxidoreductases with high reactivity to phenolic compounds in the soil were significantly up-regulated under this remediation strategy, which might be attributed to the increased relative abundance of some rhizosphere bacteria, such as Faecalibacterium, Agathobacter, and Sphingomonas. Conclusion: The findings of this study provide an economical and ecological phytoremediation strategy for the efficient remediation of oxybenzone -contaminated soils. [ABSTRACT FROM AUTHOR]

There is an argent need to find safer, environmentally friendlier as well as efficient alternatives. Effect of some fumigants on activities of dehydrogenase (DHase), peroxidase (POD), and polyphenol oxidase (PPO) in soil was carried out. Three types of fumigants were tested: true-fumigants; dimethyl disulfide (DMDS), fumigant generators, phosphine (PH3), 1,4-Dichlorobenzene (1,4-D), and formaldehyde (CH2O), and bio-fumigants an essential oil of garlic, jojoba, citrus, and argan. Mini-atmosphere method was used for fumigant generators and soil drench method was used for true- and bio-fumigants. The results revealed that DMDS at concentration of 2000 and 20 mg/kg inhibited soil enzymes within the first four days, then reach the level of the enzymatic activity of a control soil sample. Almost the same trend of the effect of phosphine was obtained from either aluminum phosphide (AlP) or zinc phosphide (Zn3P2). Phosphine at 5 mg/L caused an increase in the DHase, POD and PPO activities while, at 150 mg/L, it caused inhibition approximately of 25%. Various essential oils proved to be harmless or very low effect for the soil enzymes. For the effect of all fumigants, the maximum enhancement percentage in the DHase was 37.5% while the maximum inhibition was 25%. Also, the maximum induction was 30% while the maximum reduction in POD activity was 42%. In addition, 48% and 40% were the maximum of stimulation and reduction, respectively in the PPO. Therefore, the activities of DHase, POD, and PPO found to be sensitive to fumigants and proved to be a good indicator of the degree of soil contamination with tested fumigants. [ABSTRACT FROM AUTHOR]

Afforestation of subtropical grasslands increased during the last decade and their impacts on soil biota and functions are not well known. Here we investigated the effects of grassland afforestation with Eucalyptus on soil Collembola communities in southern Brazil. By using paired transects (native grassland vs. plantation), we assessed Collembola taxonomic and functional composition and diversity and their relations with plant diversity and soil microbial and physical–chemical parameters. Eucalyptus plantations significantly decreased plant richness, soil pH, and soil temperature. Microbial biomass, soil basal respiration and enzyme activities were negatively affected by grassland afforestation, which may indicate an effect on decomposition, soil fertility, and carbon stock. At a regional scale, grassland afforestation diminished the richness, and at a local scale changed the taxonomic and functional composition of Collembola communities. An environmental filtering mechanism is suggested triggering trait turnover from open (grassland) to a closed canopy habitat (tree plantation). While grassland presented high abundance of larger, eyed, and pigmented Collembola, Eucalyptus favored smaller, blind, and non-pigmented Collembola with shadow-adapted sensorial structures. Our results on afforestation effects in subtropical grasslands are similar to those described for temperate zone, and may underpin the development of conservation strategies for land-use on subtropical grasslands. [ABSTRACT FROM AUTHOR]

Mining bodies as remains of mining activities are a source of risk elements that contaminate individual components of the environment and may seriously danger human health. The mining area of Dubnik opal mines (Eastern Slovakia) is known for mining gold, silver, and antimony, but above all, it is a world-famous opal deposit. The study aims to determine the content of risk elements (As, Cd, Cu, Fe, Hg) in soils taken from mining bodies (6 heaps of mining material, 6 open mining pits) and to evaluate their impact on the activity of soil enzymes (urease, acid, and alkaline phosphatase, fluorescein diacetate, and β-glucosidase), nutrient content (Na, K, Mg, Ca) and soil reaction (pH). The aim of the research was also to compare the state of pollution between two types of mining bodies and the influence of pollution on selected soil characteristics. The content of hazardous substances in the soils reached extremely high and above the limit values, especially on the heaps of mining material. Urease was evaluated as the most sensitive soil enzyme while β-glucosidase showed the highest resistance to contamination. The content of Na, K, and Mg was significantly higher on the heaps of mining material compared to open mining pits. [ABSTRACT FROM AUTHOR]

In cropping systems, the choices adopted for the tillage system used and plants cultivated can strongly influence the soil microbial population and its functional profile. Arbuscular mycorrhizal fungi are an important component of soil microbiome and their mutualistic symbiosis with the majority of higher plants grant the latter a wide range of benefits. The extraradical mycelium developed by these fungi expands the volume of soil influenced and harbours a diversity of microbes establishing a distinct environment of complementary interactions. We assessed how growing plants with different levels of mycotrophy modifies the biological activity profile in the soil under Mn toxicity and whether this is modified by soil disturbance. Following mycotrophic plants, soil contained a more active microbiome than after the non‐mycotrophic plants, as expressed by higher values of soil basal respiration or dehydrogenase activity. Additionally, the count of phosphorus solubilizes and activity of phosphatase were greater after mycotrophic plants. Even among mycotrophic plants, different profiles of biological activity can be distinguished after growing a legume or grass. ERM disruption by soil disturbance decreased most of the parameters studied and for phosphatase activity and P solubilizers in a more significant way. These results indicate that even under Mn toxicity, the microbiome associated with AMF symbiosis following mycotrophic plants growth presented a higher biological activity and had a differential biological response towards the stress imposed by soil disturbance, when compared with the microbiome associated with non‐mycotrophic roots. [ABSTRACT FROM AUTHOR]

