Changes In Soil Chemical Properties Research Articles

Dairy effluent applications to a pasture enhance soil fertility and microbial activity without impacting soil bacterial and fungal community composition

Farm dairy effluents (FDE) from washing the milking parlor contain manure, urine, and chemicals and constitute a large amount of wastewater. Applying FDE as soil fertilizers to pastures can enhance forage yield and improve soil nutrient status. Since the dairy industry is increasingly attempting to maximize returns through better utilization of forage with lesser inputs, there is demand for a supply of FDE as fertilizers. Nevertheless, the impact of this practice on soil microbiota remains largely unexplored. It must be studied before large-scale soil disposal to avoid diminishing microbial diversity or enhancing pathogen abundance. This study evaluated the effects of applying lagoon-stored (Lagoon) and raw dairy effluents (Raw) at a rate of 50 kg N ha−1 in four equal doses, in comparison to urea fertilization, on soil fertility and the activity, abundance, and community structure of soil microbiota. Raw was obtained after solid separation, and Lagoon corresponds to the Raw stationed in a two-lagoon system. Microbial activity was assessed as basal respiration, potentially mineralizable N, potential nitrification activity, and enzymatic activities. The catabolic activity of the microbial community was evaluated using Biolog Ecoplates™. Bacterial and fungal community composition and diversity were analyzed through amplicon sequencing of 16S rRNA and ITS2. The application of FDE benefited soil fertility and microbial activity. Lagoon had the most potent effects on soil available P and extractable K+, Na+, Mg2+ and Ca2+. Soil treated with Raw displayed higher microbial activities, such as dehydrogenase, basal respiration, urease, and potentially mineralizable N, than the other treatments. FDE did not significantly alter the microbial composition, abundance, or functional diversity. In conclusion, in this short-term trial, despite changes in soil chemical properties and microbial activity, the composition and diversity of the bacterial and fungal communities remained unaffected by FDE irrigation.

Perubahan Sifat Kimia Tanah Tercemar Merkuri Dengan Berbagai Modifikasi Pemberian Biochar Dan Tanaman Akar Wangi (Vetiveria zizanioides (L.)

This research aims to determine changes in the chemical properties of mercury-contaminated soil with various modifications in the application of biochar and vetiver grass (Vetiveria zizanioides (L.). This research uses an experimental method with an ex-situ remediation approach which was carried out from October 2023 to January 2024 at greenhouse. Sampling of mercury-contaminated soil was carried out on former traditional gold mining land in Segubuk Hamlet, Kuang Village, Taliwang District, West Sumbawa Regency. Soil sampling was carried out at 13 locations determined by purposive sampling and carried out using a soil drill soil (pH H2O, C-organic and CEC) as well as analysis of the total concentration of mercury (Hg) in the soil before and after the experiment. The results showed that the application of biochar alone and biochar planted with vetiver grass (Vetiveria zizanioides (L.) had a significant effect) on changes in soil chemical properties and is effective in reducing the concentration of mercury (Hg) in the soil. Biochar application can improve soil chemical properties by increasing pH, organic C, and soil CEC. On the other hand, the release of H+ ions from the carboxyl functional group (-COOH) in biochar has the opportunity to form complexes with heavy metal ions so that it can reduce their concentration in the soil.

The Potential Impact of Long-Term Copper Fungicide Sprays on Soil Health in Avocado Orchards

The long-term use of copper (Cu)-based fungicide sprays in orchards is associated with changes in soil Cu levels. However, there is a gap in knowledge regarding the potential accumulation of Cu in orchards and the associated impacts on the soil microbial structure. This study assessed the possibility of Cu accumulation in different avocado orchard farms and further evaluated the potential effect on soil microbial activities. Soil Cu levels were quantified in Tauranga and Northland, and three avocado orchards were analysed in each experimental location. All avocado farms in both sites received Cu-based fungicide sprays for over eight years. Soil samples were collected at a 0–20 cm depth from all six orchards. The soil total and bioavailable Cu, changes in soil chemical properties, microbial biomass, dehydrogenase activity, alkaline phosphatase activity, and acid phosphatase activity were measured. The results revealed that the total Cu and bioavailable Cu concentrations in Tauranga orchards were 81.3 and 0.32, 196.7 and 0.82, and 33.6 and 0.31 mg Cu kg−1 in Farms 1, 2, and 3, respectively. In Northland orchards, the total Cu and bioavailable Cu were 54.5 and 0.06, 18.4 and 0.77, and 46 and 0.34 mg Cu kg−1 in Farm 1, 2, and 3, respectively. Five out of six of the avocado orchard farms assessed in this study had total Cu concentrations greater than 30 mg Cu kg−1 reported in New Zealand native land. The magnitude of Cu accumulation was linked with soil pH and C content. No clear trend was observed between soil Cu concentrations and the soil microbial activity. Our study results demonstrated that the long-term use of Cu-based fungicide sprays can elevate Cu concentrations in orchard soils. Mitigation strategies need to be explored to abate the accumulation of Cu in orchard soils.

