Degree Of Soil Degradation Research Articles

ASSESSMENT OF CURRENT AND FUTURE LAND DEGRADATION UNDER CLIMATE CHANGE IN THE UPSTREAM OUERGHA WATERSHED (MOROCCO) USING GIS AND AHP METHOD

Land degradation is a worldwide phenomenon that negatively affects the topsoil of agricultural land. The Mediterranean region is the hardest hit by this phenomenon, which is set to increase due to climate change. This study aims to assess the susceptibility of land to degradation under climate change, based on the calculation of the Land Degradation Sensitivity Index (LDI) in the upstream Ouergha catchment in in Northern Morocco (Southern Mediterranean), using Geographic Information Systems (GIS) and the Analytic hierarchy process (AHP) multi-criteria decision analysis (MCDM) method. In this study, 4 main criteria (climate, vegetation, soil and human environment) divided into 15 sub-criteria were used to assess soil sensitivity to degradation. The weight of each criterion was assigned using the AHP method. The degree of soil degradation was classified on a map based on four categories (low, moderate, high and critical). About 14.9% of land is not very sensitive to degradation, while 37.2% of land is highly sensitive to degradation. Vegetation and climate were identified as the main drivers of land degradation (37% and 28% respectively). climate scenarios indicate a significant drop in precipitation (around 10% for RCP 4.5 and 20% for RCP 8.5 scenarios by 2050), which accelerates soil degradation. The result represents a planning tool that can help decision-makers to take the necessary measures to ensure sustainable soil management in the face of climate change.

Modeling of fertilization on the photosynthetic and yield indicators of melon (Cucumis melo L.) under the saline soils of southern Kazakhstan

Recommendations on the use of generalized regional fertilizers for agricultural crops lead to low fertilizer efficiency, and an imbalance of plant nutrition while identifying economic and environmental problems. The use of innovative methods with the modelling of fertilizers with balanced doses of nutrients used based on the needs of crops, the potential of fertility and the degree of soil degradation should be the main condition for sustainable precision farming. Therefore, a field experiment to study the application of mineral fertilizers on melon was carried out under two saline backgrounds of light serozem at a farmer’s field, Maktaaral District, Kazakhstan during 2022. The experiment was laid out in a randomized complete block design (RCBD) with 10 treatments: T1–Control (no fertilizer), T2–N120P80, T3–N120K80, T4–P80K80, T5–N120P80K80, T6–N60P80K80, T7–N180P80K80, T8–N120P120K80, T9–N120P80K120 and T10–N157K256 and N93K96 for a targeted yield of 30 and 20 t/ha on low and medium-saline soils, respectively, each replicated thrice. Ammonium nitrate (34%), double superphosphate (45%) and potassium sulfate (51%) were used as fertilizers. The study of photosynthetic productivity of plants showed that the accumulation of dry biomass (from 1.9 to 10.37 t/ha) and leaf area (from 7.8 to 26.5 m2/ha) adequately changed with changes in doses and ratios of fertilizers. On the low salinity background, high early yields were provided by T5 and T10-10.1 and 10.9 t/ha, against a medium saline background, they were lower than low saline background of 1.7 and 2.3 t/ha, respectively. When modelling the effect of fertilizers on the formation of an early melon crop, the unilateral action of nitrogen fertilizers, the interaction of nitrogen fertilizer with potash fertilizer and the interaction of phosphorus fertilizer with the soil salt concentration have been excluded from the equation as insignificant (P less than 0.05).

Composted biosolids amendments for enhanced soil organic carbon and water storage in perennial pastures in Colorado

Land management of grasslands can play a significant role in climate change mitigation by influencing soil carbon (C) storage. Soil amendments, such as adding compost, have been shown to increase soil C storage while simultaneously increasing plant productivity and soil water holding capacity (WHC), factors that provide immediate benefits to ranchers. Research to date has mainly focused on temperate annual grasslands. However, little is known if irrigated perennial pasturelands in cold, arid climates respond similarly. This study’s objective was to determine the immediate effects of a 5 cm depth application of biosolids compost on plant productivity, soil moisture, and soil C storage. Research sites were established at four ranches in Gunnison, CO, a high-elevation, arid region. During the first year, there was a significant increase in total aboveground biomass (AGB) across three of the four sites (F3,32 = 62.3, p < 0.001), resulting in a difference in total AGB of 199.83 g·m−2 (95% CI 133.6 – 266.1 g·m−2) between the control and treatment, an average increase of 109% (SE ± 20%). There was a significant increase in soil moisture in the treatment plots relative to the controls at each site for most of the growing season (July-Oct). On average, soil organic matter (SOM) increased by 32% SE ± 10.5, with two sites demonstrating a significant increase. Soil C stocks increased across sites with biosolids, but this was only significant at one site (F1,32 = 7.05, p = 0.012), the most degraded of all four pasturelands. This study demonstrated that a single application of biosolids compost could elicit a significant increase in soil moisture throughout the growing season and increase plant biomass production. Biosolid applications can also increase SOC. However, this response's magnitude is site-specific and is associated with the degree of soil degradation, which might be related to land management history. Using biosolids compost on pasturelands seems to be a positive strategy to improve soil health and its associated co-benefits. Still, managers should consider the degree of degradation of their land when determining cost benefits.