Natural products such as wood distillate (WD) are promising alternatives to xenobiotic products in conventional agriculture and are necessary in organic farming. A field study gave insight into the effectiveness of WD applied as foliar spray (F-WD), soil irrigation (S-WD), and their combination as growth promoters for field beans. The soil fertility and quality parameters, plant growth, nutrient uptake, and resource partitioning within plants were evaluated. In a pot trial, we tested the effect of S-WD on root nodule initiation and growth. S-WD increased DOC and microbial biomass by approximately 10%, prompted enzyme activities, and increased nitrate and available phosphorus in soil, without affecting the number and growth of nodules in field beans. In contrast, the F-WD slightly reduced the DOC, exerted a lower stimulation on soil enzymes, and lowered the soil effect in the combined distribution. In field beans, the F-WD reduced the stem height but increased the number of pods per stem; S-WD increased the N and P concentrations of leaves and the N concentration of the pods. Moreover, all WD treatments retarded plant senescence. The WD revealed itself to be promising as a growth promoter for grain legumes, but further research is needed to understand the interference between the combined soil and foliar applications. [ABSTRACT FROM AUTHOR]

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While irrigation with treated wastewater and using farmyard manure are important in the effective use of resources, this dual considers a more economical strategy by improving the soil properties thus increasing the yield. However, soil-sourced CO2 production that may occur in this case reveals the risks of both global warming and infertility of the soils with carbon loss from the soil. In this case, biochar, an organic improver, provides carbon sequestration, reducing emissions and maintaining soil fertility. However, the emission-reducing and soil-improving effects of the biochar, which is prepared by the pyrolysis of organic-raw-material at different temperatures, are not clear depend on the pyrolysis temperatures. In this study, the emission-reducing and improving physical-chemical properties and enzyme activity of soil by mixing farmyard manure and its biochars prepared at different temperatures into the soil irrigated with treated wastewater were investigated. The results showed that the biochar prepared at low pyrolysis temperatures had a higher improvement effect on the porosity, wet aggregate stability, organic matter/carbon, total N and cation exchange capacity of soil, and biochar prepared at high temperatures increased the EC and pH of the soil more, while the application of biochar prepared at low temperatures to the soil resulted in a decrease in bulk density of the soil. In addition, while the highest enzyme activities were obtained from farmyard manure, the biochar prepared at low temperatures increased the enzyme activity of the soil more than high temperatures. The improvement in soil properties was higher in irrigation with treated wastewater according to fresh water but it caused 42.7% more CO2 production from soil. While 20.6% to about 2 times more soil CO2 production was obtained from farmyard manure according to soil and biochar treatments, its biochars significantly reduced CO2 emissions and the emission-reduction effect of biochars with increasing pyrolysis temperature was further increased. Considering that biochar prepared at low temperatures supports the improvement in soil properties but causes higher CO2 production, in the irrigation conditions with treated wastewater, the use of farmyard manure biochar prepared at high temperatures was found to be advisable to improve agricultural and environmental sustainability. [ABSTRACT FROM AUTHOR]

Antibiotic accumulation in plants and soils is an increasing problem in agriculture and is receiving more attention. However, the effects of beneficial symbiotic fungi on the accumulation of antibiotics in plant organs and recovering soil microbial activities have not been adequately investigated. For these purposes, a pot experiment was conducted as a completely randomized design with a factorial arrangement and three replicates. The first factor was the fungus type (non-inoculated control, Funneliformis mosseae, and Serendipita indica) and the second factor was the types of antibiotics (without antibiotics, 50 and 100 mg kg−1 of tetracycline or chlortetracycline). We measured the accumulation of antibiotics in shoots of lettuce (Lactuca sativa) and microbial activities (activities of urease, dehydrogenase, catalase, total enzyme activity (TEA) index, and microbial biomass carbon (MBC)) in soil. Both levels of tetracycline and chlortetracycline diminished the shoot dry biomass of lettuce and root colonization with F. mosseae and S. indica. Inoculation of lettuce with both symbiotic fungi improved plant growth in soils amended with antibiotics compared to non-inoculated treatment. F. mosseae and S. indica increased the accumulation of antibiotics in the shoots. For example, the F. mosseae and S. indica increased the accumulation of tetracycline at the amended level of 100 mg kg−1 by 44.6% and 55.9% compared to the non-inoculated control treatment, respectively. Both fungi recovered urease activity and TEA index and did not affect oxidoreductase activity and MBC in soil. Enzyme activities positively correlated with shoot dry biomass, and negatively correlated with antibiotic accumulation in the shoots. We concluded that symbiotic fungi probably control lettuce growth and antibiotic accumulation in shoots by altering rhizosphere enzyme activities. [ABSTRACT FROM AUTHOR]

