Soil Systems

17 pages, 879 KiB

Open AccessArticle

Urban Market Gardening Improves Soil Health: A Case Study in Burkina Faso

by Rayangnéwendé Adèle Ouédraogo, Fabèkourè Cédric Kambiré, Laurent Cournac and Charles L. Bielders

Soil Syst. 2025, 9(2), 59; https://doi.org/10.3390/soilsystems9020059 - 4 Jun 2025

In sub-Saharan Africa, urban market gardening is characterized by the intensive use of chemical inputs, which could have adverse effects on soil health. This study therefore aimed to assess the impact of urban market gardening on soil health. Topsoil samples were collected from [...] Read more.

In sub-Saharan Africa, urban market gardening is characterized by the intensive use of chemical inputs, which could have adverse effects on soil health. This study therefore aimed to assess the impact of urban market gardening on soil health. Topsoil samples were collected from 69 plots at a market gardening site in Bobo-Dioulasso, Burkina Faso, with cultivation histories ranging from 0 to over 50 years. Twenty-six chemical, biological, and physical soil properties were analyzed. Principal component analysis was used to identify minimum data sets for the assessment of soil health. The selected variables were standardized and aggregated into two soil health indices on a scale from 0 to 100: an overall index based on all properties combined and an average index based on the mean of the biological, physical, and chemical components of soil health. Both indices revealed a clear improvement in soil health over time, with the overall index rising from an initial value of 0.35 to 0.64 after 60 years and the average index rising from 0.30 to 0.62. The average index, which enables the separate assessment of its three components, accounted for a greater share of the temporal variability (R² = 0.59) than the overall index (R² = 0.47). These findings highlight the positive impact of urban market gardening practices on soil health at the study site, which was attributed to the large additions of organic amendments. Full article

(This article belongs to the Special Issue Integrated Soil Management: Food Supply, Environmental Impacts, and Socioeconomic Functions: 2nd Edition)

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14 pages, 1141 KiB

Open AccessArticle

A Novel Biostimulant–Biochar Strategy for Improving Soil Quality and Salinity Tolerance in Medicinal Mint (Mentha longifolia L.)

by Mamdouh A. Eissa, Modhi O. Alotaibi, Mashael M. Alotibi, Alya Aljuaid, Taghreed Hamad Aldayel and Adel M. Ghoneim

Soil Syst. 2025, 9(2), 58; https://doi.org/10.3390/soilsystems9020058 - 2 Jun 2025

Abstract

This study evaluated the combined application of biochar (BC) and Spirulina platensis (SP) as a sustainable strategy to improve soil quality and salinity tolerance in mint (Mentha longifolia L.) cultivated in sandy soils. A pot experiment was conducted using saline irrigation water [...] Read more.

This study evaluated the combined application of biochar (BC) and Spirulina platensis (SP) as a sustainable strategy to improve soil quality and salinity tolerance in mint (Mentha longifolia L.) cultivated in sandy soils. A pot experiment was conducted using saline irrigation water (5 dS m⁻¹) with four treatments: control, BC alone, SP alone, and BC + SP applied at 1% (w/w), arranged in a randomized complete block design with three replicates. Salt stress reduced plant height and biomass yield by 16% and 27%, respectively, and increased sodium (Na⁺) in shoots by 74%, causing ionic imbalance and decreased soil microbial biomass carbon by 19%. The combined BC + SP treatment significantly improved soil microbial biomass carbon (SMBC) by 100%, reduced soil Na⁺ by 41%, and enhanced K⁺/Na⁺ and Ca²⁺/Na⁺ ratios by 138% and 133%, respectively. Under salinity, BC + SP increased nutrient concentrations in mint shoots, including N (120%), P (106%), K (88%), Ca (67%), Fe (70%), Mn (50%), Zn (44%), and Cu (70%), and improved leaf chlorophyll content. These results demonstrate that BC and SP synergistically mitigate salinity stress by improving soil properties, nutrient uptake, and ionic balance, making BC + SP a promising sustainable amendment for saline sandy soils. Full article

(This article belongs to the Special Issue Research on Soil Management and Conservation: 2nd Edition)

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34 pages, 6650 KiB

Open AccessArticle

Salinity of Irrigated and Non-Irrigated Chernozems and Kastanozems: A Case Study of Causes and Consequences in the Pavlodar Region, Kazakhstan

by Dauren Rakhmanov, Bořivoj Šarapatka, Marek Bednář, Jan Černohorský and Kamilla Alibekova

Soil Syst. 2025, 9(2), 57; https://doi.org/10.3390/soilsystems9020057 - 28 May 2025

Abstract

This study investigated soil salinization processes in the Pavlodar region of Kazakhstan by comparing key soil parameters—namely, electrical conductivity (EC), pH, exchangeable sodium percentage (ESP), and sodium adsorption ratio (SAR) under irrigated and non-irrigated conditions across different agro-climatic zones and soil types (Haplic [...] Read more.

