Enhanced effects of walnut green husk solution on the phytoextraction of soil Cd and Zn and corresponding microbial responses

Chemosphere ◽  
2021 ◽  
pp. 133136
Author(s):  
Xing Liu ◽  
Yingxin Wu ◽  
Yang Lu ◽  
Xiaowen Liu ◽  
Junjun Liu ◽  
...  
Keyword(s):  
2021 ◽  
Author(s):  
Christoph Rosinger ◽  
Michael Bonkowski

AbstractFreeze–thaw (FT) events exert a great physiological stress on the soil microbial community and thus significantly impact soil biogeochemical processes. Studies often show ambiguous and contradicting results, because a multitude of environmental factors affect biogeochemical responses to FT. Thus, a better understanding of the factors driving and regulating microbial responses to FT events is required. Soil chronosequences allow more focused comparisons among soils with initially similar start conditions. We therefore exposed four soils with contrasting organic carbon contents and opposing soil age (i.e., years after restoration) from a postmining agricultural chronosequence to three consecutive FT events and evaluated soil biochgeoemical responses after thawing. The major microbial biomass carbon losses occurred after the first FT event, while microbial biomass N decreased more steadily with subsequent FT cycles. This led to an immediate and lasting decoupling of microbial biomass carbon:nitrogen stoichiometry. After the first FT event, basal respiration and the metabolic quotient (i.e., respiration per microbial biomass unit) were above pre-freezing values and thereafter decreased with subsequent FT cycles, demonstrating initially high dissimilatory carbon losses and less and less microbial metabolic activity with each iterative FT cycle. As a consequence, dissolved organic carbon and total dissolved nitrogen increased in soil solution after the first FT event, while a substantial part of the liberated nitrogen was likely lost through gaseous emissions. Overall, high-carbon soils were more vulnerable to microbial biomass losses than low-carbon soils. Surprisingly, soil age explained more variation in soil chemical and microbial responses than soil organic carbon content. Further studies are needed to dissect the factors associated with soil age and its influence on soil biochemical responses to FT events.


2017 ◽  
Vol 593-594 ◽  
pp. 508-522 ◽  
Author(s):  
J.J. González Costa ◽  
M.J. Reigosa ◽  
J.M. Matías ◽  
E.F. Covelo

2015 ◽  
Vol 6 ◽  
Author(s):  
Jürg B. Logue ◽  
Stuart E. G. Findlay ◽  
Jérôme Comte

Author(s):  
Wenxing Li ◽  
Peihua Zhang ◽  
Hao Qiu ◽  
Cornelis A. M. Van Gestel ◽  
Willie J. G. M. Peijnenburg ◽  
...  

2022 ◽  
Vol 301 ◽  
pp. 113837
Author(s):  
Mao Gao ◽  
Fan Tang ◽  
Kaidi Wang ◽  
Fanjian Zeng ◽  
Yan Wang ◽  
...  
Keyword(s):  

2011 ◽  
Vol 35 (2) ◽  
pp. 645-654 ◽  
Author(s):  
Bruno Fernando Faria Pereira ◽  
Danilo Eduardo Rozane ◽  
Suzana Romeiro Araújo ◽  
Gabriel Barth ◽  
Rafaela Josemara Barbosa Queiroz ◽  
...  

Among the toxic elements, Cd has received considerable attention in view of its association with a number of human health problems. The objectives of this study were to evaluate the Cd availability and accumulation in soil, transfer rate and toxicity in lettuce and rice plants grown in a Cd-contaminated Typic Hapludox. Two simultaneous greenhouse experiments with lettuce and rice test plants were conducted in a randomized complete block design with four replications. The treatments consisted of four Cd rates (CdCl2), 0.0; 1.3; 3.0 and 6.0 mg kg-1, based on the guidelines recommended by the Environmental Agency of the State of São Paulo, Brazil (Cetesb). Higher Cd rates increased extractable Cd (using Mehlich-3, Mehlich-1 and DTPA chemical extractants) and decreased lettuce and rice dry matter yields. However, no visual toxicity symptoms were observed in plants. Mehlich-1, Mehlich-3 and DTPA extractants were effective in predicting soil Cd availability as well as the Cd concentration and accumulation in plant parts. Cadmium concentration in rice remained below the threshold for human consumption established by Brazilian legislation. On the other hand, lettuce Cd concentration in edible parts exceeded the acceptable limit.


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