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Agricultural practices significantly impact soil properties and ecological functions, highlighting the importance of comprehensive soil health assessments. Traditionally, these assessments have focused on physical and chemical indicators, often neglecting microbiological properties. This review explores the potential of microbiological indicators in evaluating the effects of agricultural practices on soil ecological functions, emphasizing their significance and addressing challenges associated with their application. A key advantage of microbiological indicators is their high sensitivity and rapid response to environmental changes. These indicators can be grouped into three categories: microbial biomass and abundance, microbial taxonomic composition and diversity, and microbial activity. Among these, microbial biomass carbon, basal respiration, and decomposition rates are considered the most reliable and interpretable indicators. Microbial taxonomic composition and diversity remain limited in their diagnostic and predictive capabilities due to challenges in interpretation. Integrating microbiological indicators offers a more holistic understanding of the interactions between agricultural practices and soil health, enhancing our ability to monitor, manage, and preserve soil ecosystems. To facilitate their adoption in agricultural production and land management, further efforts are needed to improve the interpretability of these indicators and to establish standardized criteria for soil health assessment. [ABSTRACT FROM AUTHOR]

The effect of land use on the formation of the metabolome of typical Chernozem is studied. Typical Chernozems (Haplic Chernozems) of four land uses—55-year-old permanent bare fallow, the plot untilled for 21 years after permanent bare fallow, and 4-year field experiments with zero tillage and traditional tillage—from the long-term field experiments at the Kursk Federal Agricultural Research Center (Cheremushki, Kursk oblast, Russia) are analyzed. To study the soil metabolome, the water extracts of both fumigated and nonfumigated soil samples are assayed for the contents of dissolved organic (DOC) and microbial biomass (Cmic) carbon species using high-temperature catalytic oxidation; the soil metabolites are analyzed using gas chromatography–mass spectrometry. The effect of postagrogenic Chernozem transformation on the accumulation of labile soil carbon species is demonstrated by the case study of the plot untilled for 21 years. Plowing of Chernozems in the absence of plant litter decreases the content of labile carbon. A positive effect of no-till practice on the content of labile carbon species is observable at the level of a trend. According to metabolomic analysis, 21 compounds involved in the metabolism of carbohydrates, lipids, and nitrogenous substances are identified in Chernozems. The Shannon diversity index shows that tillage has a negative effect on the complexity of metabolic profiles in Chernozems. Untilled Chernozems and those under permanent fallow conditions display the most contrasting metabolic compositions with the prevalence of metabolites having plant and microbial origin, respectively. The metabolites of a plant origin tend to accumulate in the chernozem under no-till conditions. The components of the carbohydrate metabolism are prevalent in the metabolomic profile of arable chernozemic soils and the components of nitrogen and lipid metabolism predominate in the untilled soils. [ABSTRACT FROM AUTHOR]

Biochar is well-accepted as a viable climate mitigation strategy to promote agricultural and environmental benefits such as soil carbon sequestration and crop productivity while reducing greenhouse gas emissions. However, its effects on soil microbial biomass carbon (SMBC) in field experiments have not yet been thoroughly explored. In this study, we collected 539 paired globally published observations to study the impacts of biochar on SMBC under field experiments. Our results suggested an overall positive impact of biochar (21.31%) on SMBC, varying widely with different climate conditions, soil types, biochar properties, and management practices. Biochar application exhibits significant impacts under climates with mean annual temperature (MAT) < 15 °C and mean annual precipitation (MAP) between 500 and 1000 mm. Soils of coarse and fine texture, alkaline pH (SPH), soil total organic carbon (STC) content up to 10 g/kg, soil total nitrogen (STN) content up to 1.5 g/kg, and low soil cation exchange capacity (SCEC) content of < 5 cmol/kg received higher positive effects of biochar application on SMBC. Biochar produced from crop residue, specifically from cotton and maize residue, at pyrolysis temperature (BTM) of < 400 °C, with a pH (BPH) between 8 and 9, low application rate (BAP) of < 10 t/ha, and high ash content (BASH) > 400 g/kg resulted in an increase in SMBC. Low biochar total carbon (BTC) and high total nitrogen (BTN) positively affect the SMBC. Repeated application significantly increased the SMBC by 50.11%, and fresh biochar in the soil (≤ 6 months) enhanced SMBC compared to the single application and aged biochar. Biochar applied with nitrogen fertilizer (up to 300 kg/ha) and manure/compost showed significant improvements in SMBC, but co-application with straw resulted in a slight negative impact on the SMBC. The best-fit gradient boosting machines model, which had the lowest root mean square error, demonstrated the relative importance of various factors on biochar effectiveness: biochar, soil, climate, and nitrogen applications at 46.2%, 38.1%, 8.3%, and 7.4%, respectively. Soil clay proportion, BAP, nitrogen application, and MAT were the most critical variables for biochar impacts on SMBC. The results showed that biochar efficiency varies significantly in different climatic conditions, soil environments, field management practices, biochar properties, and feedstock types. Our meta-analysis of field experiments provides the first quantitative review of biochar impacts on SMBC, demonstrating its potential for rehabilitating nutrient-deprived soils and promoting sustainable land management. To improve the efficiency of biochar amendment, we call for long-term field experiments to measure SMBC across diverse agroecosystems. Highlights: 539 field observations were synthesized to investigate biochar impact on the microbial biomass carbon. Biochar application increased microbial biomass carbon (SMBC), especially in degraded soil. Biochar impact on SMBC highly depended on the aging time of biochar in the soil. [ABSTRACT FROM AUTHOR]

Soil organic carbon plays an important role in climate change mitigation, and can be strongly affected by plant diversity. Although a positive effect of plant diversity on soil organic carbon storage has been confirmed in grasslands and forests, it remains unclear whether this effect exists in wetlands. In this study, we investigated plant diversity, soil properties and soil organic carbon across five typical wetlands of northern China, to test the effect of plant diversity on soil organic carbon and clarified the regulators. Increasing plant diversity significantly increased belowground biomass of wetland plant communities, and both soil organic carbon content and storage were significantly positively related to wetland plant diversity. The positive effect of plant diversity was influenced by belowground biomass of wetland plant communities, soil microbial biomass carbon, and soil properties, especially soil water content and bulk density. The structural equation model showed that soil organic carbon storage was dominantly affected by microbial biomass carbon, plant diversity and biomass, with standardized total effects of 0.66 and 0.47, respectively, and there was a significant positive relationship between soil organic carbon and microbial biomass carbon. These results suggest that increasing plant diversity can potentially promote the ability of wetlands to store organic carbon in soils. The findings highlight the importance of plant diversity on soil organic carbon in wetland ecosystems, and have implications for managing wetlands to increase carbon sinks and to mitigate global climate change. [ABSTRACT FROM AUTHOR]