This study investigated soil salinization processes in the Pavlodar region of Kazakhstan by comparing key soil parameters—namely, electrical conductivity (EC), pH, exchangeable sodium percentage (ESP), and sodium adsorption ratio (SAR) under irrigated and non-irrigated conditions across different agro-climatic zones and soil types (Haplic Chernozems, Haplic Kastanozems). The focus was on understanding the effects of irrigation and natural factors on soil salinization. Statistical analysis, including descriptive statistics and significance testing, was employed to evaluate differences between soil types, locations, and management practices. The research revealed secondary salinization (EC > 2 dS/m, ESP > 15%) in the topsoil of irrigated Haplic Kastanozems soils in the central Aksu district. This degradation was markedly higher than in non-irrigated plots or irrigated Haplic Chernozems in the northern Irtysh district, highlighting the high vulnerability of Haplic Kastanozems soils under current irrigation management given Aksu’s climatic conditions, which are characterized by high evaporative demand (driven by summer temperatures) and specific precipitation patterns that contribute to soil moisture deficits without irrigation. While ESP indicated sodicity, SAR values remained low. Natural factors, including potentially saline parent materials and likely shallow groundwater dynamics influenced by irrigation, appear to contribute to the observed patterns. The findings underscore the need for implementing optimized irrigation and drainage management, particularly in the Aksu district, potentially including water-saving techniques (e.g., drip irrigation) and selection of salt/sodicity-tolerant crops. A comprehensive approach integrating improved water management, agronomic practices, and potentially soil amendments is crucial for mitigating soil degradation and ensuring sustainable agriculture in the Pavlodar region. Further investigation including groundwater monitoring is recommended. Full article

(This article belongs to the Special Issue Research on Soil Management and Conservation: 2nd Edition)

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15 pages, 1773 KiB

Open AccessArticle

Accumulation of Soil Metal(loids) in Fast-Growing Woody Plants of the Post-Mining Area of Freiberg, Germany

by Viktoriia Lovynska, Oliver Wiche, Hermann Heilmeier, Alla Samarska and Roland Bol

Soil Syst. 2025, 9(2), 56; https://doi.org/10.3390/soilsystems9020056 - 23 May 2025

Abstract

Soil pollution is a global threat that seriously affects biodiversity in (agro)ecosystems and may compromise water and food quality. Therefore, the ability of tree species (Populus tremula, Salix caprea, and Betula pendula) to accumulate and phytoextract specific toxic heavy metals from [...] Read more.

Soil pollution is a global threat that seriously affects biodiversity in (agro)ecosystems and may compromise water and food quality. Therefore, the ability of tree species (Populus tremula, Salix caprea, and Betula pendula) to accumulate and phytoextract specific toxic heavy metals from soil was investigated. The study was conducted in and near relict mining areas of Freiberg (Germany) and sampling sites selected according to their spatial location relative to potential sources of metal(loid)s. The concentrations of geogenic (P, Fe, Mn, Ca) and pollutant (Pb, Cd, Zn, As) elements in soil and the present trees were measured using ICP-MS. The highest total soil concentrations of As (8978 µg g⁻¹) were found within the Davidschaft mining area, and for soil Pb, both in the Davidschaft vicinity (328 µg g⁻¹) and mining area (302 µg g⁻¹). Unexpectedly, the highest soil Zn (0.64 mg g⁻¹) and Cd (3.5 mg g⁻¹) concentrations were found in Freiberg city Forest. The lowest soil concentrations of pollutants (As, Cd, Pb, and Zn) were recorded for Seifersdorf. Total soil P was highest in Colmnitz, but Ca, Mn, and Fe concentrations were very similar across all sites. The available concentration of all measured toxic elements in the soil generally decreased in the order Davidschaft > Davidschaft vicinity, Colmnitz > Seifersdorf = Freiberg city forest. All studied tree species had higher concentrations of the essential elements in leaves than in branches. Generally, higher values of bioaccumulation coefficients (especially for Cd) were found for Salix caprea compared with Populus tremula and Betula pendula. Full article

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16 pages, 902 KiB

Open AccessArticle

Effects of Biofertilizers on Soil Quality and Vegetative Development of Mahogany (Swietenia macrophylla) and Yaca (Artocarpus heterophyllus) in the Central Peruvian Jungle

by Andrea Castro-Cárdenas, Juanita Ciriaco-Poma, Juan Z. Dávalos-Prado and Víctor Soto-Aquino

Soil Syst. 2025, 9(2), 55; https://doi.org/10.3390/soilsystems9020055 - 20 May 2025

Abstract

The sustainability of agricultural production and the conservation of tropical ecosystems face significant challenges due to processes such as climate change and soil degradation. This study evaluated the impacts of three biofertilizers—biol (T02), vermicompost (T03), and bokashi (T04)—on soil quality and the vegetative [...] Read more.

The sustainability of agricultural production and the conservation of tropical ecosystems face significant challenges due to processes such as climate change and soil degradation. This study evaluated the impacts of three biofertilizers—biol (T02), vermicompost (T03), and bokashi (T04)—on soil quality and the vegetative development of two typical plants, Mahogany (Swietenia macrophylla) and Yaca (Artocarpus heterophyllus), cultivated in the Asháninka locality in the Central Peruvian Jungle. Using a completely randomized experimental design, it was generally found that treatments T04 and, to a lesser extent, T03 improved the soil quality and consequently enhanced the vegetative development of Mahogany and Yaca. Compared with the untreated controls (T01), these biofertilizers generated less dense and more porous soils and increased the water retention, organic matter, pH, and the availability of nitrogen and phosphorus nutrients. They also promoted greater biodiversity. These qualities, in turn, stimulated the vegetative development of Mahogany and Yaca, whose leaves showed considerable content of chlorophyll A and B and total chlorophyll. Thus, T03 and especially T04 proved to be effective biofertilizers for the treatment of tropical soils, promoting efficient plant growth and development in species such as Mahogany and Yaca. These findings highlight the great potential of the biofertilizers T03 and T04 in achieving sustainable agricultural production, as well as for the conservation and improvement of tropical forests. Full article

