Increase In Cation Exchange Capacity Research Articles

Correlation of Soil Chemical, Biological, and Physical Characteristics on Productivity of Maize in Cibugel District, Sumedang Regency

Maize as one of the national food commodities, experiences an increase in demand every year. Both internal and external factors influenced the growth of corn plants. Internal factors originated from the plant, such as inherited genetic traits, while external factors came from the environment, including soil properties and climate. External factors that affected plant growth included biological, physical, and chemical soil characteristics. This research aimed to understand the interrelation between soil acidity (pH), phosphorus availability (P), cation exchange capacity (CEC), nitrogen-fixing bacteria, earthworm population, carbon-nitrogen ratio (C/N), and soil texture on the productivity of maize in Cibugel District and how these factors were interconnected to support plant growth. The research employed a descriptive survey and comparative method, with soil samples taken from 18 soil samples from six villages in the Cibugel Subdistrict, Sumedang Regency. The correlation analysis results showed a significant positive relationship between cation exchange capacity and corn productivity and a significant negative relationship between available phosphorus and corn productivity. This implied that increasing cation exchange capacity could enhance productivity while increasing available phosphorus could decrease productivity. The research aided in identifying soil characteristics influencing high land productivity in the area.

Biochar Application Reduces Saline–Alkali Stress by Improving Soil Functions and Regulating the Diversity and Abundance of Soil Bacterial Community in Highly Saline–Alkali Paddy Field

Saline–alkali soils seriously restrict the soil functions and the growth and diversity of soil microorganisms. Biochar can alleviate the negative effects of saline–alkali stress. However, it remains unclear how biochar reduces saline–alkali stress by improving soil functions and regulating the abundance and diversity of the soil bacterial community in highly saline–alkali paddy fields. To address this, a paddy field experiment was conducted in a highly saline–alkali paddy field using two nitrogen application levels (0 and 225 kg ha−1) and four biochar application rates (0, 1.5%, 3.0%, and 4.5% biochar, w/w). The results show that, compared with C0, biochar application, especially when combined with N fertilizer, significantly decreased the soil pH, exchangeable sodium percentage (ESP), saturated paste extract (ECe), and sodium adsorption ratio (SAR) while significantly increasing cation exchange capacity (CEC). These indicated that biochar can effectively reduce saline–alkali stress. Biochar application significantly increased soil content of total nitrogen (TN), alkali-hydrolysable N (AN), available P (AP), available K (AK), soil organic matter (SOM), and soil C/N ratio, both with or without N fertilization. Furthermore, biochar application further increased the relative abundance of bacterial communities and modified the bacterial community structure in highly saline–alkali paddy soils. Under C3N2, C2N2, and C1N2, Chao1 increased by 10.90%, 10.42%, and 1.60% compared to C0N2. Proteobacteria, Bacteroidetes, and Chloroflexi were the top three phyla in bacterial abundance. Biochar significantly increased the abundance of Proteobacteria while reducing Bacteroidetes and Chloroflexi, regardless of N fertilization. Correlation analysis results showed that the improvements in soil chemical and saline–alkali properties, as well as nutrient bioavailability after biochar application, had a positive effect on bacterial communities in highly saline–alkali paddy soils.

