Topsoil Nutrients Research Articles

Predicting soil nutrients with PRISMA hyperspectral data at the field scale: the Handan (south of Hebei Province) test cases

ABSTRACT This research investigates the suitability of PRISMA and Sentinel-2 satellite imagery for retrieving topsoil properties such as Organic Matter (OM), Nitrogen (N), Phosphorus (P), Potassium (K), and pH in croplands using different Machine Learning (ML) algorithms and signal pre-treatments. Ninety-five soil samples were collected in Quzhou County, Northeast China. Satellite images captured soil reflectance data when bare soil was visible. For PRISMA data, a Linear Mixture Model (LMM) was used to separate soil and Photosynthetic Vegetation (PV) endmembers, excluding Non-Photosynthetic Vegetation (NPV) using Band Depth values at the 2100 nm absorption peak of cellulose. Sentinel-2 bare soil reflectance spectra were obtained using thresholds based on NDVI and NBR2 indices. Results showed PRISMA data provided slightly better accuracy in retrieving topsoil nutrients than Sentinel-2. While no optimal predictive algorithm was best, absorbance data proved more effective than reflectance. PRISMA results demonstrated potential for predicting soil nutrients in real scenarios.

Distinct latitudinal patterns and drivers of topsoil nitrogen and phosphorus across urban forests in eastern China.

Nitrogen (N) and phosphorus (P) are the two most important macronutrients supporting forest growth. Unprecedented urbanization has created growing areas of urban forests that provide key ecosystem services for city dwellers. However, the large-scale patterns of soil N and P content remain poorly understood in urban forests. Based on a systematic soil survey in urban forests from nine large cities across eastern China, we examined the spatial patterns and key drivers of topsoil (0-20 cm) total N content, total P content, and N:P ratio. Topsoil total N content was found to change significantly with latitude in the form of an inverted parabolic curve, while total P content showed an opposite latitudinal pattern. Variance partition analysis indicated that regional-scale patterns of topsoil total N and P contents were dominated by climatic drivers and partially regulated by time and pedogenic drivers. Conditional regression analyses showed a significant increase in topsoil total N content with lower mean annual temperature (MAT) and higher mean annual precipitation (MAP), while topsoil total P content decreased significantly with higher MAP. Topsoil total N content also increased significantly with the age of urban park and varied with pre-urban soil type, while no such effects were found for topsoil total P content. Moreover, topsoil N:P ratio showed a latitudinal pattern similar to that of topsoil total N content and also increased significantly with lower MAT and higher MAP. Our findings demonstrate distinct latitudinal trends of topsoil N and P contents and highlight a dominant role of climatic drivers in shaping the large-scale patterns of topsoil nutrients in urban forests.

Estimation of Soil Loss for Different Soil Series, Tillage Management and Slopes under Soybean Cropping in Malwa Agro-Climatic Zone

The soil erosion can cause a reduction in agricultural productivity, ecosystem disturbances, and pollution of water. Physical and climatic features of a catchment such as topographic conditions, land use land cover, rainfall intensity, and the soil characteristics are the key significant factors of the soil erosion. The loss of the top fertile soil nutrients is intensely increasing. In present study soil loss for 12 soil series viz., Kheri, Bararia, Junapania, Namali, Dhamaniya Diwan, Dhodar, Surajpura, Paroliya, Ratangarh, Khermaliya, Morwan and Hathipura and 3 different tillage management viz., conventional tillage, ridge and furrow system and no tillage system under soybean crop in Malwa Agro-climatic Zone in central India has been estimated. The soil loss for four different sloes viz., 1%, >1% to < 3%, >3 to <5% and >5% under these soil series and management practices have been studied. The results of the study revealed that soil loss found decreased with decrease in slope and vice-versa. Similarly, the soil loss was found higher under conventional tillage (4.134 t acre-1 y-1) as compared to the ridge and furrow system (1.447 t acre-1 y-1) and no tillage system (1.033 t acre-1 y-1). The Bararia soil series (4.196 t acre-1 y-1) found most vulnerable to the soil loss whereas the Dhodar soil series (1.036 t acre-1 y-1) was found resistant to soil loss under soybean cropping in Malwa Agro-climatic Zone.