Soil microbial biomass carbon (MBC) plays an essential role in driving and regulating global cycling of carbon (C) which is critically important to climate system. However, the pivotal transect-scale determinant factor for the content of soil MBC, along with the variation pattern in different natural forests and soils has not been sufficiently investigated. In this study, 252 soils samples (6 replicates and 3 depths for each site) were sampled from 14 forests which lie in 7 soil types along the 4000 km North-South transect of Eastern China. We found that the highest content of soil MBC in the whole soil profile with 556.69 ± 14.59 mg C kg− 1 occurred in the subalpine coniferous forest, and the lowest content was observed with 53.11 ± 10.22 mg C kg− 1 in warm coniferous forest. From the angle of soil type, in the whole soil profile Haplic Andosol had the highest content of soil MBC with 480 mg C kg− 1, while Haplic ferralsol possessed the lowest content of MBC with 102 mg C kg− 1. In addition, over the North-South transect of Eastern China the strongest correlation was observed in between the content of soil MBC and altitude (ALT) (R2 = 0.64), followed by soil type (R2 = -0.61), mean annual temperature (MAT) (R2 = -0.56). We concluded that the content of soil MBC in natural forests is mainly controlled by ALT on a transect scale. We believed that the soil C in Yue spruce-fir forest was relatively stable, which can be an option to be a specific forest to optimize forest management and to contribute to mitigating climate change. [ABSTRACT FROM AUTHOR]

Continuous agricultural activities lead to soil organic carbon (SOC) depletion, and agroecological intensification practices (i.e., reduced soil disturbance and crop diversification) have been suggested as strategies to increase SOC storage. The study aims to assess the effect of agroecological intensification levels (lower (T1) and highest (T2)) on the soil C pool and aggregate stability and validate the correlation between different variables compared to the control (lowest/none (T3), where agroecological intensification was not applied. The C-stock, soil microbial biomass carbon (SMB-C), SOC, water extractable organic carbon (WEOC) in bulk soil, fine and coarse soil aggregates, and water-stable aggregates (WSA) were measured during maximum nutrient uptake in plants under diversified agroecological practices across different environmental conditions (core sites: Italy (CS1), France (CS2), Denmark (CS4), Spain (CS5), Netherlands (CS6), Lithuania (CS7), Turkey (CS8), and Belgium (CS9)). The soil aggregate stability varied among the CSs and treatments. At sites CS7 and CS9, WSA was higher in T1 and T2 compared to the control; a similar trend was observed at other sites, except CS1. SMB-C differed among the core sites, with the lowest value obtained in CS5 (52.3 μg g−1) and the highest in CS6 (455.1 μg g−1). The highest average contents of SOC and WEOC were obtained in bulk soil at CS2 (3.1 % and 0.3 g kg−1 respectively). Positive and statistically significant (p < 0.001) correlations were detected among all variables tested with SOC in bulk soil and WSA. This study demonstrates the significance of agroecological practices in improving soil carbon stock and optimizing plant–soil–microbe interactions. [ABSTRACT FROM AUTHOR]

Agricultural Wastes, Co-products, and By-products (AWCB) can be recycled to produce profitable added-value products, such as organic fertilizers. Newly produced AWCB-based fertilizers were thus tested both under laboratory and field conditions in a two-year organic zucchini-lettuce rotation. In a split plot experimental design, the main-plot factor being the green manure (GM) presence or absence, the following fertilizing treatments were compared: (i) co-composted cattle manure anaerobic digestate; (ii) re-composted olive waste compost; (iii) a commercial dried manure organic fertilizer, and iv) a municipal solid waste compost. The aims were to assess: the potential C and N mineralization, changes on soil microbial and chemical properties and the crop yields. Moreover, the residual effect of the fertilization applied before zucchini transplanting on lettuce yield was evaluated. The composts and the commercial organic fertilizer did not significantly change the soil microbial and chemical properties, and crops yield. The GM was the most effective treatment, as highlighted by the highest microbial biomass carbon and dehydrogenase activity, the highest C and N input and the increase of soil TOC. Weather conditions may have contributed to a 55% higher zucchini yield in the second cropping cycle, despite the lowest soil mineral N in GM, and reduced the lettuce yield by 59%. The residual effect of the fertilization applied before zucchini did not affect the subsequent lettuce yield in the first year. In conclusion, AWCB-based fertilization can enhance the soil biochemical dynamics in organic vegetable systems, particularly combined with other agroecological practices, such as GM. Statement of Novelty: Agricultural Wastes, Co-products, and By-products (AWCB), generated in huge amounts along the agrifood systems, should be recycled to meet the circular economy principles, thus producing profitable added-value products in agriculture, such as organic fertilizers. Although the possible utilization of many AWCB in agriculture was already evaluated by many authors, there is a need of further knowledge on the main effects on the soil of newly produced AWCB-based fertilizers under Mediterranean conditions. This is also linked to the unpredictable behaviour of AWBC due to a wide variability in physicochemical and biological properties, depending on the treatment process and raw materials used. The lack of knowledge may lead to improper application to soil, resulting in low agronomic efficiency and environmental pollution. To allow efficient and environmentally sound waste recycling, laboratory or pot experiments were set up in other studies not combining both types of experimentation. By contrast, we combined laboratory incubation with field experiments in organic crop rotations, testing newly produced AWCB-based fertilizers directly related to farm reality and site-specific context. Highlights: Fertilizers can be produced also on-farm by recycling agricultural wastes. Combined incubation experiments and field trials on AWCB fertilizers were performed. AWCB and GM are effective agroecological practices in Mediterranean area. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The research was carried out to determine the potential effect of microbiota, organic carbon, percentage of moisture content, and microbial biomass concentration as an evaluator of variation in basal soil respiration rate. Relative distribution and composition of the microbial population were estimated from six different chronosequence manganese mine spoil (MBO0, MBO2, MBO4, MBO6, MBO8, MBO10) and forest soil (FS). The variation was seen in moisture content (6.494±0.210-11.535±0.072)%, organic carbon (0.126±0.001-3.469± 0.099)%, MB-C (5.519±1.371-646.969± 11.428) µg.g-1 of soil. A positive correlation was shown between OC with MB-C (r = 0.938; p< 0.01) and moisture content (MC) (r = 0.962; p< 0.01). Variation in the basal soil respiration (BSR) and microbial metabolic quotients (MMQ) was shown to range between 0.352 ± 0.007-0.958 ±0.014µg CO2-C.g-1 and 6.5× 10-3 - 1.481×10-3 µg CO2-C.g-1 microbial-C.h-1 with BSR: OC from (2.793-0.276)% respectively. This result shows that there is a gradual increase in OC, MC, MB-C, and BSR across seven different sites due to progressive enhancement in soil fertility that leads to the initialization of succession. Stepwise multiple regression analysis further confirms the degree of variability added by microbial biomass C, moisture content, organic carbon, and microbial population on basal soil respiration in microbes. Principal component analysis enables the differentiation of seven different soil profiles into independent clusters based on cumulative variance given by physico-chemical and microbial attributes that indicate the level of degradation of land and act as an index to restore soil fertility. [ABSTRACT FROM AUTHOR]