MINERAL NITROGEN DYNAMICS OVER TIME INFLUENCED BY PEANUT-WASTE BIOCHAR APPLICATION IN ALKALINE SOIL

Soil fertility in arid to semi-arid regions is constrained by extreme temperature fluctuations. Soils of such regions typically have low fertility levels, nitrogen (N) availability (due to ammonia volatilization and denitrification), and soil organic carbon (SOC) content. An incubation experiment was conducted to assess how a peanut-waste biochar (PB), produced at 300°C, influences the mineral N and chemical properties of an alkaline soil. The treatments included five PB rates (control, 5, 10, 15, and 20g PB kg−1 soil) and two fertilizer rates [no fertilization without additions of N and phosphorus (P) and fertilization with addition of 120kg N ha−1 and 90kg P ha−1]. The soil was incubated for various durations (0, 14, 28, 42, and 56days). There were significant temporal shifts in the mineral form of N in the incubated soil. Following 56days of incubation under fertilization, the treatment with 20g kg−1 PB revealed soil nitrate-N and ammonium-N levels of 15.8mg kg‒1 and 21.1mg kg‒1, respectively. With no fertilization, 20g kg−1 PB increased mineral N by 2.3-fold over the treatment without PB. This increase was 2.6-fold with fertilization. After 56days of incubation, in the presence of 20g kg−1 PB, there was a 19% increase in cation exchange capacity under fertilization and a 21% increase under no fertilization, compared to the respective treatments without PB. Immediately after the PB application, SOC was significantly increased, corresponding to PB rates. However, substantial increases were observed only in treatments with 15 and 20g PB kg−1 soil. In conclusion, the addition of 15 and 20g PB kg−1 to alkaline soil significantly increased N availability in soil, demonstrating the importance of biochar for N management in agricultural soils.

Mineralogy, Chemistry, and Thermal and Surface Properties of Various Technological Types of K-Bentonite from the Dolná Ves Deposit (Kremnické vrchy Mts., Western Carpathians, Slovakia)

The Dolná Ves K-bentonite deposit is one of a few known economic accumulations of illite-smectite in the world. Several studies have been done on the illite-smectitic component isolated from the Dolná Ves K-bentonite, but there is a shortage of analytical data on the K-bentonite itself. The main goal of the present study was to perform mineralogical and physico-chemical characterizations of various technological types of K-bentonites from the Dolná Ves deposit to better understand the relationships between the various qualitative types and their properties. The type I (high-grade) K-bentonite contains 88–91 wt.% of illite-smectite. The type II (low-grade) K-bentonite contained substantially less illite-smectite, ranging from 37 to 63 wt.%. The illite-smectites isolated from the type I K-bentonites displayed greater expandability, contained more octahedral Mg and less octahedral Fe, had greater cation exchange capacity (CEC), smaller thickness of fundamental particles, and thinner illite-smectite crystals in comparison with illite-smectites from the type II K-bentonites. The LOI (loss-on-ignition) and Al2O3 content increased with increasing amount of illite-smectite. The increase in the expandability by 10% corresponded to an increase in CEC by ~10 meq/100 g. The type I K-bentonites had much greater mass loss at <250°C due to greater expandability. The best tilemaking performance was expected for the type I K-bentonite. This raw material could also be potentially valuable for the pharmaceutical, cosmetic and food industries. Overall, the results showed that the studied technological types of K-bentonites from the Dolná Ves deposit differ not only in terms of illite-smectite contents but also in terms of the nature of the illite-smectites.

Medium-term interactive effects of herbivores and plant life form on the biochemistry of shallow sandy soils in a protected semi-arid savanna

Savannas are characterized by the co-occurrence of two different plant life forms: grasses and trees. Herbivory plays a major role in the balance between grasses and trees in savanna ecosystems. The present study aimed to investigate the impact and interactions between long-term (i.e. 20 years) herbivory and/or its exclusion and plant life form on the soil biochemistry of a protected semi-arid savanna ecosystem in the Kruger National Park (KNP), South Africa. To study the effects of herbivory on soil properties, herbivore exclosures (fully fenced areas, partially fenced areas, and an unfenced area) were used in conjunction with plant life form (trees and grasses) were considered. Interaction effects of herbivory and plant life form on soil pH, electrical conductivity (EC), total nitrogen (TN), total carbon (TC), available phosphorus (available P), exchangeable cations (K+, Na+, Mg2+ and Ca2+) cation exchange capacity (CEC), organic matter (OM) and total microbial activity were determined on savanna soils in the Nkuhlu exclosures, KNP. Exclosures where herbivores were present had significantly higher soil pH, The presence of herbivores caused an increase in soil pH, EC, exchangeable Na, CEC, and OM. The influence of the tree canopy was significantly more pronounced in elevating total C and N, exchangeable K+, Mg2+ and Ca2+, CEC and OM than observed in the open grassland zones across all exclosures. The two-way interaction between herbivory and plant life form resulted in significant decreases in TN, TC, exchangeable K, Na and Mg in open grassland areas outside of herbivore exclosures where large animals had direct access, as compared to areas within the exclosures which was protected from animal entry herbivory. This data can be used by national parks as an indicator to increase their knowledge of environmental issues relating to maintaining and preserving landscape features of savannas.