(This article belongs to the Topic Soil Fertility and Plant Nutrition for Sustainable Agriculture—2nd Edition)

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5 pages, 161 KiB

Open AccessEditorial

The Effect of Land Use and Management on Soil Properties and Processes

by Adilson Pacheco de Souza and Frederico Terra de Almeida

Soil Syst. 2025, 9(2), 54; https://doi.org/10.3390/soilsystems9020054 - 20 May 2025

Abstract

As we delve deeper into the complexities of soil properties and processes, we must consider traditional methodologies and innovative approaches that take advantage of advances in soil management and conservation processes [...] Full article

(This article belongs to the Special Issue Land Use and Management on Soil Properties and Processes)

33 pages, 3402 KiB

Open AccessArticle

Advancing Sustainable Practices: Integrated Pedological Characterization and Suitability Assessment for Enhanced Irish Potato Production in Tsangano and Angónia Districts of Tete Province, Mozambique

by Tamara José Sande, Balthazar Michael Msanya, Hamisi Juma Tindwa, Alessandra Mayumi Tokura Alovisi, Johnson M. Semoka and Mawazo Shitindi

Soil Syst. 2025, 9(2), 53; https://doi.org/10.3390/soilsystems9020053 - 19 May 2025

Abstract

Irish potato (Solanum tuberosum) is a critical crop for food security and economic growth in Tsangano and Angónia Districts, Central Mozambique. Challenges like inconsistent yields and variable quality are often linked to suboptimal soil conditions, which limit production. This study aimed [...] Read more.

Irish potato (Solanum tuberosum) is a critical crop for food security and economic growth in Tsangano and Angónia Districts, Central Mozambique. Challenges like inconsistent yields and variable quality are often linked to suboptimal soil conditions, which limit production. This study aimed to classify and evaluate the suitability of soils for potato cultivation in Tete Province, where detailed soil assessments remain limited. Four pedons—TSA-P01 and TSA-P02 in Tsangano and ANGO-P01 and ANGO-P02 in Angónia—were examined for bulk density, texture, pH, organic carbon, and nutrient content using a combination of pedological methods and laboratory soil analysis. To determine each site’s potential for growing Irish potatoes, these factors were compared to predetermined land suitability standards. The pedons were very deep (>150 cm) and had textures ranging from sandy clay loam to sandy loam. TSA-P02 had the lowest bulk density (0.78 Mg m⁻³) and the highest available water capacity (182.0 mm m⁻¹). The soil pH ranged from 5.6 to 7.9, indicating neutral to slightly acidic conditions. Nutrient analysis revealed low total nitrogen (0.12–0.22%), varying soil organic carbon (0.16–2.73%), and cation exchange capacity (10.1–11.33 cmol⁽⁺⁾ kg⁻¹). Pedons TSA-P01, ANGO-P1, and ANGO-P02 were characterized by eluviation and illuviation as dominant pedogenic processes, while in pedon TSA-P02, shrinking and swelling were the dominant pedogenic processes. Weathering indices identified ANGO-P01 as most highly weathered, while TSA-P02 was least weathered and had better fertility indicators. According to USDA Taxonomy, the soils were classified as Ultisols, Vertisols, and Alfisols, corresponding to Acrisols, Alisols, Vertisols, and Luvisols in the WRB for Soil Resources. All studied soils were marginally suitable for potato production (S3f) due to dominant fertility constraints, but with varying minor limitations in climate, topography, and soil physical properties. The findings hence recommended targeted soil fertility management to enhance productivity and sustainability in potato cultivation. Full article

(This article belongs to the Special Issue Land Use and Management on Soil Properties and Processes: 2nd Edition)

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19 pages, 6962 KiB

Open AccessArticle

Topographic Wetness Index as a Factor of the Toxic Metals’ Accumulation by the Alkaline Sorption Barrier and the Choice of Revegetation Strategy in the Subarctic

by Marina Slukovskaya, Yury Dvornikov, Tatiana Ivanova, Ekaterina Kopeina, Anna Petrova, Anna Shirokaya, Andrey Novikov, Liubov’ Ivanova and Irina Kremenetskaya

Soil Syst. 2025, 9(2), 52; https://doi.org/10.3390/soilsystems9020052 - 16 May 2025

Abstract

Creation of alkaline bulk layers from mining waste is economically viable way to prevent the migration of toxic metals down the soil profile and revegetate heavy polluted soils over large areas. We have conducted perennial experiments on the revegetation of industrial barren located [...] Read more.

Creation of alkaline bulk layers from mining waste is economically viable way to prevent the migration of toxic metals down the soil profile and revegetate heavy polluted soils over large areas. We have conducted perennial experiments on the revegetation of industrial barren located near the operating nonferrous smelter in humid subarctic climate. A vermiculite–lizardite material from closed phlogopite mining, containing 10% layered silicates, was used to create the alkaline sorption barrier on the sites with high level of Cu/Ni pollution and wide range of topographic wetness index (TWI). We have revealed the strong effect of TWI on metal accumulation by mineral material with the highest effectiveness for the most wet sites. At the same time, the stable Ca and Mg content over seasons revealed the prolonged material effect for the maintenance of alkalinity and macronutrient supply. Further, we demonstrate the potential of Festuca rubra, Festuca ovina, Achillea millefolium, Deschampsia cespitosa, Dactylis glomerata, Rumex acetosella, Silene suecica, and for the revegetation of mineral material in dry locations. We demonstrated the effectiveness of alkaline geochemical barrier for the accumulation of toxic metals and successful plant growth in a wide range of topographic units. Full article

