scholarly journals Influence of slope aspect on the microbial properties of rhizospheric and non-rhizospheric soils on the Loess Plateau, China

Solid Earth ◽  
2018 ◽  
Vol 9 (5) ◽  
pp. 1157-1168 ◽  
Author(s):  
Ze Min Ai ◽  
Jiao Yang Zhang ◽  
Hong Fei Liu ◽  
Sha Xue ◽  
Guo Bin Liu

Abstract. Slope aspect is an important topographic factor in the micro-ecosystem environment, but its effect on the microbial properties of grassland rhizospheric soil (RS) and non-rhizospheric soil (NRS) remain unclear. A field experiment was conducted at the Ansai Research Station on the Loess Plateau in China to test the influence of slope aspects (south-facing, north-facing, and northwest-facing slopes, all with Artemisia sacrorum as the dominant species) on RS and NRS microbial biomass carbon (MBC) contents, phospholipid fatty acid (PLFA) contents, and the rhizospheric effect (RE) of various microbial indices. Soil samples were collected from the three slope aspects, including rhizospheric and non-rhizospheric region, and analyzed to determine the various related microbial indices. The results showed that MBC content differed significantly among the slope aspects in RS but not in NRS, and the RE for MBC content in the south-facing slope was larger than that in the north-facing slope. RS total, bacterial, and Gram-positive bacterial PLFA contents in the south-facing slope were significantly lower than those in the north- and northwest-facing slopes, and RS Gram-negative bacterial (G−) and actinomycete PLFA contents in the south-facing slope were significantly lower than those in the north-facing slope. In contrast, NRS total, bacterial, and G− PLFA contents in the north-facing slope were significantly higher than those in the south- and northwest-facing slopes, and NRS fungal and actinomycete PLFA contents in the north- and south-facing slopes were significantly higher than those in the northwest-facing slope. RE for all PLFA contents except fungal in the northwest-facing slope were higher than those in the south-facing slope. Slope aspect significantly but differentially affected the microbial properties in RS and NRS, and the variable influence was due to an evident RE for most microbial properties.

2018 ◽  
Author(s):  
Ze Min Ai ◽  
Jiao Yang Zhang ◽  
Hong Fei Liu ◽  
Sha Xue ◽  
Guo Bin Liu

Abstract. Slope aspect is an important topographic factor, but its effect on the microbial properties of grassland rhizospheric soil (RS) and non-rhizospheric soil (NRS) remain unclear. A field experiment was conducted at the Ansai Research Station on the Loess Plateau in China to test the influence of slope aspects (south-facing, north-facing, and northeast-facing slopes, all with Artemisia sacrorum as the dominant species) on RS and NRS microbial biomass carbon (MBC) and phospholipid fatty acid (PLFA) contents, and the rhizospheric effect (RE) of various microbial indices. MBC content differed significantly among the slope aspects in RS but not in NRS, and RE for MBC content in the south-facing slope was larger than that in the north-facing slope. RS total, bacterial, and gram-positive bacterial PLFA contents in the south-facing slope were significantly lower than those in the north- and northeast-facing slopes, and RS gram-negative bacterial (G-) and actinomycete PLFA contents in the south-facing slope were significantly lower than those in the north-facing slope. Differently, NRS total, bacterial, and G- PLFA contents in the north-facing slope were significantly higher than those in the south- and northeast-facing slopes, and NRS fungal and actinomycete PLFA contents in the north- and south-facing slopes were significantly higher than those in the northeast-facing slope. RE for all PLFA contents except fungal in the northeast-facing slope were higher than those in the south-facing slope. Slope aspect significantly but differentially affected the microbial properties in RS and NRS, and the variable influence was due an evident RE for most microbial properties.


2011 ◽  
Vol 356-360 ◽  
pp. 2422-2429 ◽  
Author(s):  
Chao Zhang ◽  
Sha Xue ◽  
Guo Bin Liu ◽  
Chang Sheng Zhang

Abandoning cropland to enable recovery of the natural vegetation has been implemented during the past decade to restore the soil quality in the Loess Plateau, China. However, natural succession on cropland in the different slope aspect is different. The present study aimed at investigating the change in soil chemical and microbial properties abandoned farmland across time, and also to compare the difference of soil chemical and microbial properties in north slope and south slope on the Loess Plateau. The results showed that the slope aspect greatly affected the soil chemical and microbial properties after the cropland was abandoned, this could be attributed to the different precipitation and temperature in the two slopes. Compared with the north slope in which the organic C, total N and available N increased with the increase of abandonment years, that of south slope fluctuated significantly. Microbial biomass C and microbial biomass N in both slopes did not differ significantly in the first 10 years abandoned cropland, then decreased drastically in 15-year sites and thereafter tended to increase. Basal respiration in both slope fluctuated greatly in the sites with different abandonment years. Enzymes activities differed significantly in two slopes.


Clay Minerals ◽  
2007 ◽  
Vol 42 (3) ◽  
pp. 373-398 ◽  
Author(s):  
M. Egli ◽  
A. Mirabella ◽  
G. Sartori ◽  
D. Giaccai ◽  
R. Zanelli ◽  
...  

