Search Results (69)

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

In citriculture, inputs like water and fertilizer are applied through traditional basin methods, thereby incurring reduced use-efficiency. The response of conventional crop coefficient-based fertigation scheduling continues to be inconsistent and complex in its field implementation, thereby necessitating the intervention of sensor-based (Internet of Things; IoT) technology for fertigation scheduling on a real-time basis. The study aimed to investigate fertigation scheduling involving four levels of irrigation, viz., I₁ (100% evapotranspiration (ET) as the conventional practice), I₂ (15% volumetric moisture content (VMC)), I₃ (20% VMC), and I₄ (25% VMC), as the main treatments and three levels of recommended doses of fertigation, achieved by reappropriating different nutrients across phenologically defined critical growth stages, viz., F₁, F₂, and F₃ (conventional fertilization practice), as sub-treatments, which were evaluated through a split-plot design over two harvesting seasons in 2021–2023. Nagpur mandarin (Citrus reticulata Blanco) was used as the test crop, which was raised on Indian Vertisol facing multiple nutrient constraints. Maximum values for physiological growth parameters (plant height, canopy area, canopy volume, and relative leaf water content (RLWC)) and fruit yield (characterized by 9% and 5%, respectively, higher A-grade-sized fruits with the I₄ and F₁ treatments over corresponding conventional practices, viz., I₁ and F₃) were observed with the I₄ irrigation treatment in combination with the F₁ fertilizer treatment (I₄F₁). Likewise, fruit quality parameters, viz., juice content, TSS, TSS: acid ratio, and fruit diameter, registered significantly higher with the I₄F₁ treatment, featuring the application of B at the new-leaf initiation stage (NLI) and Zn across the crop development (CD), color break (CB), and crop harvesting (CH) growth stages, which resulted in a higher leaf nutrient composition. Treatment I₄F₁ conserved 20–30% more water and 65–87% more nutrients than the I₁F₃ treatment (conventional practice) by reducing the rate of evaporation loss of water, thereby elevating the plant’s available nutrient supply within the root zone. Our study suggests that I₄F₁ is the best combination of sensor-based (IoT) irrigation and fertilization for optimizing the quality production of Nagpur mandarin, ensuring higher water productivity (WP) and nutrient-use-efficiency (NUE) coupled with the improved nutritional quality of the fruit. Full article

Water quality affects soils by promoting their degradation by the accumulation of salts that will lead to salinization and sodification. However, the magnitude of these processes varies with soil attributes. Saturated hydraulic conductivity (K_sat) is the rate at which water passes through saturated soil, which is fundamental to determining water movement through the soil profile. The K_sat may differ from soil to soil according to the sodium adsorption ratio (SAR), water electrical conductivity (EC_w), soil texture, and clay mineralogical assemblage. In this study, an experiment with vertical columns and constant-load permeameters was conducted to evaluate changes in soil K_sat with waters comprising five EC_w values (128, 718, 1709, 2865, and 4671 µS cm⁻¹) and five SAR values [0, 5, 12, 20, and 30 (mmol_c L⁻¹)^0.5] in combination. Horizons from nine northeastern Brazilian soils (ranging from tropical to semiarid) were selected according to their texture and clay mineralogical composition. The data obtained were fit with multiple regression equations for K_sat as a function of EC_w and SAR. This study also determined the null SAR at each EC_w level, using K_sat = 0 on each equation, to predict the SAR needed to achieve zero drainage on each soil for each EC_w level and the threshold electrolyte concentration (C_TH) that would lead to a 20% reduction of maximum K_sat. Neither the EC_w nor SAR of the applied waters affected the K_sat of soils with a mineralogical assemblage of oxides and kaolinite such as Ferralsol, Nitisol, and Lixisol, with an average K_sat of 2.75, 6.06, and 3.33 cm h⁻¹, respectively. In smectite- and illite-rich soils, the K_sat increased with higher EC_w levels and decreased with higher SAR levels, especially comparing the soil’s estimated K_sat for water with low EC_w and high SAR in combination (EC_w of 128 µS cm⁻¹ and SAR 30) and water with high EC_w and low SAR in combination (EC_w of 4671 µS cm⁻¹ and SAR 0) such as Regosol (4.95 to 10.94 cm h⁻¹); Vertisol (0.28 to 2.04 cm h⁻¹); Planosol (0 to 0.29 cm h⁻¹); Luvisol (0.46 to 2.12 cm h⁻¹); Cambisol (0 to 0.23 cm h⁻¹); and Fluvisol (1.87 to 3.34 cm h⁻¹). The C_TH was easily reached in soils with high concentrations of highly active clays such as smectites. In sandy soils, the target C_TH was only reached under extremely high SAR values, indicating a greater resistance of these soils to salinization/sodification. Due to their mineralogical assemblage, soils from tropical sub-humid/hot and semiarid climates were more affected by treatments than soils from tropical humid/hot climates, indicating serious risks of physical and chemical degradation. The results showed the importance of monitoring water quality for irrigation, mainly in less weathered, more clayey soils, with high clay activity to minimize the rate of salt accumulation in soils of the Brazilian semiarid region. Our study also proved that clay mineralogy had more influence on the K_sat than clay concentration, mainly in soils irrigated with saline and sodic waters, and that soils with highly active smectite are more prone to degradation than soils with high concentrations of kaolinite. Full article