To explore the changes and main influencing factors of soil active carbon during the autumn freeze-thaw period of three forest types in the permafrost region of the Great Daxing'an Mountains, and to provide assistance for forest soil carbon sink management in the permafrost region. Taking the Larix gmelinii forest (LY), Pinus sylvestris var. mongolica forest (ZZ) and Betula platy⁃ phylla forest (BH) as the research objects, soil samples were taken from different soil layers (0-5, 5-10, and 10-20 cm) to determine the content of soil active carbon components (dissolved organic carbon, microbial biomass carbon, and readily oxidizable organic carbon) from October 10th to November 18th, 2022, and to explore their dynamic characteristics and influencing factors. Results showed that, from October 10th to November 18th, the soil temperature in the Larix gmelinii forest, Betula platyphylla forest and Pinus sylvestris var. mongolica forest all decreased with decreasing temperature, with ranges of -0. 49 to 3. 71, -2. 10 to 2. 39, and -1. 04 to 3. 48 ℃, respectively. The content of dissolved organic carbon (DOC) in different soil layers of three forest types showed a trend of first increasing and then decreasing with the decrease of temperature, the content of microbial biomass carbon (MBC) first decreased and then increased, while the content of readily oxidizable organic carbon (ROC) fluctuated, ranging from 78. 75 to 214. 32, 101. 06 to 988. 40, and 1. 52 to 13. 94 g/kg, respectively. Among them, the soil DOC and ROC contents in the Betula platyphylla forest were significantly higher than those in the Larix gmelinii forest and Pinus sylvestris var. mongolica forest, while the soil MBC content was the highest in the Larix gmelinii forest. The three types of active carbon showed a ‘surface aggregation effect’ in different forest types, and the soil DOC content increased and the soil MBC content decreased during the freeze-thaw period, but the soil ROC content did not change significantly. The changes in soil active carbon content in Larix gmelinii forest were mainly influenced by soil moisture and microbial biomass nitrogen. Ammonium nitrogen was the dominant factor affecting the three types of soil active carbon in Betula platyphylla forest, while soil pH was the main influencing factor for the three types of soil active carbon in Pinus sylvestris var. mongolica forest. Research indicates that, the freeze-thaw effect has a significant impact on the active carbon content of typical forest soils in the permafrost regions of the Great Daxing'an Mountains, increasing soil DOC content and reducing soil MBC content, while the impact on ROC content is relatively small. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The rapid increase in biogas energy production has led to the accumulation of a significant byproduct, liquid digestate (LD). This study evaluated the effects of various LD dosages on soil CO2 respiration and microbial biomass through field trials over 1 year and 2 consecutive years. LD was applied to a maize cultivation area at dosages of 10, 30, 50, and 70 t ha−1. The results showed that LD created rapidly diminishing transient effects on soil microbial activity; in long-term applications, microbial stress became apparent at dosages of 30, 50, and 70 t ha−1. Notably, the increase in CO2 respiration diminished after about 60 days in the 1-year application, while the increase in microbial biomass was sustained for only 30 days. In the 2-year application, the effect on CO2 respiration disappeared after 30 days, with no significant change in microbial biomass. Initial applications of LD stimulated microbial activity, but high dosages in prolonged applications tended to increase stress factors on microbial communities. These findings indicate that the initial effects of LD on microbial communities can diminish quickly, and soil microorganisms may adapt over time. Additionally, high EC and ammonium concentration in LD may have negatively affected soil microbial communities. [ABSTRACT FROM AUTHOR]

A laboratory incubation experiment was conducted for 36 days to study the effect of pigeon pea biochar (PPB) and wood biochar (WB) on carbon mineralization of native soil organic carbon (SOC) and municipal solid waste compost (MSWC) applied to soil. The MSWC addition enhanced soil respiration by 2-fold (231 mg C kg-1 soil) over the control (118 mg C kg-1 soil). The PPB addition significantly (P < 0.05) increased cumulative loss of carbon as CO2, whereas WB significantly decreased the cumulative loss of C over control. Addition of PPB at 5% and 10% levels increased SOC mineralization (positive priming) +22.9% and +31.2%, respectively; whereas reduction in SOC mineralization (negative priming) was noticed in WB (5% and 10%) treated soils by -3.1% and -21.7%, respectively. Similarly, WB induced strong negative priming effects (-21.9% and -29.5%), while PPB caused a weak positive priming effect (+3.0% and +11.6%) at 5% and 10% levels on mineralization of added labile carbon substrate (MSWC), respectively. Results indicate the hardwood (Prosopis juliflora) biochar exhibits refractory properties that inhibit mineralization of both native SOC and applied organic compost (MSWC), and thereby it can be used as an amendment to stabilize native and applied organic matter in soil, which may significantly contribute to soil carbon sequestration. [ABSTRACT FROM AUTHOR]