Effects of soil amendments on growth and biomass yield of early generation seeds of sweet potato (Ipomoea batatas (L.) Lam) grown in net tunnels.

Early generation sweet potato vines are multiplied on nursery beds with high densities using soil medium within insect-proof net tunnels to inhibit the entrance of virus-transmitting insects (aphids and white flies). However, the rapid multiplication beds require suitable soil amendments to support vigorous growth of vines. To this end, farmyard manure, wood ash, sawdust, compost, coffee husk and control (soil only) were evaluated using Randomized Complete Block Design with three replications during the belg and meher seasons of 2016 to 2017 in the Chefe testing site of Hawassa Agriculture Research Center. Results also showed that the soil pH was higher by 8.9% and 1.4% due to the application of wood ash and sawdust whereas there was 9.3, 5.9 and 0.9% decrease in soil pH due to the use of compost, coffee husk and farmyard manure, respectively. All soil amendments enhanced soil moisture conservation compared to the control. A 47.0%, 31.2%, 30.3% and 26.5% increase in cation exchange capacity was observed by the end of second year due to use of coffee husk, wood ash, sawdust and farmyard manure, respectively. The potassium content was increased by 47.0%, 45.5% and 35.9% due to the use of wood ash, farmyard manure and coffee husk, respectively. The pencil root length, pencil root width and below-ground biomass were not affected significantly (P < 0.05) by differences in soil amendments (P < 0.05) in this experiment. The percentage increment in above-ground biomass due to the farmyard manure, coffee husk and compost was 62.01%, 53.56% and 49.87%, respectively higher than the control. Sawdust suppressed vine growth compared to the control. Coffee husk and farmyard manure medium produced higher number of branches (23 branches / plant) during meher whereas coffee husk produced the same during belg (14.4 branches / plant). Significantly (P < 0.05) higher number of vines was obtained due to farmyard manure (4686 vines/m2) and coffee husk (4602 vines/m2) compared to the control (2683 vines/m2). Significantly longer internodes were recorded due to the farmyard (100.6% greater) compared to the control. Thus, 50% farmyard manure, 50% coffee husk or 50% compost are recommended for better growth of pre-basic sweet potato vines in net tunnels. This study proclaimed possibility of nursery bed vine multiplication through use of local organic residues at the level of small holders and research sites during short and long rain seasons.

Biochar Functions in Soil Depending on Feedstock and Pyrolyzation Properties with Particular Emphasis on Biological Properties

Biochar effects are strongly dependent on its properties. Biochar improves physical soil properties by decreasing bulk density and increasing medium and large aggregates, leading to faster and deeper water infiltration and root growth. Improvement of the chemical properties of soil is connected with pH neutralization of acidic soils, increase of cation exchange capacity and base saturation, providing a larger surface for sorption of toxicants and exchange of cations. Biochar increases the stocks of macro- and micronutrients in soil and remains sufficient for decades. Biochar effects on (micro)biological properties are mainly indirect, based on the improvements of habitat conditions for organisms, deeper root growth providing available C for larger soil volume, higher crop yield leading to more residues on and in the topsoil, better and deeper soil moisture, supply of all nutrients, and better aeration. Along with positive, negative effects of biochar while used as a soil conditioner are discussed in the review: presence of PAH, excessive amounts of K, Ca and Mg, declination of soil pH. In conclusion, despite the removal of C from the biological cycle by feedstock pyrolysis, the subsequent application of biochar into soil increases fertility and improves physical and chemical properties for root and microbial growth is a good amendment for low fertility soils. Proper use of biochar leads not only to an increase in crop yield but also to effective sequestration of carbon in the soil, which is important to consider when economically assessing its production. Further research should be aimed at assessing and developing methods for increasing the sequestration potential of biochar as fertilizer.

