Improve Soil Chemical Properties Research Articles

Long-term application of organic matter improves soil properties and plant growth-promoting bacteria in soil communities of oil palm plantation

ABSTRACT Oil palm (Elaeis guineensis) is a major contributor to global vegetable oil production; however, ensuring its sustainability remains a critical challenge, particularly concerning soil health. In this study, we investigated the impact of long-term organic matter application as part of good soil management (GSM) practices on oil palm plantations and compared it with poor soil management practices to determine the presence of plant growth-promoting bacteria (PGPB) in soil communities. The ten-years regular application of organic matter to the soil in the GSM plots led to notable improvements in soil chemical properties, including total organic carbon, total nitrogen, available phosphorus, available potassium, and cation exchange capacity. Metagenomic analysis revealed a significantly higher abundance of beneficial microbial species exclusively found in GSM plots, supporting oil palm growth. Furthermore, a novel finding emerged from this study, as it successfully predicted the metabolic function of PGPB in soil communities using PICRUST2 provided by the soil microbiome. PICRUST2 analysis indicated that the long-term application of organic matter in GSM plots increased functional enzymes related to PGP activities, such as nitrogen fixation, phosphate solubilization, potassium solubilization, and phytohormone synthesis. This study underscores the significance of implementing GSM practices in oil palm plantations by incorporating eco-friendly materials, such as organic matter, to enhance soil health and fertility and ensure oil palm sustainability.

Effect of lime on soil chemical properties and corn growth in Ultisols Lebak, Banten

Abstract The research aimed to study the effect of lime on soil chemical changes and corn growth in Ultisol Lebak, Banten. The soil used is acidic mineral soil with a pH of 4.8 and a high exchangeable (exch) Al content of 6.3 cmolc kg−1. The research design used was a completely randomized design with 6 treatments of lime doses with 5 replications. The dose of lime applied is based on exch Al namely 0, 0.5; 1.0; 1.5, and 2.0 equivalent to 0, 3, 6, 9, and 12 t ha−1, respectively, and 1.0 exch Al of fosfatan. The results showed that lime application improved soil chemical properties as reflected by increasing soil pH, exch Ca, Mg, cation exchange capacity (CEC), base saturation (BS), and decreasing Al content and saturation. In addition, lime application increases the delta of soil pH. Soil acidity (pH) increased from 4.8 to 6.3; exch Ca levels increased from 1.61 to 12.77 cmolc kg−1, exch Mg levels increased from 0.78 to 0.88 cmolc kg−1.

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 Effects of Different Vegetation Restoration Models on Soil Quality in Karst Areas of Southwest China

Rocky desertification is a devastating process in Karst areas of Southwest China and induces serious fragmentation in ecosystems. Therefore, vegetation restoration and the scientific evaluation of soil quality are key restorative strategies in these areas. In this study, a natural closed forest and a disturbed forest with three restoration models, including an evergreen broad-leaved forest, mixed forest, and deciduous forest, were investigated in Huanjiang County. More than nineteen soil properties (including physical, chemical, and biotic properties) were analyzed across treatments, and principal component analyses (PCA) were combined with a minimum data set (MDS) applied to evaluate the soil quality. Our study sought to identify a vegetation restoration model to improve the soil quality in this area. We demonstrated that soil physical and chemical properties, microbial biomass, and enzyme activities significantly differed across all of the models. Soil water content, capillary porosity, total porosity, organic carbon, total phosphorus, available phosphorus, and urease activity were high in the mixed forest, leading to better physical soil properties. Also, relatively high soil total nitrogen, total potassium, available nitrogen, available potassium, microbial biomass C and N, catalase, sucrose, and alkaline phosphatase levels were observed in the deciduous broad-leaved forest, resulting in improved soil chemical properties. Based on the minimum data set (MDS) method, six indicators, including non-capillary porosity, organic carbon, total phosphorus, pH, microbial biomass nitrogen, and urease activity, were selected to evaluate the soil quality across the models. Our data showed that, among the five models, the deciduous broad-leaved forest had the highest soil quality index (0.618), followed by the mixed forest (0.593). Stepwise regression analysis showed that soil organic carbon explained 79.9% of the variations in the soil quality indices, suggesting it was a major factor affecting the soil quality. Thus, vegetation restoration models mainly comprised of native tree species effectively improved the soil quality in Karst rocky desertification areas, with deciduous broad-leaved forests displaying the best effects, followed by mixed forests.