Iron-metamorphic soils of normal moistening were studied in the middle taiga subzone of Karelia. The examined sites comprise arable land, hayfield, 15- and 75-year-old naturally reforested pine stands on former farmland, and 100-year-old pine forest as a control. The effects of different land use types on soil morphology and the main chemical and microbiological characteristics of the upper horizons were analyzed. The stocks of organic carbon (Corg) and microbial biomass carbon (Cmic) in 0–100-cm soil layer and the structure of carbon pools in these sites were studied. Characteristic of the soils of all sites are a uniform accumulative type of carbon distribution and similar values of C/N ratio (16–18). The soils display a low natural fertility and unfavorable agrochemical characteristics, which are considerably improvable by agricultural management. Arable land has the highest Corg (4.9%) and Ntot (0.3%) contents at a low bulk density and neutral pH. The soil under the young forest displays the highest Cmic content (419 mg C/kg); soils of arable land and hayfield, 209–211 mg C/kg; and that under mature forest stands, the minimum (144–175 mg C/kg). The stock of microbial biomass carbon in the 0–100-cm soil layer ranges from 76.5 to 132.4 g C/m2 in the studied land use types and the Cmic content in the forest litter amounts to 12.7–27.4 g C/m2. In the 0–100-cm layer, Corg stock is the maximum in arable land, amounting to 272 t C/ha, and decreases from hayfield to mature forest stand (98 to 39 t C/ha, respectively). The total ecosystem carbon stock is the maximum in arable land (275 t C/ha), which exceeds the stock in mature forest stands (206–221 t C/ha). The Corg stocks in young forest and hayfield are 105–115 t C/ha. [ABSTRACT FROM AUTHOR]

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A laboratory incubation experiment was conducted for 36 days to study the effect of pigeon pea biochar (PPB) and wood biochar (WB) on carbon mineralization of native soil organic carbon (SOC) and municipal solid waste compost (MSWC) applied to soil. The MSWC addition enhanced soil respiration by 2-fold (231 mg C kg-1 soil) over the control (118 mg C kg-1 soil). The PPB addition significantly (P < 0.05) increased cumulative loss of carbon as CO2, whereas WB significantly decreased the cumulative loss of C over control. Addition of PPB at 5% and 10% levels increased SOC mineralization (positive priming) +22.9% and +31.2%, respectively; whereas reduction in SOC mineralization (negative priming) was noticed in WB (5% and 10%) treated soils by -3.1% and -21.7%, respectively. Similarly, WB induced strong negative priming effects (-21.9% and -29.5%), while PPB caused a weak positive priming effect (+3.0% and +11.6%) at 5% and 10% levels on mineralization of added labile carbon substrate (MSWC), respectively. Results indicate the hardwood (Prosopis juliflora) biochar exhibits refractory properties that inhibit mineralization of both native SOC and applied organic compost (MSWC), and thereby it can be used as an amendment to stabilize native and applied organic matter in soil, which may significantly contribute to soil carbon sequestration.

The minimum disturbance of soil is gaining popularity in different parts of the world because of definite advantages over conventional tillage (CT) especially with respect to rice cultivation. Conventionally, rice is transplanted in puddled soil in which soil is completely broken down and destroyed in presence of standing water to create an impervious layer below the surface so as to hold the rainwater for the rice. Such practice noticeably hampers the growth of the succeeding winter crop grown under conventionally tilled soil because of alteration of soil physical characteristics. Taking into consideration, a field experiment was conducted from 2016 to 2019 to assess the alterations in soil properties resulting from various tillage systems in the cultivation of rice followed by Indian mustard, either through transplanting or direct seeding, after the cultivation of Sesbania aculeata. The experiment was conducted with 20 treatment combinations comprising of five tillage practices combining minimum tillage (MT) and conventional tillage (CT) viz., T1: CT (S: Sesbania)-CT (TR: Transplanted rice)-CT (IM: Indian mustard), T2: MT (S)-CT (TR)-MT (IM), T3: MT (S)-CT (DSR: Direct seeded rice)-CT (IM), T4: MT (S)-MT (DSR)-MT + rice residue @1.5 tha−1 (IM), T5: MT (S)-MT (DSR)-MT (IM) and four weed management practices viz., W1: recommended herbicides (S and IM: pendimethalin 0.75 kg ha−1 pre-emergence; rice: pretilachlor 0.75 kg ha−1 pre-emergence) W2: IWM: integrated weed management (W1 + manual weeding), W3: manual weeding/hoeing, W4: weedy check, laid out in a split-plot design with tillage practices in the main plots and weed management practices in the sub-plots with three replications. Weed management is excluded from the results and discussion section of the paper due to no treatment effect on soil properties. The soil properties studied under the investigation were microbial population, microbial biomass carbon, soil enzymes such as dehydrogenase, phosphomonoesterase and fluorescein di-acetate, soil available NPK, soil organic carbon, bulk density, water holding capacity, total porosity, water stable aggregates, and mean weight diameter of aggregates were significantly changed under direct seeded rice based system as compared to puddled rice based system. Findings of the experiment suggested that by minimizing soil disturbance and residue retention in winter crop not only improved soil properties but also system productivity in terms of average rice equivalent yield (18.60%) of rice-Indian mustard cropping sequence over conventional tillage system. Minimum tillage in Sesbania-direct seeded rice-Indian mustard with rice residue retention improved macro water stable aggregates (> 0.25 mm sized aggregates) (62.08%) and mean weight diameter of aggregates (1.34 mm) at 0–30 cm soil depth as compared to conventional tillage system (60.04% and 1.27 mm, respectively). The same treatment improved total porosity and water holding capacity of 0–15 cm of soil depth by 47.42% and 45.87%, respectively as compared to conventional tillage after three years of investigation. Regression analysis shows that one unit reduction in bulk density increased total porosity of soil by 1.47 units; whereas a unit improvement in total porosity improved water holding capacity of soil by 1.25 units. Other soil properties viz., soil organic carbon (16.75% in 0–15 cm depth and 25.86% in 15–30 cm depth), available nitrogen, phosphorous and potassium (1.04%, 5.40% and 1.54%, respectively); bacterial and fungal population, microbial biomass carbon (49.90%), and activity of dehydrogenase, phosphomonoesterase and fluorescein di-acetate (25.39%, 17.02% and 48.94%, respectively) were also improved under the same treatment over conventional tillage system. A significant (P ≤ 0.01) positive correlation of soil macro-aggregates, water holding capacity, soil microbial biomass carbon with soil organic carbon as well as phosphomonoesterase, dehydrogenase and fluorescein di-acetate activities with soil microbial carbon was observed. [ABSTRACT FROM AUTHOR]