Long-term and high-intensity application of inorganic fertilizer leads to a strong variation of soil characteristics. The changes in soil chemical and biological properties can significantly affect the yield of Eucalyptus plantation. However, the mechanism of soil chemical properties affecting wood volume mediated by biological factors is not clear. The purpose of this study was to identify which soil properties were affected by different fertilization intensities and to disentangle the dominant factors affecting Eucalyptus volume. After clear felling evergreen broad-leaved forest, a Eucalyptus plantation was established that was coppiced every 5 years and fertilized every year. Within this plantation, areas with different treatments were established. These treatments were a 5-year growth period (low); two times 5-year growth period (medium); and three times 5-year growth period (high). In each treatment area and in a nearby evergreen broad-leaved forest (EBLF Control), five sample plots per treatment were set up. Various biological and chemistry analyses (18 in total) were related to determining the most important path and index for optimizing Eucalyptus plantation. The analysis of variance of enzyme activity and microbial biomass showed that the soil biological characteristics decreased over 10 years of plantation, and the enzyme activity was close to the state of EBLF control in medium, while the microbial biomass failed to return to its original state during continuous planting. Redundancy analysis results show that there was a strong correlation in chemical indicators and biological characteristics. Partial least square structural equation model showed that total phosphorus, nitrate nitrogen, urease, catalase, and microbial biomass nitrogen and phosphorus were the most influential soil biochemical factors, and the indirect effect of chemical properties on volume was achieved by microorganisms through enzyme activity. Continuous planting and large-scale application of inorganic fertilizer would lead to a decrease in plantation yield and fertilizer utilization efficiency and would affect the microbial biomass and enzyme activity by destroying the stability of soil chemical properties. [ABSTRACT FROM AUTHOR]

To understand the plant (Vigna unguiculata) and plant-growth promoting bacteria (PGPB) (Microcococcus luteus WN01) interactions in crude oil contaminated soil, experiments were conducted based on the newly designed rhizobox system. The rhizobox was divided into three main compartments namely the rhizosphere zone, the mid-zone, and the bulk soil zone, in accordance with the distance from the plant. Plants were grown in these three-chambered pots for 30 days under natural conditions. The plant root exudates were determined by analyzing for carbohydrates, amino acids, and phenolic compounds. The degradation of alkane, polycyclic aromatic hydrocarbons (PAHs), and total petroleum hydrocarbons (TPHs) were quantified by GC-FID. Soil catalase, dehydrogenase, and invertase activities were determined. The microbial community structure was assessed using denaturing gradient gel electrophoresis (DGGE). Results showed that the inoculation of M. luteus WN01 significantly enhanced cowpea root biomass and exudates, especially the phenolic compounds. Bioaugmented phytoremediation by cowpea and M. luteus promoted rhizodegradation of TPH. Cowpea stimulated microbial growth, soil dehydrogenase, and invertase activities and enhanced bacterial community diversity in oil contaminated soil. The rhizosphere zone of cowpea inoculated with M. luteus showed the highest removal efficiency, microbial activities, microbial population, and bacterial community diversity indicating the strong synergic interactions between M. luteus and cowpea. This is the first study to characterize the rhizosphere effect of cowpea on microbial activities, population, and community structure in crude oil contaminated soil in the presence and absence of PGPB, M. luteus WN01. The rhizosphere of cowpea was found to be a degradation hotspot where microbial abundance and metabolic activities were most active. Cowpea-M. luteus association can be a good candidate that can be implemented in real field sites. [ABSTRACT FROM AUTHOR]

Weeds result in a significant yield loss in mungbean (Vigna radiata [L.] R. Wilczek). However, post‐emergence (POST) herbicides are limited in mungbean for broad‐spectrum weed control. Therefore, we evaluated the efficacies of different herbicides in mungbean to find a suitable broad‐spectrum POST herbicide. Nine herbicides, weed‐free check, and unweeded control treatments were tested in a randomised block design with three replications for two consecutive years. Among the tested herbicides, clodinafop‐propargyl + sodium‐acifluorfen 122.5 g a.i. ha−1 applied at 15 days after sowing (DAS) reduced the broad‐leaved weed dry weight at 35 DAS and harvest by 55.8% and by 58.6% (p < 0.05) compared with the unweeded control respectively. Notably, it minimised the total weed dry weight by 23.1%–30.3% compared with the recommended herbicide pendimethalin 1 kg a.i. ha−1 – quizalopfop‐p‐ethyl 100 g a.i. ha−1 (p ≤ 0.05). Clodinafop‐propargyl + sodium‐acifluorfen had higher weed control index (58.2% at 35 DAS and 62.1% at harvest) over the remaining tested herbicides. Unweeded controls resulted in 51% yield loss compared with the clodinafop‐propargyl + sodium‐acifluorfen that did not differ from pendimethalin − quizalofop‐p‐ethyl for seed yield of mungbean. Decreasing order of treatment efficacy on mean grain yield across two years comprised the weed‐free check, clodinafop‐propargyl + sodium‐acifluorfen and pendimethalin − quiza‐lofop‐p‐ethyl, imazethapyr + imazamox, tembotrione, and topramezone. [Correction added on 10 November 2022, after first online publication: In the preceding sentence, changes have been made to the article content to improve clarity in this version.] Application of clodinafop‐propargyl + sodium‐acifluorfen led to the greatest increase in soil microbial biomass carbon, indicating higher levels of soil biological and rhizospheric activity. We suggest that clodinafop‐propargyl + sodium acifluorfen is a suitable broad‐spectrum option for weed management of mungbean. [ABSTRACT FROM AUTHOR]

