scholarly journals Organic carbon content and its liable components in paddy soil under water-saving irrigation  

2017 ◽  
Vol 63 (No. 3) ◽  
pp. 125-130 ◽  
Author(s):  
Ma Yan ◽  
Xu Junzeng ◽  
Wei Qi ◽  
Yang Shihong ◽  
Liao Linxian ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Microbial Biomass ◽  
Microbial Biomass Carbon ◽  
Soil Microbial Activity ◽  
Water Saving ◽  
Organic Carbon Content ◽  
Soil Microbial ◽  
Water Extractable Organic Carbon ◽  
Aeration Conditions ◽  
Water Extractable

Variation of soil organic carbon (SOC) and its liable fractions under non-flooding irrigation (NFI) were investigated. In NFI paddies, the soil microbial biomass carbon (SMBC) and water extractable organic carbon (SWEC) content in 0–40 cm soil increased by 1.73–21.74% and 1.44–30.63%, and SOC in NFI fields decreased by 0.90–18.14% than in flooding irrigation (FI) fields. As a result, the proportion of SMBC or SWEC to SOC increased remarkably. It is attributed to the different water and aeration conditions between FI and NFI irrigation. The non-flooding water-saving irrigation increased soil microbial activity and mineralization of SOC, which broke down more soil organic nutrients into soluble proportion and is beneficial for soil fertility, but might lead to more CO<sub>2</sub> emission and degradation in carbon sequestration than FI paddies.  

scholarly journals Soil Aggregation and Organic Carbon Dynamics in Poplar Plantations

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 508 ◽  
Author(s):  
Zhiwei Ge ◽  
Shuiyuan Fang ◽  
Han Chen ◽  
Rongwei Zhu ◽  
Sili Peng ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Microbial Biomass ◽  
Fine Root ◽  
Microbial Biomass Carbon ◽  
Critical Role ◽  
Stand Age ◽  
Biomass Carbon ◽  
Soil Microbial ◽  
Soil Microbial Biomass Carbon

Soil resident water-stable macroaggregates (diameter (Ø) > 0.25 mm) play a critical role in organic carbon conservation and fertility. However, limited studies have investigated the direct effects of stand development on soil aggregation and its associated mechanisms. Here, we examined the dynamics of soil organic carbon, water-stable macroaggregates, litterfall production, fine-root (Ø < 1 mm) biomass, and soil microbial biomass carbon with stand development in poplar plantations (Populus deltoides L. ‘35’) in Eastern Coastal China, using an age sequence (i.e., five, nine, and 16 years since plantation establishment). We found that the quantity of water-stable macroaggregates and organic carbon content in topsoil (0–10 cm depth) increased significantly with stand age. With increasing stand age, annual aboveground litterfall production did not differ, while fine-root biomass sampled in June, August, and October increased. Further, microbial biomass carbon in the soil increased in June but decreased when sampled in October. Ridge regression analysis revealed that the weighted percentage of small (0.25 mm ≤ Ø < 2 mm) increased with soil microbial biomass carbon, while that of large aggregates (Ø ≥ 2 mm) increased with fine-root biomass as well as microbial biomass carbon. Our results reveal that soil microbial biomass carbon plays a critical role in the formation of both small and large aggregates, while fine roots enhance the formation of large aggregates.

scholarly journals Ratio of soil microbial biomass carbon to soil organic carbon in Himalayan rangeland

2018 ◽  
Vol 2 ◽  
pp. 96-101
Author(s):  
Dil Kumar Limbu ◽  
Madan Koirala
Keyword(s):  
Organic Matter ◽  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Microbial Biomass ◽  
Microbial Biomass Carbon ◽  
Biomass Carbon ◽  
Soil Microbial ◽  
Soil Microbial Biomass Carbon ◽  
Microbial Carbon

The soil microbial biomass carbon to soil organic carbon ratio is a useful measure to monitor soil organic matter and serves as a sensitive index than soil organic carbon alone. Thus, the objective of this study is to identify and quantify the present status of ratio of soil microbial biomass carbon to soil organic carbon in Himalayan rangeland and to make recommendations for enhancing balance between microbial carbon and organic carbon of the soil. To meet the aforementioned objective, a field study was conducted from 2011 to 2013 following the Walkley-Black, Chromic acid wet oxidation method, and chloroform fumigation method for analysis of microbial carbon and organic carbon respectively. The study showed that the heavily grazed plot had significantly less value of ratio than occasionally grazed and ungrazed plots. The ratio was significantly high on legume seeding plot compared to nonlegume plot, but the ratio was independent of soil depth. Soil microbial biomass appeared to be more responsive than soil organic matter.

Seasonal Dynamics of Soil Microorganism in Zhalong Reed Wetland

2011 ◽  
Vol 71-78 ◽  
pp. 2992-2998
Author(s):  
Ling Ma ◽  
Sheng Nan Liu ◽  
Xin Hua Ding ◽  
Wei Ma
Keyword(s):  
Microbial Biomass ◽  
Seasonal Dynamics ◽  
Soil Microbial Biomass ◽  
Soil Microbes ◽  
Microbial Biomass Carbon ◽  
Organic Carbon Content ◽  
Biomass Carbon ◽  
Carbon And Nitrogen ◽  
Soil Microbial ◽  
Soil Microbial Biomass Carbon

