Agricultural Soils

This study was conducted to assess the potential ecological and human health risk of toxic metals
in agricultural soils near the industrial areas of Bangladesh. In this study, six toxic metals
(chromium, nickel, copper, arsenic, cadmium, and lead) were assessed in 58 soil samples of five
different sampling sites around the industrial areas of Jhenaidah and Kushtia districts in
Bangladesh. Toxic metals were measured using inductively coupled plasma mass spectrometer.
Potential ecological and human health risk were assessed through enrichment factor (EF), contamination
factor (Cf
i ), geoaccumulation index (Igeo), pollution load index (PLI), toxic unit analysis,
chronic daily intake through exposure pathway, hazard quotient, and hazard index. The mean
concentrations of Cr, Ni, Cu, As, Cd, and Pb were found to be 5.78, 21.0, 31.8, 8.05, 1.20, and
19.2 mg/kg, respectively. Metals concentrations were found below the recommended value set
by Dutch standard, Canadian guidelines, and Australian guidelines except Cd. Principal component
analysis indicates that most of the metals in agricultural soils are coming from industrial
sector. The mean values of EF, Igeo, Cf
i, PLI, and toxic units were found safe level for all metals
except Cd. In the view of potential ecological risk (PER), soils from all sampling sites indicated
moderate to very high PER. Total target hazard quotients for all the studied metals in total sampling
sites were <1 and cancer risk values were <10
6 indicating low noncarcinogenic and cancer
risk for adult and children.

A B S T R A C T: There is interconnection between soil quality, water quality, and food safety that is necessary to evaluate pollution levels in these components. Soil contamination by potentially hazardous elements may pose direct and indirect threats as negative impacts on the plant growth and yield, entering the human food chain with potentially negative effects on human health. Intensive agriculture (industrial agriculture) in agro-industry could have resulted in an enrichment of potentially hazardous elements in soils and accumulation in crops because of excess use of fertilizers and amendments. Unfortunately, despite these conditions, there were few or no investigations of potentially hazardous elements in farming areas of agro-industry sectors. This research was undertaken in agricultural lands of Moghan agro-industry complex located in the Moghan's plain (as one of the main poles of agriculture) in the north of Ardebil province and west of the Caspian Sea. The present study was designed to investigate the concentrations of Cd and Pb in agricultural soils, irrigation water, Alfalfa and commonly used fertilizers in the agricultural lands of Moghan agro-industry. The results showed that the average concentrations of the Cd and Pb in agricultural soils of Moghan agro-industry complex were 0.55 and 163.60 mg·kg − 1 , respectively. Moreover, the mean concentrations of Cd and Pb were 0.61, and 0.07 μg·l − 1 in irrigation water samples, respectively, 0.45, and 0.009 mg·kg − 1 in Alfalfa samples, 0.62 and 51.87 mg·kg − 1 in superphosphate fertilizer samples, 0.67 and 51.87 mg·kg − 1 in animal manure samples and 0.001 and 3.66 mg·kg − 1 in urea fertilizer samples. Superphosphate fertilizer showed higher content of Cd and Pb than urea fertilizer, indicating the importance of phosphate fertilizer on the accumulation of potentially hazardous elements in soils. Based on the results of this research and values of Transfer Factor (TF), it was found that the Alfalfa (Medicago scutellata) had high ability to accumulate cadmium from contaminated soils, but the accumulation rate of Pb was much lower than Cd. Phosphate fertilizer and/or animal manure may be the main sources of contribution by Cd and Pb in the agricultural soils of the study area, but irrigation water had no significant effect on the potentially hazardous elements accumulation in soil.

