Paving the way toward soil safety and health:current status,challenges,and potential solutions

Soil is a non-renewable resource,providing a majority of the world’s food and fiber while serving as a vital carbon reservoir.However,the health of soil faces global threats from human activities,particularly widespread contamination by industrial chemicals.Existing physical,chemical,and biological remediation approaches encounter challenges in preserving soil structure and function throughout the remediation process,as well as addressing the complexities of soil contamination on a regional scale.Viable solutions encompass monitoring and simulating soil processes,with a focus on utilizing big data to bridge micro-scale and macro-scale processes.Additionally,reducing pollutant emissions to soil is paramount due to the significant challenges associated with removing contaminants once they have entered the soil,coupled with the high economic costs of remediation.Further,it is imperative to implement advanced remediation technologies,such as monitored natural attenuation,and embrace holistic soil management approaches that involve regulatory frameworks,soil health indicators,and soil safety monitoring platforms.Safeguarding the enduring health and resilience of soils necessitates a blend of interdisciplinary research,technological innovation,and collaborative initiatives.

Safety-efficiency trade-offs in the cotton xylem：acclimatization to different soil textures

The acclimatization of plant xylem to altered environmental conditions has attracted considerable attention from researchers over several decades. Plants growing in natural environments must seek a balance between water uptake and the water loss of leaves from evaporation. Thus, the adaptation of xylem to different soil textures is important in maintaining plant water balance. In this study, we investigated the xylem changes of cotton（Gossypium herbaceum L.） xylem in sandy, clay and mixed soils. Results showed that soil texture had a significant effect on xylem vessel diameter and length of stems and roots. Compared with G. herbaceum growing in the clay soil, those plants growing in the sandy soil developed narrower and shorter xylem vessels in their roots, and had a higher percentage of narrow vessels in their stems. These changes resulted in a safer（i.e. less vulnerable to cavitation）, but less-efficient water transport system when soil water availability was low, supporting the hydraulic safety versus efficiency trade-off hypothesis. Furthermore, in sandy and mixed soils, the root： shoot ratio of G. herbaceum increased twofold, which ensures the same efficiency of leaves. In summary, our finding indicates that the morphological plasticity of xylem structure in G. herbaceum has a major role in the acclimatization of this plant species to different soil textures.

Reasonable selection of yield criteria for quantitative analysis of unsaturated soil slope stability

The yield criterion parameters of the soil material change with different values of the cohesion and the angle of friction because of sustained rainfall infiltration. Based on the Mohr-Coulomb(M-C) and Drucker-Prager(D-P) yield criteria, some reasonable yield criteria selections were discussed for quantitative analysis of unsaturated soil slope stability. Moreover, a critical point was found at the effective angle of friction equaling to 16.5° by transformation of parameters related to unsaturated soil under sustained rainfall. When the effective angle of friction more than 16.5° through parameter transformation of different yield criteria under natural condition, the calculation result of the safety factor was such that: f(DP1) > f(M-C) > f(equivalent M-C) > f(DP2) > f(DP3). While the effective angle of friction less than 16.5°, through parameter transformation, the safety factors were in the following order: f(DP1) > f(M-C) > f(DP2) > f(equivalent M-C) > f(DP3). The calculated results from a case study showed that the equivalent M-C yield criterion should be the best at evaluating soil slope stability before rainfall; the DP2 yield criterion should be selected to calculate the soil slope stability at the effective angle of friction less than 16.5° under sustained rainfall. The yield criterion should be selected or adjusted reasonably to calculate the safety factor of unsaturated soil slopes before and during sustained rainfall.

Research Progress on Remediation Technology Suitable for Farmland Soil Contaminated by Cd

Cd contamination range of farmland soil in China is wide,which has constituted a major threat for food safety and residents＇ health. Via multi-year development,there are more remediation methods suitable for soil contaminated by Cd among the world,but some methods are only suitable for the contaminated sites and indoor research,and can not be applied in large-range contaminated farmland. We analyze the source of Cd in farmland soil. By combining farmland＇s characteristics,three remediation techniques（ low-absorption crops plantation,soil solidification and phytoremediation） and their effects are analyzed,and the existing problems and research prospects of the above techniques are explored. The research could provide reference for restoring farmland soil contaminated by Cd in China,recovering its production function and enhancing food safety standards.

Accumulation of mercury in rice grain and cabbage grown on representative Chinese soils

A pot culture experiment was carried out to investigate the accumulation properties of mercury(Hg) in rice grain and cabbage grown in seven soil types(Udic Ferrisols, Mollisol, Periudic Argosols, Latosol, Ustic Cambosols, Calcaric Regosols, and Stagnic Anthrosols) spiked with different concentrations of Hg(CK, 0.25, 0.50, 1.00, 2.00, and 4.00 mg/kg). The results of this study showed that Hg accumulation of plants was significantly affected by soil types. Hg concentration in both rice grain and cabbage increased with soil Hg concentrations, but this increase differed among the seven soils. The stepwise multiple regression analysis showed that pH, Mn(II), particle size distribution, and cation exchange capacity have a close relationship with Hg accumulation in plants, which suggested that physicochemical characteristics of soils can affect the Hg accumulation in rice grain and cabbage. Critical Hg concentrations in seven soils were identified for rice grain and cabbage based on the maximum safe level for daily intake of Hg, dietary habits of the population, and Hg accumulation in plants grown in different soil types. Soil Hg limits for rice grain in Udic Ferrisols, Mollisol, Periudic Argosols, Latosol, Ustic Cambosols, Calcaric Regosols, and Stagnic Anthrosols were 1.10, 2.00, 2.60, 2.78, 1.53, 0.63, and 2.17 mg/kg, respectively, and critical soil Hg levels for cabbage are 0.27, 1.35, 1.80, 1.70, 0.69, 1.68, and 2.60 mg/kg, respectively.

Cadmium in soybeans and the relevance to human exposure

Introduction Cadmium is considered a human carcinogen by the International Agency for Research on Cancer（IARC,1993）and the US National Toxicology Program（NTP,1997）.Cadmium contamination of food crops is a persistent issue for both the agricultural industry as well as consumers.This is an issue for agriculture because cadmium can be present in soils naturally or as a result of industrial processes and can contaminate foods that are consumed by humans.Industrial