Improving soil chemical properties and okra (Abelmoschus esculentus) yield through complementary applications of biochar, and organic and inorganic fertilizers

In spite of okra’s importance to food security in developing countries, its production is limited by low soil nutrient and health status. A screenhouse study examined soil chemical properties, okra growth and yield under complementary application of biochar, organic and inorganic fertilizer in an Ultisol. The treatments comprised 5 kg soil each amended with 5 t biochar ha−1, 5 t poultry manure compost (SPM) ha−1, urea at 56 kg N ha−1, urea (28 kg N ha−1) + 5 t biochar ha−1, 5 t ha−1 (2:1, PM: biochar) (SPMB), urea (28 kg N ha−1) + 5 t ha−1 (2:1, PM: biochar) (SPMBF2). The treatments, replicated thrice, were arranged in a completely randomized design. There were two sets of plants terminated at 50% flowering (dry matter yield (DMY) and nutrient uptake) and at 10 wk post-planting for growth and yield determination. Results revealed that soil chemical properties, okra growth and yield increased responsively to the organic amendments. The SPM, followed by SPMB and SPMBF, enhanced soil pH (0.18–0.19 unit), total N (79–100%), organic carbon (75–100%), available P (55–58%) and exchangeable cations over the control and others (p < 0.05). These treatments also increased the plant’s agronomic parameters: plant height (10–19%), number of leaves, leave area (21–31%), stem girth (33–51%), DMY (59–67%), and tissue Ca, Mg and K. The SPMBF2 – treated soil had the highest fruit yield (45 g pot−1). Conclusively, sole and complementary applications of biochar and compost improved soil chemical properties, and okra growth and yields.

Aplikasi Formulasi Bahan Pembenah Tanah terhadap Beberapa Sifat Kimia Tanah Berpasir dan Produksi Tanaman Padi

Sandy soil is part of the soil fraction with low nutrient content, organic matter, and cation exchange capacity. This is due to the leaching process so that nutrients are easily lost. The research aimed to improve the chemical characteristics of sandy soil and rice crop production due to the application of humic acid and silica. This research used of Completely Randomized Design method using soil amendment materials, namely humic acid (A) at the of 60 kg/ha and silica (S) at the of 5 tons/ha consisting of 6 combinations of comparisons repeated 4 times. Variables of analysis parameters include pH, cation exchange capacity, organic matter, N-NH4+, N-NO3- and rice crop production. The data obtained were analyzed by analysis of variance (ANOVA). If the results showed a significant effect, it was continued with the Honestly Significant Difference (HSD) test at the 5% level. The results showed that the application of soil amendment in the from humic acid and silica with various treatments on sandy soil was only able to improve CEC by 3,18% and Organic-C by 0,08%. In contrast soil pH and N-available didn`t give significant results in improving soil chemical properties and rice crop production. It`s recommended to conduct further research on the dose used in soil amendments so that it can effect nitrogen parameters and rice crop production in sandy soil. Keywords: humic acid, silica, sandy soil

Short-term effect of no-tillage management on the chemical attributes and bacterial diversity in soils in an organic production system

No-tillage (NT) has been adopted in organic agriculture as an alternative to conventional tillage (CT) for improving soil conservation. Cover crops (CC) play a vital role in this process by providing straw and releasing nutrients into the soil. Therefore, in this study, we aimed to evaluate the effects of NT and CT management on the chemical properties and bacterial diversity of soil following the cultivation of diverse CC in an organic system. The experiment was conducted using a randomized block design with subdivided plots, wherein the plots represented CT and NT, and the subplots represented the diverse CC tested, including pearl millet, sunn hemp, jack bean, seed mixes 1 and 2 (containing 100 % and 50 % of the recommended seeding rates for each crop), and spontaneous plants. The evaluations were conducted one year after the experiment was conducted. The results demonstrated that NT promoted increases in soil magnesium, phosphorus, and organic carbon contents, including increased bacterial richness. Moreover, NT resulted in a higher abundance of Bacteroidetes, GAL15, and Myxococcota. Conversely, CT favored a greater relative abundance of Actinobacteria, in addition to the members of Bacteroidetes. Regarding the influence of CC, no significant differences were observed in the diversity and structure of the bacterial communities, except for subgroup 17, which was more abundant in spontaneously grown plants. NT proved to be more effective than CT in improving soil chemical properties and bacterial diversity, implying its potential to contribute to sustainable agricultural systems.