The salinity and alkalinity of soils are two fundamental factors that limit plant growth and productivity. For that reason, a field study conducted at Sakha Agric. Res. Station in Egypt during the 2022–2023 winter season aimed to assess the impact of gypsum (G), compost (C), and zinc foliar application in two images, traditional (Z1 as ZnSO4) and nanoform (Z2 as N-ZnO), on alleviating the saline–sodic conditions of the soil and its impact on wheat productivity. The results showed that the combination of gypsum, compost, and N-ZnO foliar spray (G + C + Z2) decreased the soil electrical conductivity (EC), sodium adsorption ratio (SAR), and exchangeable sodium percentage (ESP) by 14.81%, 40.60%, and 35.10%, respectively. Additionally, compared to the control, the G + C + Z2 treatment showed improved nutrient content and uptake as well as superior wheat biomass parameters, such as the highest grain yield (7.07 Mg ha−1), plant height (98.0 cm), 1000-grain weight (57.03 g), and straw yield (9.93 Mg ha−1). Interestingly, foliar application of N-ZnO was more effective than ZnSO4 in promoting wheat productivity. Principal component analysis highlighted a negative correlation between increased grain yield and the soil EC and SAR, whereas the soil organic matter (OM), infiltration rate (IR), and plant nutrient content were found to be positively correlated. Furthermore, employing the k-nearest neighbors technique, it was predicted that the wheat grain yield would rise to 7.25 t ha−1 under certain soil parameters, such as EC (5.54 dS m−1), ESP (10.02%), OM (1.41%), bulk density (1.30 g cm−3), infiltration rate (1.15 cm h−1), and SAR (7.80%). These results demonstrate how adding compost and gypsum to foliar N-ZnO can improve the soil quality, increase the wheat yield, and improve the nutrient uptake, all of which can support sustainable agriculture. [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) is known to vary among different ecosystems and soilscapes, yet the degree of variation remains uncertain. Comparing SOC levels in undisturbed ecosystems like forests with those in gradually altered ecosystems can provide valuable insights into the impact of land use on carbon dynamics. This study aimed to evaluate the effects of different land uses on soil fertility parameters in the tropical region of Kerala, focusing on forests as well as cultivated agricultural landscape such as coconut, pepper, tapioca, acacia plantations, and mixed home garden cropping systems. Significant variations were observed among different crops and land use systems in terms of soil fertility. Forests exhibited the highest SOC content at 3.78 g kg−1, while acacia plantations showed the lowest at 0.76 g kg−1. Additionally, various soil properties such as different carbon fractions (e.g., humic acid, fulvic acid), total nitrogen, carbon, available nutrients, physical properties, aggregate size fractions, microbial biomass carbon, and spectral signatures differed significantly across the different land uses. These findings suggest a decline in soil fertility in altered ecosystems compared to adjacent forest soils, highlighting the vital role of forests in conserving natural resources and maintaining soil health. In addition, among the different landscapes studied, mixed cropping systems of home gardens sustained soil fertility better than monocropping systems. The observed variations in soil physicochemical properties among different land use types indicate a threat to sustainable crop production. Effective management practices aimed at improving soil fertility and sustaining crop production in these altered ecosystems are essential. This study highlights the importance of adopting appropriate management strategies to conserve soil health and ensure sustainable crop production in tropical landscapes like Kerala. The holistic approach adopted in this study, encompassing a wide range of soil fertility parameters across various land uses, along with its implications for sustainable land management, adds significant novelty and relevance to the existing literature on soil dynamics in tropical regions like Kerala. [ABSTRACT FROM AUTHOR]

Sugarcane/soybean intercropping and reduced nitrogen (N) application as an important sustainable agricultural pattern can increase crop primary productivity and improve soil ecological functions, thereby affecting soil organic carbon (SOC) input and turnover. To explore the potential mechanism of sugarcane/soybean intercropping affecting SOC sequestration, a two-factor long-term field experiment was carried out, which included planting pattern (sugarcane monocropping (MS), sugarcane/soybean 1:1 intercropping (SB1), and sugarcane/soybean 1:2 intercropping (SB2)) and nitrogen addition levels (reduced N application (N1: 300 kg·hm−2) and conventional N application (N2: 525 kg·hm−2)). The results showed that the shoot and root C fixation in the sugarcane/soybean intercropping system were significantly higher than those in the sugarcane monocropping system during the whole growth period of sugarcane, and the N application level had no significant effect on the C fixation of plants in the intercropping system. Sugarcane/soybean intercropping also increased the contents of total organic C (TOC), labile organic C fraction [microbial biomass C (MBC) and dissolved organic C (DOC)] in the soil during the growth period of sugarcane, and this effect was more obvious at the N1 level. We further analyzed the relationship between plant C sequestration and SOC fraction content using regression equations and found that both plant shoot and root C sequestration were significantly correlated with TOC, MBC, and DOC content. This suggests that sugarcane/soybean intercropping increases the amount of C input to the soil by improving crop shoot and root C sequestration, which then promotes the content of each SOC fraction. The results of this study indicate that sugarcane/soybean intercropping and reduced N application patterns can synergistically improve plant and soil C fixation, which is of great significance for improving crop yields, increasing soil fertility, and reducing greenhouse gas emissions from agricultural fields. [ABSTRACT FROM AUTHOR]

Processes of water retention and movement and the hydraulic conductivity are altered in the rhizosphere. The aim of this study was to investigate the physical-hydric properties of soil aggregates in the rhizosphere of annual ryegrass (Lolium multiflorum) cropped in a Kandiudalfic Eutrudox, taking into account aspects related to soil aggregate stability. Soil aggregates from rhizosphere soil (RZS) and soil between plant rows (SBP) were used to determine soil water retention curves (SWRCs) and saturated hydraulic conductivity (Ksat). In addition, properties related to soil aggregate stability, such as water-dispersible clay, soil organic carbon (SOC), and microbial activity, were also assessed. The higher microbial activity observed in the RZS was facilitated by increased SOC and microbial activity, resulting in improved soil aggregation (less water-dispersible clay). For nearly all measured matric potentials, RZS had a higher water content than SBP. This was attributed to the stability of aggregates, increase in SOC content, and the root exudates, which improved soil water retention. The increase in total porosity in RZS was associated with improved soil aggregation, which prevents deterioration of the soil pore space and results in higher Ksat and hydraulic conductivity as a function of the effective relative saturation in RZS compared to SBP. [ABSTRACT FROM AUTHOR]