Cover crops serve as an essential source of nutrients in the soil and generally improve the soil's properties. Cover crops' production is considered a benefit of the soil quality; by protecting the soil from erosion, reducing the weeds and the so-called soil-borne plant pathogens. Different varieties of cover crops can be cultivated such as legumes, non-legumes, brassica, and grass-type of plants with a variability of the symbiosis. A pot experiment was carried out with five cover crops, as non-symbiont (Brassica carinata B.c.), single-symbiont with arbuscular mycorrhiza fungi (AMF) (Phacelia tanacetifolia P.t., Avena strigosa A.s.) and double symbiont with AMF and nitrogen-fixing bacteria (Vicia benghalensis V.b., Vicia faba V.f.) crops; and a mixture of the five species, placed in sandy soil (arenosol) in plastic pots (5000 g soil) in 4 repetitions. One of the pots with mixed cover crops was inoculated by AM fungi industrial product. We measured soil biological activity of dehydrogenase (DHA) and fluorescein-diacetate (FDA) enzymes, the frequency of AM fungi (F%), the all protein, glomalin content and electrical conductivity (EC) of the soils. Mixture of all the cover crops resulted maximum EC and significantly enhanced the enzymatic, DHA, FDA activities in comparison with single plants. Mycorrhiza colonization frequency was high in all cover crops except the mustard (B.c.), as non-symbiont. Vetch (V.b.), as double symbiont was responding very positively to AMF inoculation, and enhanced the performance of its growth. It was found in the pot experiment, that vetch, has the highest capacity to retain soil-protein, glomalin concentration, as well. The mixture of five cover crops could be suggested to use, due to the synergistic positive performance of the individual crops, and the better functioning of beneficial fungal / bacterial symbiosis. [ABSTRACT FROM AUTHOR]

Crop varieties resistant to multiple herbicides have been developed to provide better control of weed populations in row-crop fields where glyphosate resistance has become common. These new varieties include lines of maize (Zea mays) resistant to both glyphosate and 2,4-dichlorophenoxyacetic acid (2,4-D). As these herbicides have the potential to impact microbial communities in soil, there is concern that their co-application may have a greater effect on activities linked to soil nutrient cycling than if they were applied individually. To investigate this possibility, a field study was conducted on 2,4-D+glyphosate-resistant maize to determine the impact of 2,4-D alone and 2,4-D+glyphosate on extracellular enzyme activity in both bulk and rhizosphere soil. Maize was treated at the V2 and V8 developmental stages. Changes in soil activities were small in magnitude and inconsistent between timepoints. 2,4-D+glyphosate-treated plots had higher beta-glucosidase, cellobiohydrolase, and phosphatase activities, but only after the V2 application in bulk soil in the first year of the study, while no significant effects were observed in the rhizosphere. Enzyme activities were more impacted by soil organic matter than herbicide treatments. These results suggest that, when applied at label rates, 2,4-D+glyphosate application will not adversely affect soil microbial enzyme activities. [ABSTRACT FROM AUTHOR]

In order to study the effect of green manure return for stabilized spring maize (Zea mays L.) grain yield (GY) we reduced nitrogen fertilizer input by regulation and examined effects on soil nutrients, enzyme activity, and fungal communities. This two-year field experiment was conducted in the North China Plain. The field experiment was undertaken with a split-plot design; the primary plots were winter fallow (WF) and green manure (GM), and the split-plots were five N application rates of 0 (N0), 189 (N189), 216 (N216), 243 (N243), and 270 (N270) kg ha−1. The results showed that, spring maize GY under GM treatments (GYGM) were significantly increased by 5.38–11.68% more than WF treatment (GYWF), and GYWF and GYGM significantly increased by 35.9–91.5% and 80.1–135.5% across all N treatments. By linear-platform model analysis, spring maize under GM treatments obtained higher GY, reaching 1270.5–14,312.2 kg ha−1 with optimized N application rate at 238–265 kg ha−1, which resulted in a GY higher than WF (11,820.0 and 13,654.2 kg ha−1) and N reduced 11.2% (238 vs. 268 kg ha−1). GM treatment significantly increased soil organic carbon by 3.90–12.23% more than WF over all N application rates, and total nitrogen and available nitrogen were significantly increased by 3.79–15.76% and 4.87–17.29%, with total phosphorus and available phosphorus for GM higher than WF by 6.1–13.6% and 9.6–5.3%, respectively. However, there were lesser effects of GM on total potassium and available potassium. Compared to WF, soil catalase, sucrose, urease, and alkaline phosphatase activity were significantly increased by 6.2–16.4%, 5.8–48.1%, 3.3–21.5% and 11.5–82.3%, respectively, over all N application rates under GM over two years. GM increased Zygomycota and Basidiomycota relative abundances significantly, and reduced Thielavia, unclassified fungi, and Podospora relative abundances by 35.35%, 52.92% and 52.77% more than WF treatment, respectively. In summary, due to the GM return into fields, increased soil nutrients were available, which were positively affected by soil enzyme activity and fungal communities, and reduced nutrient requirements, and so the farmers could obtain a spring maize grain yield higher than 14,000 kg ha−1 with a reduced 11.2% N application rate from 268 kg ha−1 to 238 kg ha−1 by sowing winter green manure for a long time period in the North China Plain. [ABSTRACT FROM AUTHOR]