Conservation agriculture works as a catalyst for sustainable sodic soil reclamation and enhances crop productivity and input use efficiency: A scientific inquiry

Soil sodicity is a growing concern for crop growth and development in arid and semi-arid regions of the world. Conservation agriculture (CA) provides an effective solution towards reclamation of degraded sodic lands and enhance the crop productivity. A field experiment was carried out to assess the sodic soil reclamation potential of CA based management practices including zero tillage, legume (mungbean; Mb) rotation, residue (+R) mulch, and subsurface drip irrigation (SDI) for three years under rice-wheat (RW) system. The system scenarios (Sc) comprised of multiple indicators to measure their impact on soil properties as well as system productivity, profitability, water and nitrogen use efficiency. The results indicated that soil pHs under Sc5-Sc8 (CA-based SDI scenarios) was significantly (p < 0.05) lowered by 2.16, 2.16 and 1.33% compare with mean of Sc1 and Sc2 (CT-based system; 9.10, 8.29 and 8.14) at all three soil layers (0-5, 5-15 and 15-30 cm), respectively. Similarly, the exchangeable sodium percentage (ESP) was lowered by 2.9, 11.2 and 14.9% under CA-based scenarios with residue management compared with CT-based system (mean of Sc1 and Sc2; 15.2, 17.2 and 28.6%) during the study. The concentration of extractable anions (COЗ2‾, HCOЗ‾, Cl‾) decreased notably whereas, soil organic carbon and soil solution cations (Na+, Ca2+, Mg2+) concentration were increased under CA based management SDI plots. In addition, CA with SDI scenarios (mean of Sc5-Sc8) proved to be more productive and water-efficient than CA-based flood irrigation (FI; mean of Sc3 and Sc4). Moreover, CA-based FI and SDI scenarios saved 29.5 and 60.7% irrigation water, and improved the partial factor productivity of nitrogen (PFPN) by 6.8 and 24.4%, respectively compared to CT-R (conventional tillage without residue) based Sc1. Therefore, CA practices can potentially reduce sodicity and improve soil chemical properties for profitable crop cultivation.

Soil physical, chemical and biological properties in Conilon coffee intercropping systems

ABSTRACT Shaded coffee systems may offer a series of benefits, however, studies on shaded cultivation of Conilon coffee crops are still scarce in the literature. This study aimed to evaluate the soil physical, chemical, and biological properties of two Conilon coffee intercropping systems from southeastern Brazil. Two commercial coffee crops – one shaded by macadamia trees and the other by green dwarf coconut trees – were evaluated according to three treatments: coffee plants in the inter-row of the tree species; coffee plants in the same row of the trees; and unshaded coffee. The experimental design was a completely randomized with four replicates. Coffee plants intercropped with macadamia trees, both intra- and inter-row, resulted in less soil compaction than unshaded systems. As for intercropping with green dwarf coconut trees, the unshaded system presented lower soil resistance to penetration. Differences in physical properties between treatments allow no inferences about intercropping systems influence on green coconut trees. Intercropped coffee improves soil chemical properties, resulting in greater soil fertility than unshaded systems, and showed greater soil organisms. These findings indicate that Conilon coffee-macadamia intercropped with tree species represents a promising alternative for sustainable soil management.

Comparative effects of humic acid and charcoal on soil, growth, and biomass properties of lupine (Lupinus albus L.)