Irragric anthrosols form as a result of prolonged deposition of fine sediments from irrigation water. Ancient irragric soils centuries to millennia old occur in several world regions, especially in arid environments of Asia and the Americas. This article presents evidence for an ancient irragric anthrosol in the North American Southwest, along the Snaketown Canal System in the Middle Gila River Valley, Arizona. This pedostratigraphic unit was formed as a result of a millennium of irrigation by Hohokam farmers from A.D. 450 to 1450. The irragric soil consists of a mantle of silty‐to‐loamy textures with minimal soil formation overlying a natural argillic horizon on a Pleistocene stream terrace. A soil mapped independently by the United States Department of Agriculture‐Natural Resources Conservation Service with these horizons corresponds closely with the canal system. Soil within the canal system tends to be lower in salt, sodium, and pH compared with external soils. This suggests that the irragric process improved soil for crop production through long‐term leaching and additions of fresh sediments with the irrigation water. This anthropogenic process of canal sedimentation has had a long‐lasting impact on the sedimentary record and soils in this arid environment.

Soils and crops are particularly vulnerable to climate change and environmental stresses. In many agrosystems, soil biodiversity and ecosystem services provided by soils are under threat from a range of natural and human drivers. Agricultural soils are often subject to agronomic practices that disrupt soil trophic networks and make soils less productive in the long term. In this scenario, sustainable soil use aimed at improving plant/root status, growth and development plays a crucial role for enhancing the biological capacity of agricultural soils. This commentary paper is divided into the following four main sections: (i) the contentious nature of soil organic matter; (ii) soil biological quality/fertility; (iii) soil classification; and, (iv) which agricultural practices can be defined as sustainable? The published literature was analyzed within a holistic framework, with agrosystems considered as living systems where soil, vegetation, fauna and microorganisms co-evolve and are reciprocally influenced. Ultimately, this article will suggest a better stewardship of agricultural soils as a natural capital.

Wind erosion susceptibility of the Hungarian soils was mapped on national level integrating three pillars of the complex phenomenon of deflation. Results of wind tunnel experiments on erodibility of various and representative soil samples were used for the parametrization of countrywide map of soil texture compiled for the upper 5 centimeter layer of soil, which resulted in a map representing threshold wind velocity exceedance. Average wind velocity was spatially estimated with 0.5' resolution using the MISH method elaborated for the spatial interpolation of surface meteorological elements. The ratio of threshold wind velocity exceedance was determined based on values predicted by the soil texture map at the grid locations. Ratio values were further interpolated to a finer 1 ha resolution using sand and silt content of the uppermost (0–5 cm) soil as spatial co-variables. Land cover was also taken into account excluding areas which are not relevant from the aspect of wind erosion (forests, water bodies, settlements etc.) to spatially assess the risk of wind erosion. According to the resulted map of wind erosion susceptibility, about 10 % of the total area of Hungary can be identified as susceptible for wind erosion. The map gives more detailed insight into the spatial distribution of wind-affected areas in Hungary as opposed to former works.

This study quantifies the extent of heavy metal
pollution in the agricultural soils (57 samples) from Jajmau,
Kanpur, India. Heavy metal concentrations (mg/kg)
in agricultural soils, frequently irrigated with treated tannery
effluent, are significantly higher: Cr 118–3142,
Cr(VI): 2–87, Mn 341–821, Ni 24–47, Zn 78–427, V
73–110, Cd 2–13, Pb 15–69. Sludge embedded soil, mainly
comprising of tannery sludge disposed in open ground,
contains *40,500 mg/kg Cr [and 1,400 mg/kg Cr(VI)], Zn
(884), Cu (300), Cd (192), Pb (180) and Ni (68 mg/kg).
Results show *65 % of the total chromium is easily
leachable from these soils under acidic conditions. Pollution
assessment suggests that agricultural soils are highly
polluted with Cr, Cu, Cd, Pb and Zn. Spatial distribution
maps of heavy metals identifies specific areas that are
heavily contaminated with Cr, Cu, Zn, Cd, Pb and Cr(VI),
mostly along the length of the major canal constructed to
distribute the treated tannery effluents. Principal component
(PC) and cluster analysis suggest two principal components
(or two clusters) that explain 83 % of data
variability. PC1 positively correlates with Cr, Cu, Zn,
Cr(VI), Pb, Cd and OM, which is attributed to anthropogenic
activities, i.e. irrigation by treated tanneries effluent, open dumping of Cr sludge. PC2 strongly correlates with
Fe, Ni, Co, V and Mn, which is attributed to weathering of
parental materials. This study clearly reveals significant
metal pollution including Cr(VI) pollution in Jajmau,
which can lead to widespread soil and groundwater
contamination.