Aims: Soil microbial communities are among the most diverse communities that might be affected due to transgenic crops. Therefore, risk assessment studies on transgenes are essentially required as any adverse effects may depend not only on the specific gene and crop involved but also on soil conditions. Methods and results: The present study deals with the comparison of bacterial populations, root exudates and activities of soil enzymes in nontransgenic and AVP1‐transgenic wheat rhizosphere, overexpressing vacuolar H + pyrophosphatase for salinity and drought stress tolerance. Amounts of organic acids and sugars produced as root exudates and activities of dehydrogenase, phosphatase and protease enzymes in soil solution showed no significant differences in AVP1‐transgenic and nontransgenic wheat rhizosphere, except for urease and phenol oxidase activities. The higher copy number of nifH gene showed the abundance of nitrogen‐fixing bacteria in the rhizosphere of AVP1‐transgenic wheat compared with nontransgenic wheat. nifH gene sequence analysis indicated the common diazotrophic genera Azospirillum, Bradyrhizobium, Rhizobium and Pseudomonas in AVP1‐transgenic and nontransgenic wheat except for Zoogloea detected only in nontransgenic wheat. Using 454‐pyrosequencing of 16S rRNA gene from soil DNA, a total of 156, 282 sequences of 18 phyla were obtained, which represented bacterial (128,006), Archeal (7928) and unclassified (21,568) sequences. Proteobacteria, Crenarchaeota and Firmicutes were the most abundant phyla in the transgenic and nontransgenic wheat rhizosphere. Further comparison of different taxonomic units at the genus level showed similar distribution in transgenic and nontransgenic wheat rhizospheres. Conclusion: We conclude that the AVP1 gene in transgenic wheat has no apparent adverse effects on the soil environment and different bacterial communities. However, the bacterial community depends on several other factors, not only genetic composition of the host plants. Significance of the study: The present research supports introduction and cultivation of transgenic plants in agricultural systems without any adverse effects on indigenous bacterial communities and soil ecosystems. [ABSTRACT FROM AUTHOR]

Plant rhizo‐microbiome comprises complex microbial communities that colonize at the interphase of plant roots and soil. Plant growth‐promoting rhizobacteria (PGPR) in the rhizosphere provide important ecosystem services ranging from the release of essential nutrients for enhancing soil quality and improving plant health to imparting protection to plants against rising biotic and abiotic stresses. Hence, PGPR serve as restoring agents to rejuvenate soil health and mediate plant fitness in the facet of changing climate. Though it is evident that nutrient availability in soil is managed through inter‐linked mechanisms, how PGPR expedite these processes remain less recognized. Promising results of PGPR inoculation on plant growth are continually reported in controlled environmental conditions, however, their field application often fails due to competition with native microbiota and low colonization efficiency in roots. The development of highly efficient and smart bacterial synthetic communities by integrating bacterial ecological and genetic features provides better opportunities for successful inoculant formulations. This review provides an overview of the interplay between nutrient availability and disease suppression governed by rhizobacteria in soil followed by the role of synthetic bacterial communities in developing efficient microbial inoculants. Moreover, an outlook on the beneficial activities of rhizobacteria in modifying soil characteristics to sustainably boost agroecosystem functioning is also provided. [ABSTRACT FROM AUTHOR]

Abstract Background Ratooning in sugarcane is a crucial strategy for ensuring the long-term sustainability of the sugarcane industry. Knowledge gap relating to the interaction between rhizosphere microbiome and ratooning crop, particularly the impact of different sugarcane cultivars on the rhizosphere microbiome in consecutive ratooning, requires additional research. The response of two different sugarcane cultivars, viz ZZ-1 and ZZ-13, were evaluated in consecutive ratooning towards the rhizosphere microbial community and cane morphological characters. Results Significant changes in the rhizosphere microbiome were observed in the second ratooning over the years. Several important genera were observed in high abundance during the second ratooning, including Burkholderia, Sphingomonas, Bradyzhizobium, and Acidothermus. Cultivar ZZ-13 caused more alterations in the rhizosphere microbiome than ZZ-1, resulting in a more favorable rhizosphere environment for sugarcane growth. The genotypes also varied in terms of nutrients and enzyme activity over the years. There were significant differences between the genotypes and year for number of stalks and yield was significant for genotypes, years and genotype × year. Conclusion This finding will help to understand thorough interactions between rhizosphere microorganisms and ratoon sugarcane and lay the foundation for promoting and maximizing yield as far as possible. In the future, this work can serve as guidance in sugarcane husbandry, mainly in Guangxi, China.