Recently, charcoal and humic acid application in soils is a burgeoning area of research due to its profound impact on soil properties and crop yields. Charcoal contributes to improved soil structure, enhanced water-holding capacity, and increased carbon sequestration while humic acid, a component of organic matter, enhances nutrient retention and availability, fostering healthier plant growth and long-term soil health. The experiments were conducted on November 20, 2022, at Grdarasha Research Station, College of Agricultural Engineering Sciences, Salahaddin University-Erbil, Iraq. Two organic sources (humic acid and charcoal) were used to improve soil chemical properties, growth, and biomass characteristics of white lupines. Humic acid at the levels of (0, 10, and 15 g m-2), respectively along with 1 kg m-2 of charcoal. Results showed that essential elements and heavy metals in soil were increased and improved with adding humic acid and charcoal, and then well-affected root ability to uptake nutrients. The great values of germination rate, leaf number (LN), and fresh and dry shoot weights were found when charcoal was stirred to the soil (83.33%, 15.67 LN plant-1, 10.91, and 2.24 t ha-1), respectively. While the longest root length was recorded when humic acid applied at rate of 10 g m-2 (24.22 cm), it was true about the enhancement of cluster roots. Despite that, humic acid at the rate of 15 g m-2 caused to improve fresh and dry root and shoot weights, which were compared to control treatment. The final results indicated that by adding humic acid (H), and charcoal (CH) could improve soil chemical properties, and then may affect positively microorganisms, which can promote plant growth by transforming, solubilizing, and mobilizing soil nutrients. As well, lupinus seemed as phytoremediation (uptake) in case of some heavy metals.

Impact of bio-digestate and fertilization on the soil chemical properties, growth and yield of maize (Zea mays L.)

Recognizing the significance of maize cultivation, it is imperative to determine the appropriate levels of NPK fertilizer along with the supplementary inclusion of bio-digestate (an organic fertilizer), to achieve optimal soil chemical properties and crop yields. Hence, a field study was conducted in 2022 at the Teaching and Research Farm of Bowen University, Iwo, Osun State, Nigeria. The study evaluated the effects of bio-digestate fertilizer (D), applied alone and integrated with urea (N), single superphosphate (P) and muriate of potash fertilizers (K) at low (N1K1P1) and high (N2P2K2) rates on soil chemical properties, growth, and yield of maize (Zea mays (L.). The treatments consisted of application of: D at 2500 L/ha alone, D + N1 P1 K1, D + N1 P1 K2, D + N1 P2 K1, D + N1 P2 K2, D + N2 P1 K1, D + N2 P1 K2, D + N2 P2 K1, D + N2 P2 K2, Control. N1 = 60 kg N/ha, N2 = 120 kg N/ha, P1 = 30 kg P2O5/ha, P2 = 60 kg P2O5/ha, K1 = 30 kg K/ha, K2 = 60 kg K/ha. The 10 treatments were arranged in a randomized complete block design and replicated three times. Results showed that bio-digestate (D) fertilizer applied alone or integrated with NPK fertilizers improved soil chemical properties, growth, and yield of maize compared with the control. High rate of fertilizer DN2P2K2 increased soil chemical properties and growth parameters of maize relative to low rates DN1P1K1 whereas a higher yield was recorded at a low rate DN1P1K1 relative to a high rate of fertilizer DN2P2K2. Overall, the treatment DN1P1K1 demonstrated the highest grain yield. D alone increased shelled maize yield by 187.9 % relative to no application of any amendment (control), also integrating D with N1P1K1 (DN1P1K1) increased maize yield by 97.2% relative to D alone. Bio-digestate can be used for maize cultivation in lonely soil especially when integrated with NPK fertilizer. Therefore, to avoid waste of fertilizer due to cost and negative environmental effects of excessive fertilization, the lower rate of NPK fertilizer: N (60 kg N/ha), P (30 kg P2O5/ha), and K (30 kg K/ha) with 2500 L/ha of bio-digestate (DN1P1K1) is recommended for sustainable maize production.

Short Term Effect of Vermicompost on Soil Chemical Properties under Maize (Zea mays L.) Field in Northern Ethiopia