The decline in soil productivity due to intensive cultivation, unbalanced fertilization and climate change are key challenges to future food security. There is no significant research conducted on the effect of organic amendments on soil properties and active carbon fractions in organic-matter deficient soils under changing climate. Biochar (BC) is a stabilized organic amendment produced from organic materials and is increasingly recognized as being able to improve soil health and crop productivity. The present study was conducted to determine the efficacy of compost (CM) (0.5%, 1%) (w/w) and animal manure (AM) (0.5%, 1%) (w/w) alone and combined with 3% (w/w) biochar, on soil carbon fractions, soil properties, and crop growth in a low-fertile soil. The results revealed significant increased 46% plant height, 106% and 114% fresh and dry shoot weight respectively, and 1,000-grain weight increased up to 40% when 3% BC with 1% CM was applied, compared to a control. Similarly, substantial increases in 69% soil organic matter, and 70% carbon pool index were observed at 3% BC, and under 3% BC with 1% CM increased 11% microbial biomass carbon compared to the control. Overall, the results suggest that 3% BC addition along with 1% CM and AM (1%) had greater potential to improve the soil carbon pool, microbial biomass, and soil health, all of which will ultimately enhance maize yield when grown in low-fertility soil. The application of BC, CM, and AM are a viable green approach, that not only boosts crop yields and improves soil properties and but also contributes to a circular economy. [ABSTRACT FROM AUTHOR]

Soil disinfestation has been widely used as an effective strategy to improve soil health and crop yield by suppression of soil-borne plant pathogens, but its effect on soil organic carbon (SOC), a crucial factor linked to climate change, remains unknown. A microcosm trial was conducted to evaluate microbial residue carbon (MRC) and its contribution to SOC under chemical soil disinfestation (CSD) with quicklime (QL) and chloropicrin (CP), as well as anaerobic soil disinfestation (ASD) with maize straw (MASD) and soybean straw (SASD). The SOC concentrations were increased by both CSD and ASD. Also, total SOC-normalized MRC concentration was enhanced, with a considerable increase in soil bacterial and fungal MRC, particularly evident under CP and SASD treatment. Due to broad-spectrum biocidal activities, decreased SOC-normalized microbial biomass carbon (MBC) was consistent with the reductions in bacterial and fungal phospholipid fatty acids (PLFAs), consequently increasing MRC accumulation under CSD. Similarly, ASD decreased fungal PLFAs while shifting bacterial PLFAs from aerobic to anaerobic taxa or from gram-negative to -positive taxa, both of which contributed to both MBC and MRC buildup. Collectively, the findings demonstrate that ASD can efficiently increase SOC concentration, with distinct mechanisms underlying MRC generation when compared to traditional CSD. [ABSTRACT FROM AUTHOR]

Copyright of Soil Management & Sustainable Production is the property of Gorgan University of Agricultural Sciences & Natural Resources and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil salinity and drought are major environmental challenges that significantly affect soil functioning and soil organic matter (SOM) decomposition. Despite their importance, the combined effects of drought and salinity on residue decomposition are not well understood. This study addresses this gap by evaluating the decomposition of maize residue under salinity and drought stresses over a 75-day incubation period at 20 °C under controlled conditions. The experiment included two moisture levels: optimum moisture at 80% water-holding capacity (WHC) and drought conditions at 30% WHC, in both normal (ECe = 1.48 dS m−1) and saline (ECe = 8 dS m−1) soils, with 5 g DM kg−1 soil maize residues mixed in. A control treatment without maize residue addition was also included. The results indicated that salinity stress reduced maize residue decomposition, as evidenced by lower soil respiration, decay constant, metabolic quotient (qCO2), and soil extracellular enzyme activities. While drought did not affect total soil respiration in the presence of maize residue, it significantly decreased soil extracellular enzyme activities and decay constant rates. Combined drought and salinity stress further diminished maize residue decomposition, marked by reduced soil respiration, decay constant, microbial biomass carbon, and soil extracellular enzyme activities, while dissolved organic carbon (DOC) and qCO2 increased significantly. Similarly, extracellular enzyme activities were significantly reduced under abiotic stresses and further diminished under combined stress conditions. In conclusion, the simultaneous occurrence of drought and salinity can have compounded detrimental effects on microbial functioning, particularly in the presence of fresh plant residues. [ABSTRACT FROM AUTHOR]

Soil organic carbon plays an important role in climate change mitigation, and can be strongly affected by plant diversity. Although a positive effect of plant diversity on soil organic carbon storage has been confirmed in grasslands and forests, it remains unclear whether this effect exists in wetlands. In this study, we investigated plant diversity, soil properties and soil organic carbon across five typical wetlands of northern China, to test the effect of plant diversity on soil organic carbon and clarified the regulators. Increasing plant diversity significantly increased belowground biomass of wetland plant communities, and both soil organic carbon content and storage were significantly positively related to wetland plant diversity. The positive effect of plant diversity was influenced by belowground biomass of wetland plant communities, soil microbial biomass carbon, and soil properties, especially soil water content and bulk density. The structural equation model showed that soil organic carbon storage was dominantly affected by microbial biomass carbon, plant diversity and biomass, with standardized total effects of 0.66 and 0.47, respectively, and there was a significant positive relationship between soil organic carbon and microbial biomass carbon. These results suggest that increasing plant diversity can potentially promote the ability of wetlands to store organic carbon in soils. The findings highlight the importance of plant diversity on soil organic carbon in wetland ecosystems, and have implications for managing wetlands to increase carbon sinks and to mitigate global climate change.

The increasing demand for biofuels has driven the Brazilian sugarcane industry to expand into degraded pasture areas with low organic matter content and fertility. Traditionally, sugarcane is cultivated in sandy soils, and after five or more harvest cycles, field reform involves conventional tillage, followed by sugarcane planting in the exposed soil. However, the introduction of cover crops during this reform period has shown soil fertility benefits, although research on soil microbiology impacts is limited. This study aimed to evaluate soil microbiological attributes and sugarcane productivity following the implementation of three different reform systems in a sandy Ultisol. The three systems assessed were conventional planting in exposed soil and field reform using either soybean or Crotalaria spectabilis. Ten samples were randomly collected from a 10-hectare plot at a depth of 0.00–0.10 m, near the planting furrow, for each management system. The samples were analyzed for organic carbon, microbial biomass carbon, total glomalin, easily extractable glomalin, and sugarcane productivity. Data were subjected to an analysis of variance and means were compared using Tukey’s test. The findings indicate that cultivating C. spectabilis before planting sugarcane enhances soil health and mitigates the impacts of agricultural practices. This improvement is attributed to higher levels of microbial biomass carbon, easily extractable glomalin, and total glomalin, which contribute to increased sugarcane productivity.