Response of Soil Chemical Properties under Tef (Eragrostis tef (Zucc.) Trotter) Field to Integrated Application of Lantana camara L. Weed Vermicompost and NPS Mineral Fertilizer

Recently, the beauty of the environment, native forest plants, and crops were encroached with invasive weeds, and thus scientific community was concerned with searching for optional management of these horrible weeds. Accordingly, vermicomposting of invasive weeds with the purpose of utilization management was evaluated as an alternative option and cost-effective management. Utilization management included keeping the environment safe from expanding invasive weeds by using these weeds as vermicomposting materials. Consequently, vermicompost was produced from L. camara invasive weed and this produced vermicompost was interactively used with chemical fertilizer to appraise its effect on soil chemical properties after the tef crop was harvested. The experiment was arranged in a randomized complete block design (RCBD) in a factorial combination with three replications. Four levels of L. camara vermicompost amendment (0, 2, 4, and 6 t·ha−1) and four levels of NPS fertilizer (0, 100, 150, and 200 kg·ha−1) were used in the combination of the treatments. Disturbed composite soil sampling at a depth of 20 cm was carried out, one sample before planting and 48 samples after harvesting of the tef crop. The results showed that the combined addition of vermicompost and NPS fertilizers at the rate of 6 t·ha−1 and 200 kg·ha−1, respectively, significantly increased plant-available phosphorus (Av. P). Reversely, the pH of the soil remained unchanged when the soil was treated with the integration of vermicompost and NPS fertilizer or at their separate individual application. Most of the soil chemical properties, i.e. soil organic carbon (SOC), electrical conductivity (EC), Av. P, total nitrogen (TN), carbon-to-nitrogen ratio (C : N), and cation exchange capacity (CEC) were found to be improved when the soil was amended with the highest dose of sole L. camara vermicompost fertilizer. The two-year consecutive organic fertilizer fertilization rate increased SOC from 63.64% to 107.56%, EC from 8.70% to 22.22%, Av. P from 40.87% to 143.13%, TN from 50% to 100%, C : N ratio from 8.14% to 11.58%, and CEC from 42.11% to 63.67% versus untreated plot. Single-application NPS chemical fertilizer has only an encouraging effect on Av. P and CEC of soil. The principal driving factor for any change in soil chemical properties was the L. camara vermicompost amendment. Therefore, using L. camara weed as a vermicompost can enhance soil fertility. This study offers the opportunity to convert the large biomass of L. camara weed into vermicompost through vermicomposting.

Multi-year crop rotation and quicklime application promote stable peanut yield and high nutrient-use efficiency by regulating soil nutrient availability and bacterial/fungal community.

Diversifying cultivation management, including different crop rotation patterns and soil amendment, are effective strategies for alleviating the obstacles of continuous cropping in peanut (Arachis hypogaea L.). However, the peanut yield enhancement effect and temporal changes in soil chemical properties and microbial activities in response to differential multi-year crop rotation patterns and soil amendment remain unclear. In the present study, a multi-year localization experiment with the consecutive application of five different cultivation managements (including rotation with different crops under the presence or absence of external quicklime as soil amendment) was conducted to investigate the dynamic changes in peanut nutrient uptake and yield status, soil chemical property, microbial community composition and function. Peanut continuous cropping led to a reduction in peanut yield, while green manure-peanut rotation and wheat-maize-peanut rotation increased peanut yield by 40.59 and 81.95%, respectively. A combination of quicklime application increased yield by a further 28.76 and 24.34%. Alterations in cultivation management also strongly affected the soil pH, nutrient content, and composition and function of the microbial community. The fungal community was more sensitive than the bacterial community to cultivation pattern shift. Variation in bacterial community was mainly attributed to soil organic carbon, pH and calcium content, while variation in fungal community was more closely related to soil phosphorus content. Wheat-maize-peanut rotation combined with quicklime application effectively modifies the soil acidification environment, improves the soil fertility, reshapes the composition of beneficial and harmful microbial communities, thereby improving soil health, promoting peanut development, and alleviating peanut continuous cropping obstacles. We concluded that wheat-maize-peanut rotation in combination with quicklime application was the effective practice to improve the soil fertility and change the composition of potentially beneficial and pathogenic microbial communities in the soil, which is strongly beneficial for building a healthy soil micro-ecology, promoting the growth and development of peanut, and reducing the harm caused by continuous cropping obstacles to peanut.

