Soil Samples Research Articles

The effect of intercropping on soil fertility and crop yield under smallholder farming in Rwanda: A case study of Musanze District

Intercropping, the practice of growing two or more crops simultaneously on the same piece of land, has been widely acknowledged for its potential to improve soil fertility, crop yields, pest control, and the overall economic sustainability of smallholder farms. This study investigates the effect of intercropping systems on soil fertility, crop yields, pest control, and economic outcomes among smallholder farmers in Musanze District, Rwanda. A stratified random sampling method was used to select smallholder farms that practice either intercropping or monocropping. Quantitative data on soil fertility and crop yields were analyzed using SPSS to determine the effect of intercropping compared to monocropping. Soil fertility parameters were compared using paired t-tests or ANOVA. Data were collected from 120 smallholder farms practicing either intercropping or monoculture. Soil samples were analyzed for key fertility indicators (nitrogen, phosphorus, and organic matter), while crop yields, pest incidence, and input costs were recorded throughout the growing season. Results show that intercropping significantly enhanced soil fertility, particularly nitrogen levels, by including leguminous crops that fix nitrogen. Furthermore, intercropping increased overall crop yields by 15–30% compared to monoculture farming, with the highest yield improvements observed in maize-bean and maize-potato intercropping systems. Intercropping also demonstrated an effective reduction in pest populations, especially for maize stalk borers and aphids, resulting in lower pesticide use and better crop health. Economically, intercropping systems were more cost-effective, as they required fewer chemical inputs (fertilizers and pesticides) and offered greater market value through the combined sale of multiple crops. The study highlights that intercropping not only improves soil fertility and yields but also contributes to greater income diversification and financial resilience for smallholder farmers in Musanze District. This research underscores the importance of promoting intercropping as a sustainable agricultural practice in Rwanda, offering multiple benefits to smallholder farmers by enhancing soil health, boosting yields, controlling pests, and improving economic stability. Further policy support and farmer education on best intercropping practices are essential to maximize these benefits and encourage widespread adoption.

Patterns and drivers of soil microbial carbon use efficiency across soil depths in forest ecosystems

Subsoils below 30 cm store more than half of global soil carbon. Microbial carbon use efficiency (CUE) serves as a key indicator of microbial control over soil carbon turnover, but the general patterns and drivers of microbial CUE across soil depths remain poorly understood. Here, we report a decreasing trend in microbial CUE with increasing soil depths through large-scale soil sampling across 60 sites spanning tropical to boreal forests. Using multiple analytical and statistical approaches complemented by experiments, we further identify depth-dependent drivers of microbial CUE. In the topsoil (0–10 cm), microbial CUE is primarily regulated by microbial diversity, whereas in deep subsoil (70–100 cm), it is predominantly driven by soil physicochemical protections. Our findings underscore the need to incorporate depth-specific microbial CUE drivers into carbon cycle models for more accurate predictions of whole-soil carbon storage and its feedback to climate change.

Possible transition from Silandic to Aluandic Andosols with acidification as evidenced by detailed profile investigation of two well-preserved forest Andosols in Japan

