scholarly journals Effects of short-term grazing prohibition on soil physical and chemical properties of meadows in Southwest China

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11598
Author(s):  
Guiqing Zhu ◽  
Chaoxiang Yuan ◽  
Hede Gong ◽  
Yanling Peng ◽  
Changjiang Huang ◽  
...  

Background Grassland plays an important role in the ecosystem, but overgrazing harms the grassland system in many places. Grazing prohibition is an effective method to restore grassland ecosystems, and it plays a great role in realizing the sustainable development of grassland systems. Therefore, it is necessary to carry out research on the influence of regional grazing prohibition on the physical and chemical properties of different grassland systems. Methods In Potatso National Park, Southwest China, we selected experimental plots in the artificial grazing meadow area to study the effects of grazing prohibition on plant and soil indexes in subalpine meadows and swamp meadows. We investigated the biomass and species diversity of grazing prohibition treatment and grazing treatment plots and sampled and tested the soil index. The variation percentage was used to remove the original heterogeneity and yearly variation, allowing us to compare differences in plant index and soil index values between grazing prohibition and grazing treatments. Results Grazing prohibition increased the aboveground biomass, total biomass, total meadow coverage, average height, richness index, Shannon diversity index and evenness index and reduced the belowground biomass and root/shoot ratio in the subalpine meadow and swamp meadow. Additionally, grazing prohibition reduced the pH and soil bulk density and increased the soil total carbon, soil organic carbon, soil total nitrogen, soil hydrolyzable nitrogen, soil total phosphorus and soil available phosphorus in the subalpine meadow and swamp meadow. Nonmetric multidimensional scaling (NMDS) analysis showed that both plant indexes and soil indexes were significantly different between grazing and grazing prohibition treatments and between meadow types. Short-term grazing prohibition had a great impact on improving the fertility of meadow soil in the study area. We suggest that long-term and extensive research should be carried out to promote the restoration and sustainable development of regional grassland systems.

2018 ◽  
Vol 44 ◽  
pp. 00197 ◽  
Author(s):  
Katarzyna Wystalska ◽  
Krystyna Malińska ◽  
Renata Włodarczyk ◽  
Olga Chajczyk

Pyrolysis of biomass residues from agriculture and food processing industry allows production of biochars with diverse physical and chemical properties for a wide range of applications in agriculture and environmental protection. Biochars produced from pelletized sunflower husks through slow pyrolysis in the range of temperatures (480–580°C) showed total carbon of 70.53%–81.96%, total nitrogen of 1.2%, alkaline pH (9.37–10.32), low surface area (0.93–2.91 m2 g-1) and porosity of 13.23–15.43%. Higher pyrolysis temperatures resulted in lower biochar yields. With the increase in temperature the content of organic matter, nitrogen, Ca and Mg decreased whereas the increase in temperature resulted in higher contents of total carbon and phosphorus. Produced biochars showed potential for agricultural applications.


2005 ◽  
Vol 15 (4) ◽  
pp. 752-757 ◽  
Author(s):  
Amanda Wiberg ◽  
Richard Koenig ◽  
Teresa Cerny-Koenig

Popular press articles report that consumers often experience inconsistent results with retail potting media; however, few reports in the popular or scientific literature have quantified the variability in media properties. The purpose of this study was to assess the variability in physical and chemical properties among different brands of retail potting media and within certain brands. Twenty-four different packages of branded media, and multiple packages of five brands, were acquired from nine regional and national retail chain stores located in the Salt Lake City, Utah, area. Samples were analyzed for five physical and nine chemical properties. The coefficients of variation (cvs) among brands for initial gravimetric water content, bulk density, porosity, water retention, and air space were 85%, 74%, 21%, 59%, and 44%, respectively. The cvs among brands for saturated media (SM) pH, SM extract electrical conductivity (EC), nitrate-nitrogen (NO3-N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), total carbon (C), total nitrogen (N), and C:N ratio were 18%, 81%, 132%, 153%, 96%, 78%, 71%, 36%, 45%, and 49%, respectively. Only one of the 24 brands met all published standards for chemical properties of premium media. Thirteen of the brands did not meet standards for NO3-N; 12 did not meet standards for pH; and six did not meet standards for EC. There was more variation in physical and chemical properties among brands than within a brand of media. Label information describing media composition was not consistent with certain physical and chemical properties. No recommendations can be made which would allow consumers to select media that meets published standards. These results indicate better awareness of and/or adherence to standards is needed by the retail media industry to improve product quality and consistency.