Effect of intercropping maize and sunn hemp at different times and stand densities on soil properties and crop yield under in-field rainwater harvesting (IRWH) tillage in semi-arid South Africa

Abstract Background Evidence suggests that manipulating intercropping timing and stand density within intercropping systems could enhance crop yields. However, our current understanding of the effects of intercropping a cover crop on soil chemical properties and moisture still needs to be improved. This study investigates the effects of intercropping sunn hemp with maize at different timings and stand densities on selected soil properties and crop yield. Materials and methods A split-plot experiment was conducted under the in-field rainwater harvesting (IRWH) tillage. The trial had three intercropping times (simultaneously with maize planting, at V15 maize growth stage, and R1 maize growth stage) as the main plot factors and three stand densities (16, 32, and 48 plants m−2) as the subplot factors, with three replicates for both the 2019/20 and 2020/21 seasons. Changes in soil properties were assessed within the uppermost layer (0-30 cm). Soil moisture content was continuously monitored throughout the growing season and specific soil chemical properties were analyzed at harvest. Results The results showed that the interaction of sunn hemp intercropping period and stand densities did not significantly influence most of the measured soil properties. The early planting of sunn hemp had significantly 32.4% higher soil organic matter (SOM) than the last planting date at low stand density. After two growing seasons SOM, nitrogen, potassium, and manganese were significantly enhanced by 39.7%, 19.0%, 21% and 60.6% respectively. However, during the same period calcium, sodium and iron were significantly reduced by 13.4%, 46.1% and 78.0% respectively. The management of sunn hemp crop had significant effect on maize grain yield across the two seasons. The maize yields in the medium and high stand densities in the first season were significantly 15.3% and 34.3% higher than in the second season, respectively. Conclusion Due to the intercropping treatments, the retention of sunn hemp residues with varying quantities and qualities may have influenced the soil nutrient dynamics in the short-term. Significant changes in soil chemical properties and yield may need more time, and future research should be conducted out in agricultural regions with different soil mineral matrices.

Changes in Soil Chemical Properties and Growth of Palm Oil (Elaeis guineensis Jacq) with Comparative Composition of Plant Media

One of the benefits of Oil Palm Empty Fruit Bunches (OPEFB) waste can be processed into bokashi as a planting medium for oil palm nurseries. The research aims to: Determine changes in soil chemical properties due to the comparison of planting media, and obtain the best ratio of planting media to the best seedling growth in Main-Nursery. The research was conducted in Koto Panjang Ikur Koto Village, Koto Tangah District, Padang City. The study was conducted in January-April 2022. RAL design (completely randomized design) with 4 treatments and 6 replications. One experimental unit consist of 3 polybags of plants so there are 72 polybags of plants. Treatment: A = Control (Without Bokashi OPEFB), B = Topsoil: Bokashi OPEFB (1:3), C = Topsoil: Bokashi OPEFB (1:1), and D = Topsoil : Bokashi OPEFB (3:1). The results showed: Treatment B or Topsoil : Bokashi OPEFB (1:3) is the best, cause increase in soil chemical properties: pH 1.17 units; C-organic 1.98%; N-total 0.11%; P-available 4.01 ppm; K-dd 0.48 me/100g; Mg-dd 1.42 me/100g; and Ca-dd 2.67 me/100g. OPEFB bokashi application was significantly different to increase the plant height, not significant to wet weight and dry weight of the plant.