Dynamic Response and Adaptation of Grassland Ecosystems in the Three-River Headwaters Region under Changing Environment: A Review.

The Three-River Headwaters Region (TRHR) is crucial to the sustainable development of China and Southeast Asia. The sustainability of grassland ecosystems in the region has been seriously challenged in recent years. This paper reviewed the changes in the grasslands of the TRHR and their responses to climate change and human activities. The review showed that accurate monitoring of grassland ecological information is the basis for effective management. Although alpine grassland coverage and the above-ground biomass of the alpine grassland have generally increased in the region over the past 30 years, the degradation has not been fundamentally curbed. Grassland degradation substantially reduced topsoil nutrients and affected their distribution, deteriorated soil moisture conditions, and aggravated soil erosion. Grassland degradation led to loss of productivity and species diversity, and this is already harming the well-being of pastoralists. The "warm and wet" trend of the climate promoted the restoration of alpine grasslands, but widespread overgrazing is considered as one of the main reasons for grassland degradation, and related differences still exist. Since 2000, the grassland restoration policy has achieved fruitful results, but the formulation of the policy still needs to integrate market logic effectively and strengthen the understanding of the relationship between ecological protection and cultural protection. In addition, appropriate human intervention mechanisms are urgently needed due to the uncertainty of future climate change. For mildly and moderately degraded grassland, traditional methods are applicable. However, the severely degraded "black soil beach" needs to be restored by artificial seeding, and the stability of the plant-soil system needs to be emphasized to establish a relatively stable community to prevent secondary degradation.

Traditional human practices protect diversity of open forests threatened by ticking nutrient time bomb

Open forests are among the world's most species-rich ecosystems but these are now suffering from strong environmental pressure. With the increasing frequency of drought events accompanying climate change, open forests are now at high risk of canopy openness, an associated increase in nutrient load, and a consequent reordering of the plant community. Based on an 11-year field manipulative experiment, we examined whether the reintroduction of traditional forest uses, in particular the regular removal of litter which has been practiced for many centuries in Europe, may mitigate eutrophication and protect the ancient plant diversity of open forests. We examined vascular plant composition in 64, 3 × 3 m plots in 32 randomized blocks, each consisted of one litter-removal and one control plot in a subcontinental thermophilous oak forest dominated by Quercus petraea (Czech Republic, Central Europe). We analyzed how regular litter removal influenced the changes in topsoil nutrients and diversity and abundances of perennial, short-lived monocarpic and open oak forest plant species after eleven years of the annual application of this management. The regular litter removal significantly mitigated eutrophication by a reducing total nitrogen, and significantly decreased the amounts of base cations Ca2+ and Mg2+ in the topsoil. The studied plant species groups responded differently. Perennial and open oak forest species significantly increased their richness and abundances in the litter-removal plots and at the same time their diversity did not change significantly depending on inter-annual weather conditions. In contrast, litter removal negatively affected abundances of short-lived monocarpic species, whose richness was also considerably influenced by weather conditions (decreased the most in years with spring droughts). Moreover, we have found a protective effect of regular litter removal on drought-sensitive open oak forest species that survived in the litter-removal plots, whereas some completely disappeared from control sites during the period of repeated drought events. Our study thus demonstrates that litter removal is a tool with high potential in maintaining biodiversity in open forests affected by climate change.