Legumes in cropping sequence can strongly moderate soil biodiversity and its biochemical status, which could influence soil fertility and productivity. However, their impact on soil microbes and their relationships with soil chemical variables during the subsequent crop growth is not understood enough. In this study, we analyzed the changes in bacterial and fungal communities structure through 16S rRNA and ITS amplicon sequencing, respectively, across crop rotation with faba bean (faba bean-wheat-triticale, F) and without faba bean (wheat-wheat-triticale, W). Rhizosphere and bulk soil samples were taken during the triticale growth stages (stem elongation and maturity). Soil enzymatic activity and chemical properties were also determined. Study factors (crop rotation, soil compartment, growth stage) affected N, C, and P transformations, as indicated by the activity of soil enzymes, and F was more beneficial than W for protease, urease, and acid phosphomonoesterase activities, as opposed to cellulase activity. Changes in the chemical properties led to the shift in soil microbial communities with different bacterial and fungal communities' responses. F treatment enhanced the abundance of the bacterial genera representatives such as Streptomyces and Candidatus Udaeobacter while suppressing the abundance of Jatrophihabitans and Terrabacter. Crop rotation significantly influenced fungal genera and a greater abundance of Helgardia, Pseudogymnoascus, Monocillium, Fusarium, Chaetomium, and Vishniacozyma under F than W was noted and the adverse situation was noted for Peziza and Rhizopus. Rotation type significantly affected the alfa-diversity of the fungal, but not bacterial community. Beta-diversity analyses (nMDS, cluster) indicated that the main factor grouping samples were soil compartment and growth stage for the bacterial and fungal microbiome, respectively. The PERMANOVA results revealed significant effects of all factors on bacterial and fungal microbiomes. Different soil chemical variables governed bacterial and fungal communities. C org , pH, P, Mg, and C org , pH were the most important soil factors regulating bacterial and fungal community structure by crop rotation, respectively. Bacterial and fungal communities were more related to the content of N tot in rotation with than without faba bean. The findings of this study contribute to a deeper insight into the relation between the faba bean in cropping sequence and soil microbiome, and modulation crucial soil conditions for the productivity of the successive crop. • Crop rotation significantly affected fungal alfa-diversity, not bacterial community. • C org , pH, P, Mg shaped bacterial, and C org , pH fungal communities by crop rotation. • Soil N tot correlated more with microbial genera in rotation with than without faba bean. • Soil compartment and growth stage influenced the microbiome more than crop rotation. • Soil Mg and N tot mostly contributed to the dissimilarity between crop rotations. [ABSTRACT FROM AUTHOR]

• Meta-analysis of foliar index and harvest metrics in apple based intercropped systems was carried out. • Potential of legumes, pulses and millets in cultivation pattern in apple were determined. • Relationship studies and PCA amongst CS vis-a-vis apple productivity were also determined. Crop diversification is a mutual beneficial approach that improves agricultural resilience while promoting food security, livelihood income, and environmental enhancement. Six apple-based cropping systems (CS) in dry temperate ecosystem of Himachal Pradesh, India were selected. The companion (intercrops) comprising were peas, kidney beans, barley, maize, buckwheat and garlic along with apple monoculture as control. The representative sample size of five sub-locations from three blocks in Kinnaur district viz. , Nichar, Kalpa and Pooh each with four orchards were selected. Based on the apparent performance of trees, the optimal sample size from each of total 60 apple orchards were determined. The study assessed the nutrient availability potential of legumes, pulses and millets-based cropping systems with regard to foliar nutrient indicators, enzymatic assessment and cultivation pattern. Fruit set and yield in apple + pea CS was determined to be 2.70, 3.78 and 3.45, 7.47 times higher than apple + buckwheat CS. Leaf N, P and K content varied from 1.85–2.36, 0.157–0.200 and 1.24–1.51 per cent, respectively. In addition, 10AM fungal species of five different genera namely, Glomus, Gigaspora, Scutellospora, Sclerocystis and Acaulospora were isolated, identified and characterized. The activity of alkaline and acid phosphatase in the rhizosphere was increased in apple + pea CS by 32.62 and 33.09 per cent, respectively. DOP indexing indicated that foliar supplementation from cropping systems in apple trees led to elevated concentrations of N, Fe, Zn and Cu in leaves. The positive and statistically significant relationship was also found between fruit yield and leaf nutrient content. Multiple regression analysis revealed that generative traits and leaf nutrient content collectively contributed to the variation in fruit yield of apple trees. Furthermore, path analysis revealed that leaf nutrient content and generative traits exerted a positive and direct influence on yield. The cropping systems that were utilised have exhibited a prime effect on soil enzymatic activity in rhizosphere, cropping behaviour, nutrient availability and residue management. Consequently, the study has drawn the conclusion that adopting apple CS could substantially boost fruit yield and crop efficiency, enabling an effective alternative for conventional farming. The demands of rural livelihoods could be satisfied by this shift, particularly in fragile dry temperate ecosystem. [ABSTRACT FROM AUTHOR]

Sustainable management of the Amazon rainforest is fundamental for supporting life on earth because of its crucial role in sequestering carbon. One of the species grown in the forest is açaí (Euterpe oleracea), which is an important food and income source for its inhabitant. The acai seed, resulting from the processing of the fruit, is a solid organic residue, which has been an agent of undesirable environmental impacts such as natural landscape modifications, clogging sewers and water courses, eutrophication of surface waters. In this research, we evaluated the use of wood chips as a source of energy in a rustic oven to produce acai biochar so that family farmers carry out sustainable management of the residue and use biochar to improve soil quality and produce seedlings of native plants to regenerate degraded forests. The experiment was conducted in Pará, Brazil, Amazon region, using a randomized complete block design. A factorial treatment structure was implemented consisting of four biochar particle sizes (3, 5, 7, and 12 mm), 4 application rates (4, 8, 16, and 32 t ha−1), and a biochar-free control, with 5 replications. The results showed that the methodology for biochar production was easy to apply and low cost, allowing its use by family farmers. The combination of biochar rate and particle size affected soil properties and the development of black pepper seedlings in different ways. The soil properties affected were water retention capacity, moisture, fluorescein diacetate hydrolysis and arylsulphatase activity. The growth parameters of the affected black pepper seedlings were height and root system development. [Display omitted] • Local production of biochar contributes to sustainable land use in the Amazon region. • Acai seed biochar improves soil quality and black pepper seedling growth. • Dead plant chips and a rudimentary oven produced good quality biochar. • The acai seed biochar rate-particle size combination differentially affects soil properties and seedling growth. • Acai management is a component of the green economy in the Amazon region. [ABSTRACT FROM AUTHOR]

