Disentangling the drivers of total and available phosphorus distributions in Swiss soils

This study was conducted in Ifite-Nanka, Orumba North L.G.A. in Anambra state, Nigeria. The aim of the research was to evaluate the effect of three land use types on soil organic carbon (SOC) and physical properties and to determine the factors that contributed to the stability of the eroded sites. Horizon variability of these soil parameters was also determined. The result showed that Oil palm plantation had significantly (p < 0.05) highest SOC value (0.51 %) followed by arable cropping (0.46 %) and least in cashew plantation (0.28 %). Oil palm plan- tation had the highest value of water stable aggregate (WSA) (15.35) followed by arable farm land (11.67) and least was cashew plantation but aggregate stabil- ity (AS) was highest in arable cropping. Along the profile, SOC was highest in A horizon and so was the WSA and AS. Among SOC, clay and sand content used in determining the stability of the soil, SOC explained 64.9 % and 45.5 % varia- tions in AS and WSA respectively. Collapsing the structural and stability indi- ces, more of the structural indices were improved in arable land use while more of the stability indices were improved oil palm plantation plots.

Soil quality in an agroecosytem is considerably influenced by land use and management practices. Twenty two potential soil quality indicators were used to assess the effects of five different land use types (arable land, plantation, agroforestry, marginal land and native forest) on soil quality in Akufo and Atan farm settlements in Ibadan, southwestern Nigeria. A total of sixty-two fields were selected from which soil samples were taken at a depth of 0-15 cm and subjected to laboratory analysis. Majority of the evaluated physicochemical properties varied significantly among the land uses and whereas native land performed relatively better for most of the observed attributes, arable and marginal lands performed worse. Due to the moderate to strong significant correlation among the potential indicators, they were subjected to principal component analysis and only seven indicators were selected to compute the soil quality index (SQI). In both Akufo and Atan, native land had the highest SQI (0.8250 and 0.860 respectively) which was significantly different (P = .05) from all the agricultural land uses, except plantation (0.739 and 0.750 respectively). Whereas marginal field in Atan was most degraded (SQI = 0.455), it was closely followed by arable fields in both locations. This study indicates that the current agricultural land use and soil management practices in Akufo and Atan farm settlements have negatively impacted soil quality; however, the degree of degradation was strongly influenced by the concentration of soil organic carbon in the understudied land use systems. It also emphasizes the need to promote the use of sustainable management practices among agricultural land users, so as to increase soil organic carbon stock, and improve soil quality and land productivity.

Soil is a natural capital which supplies valuable ecosystem services including carbon and nitrogen storage. Agroecosystems play an important role in soil organic carbon (SOC) and soil total nitrogen (NT) accumulation. The aim of this study was to analyse SOC stock (SOCS) and NT stock (NTS) in relation to land use (arable land-AL, permanent grasslands-PG), management, soil depth, and selected soil properties of six soil subtypes (Rendzic Leptosol—LPrz, Dystric Cambisol—CMdy, Stagnic Cambisol—CMst, Haplic Fluvisol—FLha, Gleyic Fluvisol—FLgl, Haplic Chernozem—CHha) which are the most widespread in Slovakia. SOCS for a 50 cm deep soil profile ranged from 161 t.ha−1 in CHha to 59 t.ha−1 in FLgl in grasslands, and in arable lands from 111 t.ha−1 in CHha to 38 t.ha−1 in CMst. In grasslands, FLs and CMst showed the significantly lowest SOCS and NTS in comparison to CMdy, LPrz, and CHha. The mean soil NT content in arable land and grasslands was 2.21 g.kg−1 and 2.82 g.kg−1, respectively. ANOVA showed that soil subtype, land use, and site have significantly affected SOCS but not NTS. The correlation analysis revealed correlations between SOCS and NTS. SOCS was also correlated with C:N, pH, P, and K. This study should help to encourage practices to maintain soil C and soil properties and to ensure the sustainability of the functions of many soil types in Slovakia.