Disentangling effects of upslope runoff and sediment on soil nutrients on the hilly slopes of the Loess Plateau, China

Upslope runoff and sediment critically influence soil erosion, while their impact on the subsequent downslope nutrient distribution has not been examined, consequently hindering the exact assessment of the effects of erosion on soil biogeochemical cycles. Herein we selected two groups of wide and narrow slopes on the middle Loess Plateau, with each slope group including slopes with and without upslope runoff and sediment. For each slope, we collected soil samples from topsoil along the slope at different distances from the upper slope to the lower slope, and collected samples from depths of 0–60 cm at the upper, middle and lower positions of the slope. The contents of soil organic matter and nutrients were analysed. The purpose of this study was to disentangle the effects of upslope runoff and sediment on spatial distribution of soil nutrients on slopes of different widths. We showed that compared with slopes without upslope runoff and sediment, upslope runoff and sediment increased the content of most nutrients in topsoil on the wide slope, but had a contrasting effect on the narrow slope. Upslope runoff and sediment reduced the random spatial heterogeneity of soil nutrients on both the wide and narrow slopes, with greater effects observed on the narrow slope. The influence of upslope runoff and sediment on the profile distribution of soil nutrients varied with slope position and slope width, and was nutrient type-dependent. These results indicated that slope topographical conditions interact with upslope runoff and sediment in influencing vertical and horizontal patterns of soil nutrients on slopes.

Selection of suitable type and application rate of biochar for alfalfa (Medicago sativa L.) productivity in ridge-furrow rainwater-harvesting in semiarid regions of China

Ridge-furrow rainwater-harvesting (RFRH) has emerged as an effective technology to mitigate drought stress, control soil erosion, and increase crop yield in semiarid regions of China. However, the use of plastic film mulch in RFRH makes this technology impractical. A field experiment was conducted for three consecutive years in a randomized complete block design to determine 1) the runoff coefficient for ridges compacted with soil mixed with two types of biochar (rice straw biochar and cow dung biochar) at two application rates (single application rate i.e., 3 × 104 kg ha−1; and double application rate i.e., 6 × 104 kg ha−1; and 2) the effects of the ridges compacted with soil mixed with two types of biochar at two application rates on soil physico-chemical properties, economic benefit, fodder yield and water use efficiency (WUE) of alfalfa, and ridges compacted with soil (no biochar) as control. The average runoff coefficient for NB, SRSB, DRSB, SCDB, and DCDB (NB, SRSB, DRSB, SCDB, and DCDB were ridges compacted with soil, compacted with soil mixed with single rice straw biochar application, double rice straw biochar application, single cow dung biochar application, and double cow dung biochar application, respectively) over these three years was 31%, 28%, 27%, 22%, and 21%, respectively. Ridges compacted with soil-biochar crust had lower runoff coefficients, soil water storage, net income, and higher soil nutrients, when compared to ridges compacted with soil. The topsoil temperature at ridge tops was affected by the ridges compacted with soil-biochar crust, but the topsoil temperature at furrow bottoms was not affected. Compared to ridges compacted with soil mixed with cow dung biochar, ridges compacted with soil mixed with rice straw biochar had lower soil nutrients, and higher soil water storage resulting in higher fodder yield and WUE of alfalfa. With runoff, the nutrients in biochar flowed from ridges to furrows, becoming usable for plants. Ridges compacted with soil-biochar crust increased topsoil nutrients, especially soil organic matter ranging from 15% to 34%, resulting in high fodder yield and WUE of alfalfa. Compared to NB, annual fodder yield for SRSB, DRSB, SCDB, and DCDB increased by 9.0%, 5.9%, 4.4%, and 3.8%, respectively, over three years, while WUE for the same treatments increased by 2.81, 1.95, 0.65, and 0.45 kg ha−1 mm−1. Rice straw biochar at an application rate of 3 × 104 kg ha−1 was found to be suitable type of biochar for increase in fodder yield and WUE of alfalfa in RFRH. Future studies should be conducted in the form of long-term field study to determine economic benefits of biochar application.