Does century-old biochar affect soil interrill erodibility on cropland soils? A study on pre-industrial kiln sites

Adding biochar to soils is being advocated to mitigate soil erosion. However, given biochar aging and persistency in soils, the effects of biochar on soil in the long-term are important to investigate yet remain largely unknown. The objective was therefore to determine the long-term effect of biochar on interrill erosion on cropland soils. Experiments were conducted using topsoil from three fields of different textures (silt loam, loam and sandy loam). Each field was characterized by the presence of kiln sites containing century-old charcoal used as proxy to investigate the long-term impact of biochar. Aggregate stability was measured using the method of Le Bissonnais (1996), whereas interrill erosion was studied using two successive (24-h apart) rainfall simulation experiments (84 mm h−1, 90 min.). The presence of historical charcoal in kiln sites did not affect soil aggregate stability, irrespective of charcoal-C content or soil type. For the first rainfall simulation only, the century-old charcoal reduced both the final runoff and soil loss rates by, respectively, 15.4 mm h−1 and 12.1 g m−2 h−1 for each percent increase in charcoal-C content. As a result, Meyer’s interrill erodibility decreased with increasing charcoal-C content. However, because the final runoff and soil loss rates decreased to a similar extent with increasing charcoal-C content, Kinnell’s interrill erodibility was unaffected by charcoal-C content. These effects on interrill erosion parameters were independent of soil type and could not be related to changes in soil chemical properties. The measured reduction in runoff and soil loss were attributed to delayed crust development, which could be related to increasing proportions of clods in the soil samples with increasing charcoal-C content. Further research may be needed to confirm the observed trends and underlying mechanisms over a wider range of soil types.

Impact of Pyrolyzed and Unpyrolyzed Animal Manures on Soil Properties, Carbon Sequestration, and Clover Productivity in Andisol

The use of organic waste in agricultural soil can enhance crop yields, improve waste management, and boost soil carbon (C) sequestration. However, more field data are required to fully understand the impacts of pyrolyzed and unpyrolyzed animal manures. The objectives of this study were (i) to analyze the impact of two pyrolyzed and unpyrolyzed manures on soil properties, soil C storage, and clover productivity and (ii) to examine the biochar’s movement through the soil profile. Poultry litter (PL), dairy manure (DM), poultry litter biochar (PLBC), and dairy manure biochar (DBC) were applied at rates of 8 t ha−1 in a field experiment with red clover (Trifolium pratense L. var. Quiñequeli) in an Andisol. We monitored changes in soil chemical properties, foliar properties, and crop yield after three clover cuttings. To examine the movement of biochars through the soil profile, we set up a lab experiment where field conditions were simulated. PLBC, DBC, and PL increased soil pH by 0.5 (6.44), 0.28 (6.22), and 0.25 (6.19) units, respectively. Soil available P increased in both pyrolyzed and unpyrolyzed PL treatments (by 8.53 mg P kg−1, on average). Clover yields only increased in treatments with amendments that provided more available P and increased the pH. The addition of DBC increased soil total C (30.3%). Both biochars added to the soil surface exhibited little movement through the soil profile (2 to 4 cm). In this study, the pyrolysis of manures emerged as an option for reducing waste volume from the farming industry. Manure biochars proved useful at low rates for enhancing crop yields (PLBC) and storing C in the soil (DBC).

Different responses of lipids and lignin phenols to nitrogen addition in meadow grassland soil

PurposeNitrogen (N) enrichment can affect the composition and stability of soil organic carbon (SOC) pools by altering vegetation and soil properties. However, the response of plant-derived carbon components in soil to different N addition levels is unclear. We investigated the changes and potential driving processes of plant-derived carbon components (especially lignins and lipids) in meadow grassland soils under long-term N addition in eastern Inner Mongolia, China.Materials and methodsBiomarker technology was utilised to analyse changes in plant-derived carbon components (C>20 free lipids, bound lipids, and lignin phenols) in soil under different N addition levels, including changes in soil chemical properties, enzyme activity, plant biomass, and diversity under N addition, as well as the specific pathways involved.Results and discussionWe found that high levels of N addition significantly reduced the concentration of soil lignin phenols whereas increased the accumulation of lipids (free and bound lipids). Compared with changes in plant biomass and diversity, soil chemical properties and enzyme activity play a more significant role in regulating the accumulation and degradation of plant-derived carbon. Structural equation modelling (SEM) showed that decreases in lignin phenol concentration were related to specific biochemical decomposition processes (increased polyphenol oxidase activity and decreased C/N). The increase in lipids associated with the protective effects of minerals mediated by pH.ConclusionsIn general, plant-derived carbon components showed inconsistent responses to N addition, lignin phenol concentration decreased and lipid concentration increased, which was mainly related to the change of soil biochemical properties. Plant-derived carbon components only showed significant changes under high N addition levels. Furthermore, our research indicates that SOC sequestration and functioning are highly dependent on soil biochemical properties, which weakens the influence of changes in plant carbon input on soil carbon storage.