ABSTRACT There are few long-term field studies on the effects of biochar on soil microbial abundance and diversity. This study aimed to evaluate doses of biochar in combination with mineral fertilizer on the activity and diversity of microorganisms in the soil of a sugarcane field. The experiment was carried out in a randomized block design, factorial 5 × 2, with four replications: five doses of eucalyptus (Eucalyptus grandis Hill ex Maiden × Eucalyptus urophylla S.T. Blake) wood biochar (0, 10, 20, 30, and 40 Mg ha−1), with and without the application of nitrogen, phosphorus, and potassium (NPK) mineral fertilizer. Soil samples were collected from the sugarcane planting line and fertilized with biochar for two consecutive years. Regardless of the NPK fertilizer, over the two years of evaluation, the height growth of sugarcane plants and total organic carbon (TOC) increased linearly with biochar doses. For microbial biomass carbon (Cmic), soil basal respiration (SBR), metabolic quotient (qCO2), microbial quotient (qMIC), and Shannon diversity index (H), the highest values were obtained where fertility correction (WFC) treatments were applied, regardless of the year of evaluation, in biochar doses between 20 and 30 Mg ha−1. On the other hand, the highest CO2 efflux values were obtained with zero doses of biochar, regardless of the NPK fertilizer applied, over the two years of evaluation. Therefore, the incorporation of biochar and NPK fertilizer into the soil contributes to increasing the soil's biological activity indicators and, consequently, the growth of sugarcane plants. It is essential to highlight the need for continuous assessments as the characteristics of biochar change over time.

Agricultural practices significantly impact soil properties and ecological functions, highlighting the importance of comprehensive soil health assessments. Traditionally, these assessments have focused on physical and chemical indicators, often neglecting microbiological properties. This review explores the potential of microbiological indicators in evaluating the effects of agricultural practices on soil ecological functions, emphasizing their significance and addressing challenges associated with their application. A key advantage of microbiological indicators is their high sensitivity and rapid response to environmental changes. These indicators can be grouped into three categories: microbial biomass and abundance, microbial taxonomic composition and diversity, and microbial activity. Among these, microbial biomass carbon, basal respiration, and decomposition rates are considered the most reliable and interpretable indicators. Microbial taxonomic composition and diversity remain limited in their diagnostic and predictive capabilities due to challenges in interpretation. Integrating microbiological indicators offers a more holistic understanding of the interactions between agricultural practices and soil health, enhancing our ability to monitor, manage, and preserve soil ecosystems. To facilitate their adoption in agricultural production and land management, further efforts are needed to improve the interpretability of these indicators and to establish standardized criteria for soil health assessment.

Microbial necromass carbon (MNC) accounts for a large fraction of soil organic carbon (SOC) in terrestrial ecosystems. Yet our understanding of the fate of this large carbon pool under long‐term warming is uncertain. Here, we show that 14 years of soil warming (+4°C) in a temperate forest resulted in a reduction in MNC by 11% (0–10 cm) and 33% (10–20 cm). Warming caused a decrease in the content of MNC due to a decline in microbial biomass carbon and reduced microbial carbon use efficiency. This reduction was primarily caused by warming‐induced limitations in available soil phosphorus, which, in turn, constrained the production of microbial biomass. Conversely, warming increased the activity of soil extracellular enzymes, specifically N‐acetylglucosaminidase and leucine aminopeptidase, which accelerated the decomposition of MNC. These findings collectively demonstrate that decoupling of MNC formation and decomposition underlie the observed MNC loss under climate warming, which could affect SOC content in temperate forest ecosystems more widespread. [ABSTRACT FROM AUTHOR]

Accurately predicting carbon‐climate feedbacks relies on understanding the environmental factors regulating soil organic carbon (SOC) storage and dynamics. Here, we employed a microbial ecological model (MEND), driven by downscaled output data from six Earth system models under two Shared Socio‐economic Pathways (SSP1‐2.6 and SSP5‐8.5) scenarios, to simulate long‐term soil biogeochemical processes. We aim to analyze the responses of soil microbial and carbon‐nitrogen (C‐N) processes to changes in environmental factors, including litter input (L), soil moisture (W) and temperature (T), and soil pH, in a broadleaf forest (BF) and a pine forest (PF). For the entire soil layer in both forests, we found that, compared to the baseline period of 2009–2020, the mean SOC during 2081–2100 increased by 40.9%–90.6% under the L or T change scenarios, versus 5.2%–31.0% under the W change scenario. However, soil moisture emerged as a key regulator of SOC, MBC and inorganic N dynamics in the topsoil of BF and PF. For example, W change led to SOC gain of 5.5%–37.2%, compared to the SOC loss of 15.5%–18.0% under L or T scenario. Additionally, a further reduction in soil pH by 0.2 units in the BF, representing the acid rain effect, significantly resulted in an additional SOC gain by 14.2%–21.3%, compared to the LTW (simultaneous changes in the three factors) scenario. These results indicate that the results derived solely from topsoil may not be extrapolated to the entire soil profile. Overall, this study significantly advances our comprehension of how different environmental factors impact the dynamics of SOC and the implications they have for climate change. Plain Language Summary: Accurately predicting carbon‐climate feedbacks relies on understanding the environmental factors regulating soil organic carbon (SOC) storage and dynamics. We aim to analyze the responses of soil microbial and carbon‐nitrogen (C‐N) processes to changes in environmental factors, including litter input (L), soil moisture (W) and temperature (T), and soil pH, in a broadleaf forest (BF) and a pine forest (PF). We found that soil moisture change would be beneficial for SOC accumulation and serves as a key regulator of MBC and inorganic N in topsoil, whereas the change in litterfall or soil temperature are favorable for SOC accumulation in the entire soil profile. Additionally, a further reduction in soil pH by 0.2 units, representing the acid rain effect, significantly resulted in an additional SOC gain by 14.2%–21.3%, compared to the scenario with simultaneous changes in L, W, and T. These results indicate that findings solely from topsoil may not be extrapolated to the entire soil profile. Overall, this study significantly advances our comprehension of how different environmental factors impact the dynamics of SOC and the implications they have for climate change. Key Points: Soil C responses to climate change are depth dependent, therefore, results from just the topsoil may not apply to the entire soil profileSoil moisture change benefits topsoil SOC accumulation, whereas litterfall and soil temperature changes favor SOC accumulation in the entire soil profileWe need to pay more attention to the effects of soil moisture and pH rather than temperature and litter‐input on soil biogeochemical processes [ABSTRACT FROM AUTHOR]