Soils contain about three times the amount of carbon globally available in vegetation, and about twice the amount in the atmosphere. However, soil organic carbon (SOC) has been reduced in many areas, while an increase in atmospheric CO2 has been detected. Recent research works have shown that it is likely that past changes in land use history and land management were the main reasons for the loss of carbon rather than higher temperatures and changes of precipitation resulting from climate change. The primary scope of this work was to estimate soil organic carbon stock (CS) variations in Italy during the last three decades and to relate them to land use changes. The study was also aimed at finding relationships between SOC and factors of pedogenesis, namely pedoclimate, morphology, lithology, and land use, but also at verifying the possible bias on SOC estimation caused by the use of data coming from different sources and laboratories. The soil database of Italy was the main source of information in this study. In the national soil database is stored information for 20,702 georeferentiated and dated observations (soil profiles and minipits) analysed for routine soil parameters. Although the observations were collected from different sources, soil description and analysis were similar, because all the sources made reference to the Soil Taxonomy and WRB classification systems, and soil analyses followed the Italian official methods. Besides horizon description and analysis, soil observations had a set of site information including topography, lithology, and land use. The SOC and bulk density referred to the first 50 cm, thus CS was calculated on the basis of the weighted percentage of SOC, rock fragments volume, and bulk density. A set of geographic attributes were considered to spatialize point information, in particular, DEM (100 m) and derived SOTER morphological classification, soil regions (reference scale 1:5,000,000) and soil systems lithological groups (reference scale 1:500,000), soil moisture and temperature regimes (raster maps of 1 km pixel size), land cover (CORINE project, reference scale 1:100,000) at three reference dates: years 1990 and 2000, and an original update to 2008, obtained with field point observations. The interpolation methodology used a multiple linear regression (MLR). CS was the target variable, while predictive variables were the geographic attributes. Basic statistical analysis was performed first, to find the predictive variables statistically related to CS and to verify the bias caused by different laboratories and surveys. After excluding the biased datasets, the best predictors were selected using a step-wise regression method with Akaike Information Criterion (AIC) as selection and stop criterion. The obtained MLR model made use of the following categorical attributes: (i) decade, (ii) land use, (iii) SOTER morphological class, (iv) soil region, (v) soil temperature regime, (vi) soil moisture regime, (vii) soil system lithology, (viii) soil temperature, (ix) soil aridity index (dry days per year), and, (x) elevation. The interaction between decade and land use variables was also considered in the model. Results indicated that CS was highly correlated with the kind of main type of land use (forest, meadow, arable land), soil moisture and temperature regimes, lithology, as well as morphological classes, and decreased notably in the second decade but slightly increased in the third one, passing form 3.32 Pg, to 2.74 Pg and 2.93 Pg respectively. The bias caused by the variables like “laboratory” and “survey source” could be as large as the 190%.

Spatial variability of soil phosphorus in the Fribourg canton, Switzerland

The aim of this chapter was to quantify the soil organic carbon (SOC) stock in the top 30 cm of mineral soil for the whole Italian territory, according to the different land use types of the Intergovernmental Panel on Climate Change (IPCC) cropland category (arable land, agroforestry, vineyards, olive groves, orchards and rice fields), as a basis for future land use scenarios and to address mitigation policy at country level. Besides, two independent studies addressing the current status and the future trends of SOC for the whole cropland category at regional level were reported. The subdivision of the cropland category into classes is functional to assess the impacts on the SOC stock due to land use changes from and to agricultural uses, providing the starting or ending point scenario. The differences emphasized for the soils of a subcategory under the different types of climate can be possibly used for future-oriented agricultural practices. The comparison of the total mean values of the different cropland subcategories shows significant differences in the SOC stock. Considering the year 2000 and applying to each subcategory area the specific average SOC stock value found in this study, the total amount of C stored in the upper 30 cm of the whole cropland category results to be 516.3 ± 156.9 Tg C. This amount represents about 17 % of the total SOC estimated for the top 50 cm of soils of total surface of Italy, which reports about 2,900 Tg C, thus indicating the importance to preserve the large amount of SOC stored in cropland category. In conclusion, given the few estimates available at European level, repeated SOC inventories aimed to define the SOC content in cropland soils are important for future stock change evaluation.

