scholarly journals Changes in Soil C:N:P Stoichiometry and Microbial Structure along Soil Depth in Two Forest Soils

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 113 ◽  
Author(s):  
Lei Hu ◽  
Luji Ade ◽  
Xinwei Wu ◽  
Hongbiao Zi ◽  
Xueping Luo ◽  
...  

The effects of interactions of soil type and soil depth on soil C:N:P stoichiometry and microorganisms are poorly understood. In this study, soil samples (0–10, 10–20, 20–30, 30–50, 50–100 cm) were collected from two soil types (Haplic luvisols and Eutric cambisols) in Sabina przewalskii Kom. forest of Qinghai-Tibet Plateau. The soil C:N ratio and soil microbial biomass (SMB) measured using phospholipid fatty acid in Eutric cambisols were significantly higher than in Haplic luvisols, while soil C:P and N:P ratios were the opposite. In the two soil types, the soil C:N ratio significantly increased with soil depth, and the soil C:P and N:P ratios declined. Structural equation modelling (SEM) indicated that soil depth directly affected soil C, N and P contents. Soil type and soil depth could directly affect soil fungal and bacterial biomass, and indirectly affect both of them through soil bulk density. Meanwhile soil fungal biomass was influenced by soil depth through Total C. These results highlighted that the vertical distribution of soil bacteria could largely be attributed to changes of soil fungi depending on soil carbon resources.


OENO One ◽  
2006 ◽  
Vol 40 (4) ◽  
pp. 177 ◽  
Author(s):  
Jacques Coipel ◽  
Begoña Rodriguez Lovelle ◽  
Catherine Sipp ◽  
Cornelis Van Leeuwen

<p style="text-align: justify;">Among other elements of the natural environment, soil greatly influences vine behaviour and berry composition. Its influence is complex, because soil affects vine water and mineral uptake, as well as temperature in the root zone. In this research, investigations were undertaken to assess whether vine development and grape quality potentiel could be linked to specific soil types. 15 dry farmed plots planted with Vitis vinifera L. cv. Grenache noir were studied in 2000 on five soil types of the Southern Côtes du Rhône (France). No clear relationship could be established between soil type, vine growth, yield and berry composition. However, vine water and nitrogen status were related to soil depth. On shallow soils, vine water and nitrogen status were low, which resulted in early shoot growth cessation and moderate yield, as well as high berry sugar and anthocyanin content. Severe water stress is known for affecting negatively berry ripening. Nevertheless, although this study was carried out under dry, Mediterranean conditions, the grapes with the highest potential for making quality red wines were obtained on the soils with the lowest water holding capacity.</p>



Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 173
Author(s):  
Huiling Guan ◽  
Jiangwen Fan ◽  
Haiyan Zhang ◽  
Warwick Harris

Soil erosion is prevalent in karst areas, but few studies have compared the differences in the drivers for soil microbial communities among karst ecosystems with different soil depths, and most studies have focused on the local scale. To fill this research gap, we investigated the upper 20 cm soil layers of 10 shallow–soil depth (shallow–SDC, total soil depth less than 100 cm) and 11 deep–soil depth communities (deep–SDC, total soil depth more than 100 cm), covering a broad range of vegetation types, soils, and climates. The microbial community characteristics of both the shallow–SDC and deep–SDC soils were tested by phospholipid fatty acid (PLFAs) analysis, and the key drivers of the microbial communities were illustrated by forward selection and variance partitioning analysis. Our findings demonstrated that more abundant soil nutrients supported higher fungal PLFA in shallow–SDC than in deep–SDC (p < 0.05). Furthermore, stronger correlation between the microbial community and the plant–soil system was found in shallow–SDC: the pure plant effect explained the 43.2% of variance in microbial biomass and 57.8% of the variance in the ratio of Gram–positive bacteria to Gram–negative bacteria (G+/G−), and the ratio of fungi to total bacteria (F/B); the pure soil effect accounted for 68.6% variance in the microbial diversity. The ratio of microbial PLFA cyclopropyl to precursors (Cy/Pr) and the ratio of saturated PLFA to monounsaturated PLFA (S/M) as indicators of microbial stress were controlled by pH, but high pH was not conducive to microorganisms in this area. Meanwhile, Cy/Pr in all communities was >0.1, indicating that microorganisms were under environmental stress. Therefore, the further ecological restoration of degraded karst communities is needed to improve their microbial communities.