(This article belongs to the Special Issue Research on Trace and Hazardous Elements and Emerging Pollutants in Soils and Sediments)

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24 pages, 3507 KiB

Open AccessArticle

Dynamics of Pharmaceuticals in the Soil–Plant System: A Case Study on Mycorrhizal Artichoke

by Francesco De Mastro, Gennaro Brunetti, Claudio Cocozza, Sapia Murgolo, Giuseppe Mascolo, Carlo Salerno, Claudia Ruta and Giuseppe De Mastro

Soil Syst. 2025, 9(2), 51; https://doi.org/10.3390/soilsystems9020051 - 15 May 2025

Abstract

Contaminants of emerging concern, such as pharmaceuticals (PhACs), are continuously introduced into agro-ecosystems through irrigation with treated wastewater (TWW). While this practice is increasingly common in drought regions, only limited information is available on the fate of PhACs within the soil–plant system. For [...] Read more.

Contaminants of emerging concern, such as pharmaceuticals (PhACs), are continuously introduced into agro-ecosystems through irrigation with treated wastewater (TWW). While this practice is increasingly common in drought regions, only limited information is available on the fate of PhACs within the soil–plant system. For this purpose, a two-year study was conducted by irrigating artichokes, non-inoculated and inoculated with different arbuscular mycorrhizal fungi, with water containing PhACs at different concentrations. The experiment, conducted in both open field and pot conditions, aimed to evaluate their potential accumulation in the soil and plant tissues. Results showed that PhACs concentrations varied according to the physicochemical properties of the compounds and the duration of irrigation. The study revealed minimal accumulation of contaminants in the soil and non-edible plant parts. This was observed only at the end of the second growing cycle, when the plants were irrigated with TWW containing trace PhAC levels. In contrast, during both pot cultivation cycles, PhACs accumulated in the soil were translocated into plant organs when irrigated with water enriched to 200 μg L⁻¹ with eight PhACs. At the end of the trial, climbazole had the highest concentration in soil, while carbamazepine and fluconazole showed greater accumulation across all plant organs compared to other PhACs. In both trials, plants inoculated with Septoglomus viscosum absorbed less PhACs compared to those inoculated with Rhizophagus irregularis + Funneliformis mosseae. These results suggest that, while the long-term use of TWW containing PhACs may improve artichoke yield, it could present different degrees of risk to both environmental and human health, depending on the concentration levels of contaminants. Full article

(This article belongs to the Special Issue Emerging Contaminants in Soil and Water: Sources, Behaviour, and Environmental and Human Health Risks)

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17 pages, 2591 KiB

Open AccessArticle

Elemental Release from Egyptian Glauconite Sediments: An Extraction Study by Various Acids

by Nada Eldawwy, Márk Horváth, Heba Naser, Abdulrahman Maina Zubairu, Gábor Halász, Éva Lehoczky, Eszter Takács, András Székács and Miklós Gulyás

Soil Syst. 2025, 9(2), 50; https://doi.org/10.3390/soilsystems9020050 - 14 May 2025

Abstract

Glauconite, a diagenetic sedimentary phyllosilicate mineral, holds significant importance in soil science, as it is commonly used in soil characterization (as in greensands) and can be identified in the field by its color and morphology. It is a potential fertilizer, rich in essential [...] Read more.

Glauconite, a diagenetic sedimentary phyllosilicate mineral, holds significant importance in soil science, as it is commonly used in soil characterization (as in greensands) and can be identified in the field by its color and morphology. It is a potential fertilizer, rich in essential macronutrients like potassium, phosphorus, calcium, and numerous micronutrients such as manganese, zinc, copper, cobalt, and nickel. In this meticulously conducted study, we extracted five individual elements (potassium, calcium, magnesium, sodium, and zinc) from washed glauconite samples separated into five different size fractions using a suite of acids. The acids employed were nitric acid, hydrochloric acid, acetic acid, and phosphoric acid, each prepared at the same molarity of 0.1 M. Water was used as the control solubilizing medium. The extractant behavior of the acids was assessed by measuring concentrations of each element by the ICP-OES device. The results demonstrate that nitric acid consistently exhibits the highest efficacy in releasing elements, followed by hydrochloric acid and phosphoric acid, while acetic acid results in the lowest release of these nutrients. These findings support the use of acidification treatment of glauconite, enhancing elemental release and potentially reducing the amount of glauconite needed as an alternative fertilizer, thus adding economic value. Full article

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17 pages, 1948 KiB

Open AccessArticle

Biochar and Kitchen Stove Ash for Improving Nutrient Availability and Microbial Functions of Tropical Acidic Soil

by Isaac Asirifi, Lars Makarowsky, Stefanie Heinze, Michael Herre, Steffen Werner, Kwame Agyei Frimpong, Robin Pierburg and Bernd Marschner

Soil Syst. 2025, 9(2), 49; https://doi.org/10.3390/soilsystems9020049 - 13 May 2025

Abstract

Tropical acidic soils exhibit inherently low fertility and reduced microbial activity, driven by low pH and accelerated organic matter mineralization, phosphorus (P) fixation, and aluminum (Al³⁺) and iron (Fe³⁺) toxicity. These constraints limit agricultural productivity, necessitating sustainable and low-cost [...] Read more.