The pasture management and desiccation times before sowing may affect the following grain crop in crop-livestock system. To explore the impacts of N fertilization applied to the palisadegrass (Urochloa brizantha) pasture and the desiccation time before soybean (Glycine max L.) sowing on attributes related to C and N cycling and on soybean yield, we conducted an experiment with palisadegras pasture grazed for 18 months receiving 300 kg ha−1 of N (+N, urea) or without N fertilization (–N), desiccated at 1, 15, 30, 45, or 60 days before soybean sowing. Assessments at the soybean sowing and at R3 stage showed that desiccation times had only minor effects on soil attributes. However, pasture N fertilization (+N) significantly decreased the soil basal respiration (9.6 vs 8.4 μg g−1 day−1 of CO 2 -C) at soybean sowing; at R3, +N decreased soil organic C (20.8 vs. 19.7 g kg−1), total N (2.1 vs. 2.0 g kg−1), and urease activity (62.6 vs. 42.4 μg g−1 h−1 of NH 4 +-N). Conversely, +N increased labile C (164 vs. 346 mg kg−1) at R3, and nitrification rate at sowing (6.6 vs. 11.6%) and R3 (2.32 vs. 5.26%). Ammonification rate increased at sowing (0.02 vs. 0.03 μg g−1 day−1 of NH 4 +-N) due to N fertilization but decreased at R3 (0.06 vs. -0.08 μg g−1 day−1 of NH 4 +-N). Besides causing negative variations in most of the soil attributes related to C and N cycling, fertilization of palisadegrass pasture with 300 kg ha−1 of N decreased soybean yield (5040 vs. 4770 kg ha−1). Desiccation times of palisadegrass did not affect the soil attributes related to C and N cycling and soybean yield so that short desiccation times before soybean sowing can optimize the forage use in the livestock phase and allow the biomass recovery after grazing for soil mulching in the no-till system of the integrated grain crop. [ABSTRACT FROM AUTHOR]

Crop rotation is an agronomic practice that can offer benefits such as increased soil aggregation, carbon storage, crop yield, nutrient transformation, and utilisation efficiency, alongside an increased abundance of microorganisms. As winter wheat is sensitive to certain forecrops, selecting suitable ones may influence productivity. This study assessed the impact of three forecrops on selected soil properties (carbon content, mineralisation, aggregate stability, and microbial biomass) at two soil depths and on wheat yield over three years. This approach introduced a novel evaluation of the interrelations between soil and crop traits. The experiment comprised the following variants: I. wheat after alfalfa (AW), II. wheat after maize (MW), and III. wheat in monoculture (WW). Compared to wheat following alfalfa, wheat monoculture displayed higher total carbon and total organic carbon and the lowest relative residual oxidisable carbon (among all variants) at depth 2 (0.15–0.30 m). In variants where wheat followed different forecrops, significantly higher carbon mineralisation activities were observed at depth 2. The greatest increases in dehydrogenase, basal, and L-alanine-induced respiration (IR) were in the depth 2 of the MW variant, whereas in depth 1 (0–0.15 m) in the AW variant, the highest L-arginine-IR and fungal biomass were recorded. The WW showed increased soil aggregate stability between depth 1 and depth 2. The MW variant did not exhibit a significant depth-dependent effect on most properties. High bacterial biomass was associated with carbon mineralisation and with an increased proportion of recalcitrant carbon in both forecrops (AW, MW). These variants improved crop yield, number of spikes, and thousand-grain weight compared to WW. While forecrop practices were only moderately effective in enhancing soil carbon storage and stabilisation at soil depth 2, they contributed positively to soil microbial abundance, mineralisation activity, and grain yield. [Display omitted] • Forecropping was beneficial to soil microbial abundance and activity. • Forecropping derived increased crop yield, number of spikes, thousand grain weight. • Alfalfa and maize forecrops increased carbon mineralization in soil 0.15–0.30 m deep. • Aggregate stability was directly depth-dependent in soil with wheat in monoculture. [ABSTRACT FROM AUTHOR]

This study evaluated the effectiveness of six Technosols designed for the remediation of polluted soils (PS) by metal(loid)s at physicochemical, biological, and ecotoxicological levels and at a microcosm scale. Technosols T1–T6 were prepared by combining PS with a mix of organic and inorganic wastes from mining, urban, and agro-industrial activities. After two months of surface application of Technosols on polluted soils, we analysed the soil properties, metal(loid) concentration in total, soluble and bioavailable fractions, soil enzymatic activities, and the growth responses of Trifolium campestre and Lactuca sativa in both the Technosols and the underlying polluted soils. All Technosols improved the unfavourable conditions of polluted soils by neutralising acidity, increasing the OC, reducing the mobility of most metal(loid)s, and stimulating both the soil enzymatic activities and growths of T. campestre and L. sativa. The origin of organic waste used in the Technosols strongly conditioned the changes induced in the polluted soils; in this sense, the Technosols composed of pruning and gardening vermicompost (T3 and T6) showed greater reductions in toxicity and plant growth than the other Technosols composed with different organic wastes. Thus, these Technosols constitute a potential solution for the remediation of persistent polluted soils that should be applied in large-scale and long-term interventions to reinforce their feasibility as a cost-effective ecotechnology.