Author(s):  
Magdalena Banach-Szott ◽  
Bozena Debska ◽  
Erika Tobiasova

AbstractMany studies report organic carbon stabilization by clay minerals, but the effects of land use and soil type on the properties of humic acids (HAs) are missing. The aim of the paper is to determine the effects of land use and soil types on the characteristics of HAs, which have a considerable influence on organic matter quality. It was hypothesised that the effect of the land use on HAs properties depends on the particular size distribution. The research was performed in three ecosystems: agricultural, forest, and meadow, located in Slovakia. From each of them, the samples of 4 soil types were taken: Chernozem, Luvisol, Planosol, and Cambisol. The soil samples were assayed for the content of total organic carbon (TOC) and the particle size distribution. HAs were extracted with the Schnitzer method and analysed for the elemental composition, spectrometric parameters in the UV-VIS range, and hydrophilic and hydrophobic properties, and the infrared spectra were produced. The research results have shown that the properties of HAs can be modified by the land use and the scope and that the direction of changes depends on the soil type. The HAs of Chernozem and Luvisol in the agri-ecosystem were identified with a higher “degree of maturity”, as reflected by atomic ratios (H/C, O/C, O/H), absorbance coefficients, and the FT-IR spectra, as compared with the HAs of the meadow and forest ecosystem. However, as for the HAs of Cambisol, a higher “degree of maturity” was demonstrated for the meadow ecosystem, as compared with the HAs of the agri- and forest ecosystem. The present research has clearly identified that the content of clay is the factor determining the HAs properties. Soils with a higher content of the clay fraction contain HAs with a higher “degree of maturity”.



Author(s):  
Pujia Yu ◽  
Hailiang Xu ◽  
Shiwei Liu ◽  
Xinfeng Zhao ◽  
Qingqing Zhang ◽  
...  