Effects of soil properties on vegetation community composition across a semiarid ecosystem

Identifying environmental factors that influence the vegetation community formation of various habitats in semiarid regions is imperative for managing these fragile ecosystems. The objective of this study was to quantify the relationships between selected environmental factors and vegetation community composition (VCC) in meadow and sand dune habitats using a structural equation model (SEM). Ecological data from 48 sample sites in semiarid sandy land were analyzed. The selected latent environmental variables included soil water (SW), topsoil salinity and sodicity, topsoil nutrients, topsoil texture (TT) and topography feature (TF). SW was the most influential factor for the Phragmites communis, Agriophyllum squarrosum, and Caragana microphylla communities composition. TT was the most influential factor for the Artemisia halodendron and Artemisia frigida - Agropyron desertorum communities composition. TF was the most influential factor for the Carex duriuscula and Phragmites communis - Bolboschoenus yagara communities composition. Considering the direct and indirect impact relationship, for the meadow habitat, TF was the primary factor causing the community distribution. For the sand dune habitat, TT was the primary factor causing the community distribution. As expected, the quantitative relationships between VCC and influencing factors differ depending on the ecological scales of interest.

Topsoil Nutrients Drive Leaf Carbon and Nitrogen Concentrations of a Desert Phreatophyte in Habitats with Different Shallow Groundwater Depths

Phreatophytes are deep-rooted plants that reach groundwater and are widely distributed in arid and semiarid areas around the world. Multiple environmental factors affect the growth of phreatophytes in desert ecosystems. However, the key factor determining the leaf nutrients of phreatophytes in arid regions remains elusive. This study aimed to reveal the key factors affecting the ecological stoichiometry of desert phreatophytes in the shallow groundwater of three oases at the southern rim of the Taklimakan Desert in Central Asia. Groundwater depth; groundwater pH and the degree of mineralization of groundwater; topsoil pH and salt concentration; topsoil and leaf carbon, nitrogen, and phosphorus concentrations of phreatophytic Alhagi sparsifolia grown at groundwater depths of 1.3–2.2 m in the saturated aquifer zone in a desert–oasis ecotone in northwestern China were investigated. Groundwater depth was closely related to the mineralization degree of groundwater, topsoil C and P concentrations, and topsoil salt content and pH. The ecological stoichiometry of A. sparsifolia was influenced by depth, pH and the degree of mineralization of groundwater, soil nutrients and salt concentration. However, the effects of soil C and P concentrations on the leaf C and N concentrations of A. sparsifolia were higher than those of groundwater depth and pH and soil salt concentration. Moreover, A. sparsifolia absorbed more N in the soil than in the groundwater and atmosphere. This quantitative study provides new insights into the nutrient utilization of a desert phreatophyte grown at shallow groundwater depths in extremely arid desert ecosystems.

Deficiency of essential elements in volcanic soils: potential harmful health effects on grazing cattle.

Several essential nutrients such as Fe, Co, Cu, I, Se, and Zn are vital to grazing cattle as they play a significant role in intracellular enzyme systems, with antioxidant and repair functions of DNA lesions. Feeds may supply most essential nutrients in adequate amounts. However, essential nutrient deficiencies are common and are mainly related to the geochemical characteristics of the soils, inherited from parent rocks. This study aims to assess the concentrations of the selected essential nutrients in topsoils and pasture grass from São Miguel Island (Azores) and discuss the possible effects of its deficiency in grazing cattle health. Sixty-eight samples of agricultural (pastures) topsoil and thirty samples of pasture grass were collected throughout São Miguel Island in areas with basaltic and trachytic parent rocks. Soil physicochemical properties and geochemical baselines of selected elements were determined on composite samples of soil and pasture grass in each site. Results indicate that the highest concentrations of the selected essential nutrients were observed in areas with basaltic soils, while the lowest values were found in areas with trachytic soils. These differences are considered of geogenic origin since they result from the weathering of volcanic parent rocks with different geochemical compositions. Data indicate a lack of some essential nutrients in topsoils (Co and Se) and/or pasture grass (Co, Cu, Se, and Zn) that can contribute to harmful health effects on grazing cattle. The uneven distribution of essential nutrients in topsoil and pasture grass and their deficiency can lead to several health problems in the cattle since these elements regulate physiological functions in biological systems. The identification of these deficit sites is important as it can help farmers to implement soil and/or animal supplementation programs to diminish possible health problems.

Vertical decoupling of soil nutrients and water under climate warming reduces plant cumulative nutrient uptake, water-use efficiency and productivity.