Аспекты экологической безопасности орошения сточными водами

The paper attempts to clarify the criteria for determining the effectiveness of wastewater irrigation based on the analysis of the response of microbial activity of the soil to the concentration of some hazardous substances that may be in the water. The authors attribute this to the fact that, according to experience, the use of reclamation measures in agricultural irrigation fields does not always fully consider the danger of suppression of the soil microbiome by components such as organochlorine substances (carcinogens) and aluminum salts in the structure of reagents used in wastewater pretreatment processes. It is proved that the orientation of soil educational processes ultimately determines the probability of development and the degree of soil degradation, therefore, the most important point is the assessment of the living conditions of soil microorganisms that mainly cause these processes. The absence of factors, suppression of the activity of the soil microbiome may be the main indicator in assessing the optimality of these conditions.

Влияние различных типов и видов мелиорации на восстановление и повышение плодородия деградированных почв

Purpose: to analyze the experience of domestic and foreign scientists in using various types of land reclamation to restore and increase the fertility of degraded soils under irrigation and rainfed conditions. Discussion. The overview of research papers, domestic and foreign literary sources, concerning the impact of various types of reclamation on the restoration of degraded soils is presented. The options for using various types of land reclamation, depending on the type and degree of soil degradation are considered. The timely application of various types of reclamation (hydro-reclamation, chemical, cultural, technical, agroforestry reclamation), separately and in a complex of measures, makes it possible to stop the degradation processes occurring in soil (salinization, oxidation, waterlogging, compaction, desertification, various types of erosion) and contributes to the restoration and increasing soil fertility. The use of various types of reclamation improved the agrophysical, water-physical and chemical properties of soils, increased the content of humus, contributed to the stimulation of accumulation of organic matter in soil, and increased the biometric indicators of cultivated crops, which was reflected in an increase of the given crops yield. Conclusions. The study of the results of domestic and foreign scientists work allows conclude that the preservation and restoration of soil fertility in agricultural areas used is impossible without the use of land reclamation. The use of hydrotechnical, biological, chemical, cultural, agrotechnical reclamation, both separately and in complex, makes it possible to increase the level of soil fertility prone to salinization, oxidation, waterlogging, compaction, desertification, and various types of erosion.

Changes in Bacterial Soil Biota under Cultivation of Crops near a Municipal Landfill Site

The study aimed to evaluate the changes in the quantitative composition of a soil bacterial community near a municipal waste landfill, and attempted to use a bacteriological coefficient to assess the degree of soil degradation. The research was carried out near a landfill site located in southern Poland. Soil samples were collected from plots on which spring wheat, field bean and potato were cultivated. Microbiological analyses included the determination of the total number of bacteria in active and dormant (sporulating) stages. The highest ratio of sporulating bacteria in relation to vegetative bacteria was found in the reclaimed sector of the landfill site. The proposed bacteriological indicator of soil quality (i.e., the ratio of the number of sporulating bacteria to the number of vegetative forms) seems to be a good index for the assessment of soil quality near the landfill site.

Assessment of earthworms as an indicator of soil degradation: A case‐study on loess soils

AbstractSoil degradation restricts the development of agriculture, and the degree of soil degradation is related to land use type, and efficient evaluation methods are helpful for the timely implementation of remedial measures to ensure soil sustainability. Earthworms are directly affected by the deterioration of soil properties during the degradation process. The feasibility of using earthworms to assess soil degradation, however, still needs to be verified. In our Loess Plateau study, earthworm biomass, density, and diversity (Shannon‐Wiener, species richness, and Pielou's evenness) were investigated under nine different land use types (natural woodland, shrubland and grassland; planted woodland, shrubland and grassland; and cropland, orchard, abandoned land) and we analyzed their relationships with soil degradation. Our results showed earthworm biomass, density, and diversity associated with a low degree of degradation were significantly higher than those associated with a high degree of degradation. Earthworms can comprehensively characterize the physicochemical properties and biological characteristics of soils under different land use types. Linear correlations showed a significant relationship between the soil degradation index and the earthworm indices, indicating that the latter could be used to effectively evaluate and represent the degree of degradation of soils on the Loess Plateau over a certain degradation range. Nevertheless, this evaluation method requires further validation before wider use.