During the past 20 years, great landscape changes took place in the northwest of China. Landscape change resulted in soil type transformations. This paper discusses the changes and fractal of soil types in oasis. In order to do it, the soil type maps of Manasi River Basin in 1987 and 2006 were used. 13 types of soil and 2 types of land-use were classified and analyzed in the study area. Results indicated many variations in characteristics. Firstly, all soil types underwent remarkable changes from 1987 to 2006 in the study area: the identified changed area was about 30% or 6506.33 km2. Secondly, in comparison with 1987, in 2006 2/3 of the area's soil types increased, while 1/3 decreased. Rapid expansion of Aquicambids (415.28 km2), and rapid decrease of Petrocambids (797.05 km2) and Aquisalids (415.93 km2) were the noticeable findings. Furthermore, Haplocambids obtained largest gains from other soil types, while Petrocambids lost largest area to other types. Additionally, the fractal relationship objectively existed between the perimeter and area of soil patches. The fractal dimension of Aquisalids, Petrocalcids and Ustifluvents became higher and their shapes became more complex during this period. The stability index was higher in 2006 which indicated that the spatial structure of soil type was more stable than in 1987. These chaotic and occasional changes were largely caused by human activities and natural conditions. Consequently, environmental managers should pay more attention to soil changes in the arid and semiarid region. Santrauka Per pastaruosius 20 metų šiaurės vakarų Kinijoje įvyko didelių kraštovaizdžio pokyčių, lėmusių ir dirvožemio tipų pakitimus. Remiantis 1987–2006 m. Manasi upės baseino dirvožemio žemėlapiais, aptariami dirvožemio tipų pokyčiai ir fraktalai oazėse. Pasirinktoje teritorijoje išskirta ir analizuota 13 dirvožemio tipų ir dvejopa žemėnauda. Nustatyta daug kintamųjų parametrų. Pirma, tirtõs teritorijos visų tipų dirvožemiai nuo 1987 iki 2006 m. žymiai pakito. Nustatytoji pokyčių zona apima apie 30 % teritorijos, arba 6 506,32 km2. Antra, palyginti su 1987 m., 2006 m. 10 dirvožemio tipų teritorija padidėjo, o 5 tipų sumažėjo. Sparčiai padidėjo Aquicambids (415,28 km2), sparčiai sumažėjo Petrocambids (797,05 km2) ir Aquisalids (415,93 km2), pokyčiai buvo žymūs. Iš visų kitų pakitusių dirvožemių tipų Haplocambids plotai padidėjo daugiausia, o labiausiai, palyginti su kitais, sumažėjo Petrocambids plotai. Be to, pastebėta, kad tarp dirvožemio teritorijos plotų ir perimetrų objektyviai egzistuoja fraktalinės sąsajos. Fraktalinės dimensijos Aquisalids, Petrocalcids ir Ustifluvents per minėtą laikotarpį padidėjo, o jų formos tapo sudėtingesnės. Stabilumo indeksas 2006 m. buvo didesnis. Tai rodė, kad erdvinė dirvožemio struktūra mažai pakito, tapo stabilesnė, palyginti nei buvo 1987 m. Šiuos atsitiktinius pokyčius iš esmės lėmė žmogaus veikla ir gamtinės sąlygos. Prieita prie išvados, kad sausojo ar pusiau sauso klimato regionuose kraštotvarkos vykdytojai dirvožemio pokyčiams turėtų skirti daugiau dėmesio.



Weed Science ◽  
1997 ◽  
Vol 45 (4) ◽  
pp. 564-567 ◽  
Author(s):  
Glen P. Murphy ◽  
David R. Shaw

Research was conducted in 1994 and 1995 to evaluate the field mobility of flumetsulam in three soils of varied texture and organic matter content but constant pH (pH = 6.0 ± 0.1). Flumetsulam was monitored to a depth of 122 cm at 28, 56, and 84 days after treatment (DAT). Flumetsulam concentrations were determined by cotton bioassay, with separate standard curves for various soil–depth combinations. Following a preemergence application of flumetsulam at 224 g ai ha−1, the herbicide was primarily limited to the upper 8 cm of soil, regardless of soil type, year, or DAT. Exceptions to this typically occurred following substantial rainfall amounts early in the season. Beyond 28 DAT, no significant concentrations of flumetsulam were detected below 15 cm. Results from this research suggest that leaching is not a significant route of flumetsulam dissipation in the field.



2013 ◽  
Vol 33 (5) ◽  
pp. 965-975 ◽  
Author(s):  
Aloisio Bianchini ◽  
Pedro H. de M. Borges

The destruction of the cotton crop residues (cotton stalks) is a mandatory procedure in Brazil for prophylactic issues, but is a subject unexplored by the research and there are few studies that deal with this issue. However, this is not encouraged in recent decades, studies aimed at developing and evaluating equipment for this purpose. The present study had the objective to evaluate six methods for mechanical destruction of cotton crop residues. Each method was defined based on the principle of operation of the active parts of the equipment, which were tested in medium texture soil and in a clayey one. The variables used to evaluate the efficiency of the equipment were the regrowth rate, the theoretical field capacity and energy demand. The equipment with convergent concave disks (DCC) and flat cutters discs from manufacturer A (CPS-a) showed the best results in cotton stalks destruction in both soil types. The harrow disc (GPD) was efficient only in clay soil. It was concluded that the equipment with convergent concave disks, among those tested, was the most efficient to destroy cotton stalks, regardless of soil type, and that the harrow disc was not included among the best performers.