Tropical acidic soils exhibit inherently low fertility and reduced microbial activity, driven by low pH and accelerated organic matter mineralization, phosphorus (P) fixation, and aluminum (Al³⁺) and iron (Fe³⁺) toxicity. These constraints limit agricultural productivity, necessitating sustainable and low-cost soil amendments essential for improving the soil fertility in such regions. This study investigated the effects of biochar, kitchen stove ash (KSA), and their combined application on the soil chemical properties, nutrient dynamics, and microbial functions in a tropical acidic soil. The treatment included the unamended control and two doses of 0.25% w/w (B₁₀) and 0.5% w/w (B₂₀) corncob biochar, 0.03% w/w kitchen stove ash (A_sh), and 0.027% w/w commercial-grade calcium carbonate (L_ime). Each biochar dose was added alone or in combination with either ash (A_sh + B₁₀ and A_sh + B₂₀) or calcium carbonate (L_ime + B₁₀ and L_ime + B₂₀). After eight weeks of laboratory incubation at 20 °C, the soil pH, N and P bioavailability, microbial biomass, and extracellular enzyme activities were measured. The combined application of 0.5% w/w biochar with 0.03% w/w KSA (A_sh + B₂₀) resulted in the most significant improvements in all of the examined soil fertility indicators than the individual amendments. Specifically, the soil pH was increased by 40% (+1.9 pH units) compared with the unamended control. Available phosphorus, mineral nitrogen, and total potassium were increased by 49%, 22%, and 36%, respectively, compared with the unamended control. Regarding the microbial parameters, the A_sh + B₂₀-treated soil showed the highest microbial respiration (+56%), microbial biomass (+45%), and extracellular C- and N-cycling enzyme activities compared with the unamended soil. The ash supplied minerals (P, K, and Mg) provided a more beneficial effect on the soil’s nutrient content and microbial functions than the calcium carbonate. The study demonstrated that underutilized kitchen ash may supplement biochar’s liming and nutrient supply potentials, even at a lower application rate, to improve the fertility of weathered acidic soil. Full article

(This article belongs to the Special Issue Integrated Soil Management: Food Supply, Environmental Impacts, and Socioeconomic Functions: 2nd Edition)

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16 pages, 3194 KiB

Open AccessArticle

Quantitative Source Identification, Pollution Risk Assessment of Potentially Toxic Elements in Soils of a Diamond Mining Area

by Anna Gololobova and Yana Legostaeva

Soil Syst. 2025, 9(2), 48; https://doi.org/10.3390/soilsystems9020048 - 13 May 2025

Abstract

Potentially toxic elements (PTEs) are the most important indicators of environmental pollution and represent a potential risk to the ecology and human health in industrial regions. Eight potentially toxic elements (Mn, Ni, Co, Cr, Pb, Zn, Cd, As) in soils formed on the [...] Read more.

Potentially toxic elements (PTEs) are the most important indicators of environmental pollution and represent a potential risk to the ecology and human health in industrial regions. Eight potentially toxic elements (Mn, Ni, Co, Cr, Pb, Zn, Cd, As) in soils formed on the territory of the industrial site of the Udachny Mining and Processing Division were considered in this study. The potential ecological risk index (RI) was calculated to determine environmental risks of soil contamination. The concentrations of PTEs decreased in the following order Mn > Ni > Zn > Co > Pb > Cr > As > Cd. In total, 19.51% of the sites in the study area exhibited a high potential ecological risk for Mn and Ni, while only 4.87% exhibited a low potential ecological risk for other PTEs. The greatest impacts on soil contamination are exerted by the areas of the Udachny and Zarnitsa pipes, tailings ponds, and the area’s highly mineralized water outlet. The results of correlation analysis (CA) and hierarchical cluster analysis (HCA) revealed that the same groups of elements were present: Co-Cr-Ni and Cd-Zn. The PMF findings demonstrate that the five main diverse sources of PTEs in this study area’s soils were natural, mining activities, transportation, and industrialization, as well as highly mineralized waters. Full article

(This article belongs to the Special Issue Emerging Contaminants in Soil and Water: Sources, Behaviour, and Environmental and Human Health Risks)

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18 pages, 3451 KiB

Open AccessArticle

Cutting-Edge Technology Using Blended Controlled-Release Fertilizers and Conventional Monoammonium Phosphate as a Strategy to Improve Phosphorus Coffee Nutrition During the Coffee Development Phase

by Mateus Portes Dutra, Leonardo Fernandes Sarkis, Damiany Pádua Oliveira, Hugo de Almeida Santiago, Gustavo Tadeu de Sousa Resende, Maria Elisa Araújo de Melo, Adrianne Braga da Fonseca, Cristhian José Hernández López, Euler dos Santos Silva, Aline dos Santos Zaqueu, Gustavo Henrique Furtado de Lima, João Marcelo Silva, Adélia Aziz Alexandre Pozza and Douglas Guelfi

Soil Syst. 2025, 9(2), 47; https://doi.org/10.3390/soilsystems9020047 - 13 May 2025

Abstract

Controlled-release fertilizers contain polymeric coatings that modify the dynamics of phosphorus (P) release in soil. This study aimed to characterize P release from physical mixtures between conventional and controlled-release fertilizers (CRFs), quantify soil P availability, and assess agronomic responses of coffee plants during [...] Read more.