Aim: The application of vermicompost (VC) to improve soil chemical properties in area that have low soil fertility status is crucial. Thus, the present study was initiated to determine impact of vermicompost on selected soil physicochemical properties. Study Design: The experiment had 7 treatments arranged in a Randomized Complete Block Design (RCBD) with five replications. Place and Duration of the Study: Hence, a field experiment was carried out in 2018 main cropping season at farmer's field at Adiha village in Kolla Tembien district, Tigray, Ethiopia. Methodology: The treatments were 5 levels of VC (0, 2.5, 5, 7.5 and 10 t ha-1), the recommended rate of N and P (46 N and 46 P2O5 kg ha-1), compost at rate of 10 t ha-1 and control. Surface soil samples were collected before planting and after maize harvesting at a depth of 0-30 cm to analyze selected soil chemical properties such as pH, extractable electric conductivity (ECe), cation exchange capacity (CEC), total nitrogen (TN), available P and exchangeable bases (K, Mg, Ca, and Na). Likewise, vermicompost and compost nutrient contents were also analyzed to know their nutrient composition. Results: Soil analysis results before sowing revealed that most of the soil chemical properties were rated as low. However, vermicompost application significantly (P≤0.05) improved the soil chemical properties. The studied soil chemical properties such as OC (1.33%), TN (0.13%), CEC (17.2 Cmol (+) kg-1), and available P (6 .38 mg kg-1) showed an improvement at VC 10 t ha-1rate as compared to the control which was respectively 0.65%, 0.04%, 7.4 Cmol(+)kg-1 and 2.45 mg kg-1. Conclusion: A significant (P≤0.05) increase in OC, TN and available P was observed with increased vermicompost rate under cultivated land.

Improvement of Soil Chemical Properties in Mature Oil Palm Plantations by Pruning and Immersing of Weeds as Cover Crops

Improvement of Soil Chemical Properties in Mature Oil Palm Plantations by Pruning and Immersing of Weeds as Cover Crops

Effect of long-term in-row branch covering on soil microorganisms in pear orchards.

Branches covering (BC) is a way to reuse the pruned branches and save the cost of ground cloth. This study investigated the effects of BC and ground-cloth covering on the soil microcosm environment by measuring the chemical properties and microbial communities at different soil depths for 6 years. The results revealed that BC significantly improved soil chemical properties, increased the abundance of bacterial microbial communities and the diversity and homogeneity of bacteria and fungi, while decreased the abundance of fungal microbial communities. There was a threshold value for the regulation of microbial communities by BC, which decreased the high-abundance communities (Proteobacteria, Ascomycota, etc.) and increased the low-abundance communities (Acidobacteriota, Basidiomycota, etc.). Fungi were more sensitive to BC than bacteria. The stability and homogeneity of microorganisms were stronger in the 15-25 cm soil layer. The bacterial phyla were dominated by Proteobacteria, with the top 10 phyla accounting for more than 80% of the relative abundance; the genera were dominated by MND1, with the top 10 genera accounting for about 10%. The fungal phyla were dominated by Ascomycota, with the top 10 phyla accounting for 50-90%; the genera were dominated by unidentified Pyronemataceae sp., with the top 10 genera accounting for 30-60%. The phyla that differed significantly between treatments were mainly Proteobacteria, Ascomycota, Acidobacteriota, and Basidiomycota. In addition, metabolism was the predominant function in bacteria, while Saprotroph was the predominant function in fungi. Bacteroidota correlated strongly with soil chemical properties and bacterial functions, while Chytridiomycota correlated strongly with soil chemical properties and Pathogen-Saprotroph-Symbiotroph. In conclusion, BC can improve soil nutrient content and optimize microbial community structure and function. Through initially assessing the effects of BC on soil nutrients and microorganisms in pear orchard rows, this study provides a reference for excavating key microorganisms and updating the soil row management model.

Impact of cellulose and lignin on restoration of vegetation and soil chemical properties for saline-alkali soil of songnen plain.

To explore the effects of cellulose and lignin on stimulating vegetation restoration and improving soil chemical properties in saline-alkali soil, a large area test was carried out, and 2 treatments were set up: T (cellulose and lignin+ Planted seeds) and CK (Planted seeds). In this study, the species, quantity, plant height, above-ground biomass, biodiversity of vegetation in the treated plots, the determination of soil chemical nutrient content, and the effect of cellulose and lignin on vegetation restoration in saline-alkali land were investigated. The results showed that: 1) Cellulose and lignin contributed to vegetation growth. Compared with CK treatment, plant height and aboveground biomass of T increased by 158.73% and 240.13%, respectively; 2) Cellulose and lignin improved soil structure, and soil porosity, and decreased soil compaction (21.95%); 3) Compared with CK treatment, T treatment decreased soil pH by 0.5 units, total salt content decreased by 30.95%, exchangeable Na+ decreased by 63.00%, and exchangeable sodium percentage (ESP) decreased by 61.51%. Furthermore, cellulose and lignin effectively improved the physical and chemical properties of saline-alkali soil, promoted the recovery of ecological environment in saline-alkali soil, and improved regional biodiversity, which will provide new methods for soil remediation and improvement in saline-alkali areas.