1969 ◽  
Vol 30 (3) ◽  
pp. 127-137
Author(s):  
Luis A. Gómez ◽  
José Lería Esmoris ◽  
B. G. Capó

The results obtained in two coffee fertilizer tests performed with the Puerto Rican variety of Coffea arabica on "Catalina Clay" are presented, statistically analyzed, and discussed. Nitrogen and phosphoric acid applications seem to be of greater importance as regards market-coffee production of the above variety in the soil type used, than are the applications of potash, which had no significant effects on the yields. These results are in sharp contrast with the results obtained by McClelland, who found potash applications to be essential and phosphoric acid applications to be not essential for maximum coffee production in Puerto Rico. It should be noted that McClelland's experiments were carried out on other soil types, which were probably not in condition to provide the coffee trees with their potash requirements.



2018 ◽  
Vol 2 (5) ◽  
pp. 238 ◽  
Author(s):  
Davide Forcellini ◽  
Marco Tanganelli ◽  
Stefania Viti

The seismic excitation at the surface can be determined through Site Response Analyses (SRA) as to account for the specific soil properties of the site. However, the obtained results are largely affected by the model choice and setting, and by the depth of the considered soil layer. This paper proposes a refined 3D analytical approach, by the application of OPENSEES platform. A preliminary analysis has been performed to check the model adequacy as regards the mesh geometry and the boundary conditions. After the model setting, a SRA has been performed on various soil profiles, differing for the shear velocity and representing the different soil classes as proposed by the Eurocode 8 (EC8). Three levels of seismic hazard have been considered. The seismic input at the bedrock has been represented consequently, through as much ensembles of seven ground motions each, spectrum-compatible to the elastic spectra provided by EC8 for the soil-type A (bedrock). Special attention has been paid to the role of the considered soil depth on the evaluation of the surface seismic input. Different values of depth have been considered for each soil type and seismic intensity, in order to check its effect on the obtained results.



2016 ◽  
Author(s):  
Matheus Henrique Nunes ◽  
Matthew P. Davey ◽  
David Anthony Coomes

Abstract. Understanding the causes of variation in plant functional traits is a central issue in ecology, particularly in the context of global change. Analyses of the drivers of traits variation based on thousands of tree species are starting to unravel patterns of variation at the global scale, but these studies tend to focus on interspecific variation, and the contribution of intraspecific changes remains less well understood. Hyperspectroscopy is a recently developed technology for estimating the traits of fresh leaves. Few studies have evaluated its potential for assessing inter- and intra-specific trait variability in community ecology. Working with 24 leaf traits for European tree species on contrasting soil types, found growing on deep alluvial soils and nearby shallow chalk soils, we ask: (i) What contribution do soil type and species identity make to trait variation? (ii) When traits are clustered into three functional groups (light capture and growth, leaf structure and defence, as well as rock-derived nutrients), are some groups more affected by soil than others? (iii) What traits can be estimated precisely using field spectroscopy? (iv) Can leaf spectra be used to detect inter-soil as well as inter-specific variation in traits? The contribution of species and soil-type effects to variation in traits were evaluated using statistical analyses. Foliar traits were predicted from spectral reflectance using partial least square regression, and so inter- and intra-specific variation. Most leaf traits varied greatly among species. The effects of soil type were generally weak by comparison. Macronutrient concentrations were greater on alluvial than chalk soils while micronutrient concentration showed the opposite trend. However, structural traits, as well as most pigments and phenolic concentrations varied little with soil type. Field spectroscopy provided accurate estimates of species-level trait values, but was less effective at detecting subtle variation of rock-derived nutrients between soil types. Field spectroscopy was a powerful technique for estimating cross-species variation in foliar traits and Si predictions using spectroscopy appear to be promising. However, it was unable to detect subtle within-species variation of traits associated with soil type.



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