The aim of this study was to reveal the decomposition differences of kiwifruit litters with different qualities and verify the “Initial Litter Quality Hypothesis”. This study took litters of ‘Jinkui’ and ‘Hort-16A’ kiwifruit as the research objects, and carried out in situ decomposition experiments. The decomposition rate, nutrients release process, and soil enzyme activities were analyzed. In this study, the litter of ‘Hort-16A’ kiwifruit decomposed faster than the litter of ‘Jinkui’ kiwifruit. The decomposition time was positively correlated with the initial concentration of C of the litters, but negatively correlated with the concentrations of N and P. Except for P and Mn, the dynamic trends of the nutrient concentrations were similar during the litter decomposition of ‘Jinkui’ and ‘Hort-16A’ kiwifruit. After 180 days of decomposition, about 85%~95% of the initial concentrations of the macro-elements of the ‘Hort-16A’ kiwifruit litter were released. The dynamic trends of protease activities were similar, but that of sucrase, β-1,4-glucosidase, polyphenol oxidase, and phosphatase were different. In conclusion, the litter quality of kiwifruit affects the decomposition rate, and the difference in decomposition rate in turn affects the dynamic processes of nutrient release and soil enzyme activity. This study provides evidence for the “Initial Litter Quality Hypothesis” in the orchard ecosystem.

Understanding the spatial–temporal variability of soil enzymatic activity and its relationship with nitrogen (N) resources in the soil and crop yield is crucial in rational management practices of mineral fertilization. The scarcity of comprehensive studies on geostatic analyses of agricultural soils and plant yields, which would take into account both temporal and spatial variability, was the reason for undertaking this research. The aim of this study was to determine the spatial and temporal variability of the activity of soil enzymes, such as acid (PAC) and alkaline (PAL) phosphatases, urease (URE) and protease (PROT), the content of N-NH4 (ammonium ions), N-NO3 (nitrate ions), phosphorus (P), pH, moisture, as well as crop yield on a conventionally managed farmland of 40 ha. During the two-year experiment, soil samples were collected from 37 measurement points. Wheat was the first tested crop, followed by oilseed rape. It was shown that all the tested soil parameters showed temporal and spatial variability, and a significant number of them were significantly higher in July. The creation of raster maps showing the distribution of the tested parameters allowed for the observation of the considerable activity of PAC, PAL, URE, and PROT, as well as a high application of N-NO3 in the southern part of the field during the growth of the plants. The statistical analysis revealed a negative interaction between the N-NH4 and N-NO3 and the urease in the soil under the cultivation of plants. The pH and the percentage of moisture in the soil also had higher values in the south of the field. This pointed to the existence of separate production zones in the south-central part of the field, characterized by a higher yield of wheat and rape. On the basis of the conducted research, it was unequivocally stated that the values of enzymatic and chemical parameters of the soil were reflected in the size of the yield obtained, which allows conclusions to be drawn with respect to the rational management of N in the production process, laying the foundations for precision agriculture.

Wood vinegar (WV) is a biostimulant and a biopesticide that contains pyroligneous acid and is used as a crop growth enhancer and biocontrol agent, but insufficient information exists on WV’s effects on soil quality and cowpea production in Ghana. A field study (2 years) was conducted to determine the appropriate method of applying WV for soil health and cowpea production, and to determine the economic benefits of WV. Assessments were on nodulation, shoot biomass, yield, value–cost ratio, soil enzymes, soil respiration, microbial biomass nitrogen (MBN), permanganate-oxidizable carbon (POXC), mineralizable C, soil pH, available nitrogen and phosphorus. Results revealed soil drenching and foliar application are efficient methods of applying WV to achieve greater shoot dry matter, nodulation and grain yield of cowpea. Economically, soil drenching, followed by foliar application, generated better economic returns than the control. Adding WV to cowpea using soil drenching and foliar application improved soil health indicators. Soil enzymes and MBN were enhanced by WV applied foliarly and through soil drenching. Soil drenching with WV produced greater POXC and mineralizable C compared to the other treatments. Conclusively, WV applied foliarly and through soil drenching improved soil health, nodulation and yields of cowpea, and enhanced profitability.

Negative public sentiment built up around bisphenol A (BPA) follows growing awareness of the frequency of this chemical compound in the environment. The increase in air, water, and soil contamination by BPA has also generated the need to replace it with less toxic analogs, such as Bisphenol F (BPF) and Bisphenol S (BPS). However, due to the structural similarity of BPF and BPS to BPA, questions arise about the safety of their usage. The toxicity of BPA, BPF, and BPS towards humans and animals has been fairly well understood. The biodegradability potential of microorganisms towards each of these bisphenols is also widely recognized. However, the scale of their inhibitory pressure on soil microbiomes and soil enzyme activity has not been estimated. These parameters are extremely important in determining soil health, which in turn also influences plant growth and development. Therefore, in this manuscript, knowledge has been expanded and systematized regarding the differences in toxicity between BPA and its two analogs. In the context of the synthetic characterization of the effects of bisphenol permeation into the environment, the toxic impact of BPA, BPF, and BPS on the microbiological and biochemical parameters of soils was traced. The response of cultivated plants to their influence was also analyzed.