Oat (Avena sativa L.) is one of the most important self-fertilizing field plants belonging to the Poaceae family. It has no significant requirements regarding growing conditions but has a very good reaction to fertilization. The current research evaluated the significance of the effects of individual applications of mineral (NPK) and organo-mineral (OMF) fertilizers, as well as their individual combination with slaked lime (calcium hydroxide, Ca(OH)₂), on the yield, morphological traits [mean number of leaves per plant—MNLP, minimum leaf length (cm) per plant—MinLL, maximum leaf length (cm) per plant—MaxLL, number of ears per plant—NEP], and physiological parameters (nitrogen balance index—NBI, content of chlorophyll—Chl, flavonoids—Flv, anthocyanins—Ant) of organic and pelleted (graded) oat plants, comparing the treatments and in relation to the control. The experiment was performed in semi-controlled glasshouse conditions, in pots, from the fourth week of March to the fourth week of June 2024, using Vertisol soil. This soil is characterized as light clay with an acid reaction. Physiological parameters were measured using a Dualex leaf clip sensor. The results obtained showed that physiological parameters in both oat types significantly differed (p < 0.05) between the treatments applied and in relation to the control, whereas the morphological traits did not significantly differ (p > 0.05) between the treatments. Statistically significant differences (p < 0.05) in the yield of both oat types were most pronounced in the OMF + Slaked Lime treatment (organic: 4.49 g pot⁻¹; pelleted: 4.61 g pot⁻¹) in relation to the control (organic: 2.48 g pot⁻¹; pelleted: 2.63 g pot⁻¹). The pelleted oats showed slightly better results for the effects of different treatments across all tested parameters compared to organic oats. In conclusion, the best results were obtained with the use of OMF + Slaked Lime, which could be proposed as the optimal fertilization treatment for pelleted and organic oat cultivation based on this research. Full article

Cigarette butts (CBs) are emerging soil contaminants, releasing chemicals upon contact with moisture. This study examined heavy metal concentrations leached from smoked and unsmoked CBs (Pall Mall, Philip Morris, and Marlboro) into OECD artificial soil and Vertisol soil and their accumulation in white mustard (Sinapis alba L.). Key physiological parameters, including germination rate, plant height, fresh weight, and dry weight, were analyzed, along with the uptake of heavy metals (Al, Fe, Mn, Zn, Ba, Ti, and Cu) and essential elements (Ca, Mg, Na, and K). Results showed that Mn had the highest bioaccumulation index (BAI = 1.10) in OECD soil, while Zn uptake was consistently high across soil types. Soil type significantly influenced plant height (χ² = 41.269, p < 0.01) and elemental composition, with Vertisol soil facilitating greater overall growth and heavy metal uptake than OECD soil. MANOVA revealed no three-way interaction among soil type, CB use, and CB brand on elemental uptake. However, two-way interactions, particularly between soil type and CB use (F (4, 39) = 40.233, p < 0.001, Wilk’Λ = 0.195), showed significant effects on heavy metal uptake. These findings highlight the complex interactions influencing plant contamination, underlining the ecological risks of CB pollution in soils. Full article