Eggplant growth in wheat straw-, wheat straw biochar- and compost-amended soils: a field study of CO2 emission dynamics, soil physicochemical, microbial, and nutrient effects

The growth of eggplant (Pusa Safed Baingan-1) was studied during the semi-arid (March to June) and humid sub-tropical (July to September) seasons of New Delhi, India. The individual effects of wheat straw biomass (WSBM), wheat straw biochar (WSBC) and compost versus the combined effect of WSBM plus compost and WSBC plus compost were determined under field conditions. The amendments were made at two different application rates: 1 wt% and 2 wt%. WSBC was successfully prepared in a proprietary kachcha reactor (Indian patent no. 380921), designed using locally sourced clay. Amendments were characterized using elemental analyzer, scanning electron microscopy (SEM), transmission electron (TEM) microscopy, Fourier transform infrared (FTIR) spectroscopy and X-Ray diffraction (XRD). The field study was conducted in 11 (1x1-meter) plots with two replicates. Basic soil health parameters including pH, electrical conductivity (EC), water holding capacity (WHC), bulk density (BD), cation exchange capacity (CEC), soil total nitrogen (STN), soil available nitrogen (SAN), soil organic carbon (SOC), soil available phosphorus (SAP), microbial biomass carbon (MBC) and mineral contents are analyzed. Observable plant growth characteristics (germination percentage, height, number of leaves, fruits, and plant biomass) were also recorded. Biochar amendment was most beneficial for enhancing the majority of these parameters. With respect to the control, a 20% decrease in bulk density, a 30% increase in water holding capacity, a 122% increase in organic carbon, a 175% increase in total nitrogen, a 23% increase in available nitrogen, and a 473% increase in available phosphorus were recorded. Furthermore, with respect to the control, a 115% increase in CEC was recorded using the compost amendment vs 84% with WSBC. Synergism between biochar and compost was reflected by high germination percentage (44%), number of fruits (600%), plant biomass weight (243%) and soil microbial biomass carbon (286%). Biomass amendment failed to show any positive influence. In summary, biochar emerges as a superior choice compared to both biomass and compost when it comes to soil amendments.

Dolomitic limestone was more effective than calcitic limestone in increasing soil pH in an untilled olive orchard

AbstractIn acid soils, when no‐tillage farmers intend to apply lime, the question arises as to whether it should be incorporated into the soil or whether it can be left on the soil surface. In this study, two types of limestone, calcitic (Lcal) and dolomitic (Lmag), were tested in two olive groves of cv. Cobrançosa, with an initial pH of 4.9 (S. Pedro) and 5.5 (Raparigas). In S. Pedro, limestone was incorporated into the soil (Lburied) and in Raparigas, it was left on the floor (Lfloor). The use of limestone significantly increased soil pH in the 0–0.10 m layer in both experiments. In the 0.10–0.20 m soil layer, only Lmag increased significantly the soil pH in comparison with the control. Lmag was more effective than Lcal in increasing cation exchange capacity (CEC) and reducing exchangeable acidity (EA) and aluminium (Al3+) in the Lfloor experiment. Both limes increased leaf calcium (Ca) concentration, and Lmag increased the leaf levels of magnesium (Mg). In Lfloor experiment (higher soil pH), soil microbial carbon (C) decreased, and microbial nitrogen (N) increased with liming, which may indicate an increase in bacteria in the soil and a decrease in fungi. In Lburied experiment (initial pH of 4.9), liming significantly increased accumulated (2018–2021) olive yield (56 and more than 67 kg tree−1, respectively, in the control and liming treatments). In Lfloor experiment (initial pH of 5.5), the accumulated olive yields did not differ significantly between treatments (average values between 105 and 115 kg tree−1). The results of this study provide evidence that liming may increase olive yield in very acid soils and that dolomitic limestone should preferably be used by no‐tillage farmers, due its higher solubility and faster effect on soil and trees.