Controlled-release fertilizers contain polymeric coatings that modify the dynamics of phosphorus (P) release in soil. This study aimed to characterize P release from physical mixtures between conventional and controlled-release fertilizers (CRFs), quantify soil P availability, and assess agronomic responses of coffee plants during the establishment phase. Two main types of P fertilizer were evaluated: conventional monoammonium phosphate (MAP) and a blend (physical mixture of conventional MAP and controlled-release P fertilizers). Both fertilizers were applied at 0, 134, 268, and 403 kg ha⁻¹ of P₂O₅. Our findings revealed a blend longevity of 3 and 6 months. P fertilization contributed to an increase in leaf area (1134.7 cm² plant⁻¹) and shoot biomass (602.8 kg ha⁻¹) and raised P in the soil (0.061 mg dm⁻³ per kg of P₂O₅ applied). P accumulation in the coffee plants ranged between 3 and 4 kg ha⁻¹. Other macronutrient accumulations in aerial parts were of the following ranges (in kg ha⁻¹): 47–60 for N, 36–46 for K, 18–22 for Ca, 5–7 for Mg, and 3–4 for S. Micronutrients accumulated (in g ha⁻¹): 454–657 for Fe; 117–160 for B; 117–149 for Mn; 58–71 for Cu; and 34–43 for Zn. Up to 74% of the nutrients were distributed in the leaves. We concluded that the use of blends did not impose any limitation on P nutrition for coffee plants and led to biomass gains (18.9%) in plagiotropic branches. P fertilization proved essential for supporting the initial growth of coffee plants and increasing coffee leaf area and P levels in the soil and promotes adequate levels of P accumulation in plants, leading to improvements in coffee crop nutrition in the establishment phase. Full article

(This article belongs to the Topic Soil Fertility and Plant Nutrition for Sustainable Agriculture—2nd Edition)

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14 pages, 853 KiB

Open AccessArticle

Conservation Reserve Program Soils Show Potential as a Soil Health Benchmark—A Southern Minnesota Case Study

by Oliver Hoffman, Christopher E. Chorpenning, Tad Trimarco, Nathan Carr, Cassidy Buchanan and James A. Ippolito

Soil Syst. 2025, 9(2), 46; https://doi.org/10.3390/soilsystems9020046 - 12 May 2025

Abstract

Soil health is an important concept in promoting sustainable agriculture and food security, yet the absence of universally accepted benchmarks limits its utility in assessing soil function. This study explored the use of Conservation Reserve Program (CRP) soils as a potential benchmark to [...] Read more.

Soil health is an important concept in promoting sustainable agriculture and food security, yet the absence of universally accepted benchmarks limits its utility in assessing soil function. This study explored the use of Conservation Reserve Program (CRP) soils as a potential benchmark to quantify the soil health gap (SHG) in Faribault County, Minnesota. Using the Soil Management Assessment Framework (SMAF), we evaluated physical, chemical, biological, and nutrient soil health indicators to derive a combined overall score that was used to quantify the SHG (i.e., benchmark soil minus test soil) between CRP and corn-based agricultural production (AP). Three paired farms were assessed, each consisting of CRP tall grass prairie established in 2001 and adjacent long-term AP. The results showed higher overall SMAF scores in CRP soils, with a mean SHG of 0.09. Land use had a strong influence on overall scores, largely driven by biological indicators such as soil organic carbon, microbial biomass carbon, and β-glucosidase activity. However, the SMAF demonstrated limited applicability in CRP systems, potentially under-representing their soil health status due to the SMAF’s agricultural emphasis and lack of ecosystem-specific factors such as pH. Full article

(This article belongs to the Special Issue Research on Soil Management and Conservation: 2nd Edition)

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31 pages, 7056 KiB

Open AccessArticle

Agronomic Effectiveness of Biochar–KCl Composites for Corn Cultivation in Tropical Soils

by Gabrielly Nayara Tavares Silva Rodrigues, Carlos Alberto Silva and Everton Geraldo de Morais

Soil Syst. 2025, 9(2), 45; https://doi.org/10.3390/soilsystems9020045 - 9 May 2025

Abstract

Potassium chloride (KCl) is the main source of potassium (K) in Brazilian agriculture, but its high import dependency and the need for split applications increase costs and expose the system to supply and efficiency risks. Understanding the availability and release kinetics of potassium [...] Read more.

Potassium chloride (KCl) is the main source of potassium (K) in Brazilian agriculture, but its high import dependency and the need for split applications increase costs and expose the system to supply and efficiency risks. Understanding the availability and release kinetics of potassium (K) from biochar-based fertilizers (K-BBFs) is crucial for optimizing their use as full or partial substitutes for KCl in Brazilian agriculture. This study evaluated biochars derived from banana peel (BP), coffee husk (CH), and chicken manure (CM), both in their pure form and co-pyrolyzed with KCl (composites) at 300 °C and 650 °C, as K sources for corn grown in two contrasting Oxisols. For pure biochars, feedstock type and pyrolysis temperature significantly influenced K content and release kinetics. Higher pyrolysis temperatures increased K content in BP and CH biochars but not in CM, while also slowing K release in CH and CM. Co-pyrolysis with KCl increased biochar yield, ash content, and K availability. Composites released more K than pure biochar but less than KCl, and at a slower rate. Notably, banana peel biochar co-pyrolyzed with KCl at 650 °C (CBP650) exhibited 36% slower K release and reduced KCl use by 82% while maintaining similar K use efficiency and corn growth. All K-BBFs matched KCl in promoting robust corn growth in clay soil, increasing biomass by 5.3 times and K uptake by 9 times compared to unfertilized (no K addition) plants. In sandy Oxisol, K-BBFs boosted biomass by up to 3.5 times compared to unfertilized plants, though some pure biochars were less effective than KCl in supporting full corn growth. Soil texture strongly influenced K availability, with sandier soils exhibiting higher K levels in solution. These findings suggest that kinetic release studies in abiotic systems, such as lysimeters with sand, are not suitable for evaluating K-BBFs as slow-release fertilizers. Due to lower K retention in sandy soil and solution K levels exceeding 1100 mg L⁻¹, split applications of some K-BBFs are recommended to prevent corn cation uptake imbalances and soil K leaching. Additionally, granulating biochar–KCl composites may enhance K retention and regulate its release in sandy Oxisols. Full article