The origin and bioavailability of nickel (Ni), chromium (Cr), and cobalt (Co) have been assessed in the Čemernica River basin among the following soil types: Leptosol on serpentinite and Fluvisol, Vertisol, and Leptosol on sandstone. Alongside the impact of serpentine rocks, part of the region also displays significant anthropogenic activity. A sequential analysis following the modified BCR procedure identified four fractions of heavy metals: F1—exchangeable and acid-soluble, F2—bound to Fe and Mn oxides, F3—bound to organic matter, and F4—residual. The overall content of Ni, Cr, and Co in the soil increases in the following order: Leptosol on sandstone, and Vertisol, Fluvisol, Leptosol on serpentinite. In most samples, the values exceed the maximum allowable concentrations in legal regulations, while in some samples, particularly in serpentine soils, they also exceed the remediation thresholds. The average contribution of nickel in the overall content decreases as follows: F4 > F2 > F3 > F1, chromium as F4 > F3 > F2 > F1, and cobalt in the most samples as F2 > F4 > F1 > F3. The percentage of Ni, Cr, and Co in the fractions of different soil types is similar to that in serpentine soils, though the absolute contents vary significantly, indicating a common origin, which is mostly geochemical. According to the Risk Assessment Code, most samples exhibit a low bioavailability risk. Full article

The aim of this work is to perform the physical characterization of ecological briquettes based on vertisols and fibers of Sorghum bicolor CS54 from the city of Maroua located in the Far North of Cameroon, a country of Sub-Saharan Africa. Three sites of study have been identified and investigated, namely ZL (Zokok Laddeo), Ngassa (NG), and KG (Kongola). Different percentages of added plant fibers have been realized, including 0%; 2%; 6%; and 8% of fiber additions for each site considered. The experimental tests have revealed that the plasticity of clays is between 16.56% and 25.96%; it is higher in the Zokok Laddéo site (25.96%); and it is between 16.56 and 23.78% for Ngassa and Kongola. The main aggregates observed in the three sites are gravel, which varies between 1.90% and 16.12%, sand between 4.99 and 53.12%, silt, which varies between 2.30 and 36.10%, and clay which fluctuates between 20 and 38.77%. The coefficient of resistance to abrasion varies between 7.19% and 24.35 for the three sites. The highest rates are those of the samples from the Ngassa site (24.35%). The linear shrinkage of the samples varies between 2.9 and 13.04%. The apparent density of the briquettes are between 1587.30 kg/m³ and 2138.13 kg/m³; they are higher for the sites of Zokok Laddéo and Ngassa. The overall coefficient of the capillary rise value is between 0.42% and 16.85%. The interval variation in the obtained results for the different parameters are for most cases and depending on the sites studied in accordance with the defined international standards. These results have proven that the addition of bicolor Sorghum fibers CS54 in vertisols could improve the performance of constructions based on local and eco-friendly materials. Full article

Cropland acidification seriously restricts sustainable agricultural development. The main purpose of this study was to determine whether deeper tilling could alleviate topsoil acidification to improve the quality of arable land. A soil column incubation experiment simulating tillage depths (10 cm, 30 cm and 50 cm) and lime addition was conducted to determine their effects on soil acidification improvement. The changes in soil pH, exchangeable acidity, ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃⁻-N), available phosphorus (AP), and microbial phospholipid fatty acids (PLFA) were analyzed. Tillage depth, lime application, and their interaction all had significant impacts on soil pH. T50 (simulated tillage depth of 50 cm) and T50+Lime (simulated tillage depth of 50 cm plus lime) treatments significantly increased the topsoil pH from 5.41 to 6.35 and 7.12, respectively. T50 treatment significantly reduced the soil exchangeable acid content compared to the T10 treatment. The nutrient accumulation along soil column indicated that the T50 and T50+Lime treatments significantly increased NO₃⁻-N and AP content in the >30–50 cm soil layer. Compared with T30, NO₃⁻-N accumulation in the >30–50 cm soil layers of T50 and T50+Lime treatments was 6.62 and 7.93 times higher, respectively. The accumulation of AP in the >30–50 cm soil layers of the T50 and T50+Lime treatments was 1.33 and 1.54 times higher than in the T30 treatment, respectively. These findings imply tillage up to 50 cm without exogenous materials could be a potential measure to reduce topsoil acidification and increase nutrition availability of >30–50 cm soil layers. Tillage of up to 30 cm combined with lime application confers greater benefits, which would particularly impact crops with shallow root systems. Subsequent field experiments will be conducted to further investigate the efficacy of these strategies in enhancing crop yield. Full article