Fertilizer application and chemical fertility of a lixisol in a crop rotation system in the southern Sudanian zone of Burkina Faso

The lack of organic matter in soils and the high cost of mineral fertilizers are constraints to the intensification of agricultural production in Burkina Faso. The aim of this study is to evaluate the effects of the joint application of organic and mineral matter on soil fertility under crop rotation conditions. The study was carried out at the research station in Farakoba, from 2018 to 2020. The system was a 4x4 split-plot factorial with 3 replications. The 4 treatments corresponded to 4 crop rotations used as the main factor and 4 manures as the secondary factor. We used 4 rotation sequences: Sorghum-Fonio, Soya-Fonio, Mung bean-fonio, Sorghum-Mung bean. The four secondary treatments corresponded to four fertilizers: control with no fertilizer application; NPK and urea; Compost+poultry manure; Compost+poultry manure+Burkina phosphate). Results showed that legume-cereal rotations resulted in a 2.3% drop in C/N ratio, while the total exchangeable base (TEB) and the cation exchange capacity (CEC) increased by 82.53% and 24.08% respectively compared to the soil at the start of cultivation. Compared to the soil at the beginning of the crop, the soya-fonio rotation resulted in CEC and TEB increases of 26.87% and 86.55% respectively. The Compost+poultry manure treatment recorded significantly higher TEB and CEC contents, followed by the Compost+poultry manure+Burkina Phosphate and Compost+NPK+Urea treatments. Compared to the Compost+NPK+Urea treatment, the Compost+Poultry manure +Burkina Phosphate treatment resulted in TEB and CEC increases of 18.7% and 5.06% respectively. The results showed a negative and non-significant correlation between C/N and the parameters Ca, Na, Mg, TEB, CEC and saturation level. On the other hand, the correlation between C/N and K was positive and non-significant (r=0.036). In a context of high mineral fertilizer costs, fertilization techniques and productivity of systems can therefore be improved by combining local fertilizing resources such as poultry manure, Burkina phosphate and legume rotations.

Phosphorus-Enriched Organomineral Fertilizers Affect the Cation Exchange Algorithm of the Soil: A Comparative Evaluation

The aim of this study is to determine the effects of phosphorus-enriched cattle manure applications on the exchangeable cations content, cation exchange capacity (CEC), and base saturation rate (BSR) of the lime soil. The research was carried out with four different levels (except control) of dairy cattle manure (M1: 10; M2: 20; M3: 30; M4: 40 t ha-1) and with four different levels (except control) of phosphorus dose (P1: 10; P2: 20; P3: 30; P4: 40 kg P ha-1) in the ecological conditions of Southwest Türkiye during the wheat vegetation period of 2019-2021. The study was carried out in medium calcareous soil (14.8%) with three replications randomized blocks experimental by composing organomineral fertilizer combinations. According to the results of the study, the highest change in exchangeable Ca and K content in soils was obtained from organomineral fertilizer applications by 11.2% and 29.7% respectively, and the highest change in exchangeable Mg and Na content was obtained from dairy cattle manure applications by 25.1% and 18.2%, respectively for M4P2 (40 t ha-1 dairy cattle manure + 20 kg P ha-1). Among the fertilization systems, the highest increase in total exchangeable cations was 13.1% and the increase in CEC was 21.3% in organomineral fertilizer applications. The fastest decrease in the BSR was also obtained from the organomineral fertilization system. As a result, it has been determined that M4P2 application is the most economical and the most effective combination in the cation exchange capacity among organomineral fertilizer combinations.