Summary Stable soil organic matter (SOM) is important for long‐term sequestration of soil organic carbon (SOC), but the usefulness of different fractionation methods to isolate stable SOM is open to question. We assessed the suitability of five chemical fractionation methods (stepwise hydrolysis, treatment with H 2 O 2 , Na 2 S 2 O 8 , NaOCl, and demineralization of the NaOCl‐resistant fraction (NaOCl + HF)) to isolate stable SOM from soil samples of a loamy sand and a silty loam under different land use regimes (grassland, forest and arable crops). The apparent C turnover time and mean age of SOC before and after fractionation was determined by 13 C and 14 C analysis. Particulate organic matter was removed by density fractionation before soils were exposed to chemical fractionation. All chemical treatments induced large SOC losses of 62–95% of the mineral‐associated SOC fraction. The amounts of H 2 O 2 ‐ and Na 2 S 2 O 8 ‐resistant SOC were independent from land use, while those of NaOCl‐ (NaOCl + HF)‐ and hydrolysis‐resistant SOC were not. All chemical treatments caused a preferential removal of young, maize‐derived SOC, with Na 2 S 2 O 8 and H 2 O 2 being most efficient. The mean 14 C age of SOC was 1000–10000 years greater after chemical fractionation than that of the initial, mineral‐associated SOC and mean 14 C ages increased in the order: NaOCl < NaOCl + HF ≤ stepwise hydrolysis ≪ H 2 O 2 ≈ Na 2 S 2 O 8 . None of the methods appeared generally suitable for the determination of the inert organic matter pool of the Rothamsted Carbon Model. Nonetheless, our results indicate that all methods are able to isolate an older, more stable SOC fraction, but treatments with H 2 O 2 and Na 2 S 2 O 8 were the most efficient ones in isolating stable SOM.

Policies for restoring soil health and mitigating climate change require information on soil organic carbon (SOC) stocks and their spatial and temporal variation, and related sequestration potentials. Using the province of Lower Austria as environmentally diverse model region, we present a detailed analysis of SOC stocks, saturation potentials and deficits along with SOC monitoring data for the past three decades.Using the provincés soil database (sampling 1991) we estimated the saturation potential for mineral-protected C (Csat) by boundary line regression to the particle fraction <20 µm (f<20µm). Compared to published work, parameterization by Lower Austrian data yielded considerably larger Csat values which agree well with independent maximum organic C load estimates based on specific surface area. Csat is particularly small in topsoils of regions with non-calcareous igneous rock, but large on fine-textured quaternary and tertiary sediments, and weathering residuals of carbonate rock. During the past three decades, the medians of SOC in grassland topsoils (0–20 cm) increased significantly (p < 0.05) by 29.7% from 39.4 to 51.1 g kg−1, corresponding to annual accumulation rates of 0.87 Mg C ha−1. SOC in cultivated soils increased by 17.1% from 12.7 to 14.8 g kg−1 (0.20 Mg C ha−1 y−1). Because of the large initial C gap, the observed SOC accumulation is not related to Cdef but likely reflects improved soil management.

Abstract. The agricultural Mediterranean areas are dedicated to arable crops (AC), but in the last decades, a significant number of AC has led to a land use change (LUC) to olive grove (OG) and vineyards (V). A field study was conducted to determine the long-term effects (46 years) of LUC (AC by OG and V) and to determine soil organic carbon (SOC), total nitrogen (TN), C : N ratio and their stratification across the soil entire profile, in Montilla-Moriles denomination of origin (D.O.), in Calcic-Chromic Luvisols (LVcc/cr), an area under semiarid Mediterranean conditions. The experimental design consisted of studying the LUC on one farm between 1965 and 2011. Originally, only AC was farmed in 1965, but OG and V were farmed up to now (2011). This LUC principally affected the horizon thickness, texture, bulk density, pH, organic matter, organic carbon, total nitrogen and C : N ratio. The LUC had a negative impact in the soil, affecting the SOC and TN stocks. The conversion from AC to V and OG involved the loss of the SOC stock (52.7% and 64.9% to V and OG respectively) and the loss of the TN stock (42.6% and 38.1% to V and OG respectively). With respect to the stratification ratios (SRs), the effects were opposite; 46 years after LUC increased the SRs (in V and OG) of SOC, TN and C : N ratio.