(This article belongs to the Special Issue Integrated Soil Management: Food Supply, Environmental Impacts, and Socioeconomic Functions: 2nd Edition)

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10 pages, 2273 KiB

Open AccessArticle

Bacterial Community in Sugarcane Rhizosphere Under Bacillus subtilis Inoculation and Straw Return

by Francisco de Alcântara Neto, Danielly Araújo Pinheiro, Sandra Mara Barbosa Rocha, Marcos Renan Lima Leite, Romário Martins Costa, Janderson Moura da Silva, Sabrina Hermelindo Ventura, Mayanna Karlla Lima Costa, Thâmara Kelly dos Santos Apollo Sousa, Rafael de Souza Miranda, Karolayne Ribeiro Caetano, Erika Valente de Medeiros, Arthur Prudêncio de Araujo Pereira, Lucas William Mendes and Ademir Sérgio Ferreira Araujo

Soil Syst. 2025, 9(2), 44; https://doi.org/10.3390/soilsystems9020044 - 4 May 2025

Abstract

Straw return enhances soil biological properties by increasing carbon and energy availability, thereby improving conditions for microbial communities. However, the introduction of beneficial bacteria, such as Bacillus subtilis, can further shape the rhizosphere bacterial composition. In this study, we combined sugarcane straw [...] Read more.

Straw return enhances soil biological properties by increasing carbon and energy availability, thereby improving conditions for microbial communities. However, the introduction of beneficial bacteria, such as Bacillus subtilis, can further shape the rhizosphere bacterial composition. In this study, we combined sugarcane straw return with B. subtilis inoculation to test whether this synergy reduces microbial specialization in the sugarcane rhizosphere. Three treatments were evaluated: (I) bulk soil (bulk), (II) rhizosphere soil with straw return but no B. subtilis inoculation (straw), and (III) rhizosphere soil with straw return and B. subtilis inoculation (straw + Bacillus). The bacterial community, including plant-growth-promoting bacteria (PGPB), was analyzed via 16S rRNA amplicon sequencing. Neither straw return nor B. subtilis inoculation significantly altered bacterial richness, diversity, or phylum-level abundance in the rhizosphere. Actinobacteria, Firmicutes, and Proteobacteria dominated the community, with Bacillus, Bradyrhizobium, and Paenibacillus as the predominant PGPB genera. Notably, only Bradyrhizobium abundance increased in the rhizosphere when straw was co-applied with B. subtilis. A co-occurrence network analysis revealed stronger microbial interactions under straw return, while B. subtilis enhanced connectivity among the PGPB. Although niche occupancy remained stable, PGPB specialization was higher with straw alone, suggesting that B. subtilis fosters a more generalist community. In conclusion, while straw return and B. subtilis inoculation did not affect overall bacterial diversity, B. subtilis increased PGPB interactions and reduced functional specialization, promoting a more generalized microbial community. Full article

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13 pages, 653 KiB

Open AccessArticle

The Influence of Black Soldier Fly Residue on Watermelon Growth and the Properties of a Coarse-Textured Ultisol

by Benedict Onyebuchi Unagwu, Chidiebere Fransica Odu, Chinedu Felix Amuji, Michael Onyedika Eze, Nancy Ekene Ebido, Chidike Ude Abara, Chioma Rosita Igboka and Uchechukwu Paschal Chukwudi

Soil Syst. 2025, 9(2), 43; https://doi.org/10.3390/soilsystems9020043 - 3 May 2025

Abstract

Improving the fertility status of nutrient-depleted soils is critical to achieving food security. The negative effects of chemical fertilizers on soils necessitate the global quest for eco-friendly, effective, and sustainable alternatives. This work assessed the effect of black soldier fly (BSF) residue application [...] Read more.

Improving the fertility status of nutrient-depleted soils is critical to achieving food security. The negative effects of chemical fertilizers on soils necessitate the global quest for eco-friendly, effective, and sustainable alternatives. This work assessed the effect of black soldier fly (BSF) residue application on soil properties and watermelon growth. The study was set up in a completely randomized design with six replications. The treatments were BSF1 (BSF applied at 10 t ha⁻¹), BSF2 (20 t ha⁻¹), BSF3 (30 t ha⁻¹), and control. The plant data collected in this study were vine length, leaf width, number of leaves, and stem girth, and the soil’s physicochemical properties were determined. The results show that BSF residue-treated soils had 20.4–49.5% higher aggregate stability and 50–160% higher hydraulic conductivity than the control treatment. BSF residue-treated soils had significantly (p ≤ 0.05) higher pH, total N, available P, exchangeable K, and organic carbon than the control treatment. BSF3 treatment had the highest effect on available P and soil pH relative to other amended treatments. High rates of BSF residue application did not significantly increase the total available N and P contents, which could suggest that BSF application at 30 t ha⁻¹ may not pose a risk of N and P pollution to water systems. BSF residue-treated soils improved (p < 0.05) watermelon growth parameters relative to the control. Watermelon leaf length was significantly (p ≤ 0.05) longer for BSF residue-treated soils than the control treatment. A similar trend was observed for the number of leaves, leaf width, and stem girth. At 4, 6, and 10 weeks after sowing, BSF residue-treated plants had 38.2–104%, 22.7–118%, and 25.7–103% longer vine lengths than the control treatment, respectively. The study results suggest that BSF residue application can enhance the fertility status of a coarse-textured ultisol for watermelon production. Full article