A novel biochar-augmented enzymatic process for conversion of food waste to biofertilizers: Planting trial with leafy vegetable

The present study developed a novel biochar-augmented enzymatic approach for fast conversion of food waste to solid and liquid biofertilizers. By augmented with 10 % of biochar and mediated with 5 % of food waste-derived hydrolytic enzymes mixture (i.e. fungal mash), 100 kg of food waste could be converted into 22.3 kg of solid biofertilizer with a water content of 30 % and 55.0 kg of liquid biofertilizer, which fulfilled Chinese national standards for solid and liquid organic biofertilizers, respectively. Field plantation results showed that the Pak Choi grown on food waste-derived biofertilizers was comparable with that on commercial ones, in terms of the vegetable productivity and nutrient contents. It was further revealed that the application of food waste-derived biofertilizers did not change soil chemical properties but enriched microbial diversity. This study clearly indicated that the biochar-augmented enzymatic approach for food waste conversion to biofertilizers was technically feasible and economically viable towards circular agriculture economy.

Zinc speciation in highly weathered tropical soils affected by large scale vegetable production

Agriculture in highly weathered tropical soils often requires considerable application of lime and fertilizers to ensure satisfactory plant nutrient levels. The consequences of these continue long-term applications is not well understood may induce changes in soil chemical properties, the abundance, and speciation of potentially toxic trace element and as well as of micronutrients in agriculture soils. In this study, we evaluated the adsorption (at pH 5) and speciation of Zn in tropical soils (both agricultural and native vegetation) as a function of fertilization and contact time using chemical fractionation analyses and X-ray absorption spectroscopy. The soils overall had high Zn adsorption capacities (∼ 700 mg kg-1), but the agricultural soil was approximately 30 % higher than of the soil under native vegetation, and the proportion of Zn in the mobile fraction was 35 % in native vegetation and 21 % in agricultural soils. Zn speciation via linear combination analysis showed a strong relationship with soil mineralogical composition and reveled that Zn associated with organic matter decreased while Zn associated with P increased after the conversion of soils from native vegetation to highly fertilized soil. Aluminosilicate soil minerals were identified as major sinks of soil Zn, accounting for 34 % of total Zn retention regardless of soil origin and land use. Association of Zn with phosphate (i.e., hopeite) was observed in the agricultural soil samples, which might be an unexpected Zn-bearing mineral in highly weathered tropical soils and could have impacts on Zn plant nutrition.

Change of soil chemical properties and the growth of Pogostemon cablin Benth on nickel-mined soil amended with rice husk charcoal

Nickel is an important main resource mineral in Southeast Sulawesi, which has deposited around 97.4 billion tons, and undoubtedly, nickel exports emerged in national and regional economic growth. Mining activities were carried out through topsoil and subsoil stripping, resulting in damage to the soil ecosystem and making it difficult for soil to recover. A study was performed to evaluate the changes in soil chemical properties and the growth of patchouli (Pogestemon cablin Benth) on nickel-mined soil treated with rice husk charcoal (RHC). A randomized block design was applied in this study, including six treatments of RHC with three replications. The treatments were without RHC (control), 1.5%, 3.0%, 4.5%, 6%, and 7.5% of soil weight. Data were analyzed descriptively for soil chemical properties; meanwhile, ANOVA was applied for plant growth. The results revealed that RHC increased soil pH, organic C, CEC, and available P, and conversely, the application of 4.5% of RHC decreased soil Ni and Fe content by 65.43% and 40.47%, respectively. The application of RHC up to 6% increased significantly the plant height and number of leaves as well as the dry weight of patchouli. The present study concluded that the use of carbon-rich soil conditioners such as rice husk charcoal is an imperative measure to restore the nickel-mined soil.