2012 ◽  
Vol 9 (75) ◽  
pp. 2450-2456 ◽  
Author(s):  
Ilaria Rea ◽  
Paola Giardina ◽  
Sara Longobardi ◽  
Fabrizio Porro ◽  
Valeria Casuscelli ◽  
...  

Hydrophobins are small proteins secreted by fungi, which self-assemble into amphipathic membranes at air–liquid or liquid–solid interfaces. The physical and chemical properties of some hydrophobins, both in solution and as a biofilm, are affected by poly or oligosaccharides. We have studied the interaction between glucose and the hydrophobin Vmh2 from Pleurotus ostreatus by spectroscopic ellipsometry (SE), atomic force microscopy (AFM) and water contact angle (WCA). We have found that Vmh2–glucose complexes forms a chemically stable biofilm, obtained by drop deposition on silicon, 1.6 nm thick and containing 35 per cent of glucose, quantified by SE. AFM highlighted the presence of nanometric rodlet-like aggregates (average height, width and length being equal to 3.6, 23.8 and 40 nm, respectively) on the biofilm surface, slightly different from those obtained in the absence of glucose (4.11, 23.9 and 64 nm). The wettability of a silicon surface, covered by the organic layer of Vmh2–glucose, strongly changed: WCA decreased from 90° down to 17°.


Author(s):  
A. Е. Аnikin ◽  
G. V. Galevsky ◽  
V. V. Rudneva

Results of studies of physical and chemical properties of rolling scale and dewatered sludge from gas-cleaning system of BOF plant quoted, carried out for estimation of technological advisability of application them in metallization processes. The studies carried out by application of standard methodics of determination of chemical, phase, grain-sized contents and density of fine and powder materials. It was determined, that content of total iron, FeO and Fe2O3oxides, Sulphur and Phosphor in the scale makes figures 73.3, 75.5, 20.9, 0.036 and 0.019 % correspondently, in the sludge – 41.2, 4.7, 53.7, 0.21 and 0.15 % correspondently. The sludge contains also up to 20.9% of CAO and 4.3% of total carbon. Grain-size contents of the scale and the sludge are considerably different: content of size grade +1.0 mm and –0.016 mm is in the scale 63.3% and 0%, in the sludge – 14.8 and 44.5 % correspondently. Real density of the scale is 4.6–4.9 g/sm3. The results obtained confirm a technological advisability of application of fine-grained scale and powdered sludge in metallization processes, including their preliminary briquetting comprising carbonic reduction agent.


2021 ◽  
Author(s):  
You-Xin Shen ◽  
Qing-he Wang ◽  
Zhi-Meng Zhao ◽  
Qiong-Fen Li ◽  
Sheng-Chun Bi

Abstract Purpose Rock outcrops (ROCs) are common structures in terrestrial ecosystems, especially in karst regions. However, their effects on adjacent soil patches and plants are rarely studied. In this study, the effects of ROCs on surrounding soils and plants were investigated. Methods Thirty isolated ROCs were randomly selected in a typical semi-humid karst grassland in Southwest China. Rainfall and ROC runoff were collected for chemical analyses. Soil physical and chemical properties and herb above- and belowground biomass were determined at 0 to 30, 31 to 60, 61 to 90, 91 to 190, and 191 to 290 cm from the ROC rock–soil interface. Results The pH and total organic carbon and Ca2+ contents were higher in ROC runoff than in rainfall. Some soil physical and chemical properties were significantly higher in samples at 0 to 30 cm, and above- and belowground plant biomass were both significantly higher from 0 to 30 cm and from 31 to 60 cm than at greater distances. The ROC effect zone, as estimated by logistic equation, was approximately 75 cm. When the area covered by an ROC was between 0.7 and 1.3 m2, herb biomass increased sharply from 0 to 30 cm and from 31 to 60 cm. Conclusions Karst ROCs affected soils and plants close to their bases, and the effects increased sharply when the area covered by an ROC was of intermediate size.