In this paper, the spatial distributions and seasonal dynamics of soil microbes and microbial biomass were investigated in a typical reed marsh in Zhalong natural wetlands.We wanted to explore the main factors that impacted their spatio-temporal patterns. The results showed that: Bacteria were dominant, followed by actinomyces and fungi were at least in the soil microbes community. The seasonal dynamics of soil microbial biomass carbon and nitrogen were more regularly, and their change patterns were significantly as "W" types. The response of soil microbial biomass in Bottom (10-30cm) to time was slower than the surface, and it fluctuated tinily in every months. The correlation analysis shows that the soil nutrient and soil microbial activity had close relationship. Soil microbial biomass carbon and nitrogen were all significantly positively correlated to quantities of fungus, organic carbon content and Alkali-hytrolyzabel N content(P<0.01), but negative extremely significantly correlated with pH (P<0.01).

scholarly journals Short term changes of microbial processes in Icelandic soils to increasing temperatures

2010 ◽  
Vol 7 (2) ◽  
pp. 671-682 ◽  
Author(s):  
R. Guicharnaud ◽  
O. Arnalds ◽  
G. I. Paton
Keyword(s):  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Temperature ◽  
Temperature Regime ◽  
Soil Microbial Biomass ◽  
Microbial Biomass Carbon ◽  
Biomass Carbon ◽  
Labile Carbon ◽  
Short Term ◽  
Soil Microbial

Abstract. Temperature change is acknowledged to have a significant effect on soil biological processes and the corresponding sequestration of carbon and cycling of nutrients. Soils at high latitudes are likely to be particularly impacted by increases in temperature. Icelandic soils experience unusually frequent freeze and thaw cycles compare to other Arctic regions, which are increasing due to a warming climate. As a consequence these soils are frequently affected by short term temperature fluctuations. In this study, the short term response of a range of soil microbial parameters (respiration, nutrient availability, microbial biomass carbon, arylphosphatase and dehydrogenase activity) to temperature changes was measured in sub-arctic soils collected from across Iceland. Sample sites reflected two soil temperature regimes (cryic and frigid) and two land uses (pasture and arable). The soils were sampled from the field frozen, equilibrated at −20 °C and then incubated for two weeks at −10 °C, −2 °C, +2 °C and +10 °. Respiration and enzymatic activity were temperature dependent. The soil temperature regime affected the soil microbial biomass carbon sensitivity to temperatures. When soils where sampled from the cryic temperature regime a decreasing soil microbial biomass was detected when temperatures rose above the freezing point. Frigid soils, sampled from milder climatic conditions, where unaffected by difference in temperatures. Nitrogen mineralisation did not change with temperature. At −10 °C, dissolved organic carbon accounted for 88% of the fraction of labile carbon which was significantly greater than that recorded at +10 °C when dissolved organic carbon accounted for as low as 42% of the labile carbon fraction.

Effects of Different Applying Fertilization Patterns on Soil Microorganisms, Organic Carbon and Respiration Flux in Maize Grown under Ridge Cultivation

2012 ◽  
Vol 518-523 ◽  
pp. 4701-4706
Author(s):  
Yun Xian Dai ◽  
Jing Hui Liu ◽  
Li Jun Li ◽  
Aodungerile Chen ◽  
Li Gang Wang ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Respiration ◽  
Carbon Content ◽  
Soil Microbial Biomass ◽  
Organic Fertilizer ◽  
Total Biomass ◽  
Organic Carbon Content ◽  
Soil Microbial ◽  
Organic Carbon Concentration

The effects of three different fertilization patterns including single chemical fertilizer(DH), chemical-organic fertilizer(HY), and single organic fertilizer (DY),no fertilizer(CK) on soil microbial biomass, soil organic carbon content, yield and soil respiration flux in ridge cultivation maize fields in the West Liaohe region were studied. The results showed that soil microbial biomass, organic carbon content, yield and soil respiration flux under HY were higher than the rest of other treatments in 2005 and 2006. The varying order of soil microbial total biomass performed as HY>DY>DH>CK on the ridge-tillage maize farmland. The soil total nitrogen concentration, organic carbon concentration and respiration of HY were significantly higher than the rest of other treatments (p HY> DH > CK; the order of biological yield was DH>HY>DY> CK; the order of grain yield was HY>DH>DY> CK and the economic coefficient of HY was the highest in both years.

scholarly journals Impact of transgenic cottons expressing cry1Ac on soil biological attributes

2013 ◽  
Vol 59 (No. 3) ◽  
pp. 108-114 ◽  
Author(s):  
K. Velmourougane ◽  
A. Sahu
Keyword(s):  
Soil Microbial Biomass ◽  
Microbial Biomass Carbon ◽  
Soil Depth ◽  
Diversity Indices ◽  
Soil Microbial Activity ◽  
Bt Cotton ◽  
Available N ◽  
Cry1ac Gene ◽  
Soil Microbial ◽  
Biological Attributes

Three transgenic Bt cotton hybrids (RCH-2 Bt, Bunny Bt and NHH 44 Bt) expressing cry1Ac gene were evaluated for their effects on soil biological, microbiological and diversity attributes at 0&ndash;15 cm and 15&ndash;30 cm soil depth under field conditions. At both soil depths, soil respiration rate and fluorescein diacetate hydrolysis were the highest in the soil under Bt cotton grown followed by non-Bt soil, and by the control bulk soil, indicating no adverse effects of Bt cotton on soil microbial activity. Urease and dehydrogenase activities, reflecting potentially available N and the oxidative metabolism in soil, respectively, also increased in the sequence no-crop variant &lt; non-Bt soil &lt; soil under Bt cotton at both soil depths. A similar trend was found with the soil microbial biomass carbon, microbial population and microbial diversity indices. These results suggest that cultivation of Bt cotton expressing cry1Ac gene may not pose ecological or environmental risk.

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