ABSTRACT In Japan, Andosols are one of the major soils and they occupy about 30% of the total land surface. Andosols with andic properties have been grouped into two distinct categories: Silandic and Aluandic, but their formation has not been well investigated with reliable soil analytical data and needs to be studied for systematic understanding. To clarify the formation process of Silandic and Aluandic Andosols, two soil profiles, collected from natural forest sites at Aya (Sil-A) and Shiiba (Alu-A) in Miyazaki Prefecture, Japan, were investigated in detail. The soil samples were taken from the soil profiles at a 5 cm interval to reveal the changes in chemical and mineralogical properties with depth. The smooth changes in soil acidity (pH(H2O), pH(KCl), and y1), carbon stock (total carbon and δ13C), cation retention properties (cation exchange capacity and base saturation), and mineralogical properties (pyrophosphate and acid-oxalate extractable iron, aluminum, and silicon) indicated that both soil profiles had been formed under well-preserved natural forests. Based on the analytical data, Sil-A was classified as a Silandic Andosol (World Reference Base for Soil Resources 2022: WRB 2022) and an Allophanic Andosol (The Fifth Committee for Soil Classification and Nomenclature 2017: FCSCN 2017), whereas Alu-A was classified as an Aluandic (0–30 cm)/Silandic (30–90 cm) Andosol (WRB 2022) and a Non-allophanic Andosol (FCSCN 2017). The changes in the chemical and mineralogical properties with high depth-resolution suggested that the allophanic material contents were increased with depth within 0 to 50 cm, and they were related with soil pH(H2O) in both soils. It was suggested that acidification had happened from upper layers, resulting in dissolution of the allophanic materials and formation of Al-humus complexes in both soils, and Alu-A would have been more deeply affected by this process than Sil-A. Therefore, the authors conclude that Silandic/Allophanic Andosols can be transformed into Aluandic/Non-allophanic Andosols with acidification, and the phenomenon is typically observed in upper layers and progresses to deeper layers.

Estimation of Soil C-Organic Content Based on Reflectance Values Generated from Spectrometer

C-Organic is an important component of soil fertility. The intensity of agricultural land use affects the organic matter content in the soil. A spectrometer can be used to measure organic matter content through reflectance values. This study aimed to compare reflectance values and C-Organic content in rice fields with planting Index (IP) of 100 and IP of 300 in Maros Regency, as well as to analyze the relationship between reflectance values and laboratory test results. The method used involved collecting soil samples from both types of rice fields, measuring reflectance using a spectrometer in the Blue, Green, Red, and NIR spectra, and analyzing their relationship with C-Organic content. The results showed that reflectance values and C-Organic content in 300 IP were higher than in 100 IP, with the highest coefficient of determination (R²) was in red spectrum, i.e. 0.9425. The C-Organic content at the research field was classified as very low, ranging from 0.61 to 1.05%, with a higher average in 300 IP (0.96%) compared to 100 IP (0.74%). This study concluded that a spectrometer can be a fast and accurate alternative for detecting soil C-Organic content, especially at a wavelength of 650 nm.

Human health risks of PAHs in soil and vegetables from Tiga, Kano State, Nigeria.

Human health risks of PAHs in soil and vegetables from Tiga, Kano State, Nigeria.

Microplastics in rice-based farming systems and their connection to plastic waste management in the Chicoral district of Espinal-Tolima.

Microplastics in rice-based farming systems and their connection to plastic waste management in the Chicoral district of Espinal-Tolima.

Below-ground carbon gradients surrounding Saskatchewan's native agricultural copses.

Below-ground carbon gradients surrounding Saskatchewan's native agricultural copses.

Exposures to polycyclic aromatic hydrocarbons among adults and children: Contributions from multiple pathways and sources.

Exposures to polycyclic aromatic hydrocarbons among adults and children: Contributions from multiple pathways and sources.

Source-oriented health risk assessment of heavy metals in soil and dust at coal resource-based urban parks in northern China based on bioaccessibilities.

Source-oriented health risk assessment of heavy metals in soil and dust at coal resource-based urban parks in northern China based on bioaccessibilities.

Environmental factors influence airborne microplastic deposition in the soil of urban allotment gardens.

The widespread contamination of urban soils by airborne microplastics (MPs) is an emerging environmental concern, particularly in urban allotment gardens (UAGs) where food production occurs. This study investigates the vertical distribution of MPs in three UAGs in Berlin, Germany, over 90 days. Soil samples were collected at three depths (surface, 1-15cm, and 15-30cm) and analysed for MPs composition and concentration, with a detection limit of 0.1μm using Optical PhotoThermal InfraRed (O-PTIR) spectroscopy. Results revealed that fibres were the dominant MP type, with the highest concentrations found in surface layers. MPs concentrations decreased with soil depth, and fibres showed limited vertical penetration. We also identified 19 different polymer types, with polyethylene terephthalate (PET), polyester (PES), and polyethylene (PE) being the most common. Temporal variations in MPs deposition were observed, with a significant peak at 90 days. Environmental factors, including PM2.5 concentration, precipitation, and wind velocity, played a role in MPs deposition. Precipitation and PM2.5 were positively associated with increased deposition, while higher wind speeds reduced MPs accumulation. These findings highlight the pervasive presence of MPs in urban soils and suggest that environmental conditions significantly influence MPs distribution. Understanding these dynamics is essential for assessing the long-term ecological impacts of MPs on soil health in urban environments.