Digital Mapping of Soil Associations and Eroded Soils (Prokhorovskii District, Belgorod Oblast)

A new method of digital mapping of the soil cover pattern with calculation of the share of soils of different taxa and degree classes for soil erosion in the soil associations is proposed. A comparative analysis of soil maps obtained using different methods of construction (visual expert and digital) and with their different contents (displaying the dominant soil or soil associations) has been performed. In the case of mapping by the visual expert method (with the display of the dominant soil), a significant underestimation of the total area of moderately and strongly eroded soils in comparison with the digital mapping is noted. These differences are due to the underestimation of the area of small polygons with moderately and strongly eroded soils in the composition of soil associations on slopes of low steepness and in shallow hollows in the visual expert method of mapping. When the content of digital maps is generalized from soil associations to dominant soil categories, a significant change in information on the degree of soil degradation by erosion is also noted. Comparison of visual expert and digital methods for mapping soils of different taxa indicates a high degree of compliance between the spatial location and area of soil delineations with similar component content in both cases. The greatest differences between the soil maps created by these methods are noted for the soils with periodic overmoistening, namely, meadow-chernozemic (Luvic Chernic Phaeozem (Oxyaquic)) and chernozemic-meadow (Luvic Stagnic Chernic Phaeozem) soils because of the poor consideration for microtopography in traditional mapping. In general, it can be concluded that the creation of a digital map is more difficult in terms of the need to use specialized computer programs and mathematical models. However, the resulting digital databases contain information of a higher level of detail than traditional soil maps.

Soil Properties Affected Vegetation Establishment and Persistence on Roadsides

Vegetation along roadsides reduces soil erosion, increases filtering of water runoff, and acts as a biodiversity corridor. The purpose of this study was to assess soil properties and evaluate their effect on vegetation establishment in roadsides. Furthermore, the effects of shoulder type (paved and unpaved) and time since seeding (0–1 year, 2–4 years, and ≥ 5 years) on soil properties were also evaluated. Roadside soil was sampled from 53 sites in three regions (Panhandle, Southcentral, and Southeastern) in Nebraska, USA. The soil was analyzed for pH, Na, Cl, electrical conductivity, exchangeable sodium percentage, and bulk density and heavy metals. At each site, vegetation was classified into one of four categories, (1) 50% plant canopy cover dominated by weedy annual grasses and forbs; and (4) > 50% plant canopy cover dominated by seeded perennial grasses. Sodium concentration exceeded the limits that can cause vegetation growth decline in all regions. Sodium and soil bulk density in all regions were clustered with the < 10% plant canopy cover category, meaning that these clustered soil properties have a significant influence on the amount of bare ground and establishment/persistence of vegetation. Heavy metal concentrations (lead, arsenic, zinc, cadmium, and nickel) were less than the thresholder in all regions. It was observed that 12–44% of roadside sites had less than 50% vegetation cover. Roadside soils of paved shoulders had lower Na and Cl concentrations than the roadside soils of unpaved shoulders. The 0–1 year since seeding had higher cadmium, arsenic, and nickel concentrations compared to ≥ 5 years since seeding. Soil degradation declined vegetation establishment along highways, and the degree of soil degradation of these roadsides varied depending on shoulder types and time since seeding.

Centrifuge modelling of lateral loading behaviour of a “semi-rigid” Mono-pile in soft clay

Mono-pile foundations have been widely used for offshore wind turbines principally due to their convenient construction and cost-effective nature. So far, little attention has been paid to large diameter “semi-rigid” piles that have distinct behaviours from flexible or ideally rigid piles. This paper presents a series of centrifuge model tests to study the deforming and bearing characteristics of a 5.9 dia. semi-rigid pile under lateral loadings in kaolin clay. For monotonic loading, a modified p–y curve analysis model considering rotational soil flow near the rotation centre of pile was proposed, highlighting the limitation of classic plane-strain based plasticity models to evaluate the ultimate lateral pile-soil resistance. For cyclic loading, a strong correlation between the degree of soil degradation and cyclic load amplitude was identified. Besides, a degradation factor model, accounting for various cyclic stress levels and soil depths, was proposed, which can be used to assess the accumulative displacement of semi-rigid piles under cyclic loadings in soft clay.