Warming-induced desiccation of the fertile topsoil layer could lead to decreased nutrient diffusion, mobility, mineralization and uptake by roots. Increased vertical decoupling between nutrients in topsoil and water availability in subsoil/bedrock layers under warming could thereby reduce cumulative nutrient uptake over the growing season. We used a Mediterranean semiarid shrubland as model system to assess the impacts of warming-induced topsoil desiccation on plant water- and nutrient-use patterns. A 6yr manipulative field experiment examined the effects of warming (2.5°C), rainfall reduction (30%) and their combination on soil resource utilization by Helianthemum squamatum shrubs. A drier fertile topsoil ('growth pool') under warming led to greater proportional utilization of water from deeper, wetter, but less fertile subsoil/bedrock layers ('maintenance pool') by plants. This was linked to decreased cumulative nutrient uptake, increased nonstomatal (nutritional) limitation of photosynthesis and reduced water-use efficiency, above-ground biomass growth and drought survival. Whereas a shift to greater utilization of water stored in deep subsoil/bedrock may buffer the negative impact of warming-induced topsoil desiccation on transpiration, this plastic response cannot compensate for the associated reduction in cumulative nutrient uptake and carbon assimilation, which may compromise the capacity of plants to adjust to a warmer and drier climate.

Spatial prediction of soil nutrients from soil, topography and environmental attributes in the northern part of Ekiti State, Nigeria

Knowledge of soil nutrient's spatial distribution and variability is useful for determining the balanced use of fertilizer inputs and for decisions making on the acquisition of land for any activity that will have its base on the lithosphere portion of the earth. This study presents statistical model for the prediction of top soil nutrients (Soil Organic Matter (SOM), Potassium (K), Phosphorus (P) and Nitrogen (N)) from soil and topographic attributes in Ekiti north, Ekiti state, Nigeria using geospatial techniques. Three topographic attributes (elevation, slope and curvature), one environmental variable (Land surface temperature, LST), one vegetation attribute (Normalized difference vegetation index (NDVI)) and four soil attributes (Water holding capacity, and bulk density) were employed to predict the spatial distribution of soil nutrient (N, P, K, SOM) in the study area. 66 samples of top soil nutrient of were collected within the study area. Topographic attributes were extracted from the obtained Digital Elevation Model (DEM) and Land use data while the soil attributes were derived from existing methodology by soil characteristics and Land use data. The derived attributes were statistically correlated with the sampled soil nutrients (N, P, K, SOM) to establish their relationships. Using Multiple Linear Regression Analysis, the contributions of individual factors in the prediction of soil nutrient (N, P, K, SOM) were established and soil nutrient model developed. The model was used to spatially predict the distribution of top soil nutrient in the study area. Results show both negative and positives correlation between the attributes and the soil nutrient (N, P, K, SOM). Spatially, the predicted top soil nutrient compared considerably well with the observed top soil nutrients.

On-site soil dislocation and localized CNP degradation: the real erosion risk faced by sloped cropland in northeastern China

Erosion-induced land degradation in the northeastern China, the Chinese breadbasket, has become one of the biggest risks to national food security. Apart from depleting topsoil, incising gullies, and waterlogging depositional sites, slope-scale erosion also spatially redistributes soil nutrients and introduces localized soil degradation. This requires to systematically understanding topography-specific spatial distribution patterns of eroded soil compositions and the relative abundance of each nutrient at different topographic settings. In this study, topsoil at predetermined space intervals were collected from two adjacent but differently curved segments (convex vs. concave) on a sloped cropland in northeastern China. The spatial distributions of topsoil soil organic carbon (SOC), total nitrogen (TN), total phosphorous (TP), and the variations of their atomic ratios were compared. Our results show that: (1) Compared with the nearby undisturbed tree rows, the SOC and TN was halved on the investigated slope, demonstrating great degradation since the land use conversion. (2) The spatial distribution of topsoil nutrients were evidently topography specific, with the SOC being comparable at slope summit, but declining from 27.57 to 4.72 g kg−1 (depletion ratio of 0.17) at the convex segment meanwhile accumulating up to 34.71 g kg−1 (enrichment ratio of 1.26) at the concave segment. Similar but more deviated spatial patterns were also observed on the TN and TP. (3) The atomic ratios of C:N:P also differed as the slope curvatures diverted, by being more variable from 51:3:1 to 105:6:1 along the convex segment but rather stable between 74:5:1 and 89:5:1 along the concave segment. (4) The lower content of SOC and the heavier δ13C along the convex segment suggest more advanced mineralization of C and thus greater susceptibility of C-limitation. Meanwhile, the slightly lower C:N ratios and the greater δ15N along the concave segment indicate greater stability of C, more advanced mineralization of N and thus likely a N-limited process. Overall, our findings demonstrate the controlling influences of minor geomorphic features to on-site soil dislocation and localized degradation at slope scale. Apart from general soil conservation measures, topography-specific practices must also be integrated to local land use policy to effectively target localized land degradation.