The impact of conservation tillage (CST) practices on soil properties, carbon sequestration and yield sustainability over short, medium, and long durations remain insufficiently understood, especially in semiarid Central India. Therefore, our objective was to investigate the effects and optimal duration of CST adoption for enhancing soil properties, carbon sequestration, and sustainable yields. We conducted a study in farmers’ fields in the Akola district of Central India, where CST had been practised for 4 to 15 years, within a soybean + pigeon pea–chickpea cropping sequence. Our findings revealed significant (p < 0.05) improvements in soil physical properties with short-term CST practices (4 to 6 years), alongside increasing availability of nitrogen and phosphorus, with longer durations of CST implementation (10 to 15 years). The lowest soil organic carbon (SOC) was observed in conventional tillage (CT_y), while all CST practices increased SOC content over CT_y, ranging from 22.2 to 38.4%. Further, experimental soil dominated passive C pools (Cfrac3 + Cfrac4). Consequently, long-term CST practices facilitated positive C sequestration rates, contrasting with negative or minimal sequestration observed in CT_y and short-term CST treatments. However, compared to CST, CT_y demonstrated higher soybean equivalent yields and comparable chickpea equivalent yields mainly due to delayed germinations induced by lower soil temperatures in CST plots. We conclude that integrating site-specific characteristics, management practices, and regional climate conditions into conservation agriculture frameworks maximizes efficacy and ensures sustainable productivity. These findings help optimize agricultural practices considering potential yield losses or minimal changes despite implementing CST. Full article

Greenhouse gas emissions from agricultural production systems are a major area of concern in mitigating climate change. Therefore, a study was conducted to investigate the effects of crop residue, nutrient management, and soil moisture on methane (CH₄) emissions from maize, rice, soybean, and wheat production systems. In this study, incubation experiments were conducted with four residue types (maize, rice, soybean, wheat), seven nutrient management treatments {N0P0K0 (no nutrients), N0PK, N100PK, N150PK, N100PK + manure@ 5 Mg ha⁻¹, N100PK + biochar@ 5 Mg ha⁻¹, N150PK+ biochar@ 5 Mg ha⁻¹}, and two soil moisture levels (80% FC, and 60% FC). The results of this study indicated that interactive effects of residue type, nutrient management, and soil moisture significantly affected methane (CH₄) fluxes. After 87 days of incubation, the treatment receiving rice residue with N100PK at 60% FC had the highest cumulative CH₄ mitigation of −19.4 µg C kg⁻¹ soil, and the highest emission of CH₄ was observed in wheat residue application with N0PK at 80% FC (+12.93 µg C kg⁻¹ soil). Nutrient management had mixed effects on CH₄ emissions across residue and soil moisture levels in the following order: N150PK > N0PK > N150PK + biochar > N0P0K0 > N100PK + manure > N100PK + biochar > N100PK. Decreasing soil moisture from 80% FC to 60% FC reduced methane emissions across all residue types and nutrient treatments. Wheat and maize residues exhibited the highest carbon mineralization rates, followed by rice and soybean residues. Nutrient inputs generally decreased residue carbon mineralization. The regression analysis indicated that soil moisture and residue C mineralization were the two dominant predictor variables that estimated 31% of soil methane fluxes in Vertisols. The results of this study show the complexity of methane dynamics and emphasize the importance of integrated crop, nutrient, and soil moisture (irrigation) management strategies that need to be developed to minimize methane emissions from agricultural production systems to mitigate climate change. Full article