Method of constructing a space-time grid of variable size images and its application in image processing of landfills

The paper proposes a method of slicing space images into areas of varying sizes to automate the image processing, beginning from the receipt of raw data (download pictures) up to mapping of the underlying surface indices. Indices calculation are based on one image (the surface and the vegetation indices temperature, indices of objects detection on the ground and etc.) and their time series (conducting temporal processing). The downloading of the sources of satellite images algorithm from the sites archives of geodata from the initial data download (the observation area, stage, time period, etc.) is also represented. The procedure of cutting images into segments of varying sizes is described. It allows to use the ?contents? of image both in general and for each pixel of the earth's surface to have a whole time series of the spectral brightness coefficients. Examples of time series of geo-referenced source images and the individual indices of the underlying surface are automatically generated by the algorithm method, for specific problems of space debris monitoring (vegetation indices reaction, the degree of soil degradation, detection of indices).

Soil physicochemical properties to evaluate soil degradation under different land use types in a high rainfall tropical region: A case study from South Sulawesi, Indonesia

Intensive cropping in the tropical region always becomes one of important driving forces of soil degradation. The primary aim of this study is to analyze the states and the dynamics of soil physicochemical properties to evaluate soil degradation in the tropical region a high rainfall on agricultural areas in South Sulawesi. A number of soil characteristics were analyzed for physical and chemical properties, and clay minerals with X-ray diffractometer. The degree of soil degradation is determined using Wischmeier and Smith equation. This study reveals that mean annual precipitation in 1979-2016 ranged from 1853.15 to 2981.30 mm/year. For land used for paddy field, palm oil, cacao and coffee plantation, the texture dominated with silt loam-clay loam, cation exchange capacity was 18.63-26.32 cmol+ kg-1, 0.98-2.91% of C-organic, 32-55% of base saturation, 0.1-3.5 cm h-1 of permeability, soil clay minerals were montmorillonite-kaolinite-halloysite, and the index erodibility was 0.3-0.5. Land used for mixed plants and shrubs, the texture dominated with silt loam-sandy clay loam, cation exchange capacity was 18.63-27.12 cmol+ kg-1, 1.09-2.89% of C-organic, 32-55% of base saturation, 0.2-4.9 cm/h of permeability, soil clay minerals were kaolinite-halloysite, and index erodibility was 0.1-0.3. Land use for cultivated in the high intensity of rainfall has changed the physicochemical properties of soils, but cultivated in monoculture has at some degree increased soil erodibility.

Comparing Transient and Steady-State Analysis of Single-Ring Infiltrometer Data for an Abandoned Field Affected by Fire in Eastern Spain

This study aimed at determining the field-saturated soil hydraulic conductivity, Kfs, of an unmanaged field affected by fire by means of single-ring infiltrometer runs and the use of transient and steady-state data analysis procedures. Sampling and measurements were carried out in 2012 and 2017 in a fire-affected field (burnt site) and in a neighboring non-affected site (control site). The predictive potential of different data analysis procedures (i.e., transient and steady-state) to yield proper Kfs estimates was investigated. In particular, the transient WU1 method and the BB, WU2 and OPD methods were compared. The cumulative linearization (CL) method was used to apply the WU1 method. Values of Kfs ranging from 0.87 to 4.21 mm·h−1 were obtained, depending on the considered data analysis method. The WU1 method did not yield significantly different Kfs estimates between the sampled sites throughout the five-year period, due to the generally poor performance of the CL method, which spoiled the soil hydraulic characterization. In particular, good fits were only obtained in 23% of the cases. The BB, WU2 and the OPD methods, with a characterization based exclusively on a stabilized infiltration process, yielded an appreciably lower variability of the Kfs data as compared with the WU1 method. It was concluded that steady-state methods were more appropriate for detecting slight changes of Kfs in post-fire soil hydraulic characterizations. Our results showed a certain degree of soil degradation at the burnt site with an immediate reduction of the soil organic matter and a progressive increase of the soil bulk density during the five years following the fire. This general impoverishment resulted in a slight but significant decrease in the field-saturated soil hydraulic conductivity.

