检索结果-南通市图书馆

Bioavailability of soil copper from Different Sources:Integrating chemical Approaches with Biological Indicators

在线全文

学校读者我要写书评

暂无评论

引用

Pedosphere 2014年第1期24卷 145-152页

作者： WANG Quan-Ying ZHOU Dong-Mei cANG Long Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of Sciences Key Laboratory of soil Environment and Pollution Remediation Institute of Soil ScienceChinese Academy of Sciences

Bioavailability is a key parameter in assessing contaminant transfer to biota. However, the input patterns and soil use types may impact the metal bioavailability. Several soil parameters were measured including chemical properties, such as pH, organic c, and cu solution/solid speciation, and biological properties, such as soil microbial biomass c （SMBc）, seed germination, and root elongation, to evaluate the bioavailability of cu contaminated soils from three different sources, i.e., non-ferrous metal mining, cu-based fungicides, and cu-smelting. The results revealed that free cu2＋ ion in soil solution and the ratios of cu fractions to total cu content in the solid phase could not be used to predict total cu content in soils. The indexes of seed germination and root elongation appeared not to be good biomonitors of cu contamination in soils, which were more sensitive to soil pH and soil organic carbon （SOc）. Relationships between SMBc and soil cu forms or the ratio of SMBc/SOc and soil cu forms showed that free cu2＋ ion and humie acid-complexed cu could significantly inhibit soil microbial activities. Our findings suggested that both metal chemical forms and biological bioassays should be considered as a complementary technique rather than an alternative to evaluate the metal bioavailability from different pollution sources.

关键词： cu contamination cu fractionation free cu2+ ion metal bioavailability soil microbial biomass c

soil Organic carbon Pools Under Switchgrass Grown as a Bioenergy crop compared to Other conventional crops

在线全文

学校读者我要写书评

暂无评论

引用

Pedosphere 2013年第4期23卷 409-416页

作者： F.G.DOU F.M.HONS W.R.OcUMPAUGH J.c.READ M.A.HUSSEY J.P.MUIR Texas A&M AgriLife Research &Extension center at Beaumont Department of soil and crop Sciences Texas A&M University Texas A&M AgriLife Research Station at Beeville Texas A&M AgriLife Research and Extension center at Dallas Texas A&M AgriLife Research and Extension center at Stephenville

Switchgrass （Panicum virgaturn L.） has been proposed as a sustainable bioenergy crop because of its high yield potential, adap- tation to marginal sites, and tolerance to water and nutrient limitations. A better understanding of the potential effects of biomass energy crop production practices on soil biological properties and organic matter dynamics is critical to its production. Our objective was to evaluate changes in c pools under a warm-season perennial switchgrass in different soils compared to typically-grown crops col- lected at college Station, Dallas, and Stephenville, TX in February 2001. Sampling depths were 0-5, 5-15, and 15-30 cm. Switchgrass increased soil organic c （SOc）, soil microbial biomass c （SMBc）, mineralizable c, and particulate organic matter c （POM-c） com- pared to conventional cropping systems. soil c concentrations were in the order： long-term coastal bermudagrass [cynodon dactylon （L.） Pers.] 〉 switchgrass or kleingrass （Panicum coloratura L.） planted in 1992 〉 switchgrass 1997 〉 conventional cropping systems. soil c concentrations tended to increase with increasing clay content. Greater microbial biomass c followed the order of Dallas 〉 college Station 〉 Stephenville, and ranged from approximately 180 mg c kg-1 soil at Stephenville to 1 900 mg c kg-1 soil at Dallas. Particulate organic c was more sensitive than other fractions to management, increasing as much as 6-fold under long-term coastal bermudagrass compared to conventional cropping systems. Our study indicated that conversion of conventional cropping systems into switchgrass production can sequestrate more SOc and improve soil biological properties in the southern USA.

关键词： cropping systems particulate organic c perennial grasses soil microbial biomass c soil mineralizable c

The Importance of Three Protozoa in corn Straw Decomposition and Nutrient Transformation

在线全文

学校读者我要写书评

暂无评论

引用

Agricultural Sciences in china 2003年第8期2卷 886-889页

作者： LIU Hai-ming, ZHAO Xiao-rong, LI Gui-tong and LIN Qi-mei(Department of soil and Water Sciences, china Agricultural University , Beijing 100094 , P. R. china) Department of soil and Water Sciences China Agricultural University Beijing 100094 P.R.China

Three typical soil protozoa of Bodo edax, colpoda cucullus and Amoeba proteus were inoculated into the soil amended with corn straw. The soils were then incubated at 25℃ for 60 days. It was found that the protozoa, particularly Bodo edax, significantly reduced soil microbial biomass c. However, the decomposition of corn straw was accelerated by the protozoa. colpoda cucullus significantly enhanced soil available P content, but Amoeba proteus decreased soil available P content. colpoda cucullus and Bodo edax did not obviously influence NH4+-N and NO3--N contents. In contrast, Amoeba proteus significantly increased both NH4+-N and NO3--N contents.

关键词： soil protozoa corn straw soil microbial biomass c