Root architecture for improved resource capture: trade-offs in complex environments.

Root architecture is a promising breeding target for developing resource-efficient crops. Breeders and plant physiologists have called for root ideotypes that have narrow, deep root systems for improved water and nitrate capture, or wide, shallower root systems for better uptake of less mobile topsoil nutrients such as phosphorus. Yet evidence of relationships between root architecture and crop yield is limited. Many studies focus on the response to a single constraint, despite the fact that crops are frequently exposed to multiple soil constraints. For example, in dryland soils under no-till management, topsoil nutrient stratification is an emergent profile characteristic, leading to spatial separation of water and nutrients as the soil profile dries. This results in spatio-temporal trade-offs between efficient resource capture and pre-defined root ideotypes developed to counter a single constraint. We believe there is need to identify and better understand trade-offs involved in the efficient capture of multiple, spatially disjunct soil resources. Additionally, how these trade-offs interact with genotype (root architecture), environment (soil constraints), and management (agronomy) are critical unknowns. We argue that identifying root traits that enable efficient capture of multiple soil resources under fluctuating environmental constraints is a key step towards meeting the challenges of global food security.

Atlantic Forest topsoil nutrients can be resistant to disturbance and forest clearing

AbstractHuman impacts can affect the soil properties through erosion and leaching, the ecosystem functions and, consequently, the capacity of a forest to regenerate. Here, we determine the effects of forest disturbance and succession on selected soil chemical properties using two different approaches, before‐after‐control‐impact (BACI) and space‐for‐time (SFT) substitution, and the threatened Atlantic Forest biome as model. We assessed with BACI the long‐term (37‐year) effects of clear cutting on soil properties by comparing data from two topsoil surveys (1978–2017) divided into two treatments: a preserved old growth forest (control) and an adjacent forest that was experimentally cleared with full tree removal (clear‐cut). We examined with SFT the relationship between stand age and soil properties using soil data from three old growth and 13 s growth forests ranging from 7 to 33 years. We found no significant differences between treatments for any soil property or significant changes in phosphorus, potassium, and calcium + magnesium over time. In contrast, pH increased and aluminum decreased in both areas. No relation was found between forest age and most of soil properties, with the exception of potassium which returned to old growth forest levels after 20 years of natural succession, and pH. BACI indicated that deforestation of old growth forest caused no significant effects on soil chemical properties after 37 years of regeneration. SFT demonstrated that soil properties did not change significantly during forest regeneration on formerly disturbed lands. Our findings indicate that natural nutrient‐depleted lowland forests were overall resistant to deforestation followed by passive regeneration at landscape scale.Abstract in Portuguese is available with online material.