Combined effects of soil texture and machine operating trail gradient on changes in forest soil physical properties during ground-based skidding

Wood extraction by heavy machinery has always been associated with soil disturbance in mountain forests, and the degree of soil degradation is influenced by several factors, including site and soil characteristics, soil moisture, type of equipment used, and number of machine passes. The effects of ground-based skidding operations on the physical properties of soils with different texture were evaluated at different levels of traffic frequency and trail gradient at two sites in an Iranian temperate forest. The treatments included combinations of three different traffic frequencies (3, 8, and 14 passes of a rubber-tired cable skidder), three levels of trail gradient (< 10%, 10%–20%, and > 20%) and two soil texture classes, clay loam (Site 1) and sandy loam (Site 2). The average gravimetric soil moisture at the time of skidding was 23% (Site 1) and 20% (Site 2). The average dry bulk density and total porosity of the undisturbed soil (control) were 0.71 g cm–3 and 73.3% at Site 1 (clay loam) and 0.86 g cm–3 and 59.1% at Site 2 (sandy loam), respectively. At site 1 (fine-textured soil), rutting began after three passes of the skidder, whereas at site 2 (coarse-textured soil), rutting occurred only after eight passes. Independent of the traffic frequency and trail gradient, machine impact on the fine-textured soil caused greater increases in bulk density and rut depth compared to that on the coarse-textured soil. After three skidder passes and independent from trail gradients, dry bulk density at Site 1 increased by 54.8% compared to that of the undisturbed control, and the increase was 45.5% at Site 2. Therefore, medium to fine-textured soils are more susceptible to compaction than coarse-textured soils. Such soils, especially when moist, should be protected using brush mats created from harvesting residues during the forest processing phase.

Remote estimation of soil organic matter content in the Sanjiang Plain, Northest China: The optimal band algorithm versus the GRA-ANN model

Soil organic matter content (SOMC) is an important factor that reflects soil fertility, land production capacity, and the degree of soil degradation. The objectives of this study were to (i) test various regression models for estimating SOMC based on published spectral parameters in the Sanjiang Plain, (ii) develop optimal band difference, ratio, and normalized difference algorithms for assessing SOMC using spectral data, and (iii) compare the performance of the proposed models using grey relational analysis-artificial neural networks (GRA-ANN) and the band difference algorithm. The SOMC data and concurrent spectral parameters were acquired in the Sanjiang Plain of Northest China in 2006. For the GRA-ANN model, GRA was used to select the sensitive spectral parameters and ANN was established to estimate SOMC. The results showed that reflectance (R) gradually decreased with increasing SOMC and the regression equations based on the spectral parameter 1/R588, Diff (1/R835), R610, R654, R550, and R520 could be used to estimate SOMC, respectively. The SOMC model based on the optimal difference index (ODI; R2=0.63 and RMSE=1.43%) outperformed those based on the optimal ratio vegetation index (ORVI; R2=0.48 and RMSE=1.82%) and normalized difference vegetation index (ONDVI, R2=0.57 and RMSE=1.56%). The GRA-ANN model presented better SOMC estimation results (R2=0.90 and RMSE=0.88%). Thus, the GRA-ANN model has great potential for SOMC estimations; however, the ODI also has merit, especially when taking into consideration the simplicity of its application. Combining different algorithms may improve SOMC estimations on a regional scale.

Potential of agricultural land management activities for increased soil carbon sequestration in Africa - a review

This paper reviewed the potential for agricultural land management activities for increased soil carbon sequestration with particular reference to Africa. The sections of this review covered different land management activities (including agroforestry, conservation tillage, fallow management, mulching/cover crops, water management, rotation, manure, fertilizer use, grazing management) which lead to carbon sequestration in different farming systems. This review has revealed that there is high potential to sequester additional carbon through selected land management practices. The performance of these practices depends on soil properties and climatic conditions, and the degree of soil degradation at the time of time of intervention. There is need to integrate these land management practices for carbon sequestration into larger sustainable development and livelihoods strategies and practices in order to enhance an holistic approach and reduce some of the constraints that may inhibit these positive effect of