New agricultural soil model approaches based on the microbiome dynamics must be considered as they can contribute to understand microbiological soil processes directly linked to substrate metabolism and the influence of these processes on plant growth. The present work presents an approach to the modelling of the interactions of the soil microbial functional diversity with the plant in terms of functions associated to specific processes of organic Carbon and Nitrogen metabolism. The substrates transformations arising in the organic matter that enters as a part of an agricultural scheme are the base for define this metabolism. As result, it has been possible to simulate a rhizospheric soil based on the concept of complex system dynamics and Individual Based Modeling known too as Agent-Based Modeling in an agricultural management context. The explicit definition of the microbiome functional diversity and the processing of the structural elements Carbon and Nitrogen, allowed representing the functional dynamics of this complex system composed by microorganisms, Carbon, Nitrogen and the plant. The variables that reflect the biology and the adaptation to the rhizospheric environment characterized the microorganisms and the assemblage community patterns in time. The main simulations output are system glucose and nitrate levels and an approach to plant growth, all resultant from the metabolic process of the considered Carbon and Nitrogen consortia. The results indicate that the microorganism's diversity assemblages and its functional expression have a fundamental role in terms of plant growth.

Evolution and change in agricultural practice is a major factor in the codification of social relations and represents one of the main resources employed by human societies to establish a durable relationship with their environment. Using a multi-proxy integrated approach, this paper seeks to decipher the long-term dynamics that have shaped agricultural landscapes in the Basque Country (N Spain). Social and economic indicators (archival records, toponymy and oral sources) are used along with geological core sampling (geochemistry, magnetic, palynological and carpological analyses) to reconstruct a diachronic sequence of human settlement and agricultural management in the village of Aizarna over the last ~1500 years. The oldest records obtained refer to non-agricultural human activities dating back to the Roman period. Later on, traces of agricultural landscape-transformation can be divided into four main phases: 1) the onset of terraced agriculture, defined by the clearance and terracing of previous forested areas during the Early Middle Ages; 2) a Late Medieval reorganisation, with new terraces being (re)constructed close to dispersed farmsteads, linked to the emergence of the modern rural landscape; 3) a new model of intensive polyculture developed during the Modern period as a consequence of the introduction of new crops of American origin; and 4) the mechanisation and commercialisation of the agricultural production over the 20th century. These results provide a valuable pathway for the investigation of currently inhabited rural contexts, and offer, for the first time in this region, an overview on long-term landscape construction in the Atlantic areas of the Basque Country.

Heavy metal (HM) contamination in agricultural soils has been a significant health concern worldwide due to their persistent and non-biodegradable nature and biomagnification to higher trophic levels. The
present study was conducted to assess Cd and Pb concentrations in soil samples collected from potato growing areas in Thall, Dir-Kohistan, and to determine their associated health and ecological risks. The contamination factor calculated for Cd (0 to 1.74) and Pb (0 to
0.91) showed their moderate to low contamination in the study area. Geo-accumulation indices of Cd and Pb were less than 1, indicating moderate soil pollution of these HM in the study area. However, the ecological riskfactor (Eri) of Cd was greater than 40 for only three soil

This paper presents the specific terms of vocabulary and diagnostic horizons necessary for a field classification of submerged Histic humipedons (peats, moors). It is simply an exposition of definitions placed side by side with photographic samples, with rather practical interest. The knowledge reported here is mandatory for people wanting to use the key of classification of these humipedons presented in Humusica 2, article 10. The paper illustrates with schemes the spatial and functional relationships between diagnostic horizons of different Histic humipedons.