scholarly journals Hubungan antara Konsentrasi Cr(VI) dan Sifat Kimia Tanah: Informasi Awal untuk Remediasi Lahan Bekas Tambang di Kalimantan Selatan

2013 ◽  
Vol 14 (2) ◽  
pp. 97-103 ◽  
Author(s):  
Akhmad Rizalli Saidy ◽  
. Badruzsaufari

High concentration of heavy metals is frequently observed as an effect of mining activity. In order to determine relationship between concentration of Cr(VI) in ex-mined land and soil chemical characteristics, 15 of soils were sampled from ex-coal and chromate mined-lands in the South Kalimantan Province. Result of the experiment revealed that soils from the ex-mined lands contained 700 - 2645 mg Cr kg-1 soil. This research also showed that 0,73-1,35% of total Cr in these soils exist in the form of hexavalent chromium (Cr(VI)) that is toxic and carcinogen. Concentration of Cr(VI) in these soils were correlated significantly with soil pH in which increasing soil pH would lead to increase in concentration of Cr(VI). In addition, increasing in soil organic carbon will be followed by decreasing concentration of Cr(VI). Relationship between concentration of Cr(VI) and soil pH and organic carbon content could be useful for preliminary information for Cr reclamation of ex-mined lands.

2018 ◽  
Vol 7 (1) ◽  
pp. 45-53
Author(s):  
MB Hossain

An experiment was conducted at Bangladesh Institute of Nuclear Agriculture (BINA) farm, Mymensingh, Bangladesh during 2010-2011 to find out the effect of different water and organic residue levels on rice production and soil organic carbon content. Organic carbon rates from rice straw (0.5, 1.0, 1.5 and 2.0 t C ha-1 including control) were evaluated under alternate wetting and drying (AWD) and continuous flooding (CF) systems. Each treatment also received the recommended dose of chemical fertilizers excluding control. Factorial experiment was laid out in a complete randomized design with three replications. Results revealed that, maximum plant height, filled grains per tiller, 1000 grains weight, grain and straw yield were also observed in continuous flooding system in combination with 2.0 t C ha-1 in 2010 and 2011, respectively. Combined use of chemical fertilizers, 2.0 t C ha-1 fresh rice straw and continuous flooding system performed better results to reduce CO2-C gas emission, increased organic carbon and rice production with maintaining optimum soil pH level. Continuous flooding with 2.0 t C ha-1 as fresh rice straw is an effective way to reduce CO2-C emission, optimize soil pH and contribute to sustainable rice production for food security.Jahangirnagar University J. Biol. Sci. 7(1): 45-53, 2018 (June)


2021 ◽  
Vol 24 ◽  
pp. e00367
Author(s):  
Patrick Filippi ◽  
Stephen R. Cattle ◽  
Matthew J. Pringle ◽  
Thomas F.A. Bishop

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.


PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245040
Author(s):  
Feng Zhang ◽  
Shihang Wang ◽  
Mingsong Zhao ◽  
Falv Qin ◽  
Xiaoyu Liu

Soil organic carbon content has a significant impact on soil fertility and grain yield, making it an important factor affecting agricultural production and food security. Dry farmland, the main type of cropland in China, has a lower soil organic carbon content than that of paddy soil, and it may have a significant carbon sequestration potential. Therefore, in this study we applied the CENTURY model to explore the temporal and spatial changes of soil organic carbon (SOC) in Jilin Province from 1985 to 2015. Dry farmland soil polygons were extracted from soil and land use layers (at the 1:1,000,000 scale). Spatial overlay analysis was also used to extract 1282 soil polygons from dry farmland. Modelled results for SOC dynamics in the dry farmland, in conjunction with those from the Yushu field-validation site, indicated a good level of performance. From 1985 to 2015, soil organic carbon density (SOCD) of dry farmland decreased from 34.36 Mg C ha−1 to 33.50 Mg C ha−1 in general, having a rate of deterioration of 0.03 Mg C ha−1 per year. Also, SOC loss was 4.89 Tg from dry farmland soils in the province, with a deterioration rate of 0.16 Tg C per year. 35.96% of the dry farmland its SOCD increased but 64.04% of the area released carbon. Moreover, SOC dynamics recorded significant differences between different soil groups. The method of coupling the CENTURY model with a detailed soil database can simulate temporal and spatial variations of SOC at a regional scale, and it can be used as a precise simulation method for dry farmland SOC dynamics.


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