Soil physicochemical properties associated with quasi-circular vegetation patches in the Yellow River Delta, China

In recent years, decreased runoff and sediment, intensified storm surge and seawater intrusion, urbanization, petroleum exploration, and production, and other factors have gradually deteriorated the unique wetland ecosystem in the Yellow River Delta (YRD). Although previous studies have analyzed the relationships between vegetation and soil properties at different scales, few studies have documented quasi-circular vegetation patches (QVPs) in the YRD, which appear to exhibit faster succession rates that make them ideal for studies on the relationships between vegetation and soil properties. Therefore, this study investigated differences in soil physicochemical properties at 0–20 cm depths between QVPs and inter-QVP bare soil areas, among QVPs, and among plant species communities. Additionally, spatial variations in soil physicochemical properties were explored in south-north and west-east transects across and within QVPs. The results showed that soils beneath QVPs had significant fertility island effects associated with soil organic matter (SOM) and total nitrogen (TN). Furthermore, these areas were richer in clay content, showed slightly higher pH values, and exhibited less available phosphorus (APH), available potassium (APO), total salt content, and silt content than those of bare soil areas. A multiple independent samples nonparametric Kruskal-Wallis H test detected significant differences in SOM, TN, APH, and pH among 18 QVPs, but no significant differences were found in APO, total salt content, sand, silt, and clay contents. Regardless of plant species, different plant species communities had significant effects on soil physicochemical properties. Particularly, soils underneath plant species communities with Tamarix chinensis were richer in SOM and TN, and they contained less APH, APO, and total salt content than those without T. chinensis. In each QVP, values of SOM and TN in soil samples along the patch perimeter were less than those of samples located midway toward the perimeter, and these values were less than those of samples centered in the patch. However, APO and total salt content values exhibited opposite changes from the perimeter to the center of the patch. The results also indicated significant differences in SOM, TN, APH, APO, and pH between south-north transect A and west-east transect B across QVPs, but no significant differences were found in total salt content, sand, silt, and clay contents. Therefore, the results of this study indicate that QVPs have significant effects on topsoil nutrients and salinity but little effects on soil texture. Furthermore, the occurrence and development of QVPs are associated with suitable soil conditions, including higher clay fractions and lower total salt content values.

Ancient settlement activities as important sources of nutrients (P, K, S, Zn and Cu) in Eastern Mediterranean ecosystems – The case of biblical Tel Burna, Israel

Human settlement activities are connected with the accumulation of nutrients in archaeological soils. We address the question of whether the large-scale mapping of the elemental composition of the topsoil in contemporary rangeland can be used for the detection of ancient settlement activities.Using portable X-ray fluorescence (pXRF), we mapped the elemental composition of contemporary soils over an area of 67ha in and around the Bronze and Iron Age settlement of Tel Burna (identified as probably corresponding with biblical Libnah).Ancient settlement activities substantially increased concentrations of nutrients (P, K, S, Zn and Cu) in the contemporary topsoil owing to the deposition of biomass ashes and organic wastes. Increased concentrations of elements were detected 2500 years after the site was abandoned and we can therefore suppose that changes in the elemental composition of the soil caused by ancient settlement activities are irreversible on a timescale in which human societies operate. Ancient settlement activities increased concentrations of nutrients in contemporary soil to the same level as recent intensive fertiliser application on an adjacent arable field used for vegetable production. Concentrations of nutrients higher than those on the tell summit were recorded only in recent cattle resting areas with intensive deposition of cattle faeces. Changes in the elemental composition of the soil caused by ancient settlement activities consequently result in differential nutrient availability for contemporary vegetation, affecting ecosystem functions for thousands of years. Using pXRF, large-scale mapping of the elemental composition of the topsoil layer at archaeological sites can help to identify the extent and provide basic information on the character of past human activities in the affected landscape units.

Restoration Affect Soil Organic Carbon and Nutrients in Different Particle‐size Fractions