Effect of montmorillonite activation method on formaldehyde content in urea-formaldehyde composites

In this paper, the synthesis of modified urea-formaldehyde (UF) composites with differently activated montmorillonite KSF (UF/KSF) was performed. Two types of montmorillonite (MMT) KSF were used: sample activated with sulfuric acid-KSF(H2SO4) and sample activated with acid and stirring-KSF(H2SO4+stirrer). In order to examine the effect of KSF activation mode on the thermal and hydrolytic stability of UF resins, thermogravimetric analysis (TGA) was performed, as well as A determination of the amount of liberated formaldehyde (FA) after acid hydrolysis. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis were used to characterize the samples of modified UF/KSF composites and differently activated KSF. Activation of KSF led to a decrease in its specific surface area (SSA) and to an increase in cation exchange capacity (CEC). SEM analysis showed that in the KSF(H2SO4+stirrer) sample, the layered microstructure was disrupted. Free formaldehyde was not detected in the sample of UF resin with KSF(H2SO4), and in the sample with KSF(H2SO4+stirrer) it was 0.06%. The UF/KSF(H2SO4) composite showed higher hydrolytic stability (3.9%) compared to UF/KSF(H2SO4+stirrer) (4.62%), but lower compared to the UF/KSF(inactive) (1.23%). TG analysis showed that the KSF(H2SO4) sample had better thermal stability than the KSF(H2SO4+stirrer) sample, but this did not contribute to the better thermal stability of UF/KSF(H2SO4) compared to UF/KSF(H2SO4+stirrer), both samples had a T5% value of 112 °C.

Soil organic matter enhances aboveground biomass in alpine grassland under drought

Increasing the resilience of plant productivity to drought is crucial for provisioning ecosystem services. Although soil organic matter (SOM) promotes plant growth, whether SOM mitigates aboveground biomass (AGB) loss due to drought in alpine grasslands remains unclear. Here, we evaluated the link between AGB and SOM across 209 alpine grassland sites along a 3,500-km aridity gradient on the Tibetan Plateau. We observed that AGB decreased in response to increasing aridity severity only when the aridity level was above a threshold of 0.37. We further found a stronger positive relationship between AGB and SOM in more arid conditions than in less arid ones, with an abrupt increase beyond an aridity threshold of 0.64. Our results confirm that SOM alleviates drought stress on AGB, mainly by reducing bulk density, increasing fine fraction aggregates, and increasing cation exchange capacity. The identified aridity thresholds and mechanisms emphasise the importance of soil carbon sequestration strategies for biomass production and climate change mitigation in arid areas.

Biochar decreases nutrient leaching in KCl-fertilized Podzols grown with black mucuna

Podzols are highly sandy soils, in which elements, such as potassium, needed by crops, are easily leached. Studies have indicated that biochar can contribute to increasing cation exchange capacity of the soil, which can improve the retention of bases. This study aimed to evaluate the effect of the poultry litter biochar combined or not with increasing doses of KCl, on leaching and soil base content, on the production of green manure biomass, and on the distribution of K in [...]

Assessing the potential of co-composting rose waste as a sustainable waste management strategy: Nutrient availability and disease control

The current limited usage of rose waste makes rose cultivation far from a sustainable circular industry. Unfavorable properties of horticultural waste such as the high lignin content of stems and high polyphenol levels in both flowers and leaves makes it difficult to re-use. These traits hamper an effective composting process and so far little studies have focused on optimizing this process. The aim of this study was to investigate the potential of (co-)composting rose waste with other on-farm available green wastes (tomato and kalanchoe) or mature rose compost to obtain an improved compost with high fertilizing capacity. In a small-scale composting system the evolution of five mixtures was closely monitored in terms of their physico-chemical parameters. The in-vitro disease suppressive capacity of mature rose compost was assessed. All mixtures resulted in stable and mature compost after six months showing industry standard suitable macro- and micro-nutrient concentrations. The matured compost showed a C/N below 10, a strong decrease in polyphenols of ≥70% and a good fertilizing capacity with an increase in cation exchange capacity since the start of ≥100%. These results demonstrate that the ligneous character of rose waste is not preventing an effective composting process. However, an increased duration of the maturation phase might be favored for optimal results. The addition of mature compost accelerated the composting process as shown by significantly increases in OM degradation rates. For the first time a high disease suppressive capacity against several common rose pathogens was shown for mature rose compost. Overall, this study showed the potential of (co-)composting rose waste as sustainable waste management strategy to further improve the circular economy waste-based objectives of the horticultural sector.