With mounting demand for high-quality agricultural products and the relentless exploitation of arable land resources, finding sustainable ways to safely cultivate food crops is becoming ever more important. Here, we investigated the effects of the integrated cropping technique "straw return + intercropping" on the soil aggregates as well as the microbial biomass carbon (MBC) content, enzyme activities and microbial diversity in soils of maize and soybean crops. Our results show that in comparison to straw removal and monoculture, straw return and intercropping increase the rhizosphere's MBC content (59.10%) of soil, along with urease (47.82%), sucrase (57.14%), catalase (16.14%) and acid phosphatase (40.66%) activities as well as the microbial diversity under maize and soybean. Under the same straw treatment, the yield of maize when intercropped surpassed that when grown in monoculture, with the land equivalent ratio of the intercropping treatment under straw return being highest. Overall, the intercropping of maize and soybean is beneficial for the healthy development of sustainable agriculture in the black soil region of northeast China, especially when combined with straw return to fields. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil enzyme activities are closely associated with soil organic carbon (SOC) or microbial biomass carbon (MBC). High correlation between SOC and MBC masks their individual effects on enzyme activities. Expressing soil enzymes activity relative to soil organic carbon (SOC) or Microbial Biomass Carbon (MBC) would normalize the differences in SOC/MBC. A long term subtropical rice-wheat system was selected to study the variation in soil-specific enzyme activity (per unit SOC and MBC) in soil aggregates under integrated nutrient management. Soil organic carbon, microbial biomass carbon and the enzyme activities like acid phosphatase (ACP), alkaline phosphatase (AKP), dehydrogenase (DHA), fluorescien diacetate hydrolysing capacity (FDA) and urease were measured in three aggregate size fractions viz., >2000, 2000–250 and <250 µm. Integrated nutrient management practices significantly increased the specific enzyme activities expressed in relation to SOC and MBC. Aggregate size fractions of 2000–250 µm size exhibited higher specific enzyme activities, when expressed in terms of SOC. Enzyme activity (per unit MBC) in aggregates also followed the same pattern with an exception to dehydrogenase activity which was almost uniform across all the aggregates size fractions. Aggregates of larger size do not always possess higher enzymes activity; even smaller macroaggregates were able to retain stable extracellular enzyme activity per unit of SOC or MBC. This study opens an alley to express soil enzymatic activities relative to SOC or MBC level in the soils, rather than expressing absolute activities. [ABSTRACT FROM AUTHOR]

Over the last decades, Pinus taeda L. plantations in southern Brazil showed a great increase in average production. However, the gains in productivity obtained by genetic selection and breeding have nowadays stabilized. Research on edaphic factors and silvicultural practices is currently performed with the aim of both increasing the productivity of P. taeda plantations and maintaining the soil quality. To this end, soil microbiological attributes are considered better indicators of soil quality as they are more sensitive than chemical and physical ones. In this study, we aimed to evaluate the relationship between microbial activity and the physical and chemical parameters of different soil types under young Pinus taeda plantations at five different sites in southern Brazil. Soil samples were collected at depths of 0-5 and 5-10 cm. The soil microbiological attributes evaluated were: potentially mineralizable nitrogen (PMN), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), microbial basal respiration (MBR), and metabolic quotient (qCO2). We also evaluated some physical and chemical soil parameters. Sites with the highest values of C, clay, and nutrients in the soil, showed higher values for the soil microbiological attributes, compared to the other study sites. The previous management with minimal tillage in some sites seems to positively affect soil quality. The MCB and MBR showed better sensitivity in indicating differences between sites and showed a good relationship with clay content, C/N ratio, K, and pH. These results suggest that site-specific characteristics such as soil type or forest management influence soil microbiological attributes in Pinus taeda plantations during initial growth in southern Brazil.

Soil management approaches have been advocated to modify the soil fertility parameters for higher agricultural production through different land systems. The present review examines the influence of organic/inorganic fertilizers and tillage practices through transformations in regulating the nutrient status, microbial components, and soil organic carbon. Fertilization along with different tillage practices have been found to affect the available plant nutrient content including macronutrients, secondary nutrients, and micronutrients. The review investigation also showed that, compared to inorganic fertilizers (INF), application of compost enhanced plant available macronutrients (N, P, K), micronutrients (Zn, Cu, Fe, Mn) and soil organic carbon (SOC) with different tillage practices. Through different land systems, transformation of the plant available macronutrients, micronutrients and microbial compositions showed their enhancement. Microbial parameters viz. microbial biodiversity, microbial biomass carbon (MBC), potentially mineralizable nitrogen (PMN), microbial biomass nitrogen (MBN) and microbial respiration reported increase. Soil organic carbon and aggregate distribution in the soil and the aggregate-associated organic carbon and physical fractions of SOC have also been reviewed. Among different tillage systems, the reduced tillage with residue incorporation and no-tillage (zero tillage) with residue mulching, significantly enhanced carbon sequestration in soil aggregates in comparison to conventional tillage with residue removal treatments. The practice of zero tillage improved dissolved organic carbon and MBC in light and heavy fractions of carbon in the upper layers of soil.

The decline in soil productivity due to intensive cultivation, unbalanced fertilization and climate change are key challenges to future food security. There is no significant research conducted on the effect of organic amendments on soil properties and active carbon fractions in organic-matter deficient soils under changing climate. Biochar (BC) is a stabilized organic amendment produced from organic materials and is increasingly recognized as being able to improve soil health and crop productivity. The present study was conducted to determine the efficacy of compost (CM) (0.5%, 1%) (w/w) and animal manure (AM) (0.5%, 1%) (w/w) alone and combined with 3% (w/w) biochar, on soil carbon fractions, soil properties, and crop growth in a low-fertile soil. The results revealed significant increased 46% plant height, 106% and 114% fresh and dry shoot weight respectively, and 1,000-grain weight increased up to 40% when 3% BC with 1% CM was applied, compared to a control. Similarly, substantial increases in 69% soil organic matter, and 70% carbon pool index were observed at 3% BC, and under 3% BC with 1% CM increased 11% microbial biomass carbon compared to the control. Overall, the results suggest that 3% BC addition along with 1% CM and AM (1%) had greater potential to improve the soil carbon pool, microbial biomass, and soil health, all of which will ultimately enhance maize yield when grown in low-fertility soil. The application of BC, CM, and AM are a viable green approach, that not only boosts crop yields and improves soil properties and but also contributes to a circular economy.