Developing a routine and cost effective capability for measuring soil organic carbon (SOC) content and composition will allow identification of land management practices with a potential to maintain or enhance SOC stocks. Coupling SOC content data and mid-infrared (MIR) spectra through the application of partial least-squares regression (PLSR) analyses has been used to develop such a prediction capability. The objective of this study was to determine whether MIR/PLSR analyses provide accurate estimates of the content and composition of SOC that can be used to quantify SOC stocks and its potential vulnerability to loss. Soil was collected from a field trial incorporating a range of land use (pasture, arable cropping and bare fallow) and tillage (intensive, minimum and no tillage) treatments over a nine-year period. The SOC content was measured by dry combustion analysis. Particulate organic carbon was separated from other forms of carbon on the basis of particle size (SOC in the &amp;gt;50 µm fraction). Resistant organic carbon was quantified using solid-state 13C nuclear magnetic resonance. The MIR/PLSR algorithms were successfully developed to predict the natural logarithms of the contents of SOC and POC in the collected soils. With initial calibration, a single MIR analysis could be used in conjunction with PLSR algorithms to predict the content of SOC and its allocation to component fractions. The MIR/PLSR predicted SOC contents provided reliable estimates of the impact of agricultural management on the 0–25-cm SOC stocks, as well as an indication of the vulnerability of SOC to loss. Development of this capability will facilitate the rapid and cost effective collection of SOC content data for detecting the impact of agricultural management treatments on SOC stocks, composition and potential vulnerability to change.

Soil organic carbon (SOC) is operationally partitioned into particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) to infer soil carbon persistence and sensitivity to disturbance or management. Yet the combined roles of climate, mineralogy, and land use in shaping these fractions remain unresolved across continental gradients. Here, we analysed 249 Australian topsoils from 65 paired sites along a 550 mm rainfall isohyet. Samples were grouped into four climate–texture clusters (Subtropical Coarse, Subtropical Fine, Temperate Coarse, Temperate Fine) to disentangle the effects of thermal and hydrological regimes, soil properties, and land use on SOC partitioning and stabilisation. Subtropical soils consistently exhibited a high proportion of MAOC (fMAOC ≈ 0.8) despite low SOC stocks, reflecting preferential retention of mineral–organic interactions under carbon-limited and water-stressed conditions. In contrast, temperate soils stored greater SOC and POC, indicating higher carbon inputs and slower decomposition. In subtropical fine-textured soils, agriculture elevated fMAOC through microbial activity and nutrient inputs, yet this occurred alongside depleted SOC and POC, highlighting a trade-off between stabilisation efficiency and carbon stock depletion. Across all clusters, land use effects were detectable but secondary to climate and mineral properties. These findings show that temperate and subtropical soils follow contrasting carbon stabilisation pathways: temperate systems store more carbon overall, while subtropical systems allocate a larger share of their carbon to mineral-associated carbon. Our climate–texture framework highlights region-specific management priorities: enhancing mineral–organic interactions through increased root inputs and organic or mineral amendments in subtropical soils, and protecting vulnerable carbon stocks through reduced disturbance and residue retention in temperate systems. • SOC stability is context dependent, not universal. • Temperature and clay jointly control particulate and mineral-associated pools. • Agriculture reduces both particulate and mineral-associated carbon stocks. • Soil carbon responses to land use depend on climate and texture. • The climate–texture framework identifies region-specific pathways.