Enhanced Nitrogen Fertilizer Input Alters Soil Carbon Dynamics in Moso Bamboo Forests, Impacting Particulate Organic and Mineral-Associated Carbon Pools

The application of nitrogen fertilizer is crucial in the cultivation of bamboo forests, and comprehending the alterations in soil organic carbon (SOC) due to nitrogen application is essential for monitoring soil quality. Predicting the dynamics of soil carbon stock involves analyzing two components: particulate organic carbon (POC) and mineral-associated organic carbon (MAOC). This study aimed to investigate the impact of high nitrogen inputs on SOC stock in Moso bamboo forests located in southwestern China. The research focused on analyzing changes in soil chemical properties, SOC content, and its components (POC and MAOC), as well as microbial biomass in the surface layer (0–10 cm) under different nitrogen applications (0, 242, 484, and 726 kg N ha−1 yr−1). The results indicate that nitrogen application significantly reduced the SOC content, while concurrently causing a significant increase in POC content and a decrease in MAOC content within the Moso bamboo forest (p < 0.05). The HM treatment notably increased the NO3−-N content to 2.15 mg/kg and decreased the NH4+-N content to 11.29 mg/kg, although it did not significantly influence the microbial biomass carbon (MBC) and nitrogen (MBN). The LN and MN treatments significantly reduced the MBC and MBN contents (71.6% and 70.8%, 62.5% and 56.8%). Nitrogen application significantly increased the Na+ concentration, with a peak observed under the LN treatment (135.94 mg/kg, p < 0.05). The MN treatment significantly increased the concentrations of Fe3+ and Al3+ (p < 0.05), whereas nitrogen application did not significantly affect Ca2+, Mg2+ concentration, and cation exchange capacity (p > 0.05). Correlation and redundancy analyses (RDAs) revealed that the increase in annual litterfall did not significantly correlate with the rise in POC, and changes in extractable cations were not significantly correlated with the decrease in MAOC. Soil nitrogen availability, MBC, and MBN were identified as the primary factors affecting POC and MAOC content. In conclusion, the application of nitrogen has a detrimental impact on the soil organic carbon (SOC) of Moso bamboo forests. Consequently, it is imperative to regulate fertilization levels in order to preserve soil quality when managing these forests. Our research offers a theoretical foundation for comprehending and forecasting alterations in soil carbon stocks within bamboo forest ecosystems, thereby bolstering the sustainable management of Moso bamboo forests.

Changes in Soil Chemical Properties and Rhizosphere Bacterial Community Induced by Soil Amendments Associated with Reduction in Cadmium Accumulation by Rice

Soil amendments have been extensively employed for the purpose of remediating soils contaminated with cadmium (Cd). However, the potential impacts of soil amendments on soil chemical properties, soil Cd bioavailability, total Cd accumulation by rice, and rhizosphere bacterial community in Cd-contaminated paddy fields located in a tropical region is still at its infancy. In this study, a commercial MgO-CaO-SiO2 conditioner (A), biochar (B), and a combination of the commercial MgO-CaO-SiO2 conditioner and biochar with a ratio of 1:1 (C) were applied at two different doses [2250 kg ha−1 (A150, B150, C150), 4500 kg ha−1 (A300, B300, C300)] to investigate their impacts on soil Cd stabilization and total Cd uptake of rice straw and grain in a Cd-contaminated remediation field experiment. Rhizosphere bacterial community diversity and composition were also assessed using high-throughput sequencing based on 16S rRNA genes. Compared with non-amendment treatment (CK), soil pH, cation exchange capacity (CEC), organic matter (OM), total nitrogen (TN), available nitrogen (AN), and nitrate (NO3−) concentrations were significantly elevated, whereas ammonium (NH4+) and soil available Cd concentrations were reduced by soil amendment treatments. Meanwhile, soil amendments significantly decreased concentrations of total Cd in both rice straw and grain, with the lowest Cd concentration in the C300 treatment. Soil pH and CEC were significantly and negatively associated with soil Cd availability and rice straw and grain Cd concentrations, while NH4+ concentration was positively correlated with soil available Cd concentration, and OM, TN, and NO3− concentrations were positively linked with rice grain Cd concentration. Soil amendments significantly increased bacterial Chao 1 and Shannon indexes and altered bacterial community composition in rhizosphere soil, due to changes in the composition of the community primarily influenced by variations in soil pH, CEC, and soil available Cd, NH4+, available phosphorous (AP) and available Potassium (AK) concentrations. Furthermore, the abundant bacterial species (Pseudomonas) and rare bacterial species (Bacillus, Candidatus_Solibacter and Streptomyces) have been up-regulated by different soil amendments, which might be in favour of soil Cd immobilization. A structural equation model also showed that soil amendments could improve bacterial diversity and change soil pH and CEC, which were conducive to hindering the removal and conversion of Cd. Overall, these results indicate that biochar-(MgO-CaO-SiO2) mixed amendments at high dosage exerted better performance compared with single application soil amendment A and B. The changes in soil chemical properties, available Cd content, and rhizosphere bacterial community assembly induced by soil amendments are closely correlated with the decrease in rice’s ability to accumulate Cd.