Adaptation potential of Miscanthus in a solonetz agricultural landscape

The aim of the study was to assess the ecological adaptability of Miscanthus cv. Soranovsky to saline agricultural landscapes and the phytomeliorative effect of the plant on saline soils. Location and time of the study. The field experimental part of the research was carried out in 2018-2020 in the central forest-steppe in the Barabinsky agrolandscape region (Experimental Research Station of the Siberian Federal Center for Agrobiotechnologies). Methods. The common methods of field and vegetation experiments, chemical analysis of soils and plant samples were used in the study. Results. Miscanthus can grow on solonetzic soils, providing a biomass yield of up to 5 t/ha under dry growing season conditions. The removal of nutrients from the soil by the biomass of Miscanthus stems was found to be low (8.2 kg/ha of nitrogen, 1.4 kg/ha of phosphorus and 9.7 kg/ha of potassium per year) due to their annual reutilization into rhizomes. This fact allow to avoid the danger of soil depletion during long-term cultivation of crops. Growing Miscanthus on meadow-chernozem solonetz for an average of three years led to changes in soil properties such as a decrease in pH, and changes in salts chemistry in the soil solution, manifested as a decrease in sodium bicarbonate content. Conclusions. Miscanthus as a crop has wide adaptation capabilities in relation to the marginal lands of the solonetz zone of West Siberia. Miscanthus plantings have a beneficial environment-forming effect on solonetz soils, due to the enrichment of soils with mineral nutrition elements and improvement of soil chemical properties.

Bacterial and fungal communities regulated directly and indirectly by tobacco-rape rotation promote tobacco production.

Tobacco continuous cropping is prevalent in intensive tobacco agriculture but often leads to microbial community imbalance, soil nutrient deficiency, and decreased crop productivity. While the tobacco-rape rotation has demonstrated significant benefits in increasing tobacco yield. Microorganisms play a crucial role in soil nutrient cycling and crop productivity. However, the internal mechanism of tobacco-rape rotation affecting tobacco yield through microbe-soil interaction is still unclear. In this study, two treatments, tobacco continuous cropping (TC) and tobacco-rape rotation (TR) were used to investigate how planting systems affect soil microbial diversity and community structure, and whether these changes subsequently affect crop yields. The results showed that compared with TC, TR significantly increased the Shannon index, Chao1 index, ACE index of bacteria and fungi, indicating increased microbial α-diversity. On the one hand, TR may directly affect the bacterial and fungal community structure due to the specificity of root morphology and root exudates in rape. Compared with TC, TR significantly increased the proportion of beneficial bacterial and fungal taxa while significantly reduced soil-borne pathogens. Additionally, TR enhanced the scale and complexity of microbial co-occurrence networks, promoting potential synergies between bacterial OTUs. On the other hand, TR indirectly changed microbial community composition by improving soil chemical properties and changing microbial life history strategies. Compared with TC, TR significantly increased the relative abundance of copiotrophs while reduced oligotrophs. Notably, TR significantly increased tobacco yield by 39.6% compared with TC. The relationships among yield, microbial community and soil chemical properties indicated that planting systems had the greatest total effect on tobacco yield, and the microbial community, particularly bacteria, had the greatest direct effect on tobacco yield. Our findings highlighted the potential of tobacco-rape rotation to increase yield by both directly and indirectly optimizing microbial community structure.