This study evaluated the effects of solely and integrated application of inorganic (NPK), commercial organic (NC), and biological (MIX, mixed strains Ensifer meliloti and Azotobacter chroococcum) fertilizers on the chemical characteristics of arugula biomass and its yield, as well as changes in soil microbiological parameters after the experiment in relation to the control treatment (Ø). The experiment was performed in semi-controlled greenhouse conditions, in pots, from the 4th decade of March to the 2nd decade of September, in 2023, at three cutting times/swaths, during one agricultural season, with Vertisol soil. For soil characterization, the following parameters were analysed: granulometric composition using sieving and sedimentation procedure; soil acidity—potentiometrically; SOM—soil organic matter by Kotzmann method; total N using CNS analyser; available P—spectrophotometrically; available K—flame photometrically; total number of microorganisms on an agarized soil extract medium; fungi on a solid Czapek agar; actinomycetes on a solid Krasiljnikov agar with saccharose; Azotobacter spp. on a liquid Fyodorov medium with mannitol; ammonifiers on a liquid medium with asparagine; and dehydrogenase activity—spectrophotometrically. For plant characterization, the following parameters were determined: N and C, both on CNS analyser; P on spectrophotometer; K on flame photometer; air-dried yield biomass. A stimulative effect on all microbiological parameters was found in the treatment with integrated use of organic and biological fertilizer, except for fungi, which grew better in the treatments with separate inorganic and organic fertilizers. Generally, the stimulative impact on plant chemical parameters manifested in combined inorganic and biological, organic and biological, and inorganic and organic fertilization treatments, and was inhibited in treatment without fertilization, in all three swaths, which could also be stated for the plant yield. Positive influence of all fertilization treatments on chemical parameters was observed for the second swath in relation to the first and the third. The total yield in the NPK+MIX treatment was 121%, and in the NC+MIX treatment, it was 87% higher compared to the control (Ø). In general, integrated use of inorganic and biological, organic and biological, and inorganic and organic fertilizers, respectively, could be proposed as an optimal fertilization treatment in arugula cultivation. Full article

Landscape has significant effects on hydrological processes in a watershed. In the Sudano-Sahelian area, watersheds are subjected to a quick change in landscape patterns due to the human footprint, and the exact role of the actual landscape features in the modification of the hydrological process remains elusive. This study tends to assess the effects of landscape on the genesis of the runoff in the Mayo Mizao watershed. To achieve this goal, 62 infiltration tests were performed at different points and depths (5 cm and 20 cm) using the double-ring method and the Porchet method. The results show that the combination of many factors (soil type, land use, and farming practices) can guide the hydraulic conductivity behavior of soils. For example, at 5 cm depths, clayey-evolved soils, such as vertisols and halomorphic soils, inhibit infiltration, as opposed to non-evolved mineral soils, such as lithosols and clayey-sandy soils. However, at 20 cm depths, gray soils with halomorphic tendencies followed by vertisols have a low sensitivity to infiltration, as opposed to soils derived from loose materials and halomorphic soils. For a given soil type, rainfed crops are the primary land use that runs against infiltration. However, the effect of tillage varies according to the soil type. Finally, given the extent of vertisols and halomorphic soils in the Far North region of Cameroon in general, and in the Mayo Mizao watershed in particular, and regarding the increase in cultivated areas, a probable reduction in the infiltration capacity of soils in this region is to be expected in the medium term. The results of this study can be used as a basis for land-use planning and sustainable watershed management in semi-arid tropical zones. Full article

The concept of soil quality (SQ) is defined as the soil's capacity to function, which is commonly assessed at the field scale. Soil quality is composed of inherent (soil suitability) and dynamic (soil health, SH) SQ, which can also be analyzed using geospatial tools as a SQ continuum (SQC). This study proposes an innovative spatiotemporal analysis of SQ degradation and emissions from land developments using the state of Iowa (IA) in the United States of America (USA) as a case study. The SQ degradation was linked to anthropogenic soil (SD) and land degradation (LD) in the state. More than 88% of land in IA experienced anthropogenic LD primarily due to agriculture (93%). All six soil orders were subject to various degrees of anthropogenic LD: Entisols (75%), Inceptisols (94%), Histosols (59%), Alfisols (79%), Mollisols (93%), and Vertisols (98%). Soil and LD have primarily increased between 2001 and 2016. In addition to agricultural LD, there was also SD/LD caused by an increase in developments often through urbanization. All land developments in IA can be linked to damages to SQ, with 8385.9 km² of developed area, causing midpoint total soil carbon (TSC) losses of 1.7 × 10¹¹ kg of C and an associated midpoint of social cost of carbon dioxide emissions (SC-CO₂) of $28.8B (where B = billion = 10⁹, USD). More recently developed land area (398.5 km²) between 2001 and 2016 likely caused the midpoint loss of 8.0 × 10⁹ kg of C and a corresponding midpoint of $1.3B in SC-CO₂. New developments are often located near urban areas, for example, near the capital city of Des Moines, and other cities (Sioux City, Dubuque). Results of this study reveal several different kinds of SQ damage from developments: loss of potential for future C sequestration in soils, soil C loss, and “realized” soil C social costs (SC-CO₂). The state of IA has very limited potential land (2.0% of the total state area) for nature-based solutions (NBS) to compensate for SD and LD. The results of this study can be used to support pending soil health-related legislation in IA and monitoring towards achieving the Sustainable Development Goals (SDGs) developed by the United Nations (UN) by providing a landscape-level perspective on LD to focus field-level initiatives to reduce soil loss and improve SQ. Future technological innovations will provide higher spatial and temporal remote sensing data that can be fused with field-level direct sensing to track SH and SQ changes. Full article