AbstractDesertification is reversible and can often be prevented by adopting measures to control the causal processes. Desertification has generally decreased in most of the arid and semiarid areas of China during the last few decades because of the restoration of degraded vegetation and soil nutrients. However, little is known about the responses of soil nutrients in different particle‐size fractions to the restoration process and about the importance of this response to the restoration of bulk‐soil nutrients. In this study, we separated bulk‐soil samples in different sieve fractions: coarse‐fine sand (2·0–0·1 mm), very fine sand (0·10–0·05 mm) and silt + clay (<0·05 mm) fractions. Soil organic carbon (SOC), N, P and K contents stored in the silt + clay were greater than the contents of non‐protected nutrients in the coarser fractions. During the restoration of desertified land, the content and stability of bulk‐soil SOC, total N and P and available N, P and K increased with increasing nutrient contents in all fractions. Topsoil nutrients stored in coarse‐fine sand and very fine sand fractions were more sensitive than those stored in the silt + clay fraction to the fixation of mobile sandy lands and vegetation recovery. The changes of bulk‐soil nutrients and their stability were decided by the soil nutrients associated with all particle‐size fractions. Path analysis revealed that SOC and total nutrients in very fine sand and available nutrients in coarse‐fine sand were the key factors driving the soil recovery. These results will help us understand soil recovery mechanisms and evaluate the degree of recovery. Copyright © 2015 John Wiley & Sons, Ltd.

The Content of Topsoil Nutrients, Ph and Organic Carbon as Affected by Long-Term Application of Mineral and Organic Fertilisers

Abstract Soil is the fundamental element in agriculture and is affected in a variety of ways. Besides other things, the long-term application of mineral and organic fertilisers can significantly influence the topsoil pool of nutrients, organic carbon content and pH. Within the scope of longterm field experiments in Praha-Ruzyně, we evaluated the effect of six fertiliser treatments - unfertilised Control, farmyard manure (FYM), cattle slurry (CAT), cattle slurry amended with straw from previous cereals (CAT+STR), mineral fertiliser (NPK) and NPK amended with FYM (NPK+FYM) on a topsoil pool of nutrient content, organic carbon content (Cox) and pH between the years 2001 and 2012. In the selected period, the fertiliser treatment did not influence the N and Cox content (ranging from 0.126% to 0.143%). Phosphorus and potassium were significantly higher in the NPK+FYM treatment (109.82 and 279.27 mg/kg, respectively), while calcium and magnesium were significantly lower in the NPK treatment (2,973 and 134.95 mg/kg, respectively). Application of mineral fertilisers significantly decreased the value of pH, influencing the Ca and Mg topsoil concentrations. Organic fertilisers cannot provide a sustainable amount of nutrients to generate high yields in a short time, but release their nutrients slowly and the range of nutrients is wider. Mineral fertilisers, if not amended with organic fertilisers, can provide huge doses of nutrients, which can be quickly reused for high yields, but negatively influence the pH value, resulting in a decrease in the pool of Ca and Mg.

Optimal soil-sampling design for rubber tree management based on fuzzy clustering

Farming management practices related to nutrient recommendation for rubber tree plantations have been a challenge for scientists, farm managers and local producers. Specific caves and building contour ledges to prevent nutrient losses through soil erosion often cause spatial variation of topsoil nutrients in such plantations of rubber trees (Hevea brasiliensis). The design of soil-sampling schemes to test chemical properties of the soil is critical for successful nutrient recommendation for rubber trees. Our objectives were to characterize the spatia variability of soil pH, macronutrient NPK and organic matter in rubber plantations and to evaluate the rationality of soil sampling schemes in rubber plantations for tree nutrient management. The study was conducted in an area of 84m2 consistent of nine rubber trees and soil samples (0–0.2m depth) were taken from 168 grid points with a dimension of 1m×0.5m. Concentrations of total nitrogen, organic matter, available phosphorus, available potassium and pH levels were determined for each soil sample. Based on their spatial variability patterns, the analyzed variables were divided into several homogeneous zones through fuzzy cluster algorithm. The number of subzones was determined using fuzzy performance index and normalized classification entropy to optimize the classification algorithm. The classification results showed that there were three optimal sampling zones for the soil chemical properties. The analysis of variance indicated that chemical properties were significantly different between the delineated zones. The delineated management zones could be used as a reference for making soil-sampling scheme in the rubber plantation. The results of this study have the implication in optimization of soil sampling planning for soil testing for nutrient recommendation. Fuzzy cluster algorithms could classify soil chemical properties into three practical zones by reducing intrazone variability, which would provide with useful information for making effective soil-sampling schemes in rubber tree plantations.