Unveiling Molecular Transformations of Soil Organic Matter after Remediation by Chemical Oxidation Based on ESI-FT-ICR-MS analysis

Remediation of soils contaminated with organic pollutants is often accomplished by chemical oxidation processes using oxidants such as persulfate or H2O2. However, it is unclear how different oxidants transform soil organic matter (SOM) and affect soil ecosystem services. Herein, two chemical oxidation technologies, Fenton reaction (FT) and base-activation of sodium persulfate (BP), were investigated to remediate diesel-polluted soils. The molecular transformation of SOM was analyzed using excitation–emission matrix fluorescence spectroscopy (EEM FS) and electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS). Fulvic acid-like substances and lipids were consumed in both treatments, while the contents of lignin-like and tannin-like substances increased after BP treatment. The oxygen to carbon ratios (O/C), modified aromaticity index (AImod), and double bond equivalent (DBE) of SOM increased significantly in BP-treated soil, while these parameters decreased in FT-treated soil (FTS), suggesting the oxygen-containing, unsaturated and aromatic compounds were produced in BPS but removed in FTS. The increased cation exchange capacity (CEC) value (81.47 cmol/kg) and germination index of wheat seed (97%) for the SOM in BPS indicate the possible favorable effect of persulfate-based treatment on soil quality. Overall, this study advances mechanistic understanding of the effects of H2O2- and persulfate-based soil remediation technologies based on the molecular compositions of SOM and soil quality.

Geological Controlling Factors of Low Resistivity Shale and Their Implications on Reservoir Quality: A Case Study in the Southern Sichuan Basin, China

At the Changning block and at the Luzhou block, the genetic mechanism of low-resistivity shale and its impact on reservoir quality are currently a hot topic on a world-wide scale. Shale with resistivity lower than 20 Ω·m is widely developed at the Wufeng-Longmaxi Formation in the Southern Sichuan Basin, bringing a considerable challenge for reservoir prediction using the electromagnetic method. This paper discusses the genetic mechanisms and reservoir qualities of three low-resistivity shale reservoir types in the Southern Sichuan Basin (the Changning block and Luzhou block). Three primary elements controlling low-resistivity shale distribution in the Southern Sichuan Basin have been deduced: widely distributed gravity flow deposits, poor structural preservation conditions and shale graphitization caused by Emeishan basalt. Specifically, (1) the shale reservoir with a resistivity &lt;12 Ω·m was uniformly distributed with gravity flow deposits in the Southern Sichuan Basin. High clay mineral contents (especially illite) in gravity flow deposits increased cation exchange capacity and irreducible water saturation at shale reservoir, decreasing electrical resistivity. (2) The resistivity of the shale reservoir close to a complex fault-fracture zone was generally lower than 20 Ω·m, indicating that poor structural preservation conditions played an important role in the wide distribution of low-resistivity shale. The resistivity of the shale reservoir near NE-trending faults at the Changning block was significantly lower than that in other areas. (3) Emeishan basalt caused extensive shale graphitization at the west of the Changning block, which was limited at the Luzhou block. The shale resistivity at the Luzhou block was not affected by graphitization. Among three types of low-resistivity shale, type III was characterized by high quartz content, high TOC, high porosity, high gas content and low graphitization. Although the resistivity of type III is generally lower that 20 Ω·m, it is still a favorable exploration target in the Southern Sichuan Basin.