Soil organic carbon (SOC) stocks represent the second-largest natural carbon reservoir globally, surpassed only by the oceans. SOC plays a vital role in maintaining ecosystem health, offering numerous benefits such as enhancing soil structure, increasing nutrient availability, and boosting water retention capacity. Beyond its ecological significance, SOC is integral to climate change mitigation, given its ability to sequester atmospheric carbon dioxide effectively. Additionally, SOC contributes to improving the physical, chemical, and biological properties of soil, making it indispensable for sustainable land management.&amp;#160;Taiwan, an island in the western Pacific Ocean, spans an area of approximately 35,800 square kilometers. Shaped like a tobacco leaf, the island extends 400 kilometers in length and 150 kilometers at its widest point. Taiwan&amp;#8217;s landscape is characterized by a Central Mountain Range running north to south, steep slopes, and geologically fragile formations. In recent decades, Taiwan has experienced significant changes in land use and land cover, particularly in urban areas where cropland and forest land on city outskirts have been replaced by infrastructure development. These transformations have directly impacted SOC levels across the island, underscoring the need for accurate mapping to estimate SOC stocks and assess soil functionality, particularly in agricultural regions.&amp;#160;Traditional ground sampling methods for estimating SOC, though precise, are often costly and labor-intensive. To address these limitations, alternative approaches, such as remote sensing, offer cost-effective solutions. Among various predictive modeling techniques, machine learning algorithms like Random Forest (RF) have emerged as highly effective tools for SOC estimation. RF models excel due to their ability to minimize correlation among individual decision trees and provide reliable error estimates, ensuring robust predictions.In this study, we combined field sampling data (2010&amp;#8211;2021) with remote sensing, topographic, and climatic datasets to estimate SOC stocks in the topsoil layer (0&amp;#8211;30 cm) of Taiwan&amp;#8217;s agricultural areas. Using the RF algorithm, we initially employed 23 explanatory variables and subsequently refined the model by eliminating less significant predictors, reducing the final set to 12 variables. The refined model demonstrated strong predictive accuracy, with R&amp;#178; values exceeding 0.70 for agriculture land in Taiwan.&amp;#160;Our findings revealed spatial variations in SOC levels, with mountainous regions exhibiting higher SOC stocks compared to suburban and low-lying agricultural areas, where values were notably lower. SOC levels for agricultural lands ranged from a maximum of 7.14 kg/m&amp;#178; to a minimum of 2.55 kg/m&amp;#178;, with an average value of 3.43 kg/m&amp;#178;. Agricultural practices incorporating agroforestry techniques showed relatively higher SOC stocks, emphasizing the role of sustainable practices in enhancing soil carbon storage.&amp;#160;The results of this study hold significant implications for long-term monitoring of SOC in Taiwan and provide a crucial reference for policymakers aiming to develop effective carbon sequestration strategies. By integrating field data with advanced modeling and remote sensing technologies, this research contributes to a deeper understanding of SOC dynamics and supports efforts to promote sustainable land management and climate resilience.

Coastal wetland ecosystems provide critical interfaces between terrestrial and marine environments, where distinctive biogeochemical conditions shape soil fertility and nutrient cycling. This study investigated the spatial distribution of soil chemical properties and primary nutrient availability across five representative land use systems in Pokkali wetlands of Kerala, India: rice monoculture, prawn monoculture, integrated rice-prawn systems, fallow lands, and mangrove stands. Surface soil samples were collected from each land use system during the pre-monsoon period and analyzed for pH, electrical conductivity, organic carbon and available nitrogen, phosphorus, and potassium. The results revealed substantial variation in soil chemical properties across land uses, with rice monoculture exhibiting extremely acidic conditions (pH 3.54) and exceptionally high nitrogen and phosphorus levels, while the rice-prawn integrated system demonstrated near-neutral pH (6.36) and the highest potassium content. Prawn monoculture showed elevated salinity and potassium accumulation but remarkably low phosphorus availability. Mangrove ecosystems maintained moderately acidic conditions with intermediate nutrient levels, reflecting inherent conservation mechanisms, whereas fallow lands displayed progressive nutrient depletion, particularly in potassium. Organic carbon content remained statistically uniform across all systems, suggesting resilient carbon dynamics in Pokkali ecosystems despite diverse management practices. These findings emphasize that different land uses create distinct biogeochemical environments with unique nutrient management requirements, and no single system simultaneously optimizes all soil fertility parameters. The study provides crucial insights for developing land use-specific nutrient management strategies to enhance productivity while maintaining long-term soil health in these valuable coastal agroecosystems