Functional leaf-trait variability and herbivory in oaks along a Mexican avocado agrosystem mosaic

Land-use changes transforming forested landscapes to avocado orchards affect abiotic conditions and ecological processes. As a consequence, such changes can also affect leaf functional traits expression of co-occurring trees in orchards and related plant–insect interactions. Here, we evaluated changes in chemical soil properties and the effects of micro-climatic variables on leaf functional traits and herbivory in Quercus castanea and Q. obtusata in fragments occurring in a mosaic with avocado orchards. We differentiate three cases: forest cover > orchards, forest cover = orchards and forest cover < orchards in Michoacan state, Mexico. In each case, at least 17 individuals of each oak species were selected to analyze leaf functional traits and herbivory. Soil samples were collected to analyze chemical properties. Soils of areas with higher proportion of forest had higher concentrations of NH4+ and K+, whereas soils with higher proportion of orchards displayed higher concentrations of Mg2+, NO3− and SO42−. Leaf thickness, fresh mass and water content were higher in areas with higher forest cover and were influenced by Mg2+, NO3−, SO42- and local climatic variables. Leaf dry weight, specific leaf area, leaf area and chlorophyll content, as well as herbivory were higher in areas with higher proportions of orchards and were affected by PO43−, total P, K+, NH4+, and by local climatic variables. These results highlight the responses and links of plant functional traits associated with soil properties and local climatic variables and their possible consequences of biotic interactions in a landscape mosaic with different covers of avocado orchards and temperate forests.

Soil chemical properties 12 years after termination of cattle manure and swine effluent applications

AbstractFor how long the nutrient supply from long‐term application of manure and swine effluent will last to sustain crop production after applications had ceased is a research gap. We quantified the change in soil chemical properties 12 years after cattle manure and swine effluent applications had ceased. Data were collected in 2008 (termination of applications) and 2020 on a long‐term animal waste study at the Kansas State University, Southwest Research‐Extension Center near Tribune, KS. Treatments were three levels of cattle manure and swine effluent (phosphorus, P; nitrogen, N; and 2N) and an untreated control. Soil profile NO3‐N declined 78%–95%, 70%–82%, and 58% from the initial amount in 2008 compared to the amount remaining in 2020 in the swine effluent, cattle manure, and an untreated check, respectively. Profile NO3‐N levels were greatly elevated by the P‐based swine effluent treatment and the 2N rate of both cattle manure and swine effluent and remained high (&gt;250 kg ha−1) after 12 years. Total nitrogen in the surface soil decreased by 11%–27% for cattle manure treatments with little change in the swine effluent and check treatments. Total carbon concentration in the surface soil decreased from 22% to 31% for cattle manure treatments and from 7% to 14% for swine effluent and check treatments. Mehlich‐3 P decreased significantly for the cattle manure treatments (41%–53%) but still remained very high (&gt;100 mg kg−1). Soil test P levels in the swine treatments were similar to the check treatment. Application of cattle manure and swine effluent has lasting effects on many soil chemical properties long after ceasing applications.

Lime and gypsum application to low-acidity soils: Changes in soil chemical properties, residual lime content and crop agronomic performance