The Impact of Camping Activities on Soil Degradation in Kuwait

Desert camping is an old tradition in Kuwait. Today's camping involves activities that negatively impact the soil due to surrounding camp sites with barriers from the top soil, off-road transport by cars, using heavy equipment such as electrical generators, camping facilities such as bathrooms with cement floors, soccer and volleyball fields. This study used remote sensing and Geographic Information System (GIS) techniques to study the role of camping activities on soil degradation in camping areas and recommend new camping sites and scenarios for environmentally safe camping. Soil erosion, soil compaction and vegetation cover decline were used as indicators for evaluating the degree of soil degradation in camping sites. Satellite images were processed, enhanced and interpreted to find out the area of camping sites. The rate of soil erosion was estimated by Revised Universal Soil Loss Equation (RUSLE). About 43% of the camping sites studied had high soil erosion rate that reached16 tons/acre/year. The other 57% of camping sites had moderate soil erosion rates of 14 tons/acre/year. Camping soil barriers increase the rate of erosion inside the camping sites. The study shows that soil and vegetation are badly affected by camping activities. Soil bulk density in camping areas surpassed that of areas not subjected to camping by an average of 12%. The vegetation coverage outside camping area was markedly higher than that inside camping. To avoid soil degradation by camping new environmentally safe sites for camping were recommended.

Climate Monitoring and Water Resources Management for Agricultural

The degree of soil degradation in Transylvanian Plain (TP) and climate change in recent years, have radically modified climatic conditions for cultural crops. Monitoring of temperature and water supply in TP aims to evaluate these two resources for agricultural production. Monitoring the thermal and water supplies from TP was performed with twenty HOBO micro stations which determine the temperature (to a height of 1 m) and rainfalls same as temperature (at 10, 30, 50 cm depth in soil) and soil moisture (at 10 cm depth). Average precipitation recorded during 2009-2011, is 498.97 mm, which is beneath the multiannual average of the area. The year 2009 indicated an average of 503.84 mm in TP, considered in the lower limit of the area, followed by the year 2010 with an annual average of 607.84 mm, the year with the closest values to normal area precipitation values. The year 2011 is extremely dry, with an average of 376.56 mm. This situation is reflected in rainfall humidity values, recorded at a depth of 10 cm in the soil, where the area average is about 0.249%. Average air temperature during 2009-2011 is 10.75Â 0C, in the soil at 10 cm depth being 11.150C, respectively 11.28Â 0C at depth of 50 cm. Low amounts of precipitation, especially their poor distribution during crop vegetation, are aggravated by the deficit of hydrological resources for TP. The average air temperature is above multiannual average of the area, which significantly influenced the optimum time of sowing and amount of biologically active degrees of temperature during the vegetation period.

Mapping of soil degradation hazards by remote sensing in Hanumangarh district (western Rajasthan)

In the present study, efforts have been made to identify and map areas affected by various soil degradation processes in Hanumangarh district of western Rajasthan. Soil degradation processes were identified by using IRS-1B satellite image of the year 1998, SOI toposheets, ground truth verification and soil studies. The kind, extent and degree of soil degradation have been mapped in an area of 9703 km2. The study reveals that the soil degradation problems were mainly due to wind erosion/deposition and water-logging, followed by salinity/alkalinity, water erosion and wind and water erosion combinedly. Nearly 38.7% area is subjected to slight and moderate degradation, which can easily be combated by adopting the suggested techniques and 17.1% area is free of hazard. Soil degradation processes have resulted in the loss of organic carbon, available Phosphorus and Potassium. Soil degradation due to water logging/salinization has also shown a significant increase in electrical conductivity and available potassium content of soil.

Development of a soil degradation assessment tool for organic olive groves in southern Spain

Forty-six organic olive orchards under different soil management systems were evaluated in the province of Córdoba (southern Spain) to assess the state of their soil properties and the degree of degradation of their topsoil, and the possibilities for monitoring any soil degradation risk. Our study indicated that 55% of the olive farms sampled (OF) presented a low soil degradation, in which most of their deficiencies were a low content in some soil nutrients such as P, which may be partly due to the moderate fertility of some soils in the area. This result could be explained by the low or moderate intensity of the farming systems used in a large part of the study area. Seven percent of the sampled OFs had a large number of physical, chemical and biological soil properties, that could be considered as being degraded, and these olive orchards were classified as seriously degraded. The remaining OFs were in an intermediate state. The degree of soil degradation was not correlated with any specific soil management method or with predicted soil erosion rates, suggesting that it was the result of specific and varied on-farm conditions difficult to detect without a field evaluation. Three soil degradation indexes were obtained through a principal component analysis of the soil properties analyzed. These indexes were able to distinguish between OFs with low soil degradation and those in a serious state of degradation. Two of the indexes are basically integrative ones that can be used in relatively large surveys considering a large number of soil properties. The third index developed used only three soil properties, organic C, water stable macroaggregates, and extractable P, and has the potential to be used as a relatively easy and inexpensive screening test of soil degradation for organic olive farms in the area.