AbstractTwo soil profile sequences on paragneiss debris in the Val di Rabbi (Northern Italy) along an altitude gradient ranging from 1200 to 2400 m a.s.l. were studied to evaluate the effect of aspect on the weathering of clay minerals. All the soils had a coarse structure, a sandy texture and a low pH. Greater weathering intensities of clay-sized phyllosilicates (greater content of smectites) were observed in soils on the north-facing slope. On the south-facing slope, smectite was found only in the surface horizon of the soil profile at the highest altitude. Hot citrate treatment of north-facing soils revealed the presence of low-charged 2:1 clay minerals, the expansion of which was hindered in the untreated state by interlayered polymers. However, the hot citrate treatment encountered some problems with the samples of the south-facing soils: as confirmed by Fourier transform infrared spectroscopy, the hot citrate treatment was unable to remove all interlayer Al polymers. The 2:1 phyllosilicates were not expanded by ethylene glycol solvation in several samples, although thermogravimetric analyses indicated the presence of clay minerals with interlayer H2O. At the same time, the collapse of clay minerals to 1.0 nm following K-saturation was evident. Theoretically, this should indicate that 2:1 phyllosilicates had no evident substitution of trioctahedral cations (Mg2+, Fe2+) by dioctahedral cations (Al3+ and Fe3+). X-ray diffraction analysis of the d060 region and determination of the layer charge of clay minerals by the long-chain (C18) alkylammonium ion, however, did not confirm this. A transformation from trioctahedral to dioctahedral species was observed and low-charge clay minerals (ξ ~0.30) were identified in the surface horizons of the south-facing sites. In the south-facing soils, the podzolization process was less pronounced because of a lower water flux through the soil and probably less complexing organic molecules that would remove the interlayer polymers. Besides the eluviation process, clay minerals underwent a process of ionic substitutions in the octahedral sheet that led to the reduction of the layer charge. This process was more obvious in the north-facing sites.


Author(s):  
Edward Derbyshire

High Asia, defined here as that great tract of land from the Himalaya- Karakoram in the south to the Tian Shan in the north and the Pamir in the west to the Qinling Mountains in the east, is a very dusty place. Whole communities of people in this region are exposed to the adverse effects of natural (aerosolic) dusts at exposure levels reaching those encountered in some high-risk industries. Outdooor workers are at particular risk. However, few data are available on the magnitude of the dust impact on human health. The effect of such far-travelled particles on the health of the human population in the Loess Plateau, and including major Chinese cities, has received relatively little attention to date. A combination of the highest known uplift rates, rapid river incision (up to 12 mm/yr: Burbank et al. 1996), unstable slopes, glaciation and widespread rock breakup by crystal growth during freezing (frost action), and by hydration of salts (salt weathering) makes the High Asia region the world’s most efficient producer of silty (defined as between 2 and 63 μm) debris. The earliest written records of the dust hazard come from China, most notably in the “Yu Gong” by Gu Ban (ca 200 BC) (Wang and Song 1983). Here, deposits of wind-blown silt (known as ‘loess’) cover the landscape in a drape that is locally 500 m thick. In North China, the loess covers an area of over 600,000 km², most of it in the Loess Plateau, situated in the middle reaches of the Huang He (Yellow River). The characteristic properties of loess include high porosity and collapsibility on wetting (Derbyshire et al. 1995, Derbyshire and Meng 2000).Thus, it is readily reworked and redistributed by water. This process concentrates silts in large alluvial fans (up to 50 x 50 km) in the piedmont zones of 6,000 m high glacier- and snow-covered mountain ranges of western China, including the Altai Shan (‘shan’ = mountains), Tian Shan, Kunlun Shan, Qilian Shan, and Karakoram. These zones are loci for human populations, and also a major source of wind-blown dust.


2016 ◽  
Vol 36 (21) ◽  
Author(s):  
朱云云 ZHU Yunyun ◽  
王孝安 WANG Xiao'an ◽  
王贤 WANG Xian ◽  
邓美皎 DENG Meijiao

2002 ◽  
Vol 36 (26) ◽  
pp. 4189-4199 ◽  
Author(s):  
Xiao Y Zhang ◽  
J.J Cao ◽  
L.M Li ◽  
R Arimoto ◽  
Y Cheng ◽  
...  

CATENA ◽  
2011 ◽  
Vol 87 (1) ◽  
pp. 90-100 ◽  
Author(s):  
Li Wang ◽  
Sanping Wei ◽  
Robert Horton ◽  
Ming'an Shao

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhiqi Wang ◽  
Xiaobo Feng ◽  
Zhihong Yao ◽  
Zhaolong Ma ◽  
Guodong Ji

Soil moisture is a crucial factor limiting the growth and survival of plants on the Loess Plateau. Its level has a severe impact on plants’ growth and development and the type and distribution characteristics of communities. This study area is the Jihe Basin in the Loess Plateau, China. Multiple linear regression models with different environmental variables (land use, topographic and meteorological factors, etc.) were developed to simulate soil moisture’s spatial and temporal changes by integrating field experiments, indoor analysis, and GIS spatial analysis. The model performances were evaluated in the Jihe Basin, with soil moisture content measurements. The result shows that soil moisture content is positively correlated with soil bulk density, monthly rainfall, topographic wetness index, land use coefficient, and slope aspect coefficient but negatively correlated with the monthly-averaged temperature and the relative elevation coefficient. The selected variables are all related to the soil moisture content and can account for 75% of the variations of soil moisture content, and the remaining 25% of the variations are related to other factors. Comparing the simulated and measured values at all sampling points shows that the average error of all the simulated values is 0.09, indicating that the simulation has high accuracy. The spatial distribution of soil moisture content is significantly affected by land use and topographic factors, and seasonal variation is remarkable in the year. Seasonal variation of soil moisture content is determined by the seasonal variation of rainfall and the air temperature (determining evaporation) and vegetation growth cycle. Therefore, the proposed model can simulate the spatial and temporal variation of soil moisture content and support developing the soil and water loss model on a basin scale.


Sign in / Sign up

Export Citation Format

Share Document