The soils of the high-elevation mountains along the East African Rift Valley are poorly understood. Assessing the potential of soils for agriculture, climate change mitigation, and environmental functioning requires insight into how they relate to the factors influencing soil formation. Between 3000 and 4120 m a.s.l., 85 soil profiles of Mount Guna were described and sampled. Standard physicochemical analyses were done on all pedons. Additionally, X-ray diffraction, Al_ox and Fe_ox content, and P fixation were performed on six selected profiles. Soils on Mount Guna included Andosols, Phaeozems, Leptosols, Regosols, Cambisols, Luvisols, and Vertisols. With increasing elevation, clay content, bulk density, and pH decreased while the C:N ratio remained constant. In contrast, sand, silt, silt-to-clay ratio, SOC, Ntotal, and SOCS increased. With a factor analysis, the soil-forming factors’ elevation/climate could be disentangled from the factor’s parent material as these affect topsoil and subsoil differently. In the ordination based on climate/elevation and parent material, Andosols and Vertisols stood out while other Reference Soil Groups (RSG) showed indistinct patterns. Soil erosion appeared as an additional soil-forming factor not accounted for by the factor analysis. The distribution of the RSG was significantly associated with elevation belts (p < 0.001), lithology (p < 0.001), and landcover (p < 0.003). On the summital ridge, the Andosols were crucial for groundwater storage due to high precipitation. Shallow and stony soils in the mid-elevation belt contributed to runoff generation. Average soil carbon stock ranged from 8.1 to 11 kg C m⁻² in the topsoil and from 29.2 to 31.9 kg C m⁻² in the upper meter, emphasizing the global importance of high-elevation areas for carbon sequestration. Full article

Soil makes important contributions to the United Nations (UN) Land Degradation Neutrality (LDN) concept and targets; however, currently, soil is not integrated into measurable information (e.g., indicators, metrics) to monitor land degradation (LD) patterns and trends. This study examines the role of soil in LDN in the UN Convention to Combat Desertification (UNCCD), and UN Sustainable Development Goal (SDG 15: Life on Land). This study is specifically focused on the LDN and biodiversity loss as they relate to an indicator 15.3.1 Proportion of land that is degraded over total land area. Tracking of LD status can be improved by using detailed soils databases combined with satellite-derived land cover maps. This study has applied these newly improved methods to quantify and map the anthropogenic LD status and trends in the contiguous United States of America (USA), as well as to identify potential land areas for nature-based solutions (NBS) to compensate for LD. Anthropogenic LD in 2016 in the contiguous USA affected over two million square kilometers, about one-third of the country’s total area, with high variability by state. Between 2001 and 2016, LD in the USA showed an overall increase of 1.5%, with some states exhibiting increases in degraded land while other states had overall improvements to their land. All ten soil orders present in the contiguous USA have been anthropogenically degraded, with Mollisols, Alfisols, and Vertisols having the highest LD levels. Compensating for LD requires a variety of strategies and measures (e.g., NBS), which often require additional land. In 2016, the potential land area for NBS was over two million square kilometers, an area approximately equal to that of degraded land. Some of the states that have high proportions of land available for potential NBS are dominated by soils (Aridisols) typical of deserts and therefore may have less promise for NBS. The variability of LD needs to be evaluated at finer spatial scales for realistic LDN analysis. Full article