Crop yield gains and improvements in surface and subsurface soil chemical properties are evident when agricultural lime and gypsum are used in high-acidity soils. However, there is scarce information on the effects of lime and gypsum application on no-till tropical soils previously treated with these additives (low-acidity soils). The duration of the effects of lime applied to the soil surface varies according to lime rate, product characteristics, soil conditions, and water and thermal regimes. Such residual effects influence the timing of lime reapplication. This study aimed to investigate the effects of surface application of agricultural lime and gypsum on soil chemical properties, soybean and second-crop corn yields, and lime residual contents. The experiment was conducted on a Red Latosol with a very clayey texture in Floresta, Paraná, Brazil. Four rates of dolomitic lime (0.0, 2.6, 5.4, and 8.1 Mg ha−1) and agricultural gypsum (0, 4, 8, and 12 Mg ha−1) were used. The experimental design was a randomized complete block with subplots and four replications. The experiment lasted for four soybean seasons and three second-crop corn seasons. At 6, 12, 24, and 36 months after treatment, soil samples were collected from the 0.00–0.05, 0.05–0.10, 0.10–0.20, 0.20–0.30, 0.30–0.40, and 0.40–0.60 m layers for chemical analysis. No significant interaction effects were observed on soil chemical properties. Liming resulted in soil alkalization, with a consequent reduction in Al3+ and an increase in Ca, Mg, base saturation, and pH. Residual lime was not detected in layers deeper than 0.05 m, suggesting a lack of physical movement of particles in the soil pore space. Residual lime was detected on surface soil (0.00–0.05 m) up to 36 months after application, demonstrating the low reactivity of lime on no-till soils. At 6 months after gypsum application, there was an increase in Ca2+ levels up to the 0.6 m layer, whereas Mg2+ levels were reduced throughout the soil profile for up to 36 months. In no-till soybean–second-crop corn rotation systems, use of agricultural gypsum alone did not provide consistent effects on crop yield and reduced foliar Mg contents. Under the studied conditions of low acidity, liming did not produce significant differences in crop yield but improved soil chemical properties for plant growth under no-till.

PENGARUH BIOCHAR TERHADAP BEBERAPA SIFAT KIMIA TANAH DAN PERTUMBUHAN TANAMAN NILAM (Pogostemon cablin Benth) PADA TANAH TAMBANG NIKEL

The purpose of this study is to know the effect of application of rice husk biochar on changes in soil chemical properties and the growth of patchouli plants (Pogestemon cablin Benth). The research was conducted at Field Laboratory II, Faculty of Agriculture, Halu Oleo University in October-December 2022. This study used a Randomized Block Design (RBD) consisted of 6 treatments biochar, which are B0 = without biochar (control), B1 = 75 g polybag-1, B2 = Biochar 150 g polybag-1, B3 = 225 g polybag-1, B4 = 300 g polybag-1, B5 = 375 g polybag-1. The results showed that biochar increase soil pH from 5.76 to 6.57, CEC from 22.79 me 100 g-1 to 39.36 me 100 g-1, Available-P from 4.71 ppm to 13.04 ppm, Organic-C from 0.20% to 1.08%, and in constrast reduced Ni content from 776.10 ppm to 234.93 ppm, Fe from 6433.53 ppm to 3450.93 ppm. The application of rice husk charcoal affected significantly , the plant height, number of leaves and dry weight of plants. Biochar application up to 300 g polybag-1 (B4) is the most efficient dose to increase patchouli plant growth on nickel mine soil.Keywords: Biochar, ex- Nickel mining soil, Patchouli plant, soil chemical properties.

Regulation of soil enzyme activity and bacterial communities by food waste compost application during field tobacco cultivation cycle

Food waste (FW) composting is an effective waste resource utilization method; however, only limited approaches of FW compost application in agriculture have been investigated. This study reports changes in soil chemical properties, enzyme activities, and bacterial communities at different tillage stages and its effects on tobacco biomass after FW compost application in tobacco cultivation field experiments. The results showed that FW compost increased tobacco biomass. Also, FW compost functioned as a fertilizer that acted mainly during the maturity (September) and fallow (December) periods of tobacco, and its effect was enhanced with increasing application rates. FW compost significantly increased soil pH, organic carbon, total nitrogen, total phosphorus, alkaliolytic nitrogen, and available phosphorus content. It enhanced soil urease, acid phosphatase, fluorescein diacetate hydrolase, and polyphenol oxidase activities. FW compost application increased soil bacterial diversity, increasing the relative abundance of dominant bacteria such as Proteobacteria and Bacteroidetes while decreasing the relative abundance of Acidobacteria and Chloroflexi. Bacterial chemoheterotrophy, aerobic_chemoheterotrophy, ureolysis, chloroplasts, nitrogen_fixation, and fermentation functions were enhanced, and the complexity of ecological networks among bacterial species increased. A combined ranking analysis showed that the soil's available phosphorus, pH, alkaline nitrogen, and total phosphorus content were the main factors influencing bacterial population dynamics. In conclusion, FW composts can be used as an alternative to fertilizers. They exerts their beneficial properties by regulating bacterial communities mainly through soil chemistry, indirectly enhancing soil enzyme activity, and increasing tobacco yield.