(This article belongs to the Special Issue Integrated Soil Management: Food Supply, Environmental Impacts, and Socioeconomic Functions: 2nd Edition)

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18 pages, 16483 KiB

Open AccessArticle

Rill Erosion and Drainage Development in Post-Landslide Settings Using UAV–LiDAR Data

by Xinyu Chen, Albertus Stephanus Louw, Ali P. Yunus, Saleh Alsulamy, Deha Agus Umarhadi, Md. Alamgir Hossen Bhuiyan and Ram Avtar

Soil Syst. 2025, 9(2), 42; https://doi.org/10.3390/soilsystems9020042 - 1 May 2025

Abstract

Accurate microtopography data are an important input for characterizing small-scale rill erosion and its progression following disturbances. UAV–LiDAR systems are increasingly accessible and have successfully been used to measure microtopography data for several applications. Yet, the use of UAV–LiDAR systems for rill erosion [...] Read more.

Accurate microtopography data are an important input for characterizing small-scale rill erosion and its progression following disturbances. UAV–LiDAR systems are increasingly accessible and have successfully been used to measure microtopography data for several applications. Yet, the use of UAV–LiDAR systems for rill erosion studies in post-landslide landscapes have not been well investigated. Therefore, the purpose of this study was to implement and evaluate a UAV–LiDAR-based workflow to capture the microtopography of a post-landslide landscape, and by doing so, to help to determine best practices for UAV–LiDAR-based rill analysis. A commercial UAV–LiDAR system was used to map three post-landslide slopes and generate digital elevation models with a 1 cm-per-pixel ground resolution. Using data captured over multiple years, temporal rill development was assessed by comparing rill cross-sections and calculating changes to rill density and erosion volume. A flow-accumulation algorithm was adopted to automatically extract the rill network. We found that a flow accumulation algorithm with a threshold value of 5000 detected the rill network with overall accuracies of >88% and F1-scores of >93%. Vertical cross-sections of individual rills revealed an increase in the depth and width of rills over a one-year period. This study demonstrates that a commercial UAV–LiDAR system can effectively describe microtopography in a post-landslide landscape and facilitate analysis of small-scale rill characteristics and the progression of rill erosion. Full article

(This article belongs to the Special Issue Land Use and Management on Soil Properties and Processes: 2nd Edition)

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12 pages, 1057 KiB

Open AccessArticle

Impact of Starter Phosphorus Fertilizer Type and Rate on Maize Growth in Calcareous Soil Irrigated with Treated Wastewater

by Majed B. Almutairi, Ibrahim Ahmed, Khaled D. Alotaibi, Saud S. Aloud and Mohamed Abdalla

Soil Syst. 2025, 9(2), 41; https://doi.org/10.3390/soilsystems9020041 - 30 Apr 2025

Abstract

Phosphorus (P) is an essential macronutrient, but its limited availability in calcareous soils remains a major constraint to crop nutrition. Treated wastewater (TWW) offers a sustainable irrigation source in arid regions, enhancing water supply and contributing nutrients such as P. This study evaluates [...] Read more.

Phosphorus (P) is an essential macronutrient, but its limited availability in calcareous soils remains a major constraint to crop nutrition. Treated wastewater (TWW) offers a sustainable irrigation source in arid regions, enhancing water supply and contributing nutrients such as P. This study evaluates the effects of TWW and tap water (TW) irrigation, combined with varying rates of phosphorus fertilizers, such as single superphosphate (SSP) and diammonium phosphate (DAP), on maize (Zea mays L.) growth, nutrient uptake, and soil properties. A greenhouse experiment was conducted using maize grown in sandy calcareous soil. TWW irrigation with SSP (40 kg/ha) and DAP (20 kg/ha) resulted in the highest shoot dry matter (2.6 g), while TW with DAP at 20 kg/ha produced 2.2 g. Root biomass was generally higher, peaking at 8.3 g under TWW-SSP (40 kg/ha) and 5.7 g under TW-SSP (40 kg/ha). Nitrogen uptake was highest under TWW, with TWW-DAP (40 kg/ha) yielding the highest N content in shoots (1.9%) and roots (1.2%). Phosphorus content peaked at TWW-DAP (30 kg/ha) in shoots (0.52%) and roots (0.26%). Potassium uptake also improved with TWW, particularly in shoots (4.5%) under TWW-SSP (40 kg/ha) and roots (2.6%) under TWW-DAP (40 kg/ha). Post-harvest soil analysis showed TWW maintained stable EC (0.3–0.5 dS/m) and neutral pH (7.6–7.8). Higher DAP rates (40 kg/ha) with TWW increased soil organic matter, nitrogen (266.2 mg/kg), phosphorus (38.0 mg/kg), and potassium (385.3 mg/kg). In contrast, TW irrigation had lower nutrient enhancement, though high DAP rates still improved soil fertility. These findings highlight the potential of integrating TWW with phosphorus fertilizers to improve crop performance and soil fertility in calcareous soils. This approach offers a sustainable alternative to conventional practices, supporting sustainable crop production in water-limited environments. Further long-term studies are recommended to assess the sustainability of TWW irrigation in arid soils. Full article

(This article belongs to the Special Issue Integrated Soil Management: Food Supply, Environmental Impacts, and Socioeconomic Functions: 2nd Edition)

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