&lt;p&gt;This study examined the impacts of land use on the physical and chemical properties of soils of land use types along agroforestry and agricultural landscapes in a rainforest zone of Nigeria. The land use systems are forest, agroforestry, fallow, and ornamental plant fields in addition to permanent crop fields (cocoa, oil palm, and citrus) and annual crop fields (maize). Profile pits were dug on the land use types and samples were collected 0&amp;ndash;20 cm and 20&amp;ndash;50 cm for laboratory analysis. Soil samples were collected from undisturbed soil and profile pits for bulk density and moisture content determination following standard analytical procedures. Among the land use types, physical properties (sand, clay, soil bulk density) and chemical properties (soil pH, SOC, total N, P, K, Ca, Mg, and CEC) differed significantly. Bulk density, pH, SOC, total, and stocks of SOC and N differed statistically for 0&amp;ndash;20 and 20&amp;ndash;50 cm soil depths with downward increases in N and SOC stocks along sampling depth. Permanent croplands (forest and agroforestry fields) had higher soil pH, SOC, total N, and CEC, while arable crop fields had relatively lower pH, SOC, TN, P, K, Ca, Mg, and CEC. Arable fields had significantly lower C and N stocks within 50 cm compared with permanent crop fields, which may be attributed to continuous tillage by the smallholder farmers and soil erosion-enhanced SOC and N removal from top soil. For both permanent and annual crop fields, SOC and total N stocks ranged from 5.75 to 3.12 kg/m&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; for 0&amp;ndash;20 cm depths and 2.44 to 1.93 kg/m&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; for deeper (20&amp;ndash;50 cm) layers. Relative to forest soil, stocks of SOC in the surface soils (0&amp;ndash;20 cm) decreased in the order: agroforestry &amp;gt; ornamental plant field &amp;gt; cocoa &amp;gt; fallow land &amp;gt; citrus &amp;gt; oil palm &amp;gt; annual cropping system. Following this decreasing order, soil deterioration indices are equivalent to 27% &amp;gt; 28% &amp;gt; 30% &amp;gt; 31% &amp;gt; 32% &amp;gt; 34% &amp;gt; 38% compared with forest soil, respectively. Strong significant correlations (&amp;lt;i&amp;gt;p&amp;lt;/i&amp;gt; &amp;lt; 0.05) were observed between SOC and TN stocks and some soil properties (bulk density, clay contents, pH, and CEC) with R&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt; values ranging from 1.0 to 0.85. It is concluded that the soil's physical and chemical properties and carbon storage potential differed among the land uses of the study site.&lt;/p&gt;

Land use system has a great impact on soil properties. The effect of land use on soil chemical, microbiological properties and soil moisture of salt-affected soils was investigated in India. Soil samples were collected from Solonetz soils under different land uses such as arable land (SnA), bare land (SnB) and pasture land (SnP). Results of the study showed that the chemical and microbiological properties of all three sites were statistically different from each other. The principal components (PC1 and PC2) retained for the analysis accounted for 86.26% of the total variance. The values of microbiological properties were the highest in SnA, intermediate in SnP and the lowest in case of SnB. Discriminant analysis of microbiological properties showed that 93.64% of variation and can be determined by MBC. The primary objective of our study was to ascertain how farmers' perceptions and decisions regarding land use systems, which are based on their experiences rather than laboratory results, align with soil physical, chemical and microbiological properties, and how they contribute to preserving soil quality. Overall, it was concluded that arable land (SnA) had more favorable chemical properties and it has been microbiologically more active in investigated salt affected (Solonetz) soils. Moreover, soil conservation and amelioration practices are suggested in bare land and pasture land to prevent further degradation and to improve the soil quality of the investigated salt affected areas. Also, it is important to educate and transfer knowledge to the farmers about the consequences of soil degradation and advocate good soil management practices (gypsum application, nutrient management, crop cover, tillage etc.).. KEYWORDS :Salt-affected soils, Arable land, Pasture land, Bare land, Farmers decision, Land use system, Soil properties.