Recycling paper to recarbonise soil

Soil organic carbon can be increased through sympathetic land management and/or directly by incorporating carbon rich amendments. Herein, a field experiment amended paper crumble (PC) to soil at a normal deployment rate of 50 t ha−1, and at higher rates up to 200 t ha−1. The nominal 50 t ha−1 PC amendment resulted a mean increase in soil carbon of 12.5 g kg−1. Using a modified Roth-C carbon fate model, the long-term (50 years) carbon storage potential of a 50 t ha−1 PC amendment was determined to be 0.36 tOC ha−1. Modelling a rotational (4 yearly) 50 t ha−1 PC amendment indicated 6.65 tOC ha−1 uplift would accrue after 50 years. Contextualised for the average farm in the East of England (~120 ha, with 79 % as arable), PC derived increases in SOC would be equivalent to 2310 t CO2e. These results support the use of PC to deliver significant levels of soil recarbonisation. Beyond carbon, PC was observed to influence other soil properties. Benefits observed included, decreased bulk density, increased water holding capacity, and increased cation exchange capacity. While PC amendment did not significantly increase wheat (Triticum aestivum) crop yield, manifold benefits in terms of increased SOC, long-term carbon storage potential, and improved soil quality sustain PC as a beneficial soil conditioner.

Mineral Neutralizers as a Tool for Improving the Properties of Soil Contaminated with Copper

In phytoremediation processes implemented in highly contaminated areas, there is a high risk of contaminant toxicity during the germination of freshly sown plants. In such conditions, it is recommended to support phytoremediation by using neutralizing additives. The present study aimed at assessing the effect of the addition of mineral neutralizers (MNs), i.e., limestone, clay, and zeolite, to soil contaminated with copper (0, 200, 400, 600 mg kg−1). Basic soil indicators were analyzed, such as pH, hydrolytic acidity (HAC), total exchangeable bases (TEB), cation exchange capacity (CEC), base saturation (BS), electrolytical conductivity (EC), total organic carbon (TOC), total nitrogen (Ntot), carbon to nitrogen ratio (C:N),, and interactions of soil micronutrients, such as Cu, Zn, Cd, Cr, Ni, Pb, Mn, and Fe with MNs. Copper contamination significantly decreased the soil pH and increased its HAC. A decrease in the share of TEB was found, which resulted in a decrease in the CEC and in BS of the soil. Among the additives, limestone had the most beneficial effect on reducing soil acidity, contributing to a significant increase in TEB, CEC, and BS. The least favorable effect was shown for clay, which generally caused the deterioration of soil properties. The MNs significantly increased the content of Zn, Cr, and Fe and lowered the content of Ni in the soil compared to the control. The demonstrated interactions indicate the diversified activity of MNs at different levels of soil contamination with copper.

Influence of poultry litter on nutrient availability and fate in plant-soil systems: A meta-analysis

Interest in using poultry litter (PL) as a nutrient source for crop production has increased in recent years. Utilization of PL can increase soil residual nutrients, thereby potentially increasing soil fertility and crop nutrient uptake. Conversely, PL addition may increase the transport of nutrients to the environment. This study aimed to elucidate the influence of PL on plant nutrient uptake, soil fertility, and environmental issues as compared to commercial fertilizer (CF) using a meta-analytic assessment. The synthesis was based on 134 studies (3,362 comparisons). Positive effects on soil fertility were observed, with PL significantly increasing cation exchange capacity (CEC), pH and soil carbon (C), total nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), and zinc (Zn) concentrations compared to CF. Effects of PL on plant macro- and micronutrients varied depending on the plant tissue parts evaluated when compared to CF, with the leaves and stems generally having lower nutrient concentrations than the reproductive parts. Poultry litter influenced plant nutrient uptake, with a slightly negative effect being observed for N but significant positive effects for P and K. In addition, our results showed that litter application significantly increased carbon dioxide (CO₂) and nitrous oxide (N₂O) fluxes, but decreased nitric oxide (NO) emission. Subsurface-banding application of PL significantly decreased N and P loss in runoff. Overall, this meta-analysis validates the positive effects of PL on plant nutrient uptake and soil fertility and demonstrates that PL can be an effective alternative nutrient source to CF for crop production.