PHYTOEXTRACTION OF CADMIUM BY ATRIPLEX HALIMUS

The possibility of remediating contaminated soils through the use of high biomass-generating, native plant species capable of removing heavy metals is receiving increased attention. The capacity of accumulation cadmium (Cd) of Atriplex halimus was tested by growing transplanted specie in a pine bark compost substrate (pH 5.6) contaminated with 100 mg Cd kg-1. After 70 days, the increase in biomass in the plant enhanced the phytoextraction of Cd. The leaf Cd concentration reached 35 mg Cd kg-1. The normal growth shown by this specie in the presence of high concentration of Cd and under conditions of high temperature and acidic pH, suggests that this specie may be used to generate a green cover on soils contaminated by metals and may contribute to their remediation

Movilidad de metales pesados en sustratos de restos de poda y bisólidos: ensayos de fitoextracción con "Rosmarinus officinalis" y "Atriplex halimus"

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Agrícola, Geología y Geoquímica. Fecha de lectura: 14-12-200

Field Monitoring of 2010-Tsunami Impact on Agricultural Soils and Irrigation Waters: Central Chile

An in situ post tsunami study was conducted to assess the effect of water management and rainfalls in soil properties and water quality at a low-lying coastal area of central Chile affected by Mw8.8 Earthquake Tsunami the night of 27 February 2010. Soil samples were taken at two depths (0 to 20 and 20 to 40 cm) during 2010 and late 2012. Water quality in a local shallow well was also monitored in 2010 and 2012. High soil salinity was recorded 2 months later than tsunami occurs, closely associated to water-soluble chloride and cations (Cl- >> Na+ >> Ca2+> Mg2+> K+), ionic toxicities, and vegetal inhibition (Vasconcellea pubescens) by less available water to plants. An initial reduction in soil pH due to ionic strength and coarse-textured class of soil was observed and the sodium adsorption ratio (SAR) in soil varied between 5.7 and 11.2 (mmol L-1)(0.5) showing to be saline. Although SARw values are very high (> 18 (mmol L-1) 0.5), it does not exist risks of reduction on soil infiltration rates according to ECw (> 5 dS m(-1)) obtained. After 2 years, soil salinity was drastically reduced in the affected areas due to high soil permeability and natural attenuation (rainfalls and leaching effects), with sulfate and bicarbonate concentrations showing excessive values. Further, irrigation water quality returned to pre-tsunami situation, with only levels of sodium slightly exceeding desirable range from health point of view. Finally, it is suggested a proper design of irrigation systems before implementing other management practice

Alteration of enzyme activities and functional diversity of a soil contaminated with copper and arsenic

Copper (Cu) mining has to address a critical environmental issue related to the disposal of heavy metals and metalloids (HMs). Due to their deleterious effects on living organisms, Cu and arsenic (As) have gained global attention, and thus their monitoring in the environment is an important task. The aims of this study were: 1) to evaluate the alteration of soil enzyme activities (EAs) and soil microbial functional diversity with Cu/As contamination, and 2) to select the most reliable biochemical indicators of Cu/As contamination. A twelve-week soil experiment was performed with four increasing levels of Cu, As, and Cu/As from 150/15 to 1000/100 mg Cu/As kg(-1). Soil enzyme activities and soil community-level physiological profile (CLPP) using MicroResp (TM) were measured during the experiment. Results showed reduced EAs over time with increasing Cu and Cu/As levels. The most Cu-sensitive EAs were dehydrogenase, acid phosphatase, and arylsulfatase, while arginine ammonification might be related to the resilience of soil microbial communities due to its increased activity in the last experimental times. There was no consistent response to As contamination with reduced individual EAs at specific sampling times, being urease the only EA negatively affected by As. MicroResp (TM) showed reduced carbon (C) substrate utilization with increasing Cu levels indicating a community shift in C acquisition. These results support the use of specific EAs to assess the environmental impact of specific HMs, being also the first assessment of EAs and the use of CLPP (MicroRes (TM)) to study the environmental impact in Cu/As contaminated soils.Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) ACM170002 21160049 Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1170264 MECEUFRO project FRO1756 Rural & Environment Science & Analytical Division of the Scottish Government CONICYT/FONDAP/1513001

Physical assessment of a Mollisol under agroecological management in the Quillota Valley, Mediterranean Central Chile

A number of agroecological practices have been proposed for assessing soil quality. Several physical soil properties have been shown to be important for determining soil quality by using the sustainability index (SI) and the cumulative rating approach. The main aim of the study was to determine the effects of different agroecological managements on the physical properties of a Mollisol in the Mediterranean central Chile. In addition, some physical properties were selected to compare the soil quality among different agroecological management practices and highly mechanized intensive systems by using the SI and cumulative rating approaches. An experimental field was defined in an area of 3.5 ha in 2014. Four sites with different agroecological practices were selected in 2019 to assess soil physical properties: rainfed Mediterranean annual prairie - no tillage (1-S), irrigated perennial prairie with deep-root species - no tillage (2-N), irrigated annual and perennial prairie - conventional tillage (4-S), irrigated vegetables and flowers - minimum tillage (4-N); an avocado orchard with traditional management was used as the control. Soil organic carbon and the following soil physical properties were selected to assess SI and CR: bulk density, total porosity, void ratio, air capacity, fast-drainage pores, relative field capacity, hydraulic conductivity, structural stability index and unavailable water pores. The applicability of the selected physical indicators to the SIs of agroecological management practices compared with the control was demonstrated. The cumulative rating index (CR) for each land use showed that all agroecological practices constituted sustainable soil management (25≤CR<30), whereas the avocado orchard showed the least sustainable management (30≤CR<40), and a change in soil use is recommended