Fast screening of gold in rock samples using polyurethane foam extraction and inductively coupled plasma mass spectrometry determination.

In this work, the volume of sample solution and concentration of gold was optimized for extraction with foam in dimensions (1 × 1 × 1) and then was used for extraction from soil samples. The results showed that the proposed technique has a good analytical efficiency compared to the standard fire assay method and the accuracy of work is in the range of 74-125 %. The equation of linear calibration curve was obtained with regression coefficient better than 0.9997, and the detection and quantification limit of the gold in aqueous and soil sample obtained 0.25 and 0.8 µg kg -1, respectively.•This method is inexpensive and fast for determination of gold in various samples.•This method has high thought of sample determination.•This method is green chemistry method.

Magnetite/reduced graphene oxide composites: A sustainable strategy for selenium immobilization and improved corn growth.

Magnetite/reduced graphene oxide composites: A sustainable strategy for selenium immobilization and improved corn growth.

A catchment-scale dataset of soil properties and their mid-infrared spectra.

The dataset presents information on soil properties and their associated mid-infrared spectra for a drainage basin of 4.2 km2, referred to as Upper Badong catchment (31°1'24''N, 110°20'35''E) in the Hubei province, China. Data were collected for topsoil in a highly diverse terrace catchment composed of woodland, cropland and small farm building. Soil properties included in this dataset are pH, texture (i.e. clay, silt and sand content), total carbon, organic carbon and CaCO3. In addition, the soil samples were scanned in the mid-infrared range. The data collection processed involved three field campaigns during 2013 and 2014 where topsoil samples were collected in a standardized way across all sites, and soil analyses in the laboratory of soil science following standard procedures. The dataset offers insights into the spatial variation of soil properties in a highly diverse catchment of central China. Researchers interested in soil research can use this dataset for various purposes, including building digital soil mapping models or soil spectroscopic models, benchmarking of models with other datasets, and research in soil erosion modelling.

Soil to plant transfer factor of 137Cs, 40K, and stable Cs in a semi-arid region.

Soil to plant transfer factor of 137Cs, 40K, and stable Cs in a semi-arid region.

Exploring the biodegradation activity of Priestia aryabhattai 1-3I, a promising chlorpyrifos-degrading strain isolated from a local phosphogypsum landfill.

Exploring the biodegradation activity of Priestia aryabhattai 1-3I, a promising chlorpyrifos-degrading strain isolated from a local phosphogypsum landfill.

Comparison of Raman and fluorescence microscopy for identification of small (< 2μm) microplastics in soil.

Comparison of Raman and fluorescence microscopy for identification of small (< 2μm) microplastics in soil.

Ecoenzymatic stoichiometry reveals that increasing altitude exacerbates soil microbial phosphorus limitation in alpine grassland ecosystems in Xinjiang.

Ecoenzymatic stoichiometry reveals that increasing altitude exacerbates soil microbial phosphorus limitation in alpine grassland ecosystems in Xinjiang.

Association of infrastructure and operations with antibiotic resistance potential in the dairy environment in India.

Association of infrastructure and operations with antibiotic resistance potential in the dairy environment in India.

Soil-to-banana transfer factor of radionuclides in Lampung, Indonesia.

Soil-to-banana transfer factor of radionuclides in Lampung, Indonesia.

Multivariate analysis of potentially toxic metal contents in soil and vegetables: Enrichment, bioconcentration, translocation from soil to vegetables, and assessment of human health toxicity.

Multivariate analysis of potentially toxic metal contents in soil and vegetables: Enrichment, bioconcentration, translocation from soil to vegetables, and assessment of human health toxicity.