Improving soil fertility through dual inoculation with arbuscular mycorrhizal fungi and Rhizobium on a eutric cambisol cultivated with forage legumes in a semi-arid region

The Sub-Saharan region of southern Africa is characterized by high temperatures, low rainfall, and poor land-use management practices such as continuous cropping without replenishment of soil nutrients. The combination of these factors has resulted in nutrient depletion and land degradation. The current study aimed at investigating the effect of arbuscular mycorrhizal fungi (AMF) and Rhizobium bacteria inoculation on soil chemical properties in field-grown forage legumes, namely, Mucuna pruriens (mucuna), Lablab purpureus (lablab) and Vigna unguiculata (cowpea), in the semi-arid region of the Eastern Cape Province (South Africa). Forage legumes were inoculated with the AMF species Paraglomus occulum and the Rhizobia bacteria species Bradyrhizobium strain and grown for 120 days. Soil samples were collected in the following sequence: prior to planting, before flowering and after harvesting the forage legumes in each of the two seasons (2017/2018 and 2018/2019) and soil chemical properties were determined using standard procedures. The results showed that the addition of dual inoculation over time greatly improved soil chemical properties when compared to the control treatment. This was advocated by the significant (P ≤ 0.05) increase in soil pH, soil organic carbon, soil organic matter, total nitrogen, phosphorus, calcium, potassium, magnesium, sodium, sulfur and iron in soils. The concentration of cation exchange capacity was significantly (P ≤ 0.05) higher in cowpea treated with Rhizobium as compared to other treatment combinations. The control treatment of mucuna forage greatly improved the concentrations of manganese, boron, copper, molybdenum, and zinc over other treatment combinations only before the flowering stage. However, the concentrations of micronutrients were significantly higher on the treatment combination of lablab and single inoculation of AMF after harvesting. Generally, dual inoculation with AMF and Rhizobia enhanced soil properties when compared to a single inoculation or untreated control.

Effect of Bio-Organomineral Fertilizer on Soil Chemical Properties and PB Content of Industrial Waste Polluted Soil

Rancaekek Sub-district is one of the agricultural centers in Bandung Regency, Indonesia, which is currently experiencing land conversion into an industrial area. The industrial activities produce waste containing heavy metal lead (Pb), which if not treated can pollute the soil and surrounding waters. Efforts to overcome soil pollution are through fertilization. The purpose of this study was to determine the effect of the dose and incubation time of Bio-organomineral fertilizer with Bacillus subtilis biological agent on improving soil chemical properties and reducing soil Pb levels. This study used a two-factor Factorial Randomized Block Design, namely the dose and incubation time of Bio-organomineral fertilizer. The results showed that the combination of Bio-organomineral fertilizer dose of 225 kg.ha-1 and an incubation time of 30 days was able to increase soil K-potential. The independent factor of Bio-organomineral fertilizer dose had a significant effect on increasing soil pH. The independent factor of incubation time had a significant effect on reducing soil Pb levels. In particular, there was an interaction between the dose and incubation time of Bio-organomineral fertilizer on soil K-potential.

Liming leads to changes in the physical properties of acidified forest soils

AbstractBackgroundForest liming is a common practice in many German forests, which aims primarily at improving soil chemical properties that have been negatively impacted by acid rain. Effects on physical functions have not yet been studied widely.AimsThe hypothesis of this study is that chemical changes after liming lead to changes in the physical properties of the humus layer and mineral soil.MethodsWe studied soil physical characteristics (water retention characteristics, air and water permeabilities, and conductivities) of limed and adjacent control plots of sandy to loamy, acidified soils under spruce and beech‐dominated stands.ResultsWe found differences between limed and control plots, especially in the humus layer and mineral top soil. Here, air capacity values (representing air‐filled macropores at −6 kPa) have experienced an increase, while available water capacities (representing the sum of dewatered mesopores between −6 and −1500 kPa) were reduced to a variable extent. These changes in pore size distributions affected gas diffusion as well as gas permeability positively. Unsaturated hydraulic conductivity was not affected. Below the top mineral soil, a tendency to a reduced macroporosity and gas permeability was observed, but no clear changes were detected.ConclusionsSmall but significant changes of soil physical properties and functions in the humus layer and top mineral soil are discussed to be an indirect effect of forest liming. Liming improves pH and nutrient availability, which in turn should have stimulated activity and abundance of soil fauna, especially earthworms. Where observed, their activity could explain the observed changes in soil physical properties. We believe that effects below the top soil might be due to mobilization and translocation of soil particles and a clogging of pores, but these depths were only studied at three plots. Compared to common liming practices, however, the investigated sites are characterized by significantly higher lime applications. The effects on practice liming areas in forestry praxis are therefore likely to be smaller than in this study.