2017 ◽  
Vol 122 (11) ◽  
pp. 3098-3107 ◽  
Author(s):  
Lacey A. Pyle ◽  
Kate L. Magee ◽  
Morgan E. Gallagher ◽  
William C. Hockaday ◽  
Caroline A. Masiello

2021 ◽  
Author(s):  
Alex de Sousa Trindade ◽  
João Baptista Silva Ferraz ◽  
Daniel DeArmond

Abstract Generally, woody residues generated from logging remain on site, although recently, forest managers have been harvesting this material for energy generation. We evaluated the impact on an Oxisol’s physical and chemical properties after removal of residues (coarse woody debris, CWD) from logging-created gaps. The logging operations occurred on private timberland in the Central Amazon. Eighteen months after creation of the gaps, soil samples were taken up to 150 cm depth in each treatment: mature undisturbed forest (FOR), gaps with residues retained on site (RET), and gaps with removal of large branches greater than 10 cm in diameter that were from logging (REM). Clay content, up to 20 cm depth, was higher in RET and REM soils than in FOR soils. Soil bulk density values increased progressively from areas of FOR to RET and REM at 0–5 cm. The highest carbon and nutrient contents were observed in the 0–5 and 5–10 cm soil layers of RET. In the 10–30 cm depth, the contents of all nutrients, except phosphorus, were higher in REM soils. According to these short-term results, it is not possible to affirm categorically that the removal of CWD has a negative impact on the nutrient status of soils in gaps created by logging operations. Study Implications: This study aimed to investigate the influence of coarse woody debris removal for energy generation on soil nutrients in a logging area in the Amazonas state, Brazil. We compared three areas, one in which the residues were removed from the gaps, another where residues in gaps were retained, and one undisturbed natural forest as control. We found that coarse wood debris removal does not significantly change soil physical properties. On the other hand, removal accelerates leaching of nutrients to greater soil depths and leads to higher calcium contents in depths to 150 cm, although the soil phosphorus decreases after debris removal.


Author(s):  
Tengfei Yan ◽  
Kremenetska Oleksiivna ◽  
Songlin He ◽  
Biyang Zhang ◽  
Zelong Yu ◽  
...  

The impoundment of dams can significantly alter shorelines, hydrological regime, sediment and nutrient cycle. With the completion of Chushandian reservoir dam, land use types around the reservoir have been profoundly affected by flooding. As yet, the characteristics of soil properties on different land use types in new built reservoir have not been fully elaborated. In this work, we investigated the variation of soil physical and chemical properties at distance scale for different land use types after short-term inundating. Soil physical properties, chemical properties, soil particle structure were determined. This study reported that short-term inundating had impacts on soil physical and chemical properties of different land use types. Our results indicated that the soil physical and chemical properties at 0 m site of each land use types may be mainly affected by the nutrient status of overlying water. The soil TN, TC of all land use types decreased gradually with the increase of distance from river bank, among which the contents of TN and TC at W2 were significantly higher than those at other sites. Compared with woodland, both abandoned cropland and grass land showed the phenomenon of soil particle loss and nutrient leaching. The characteristics of low NH4-N and high NO3-N were observed in the woodland after flooding, which may be related to denitrification. The main influencing factor is soil microbial activity at W20. The main influencing factor is soil nutrient status At W2. And at abandoned cropland and grassland, the main influencing factor is soil physical properties. The response of different land use types to short-term flooding may be mainly related to the degree of vegetation coverage. Abandoned cropland showed stronger resilience, while grassland showed stronger tolerance. The present study suggested that early and timing restoration will be an effective way to repair the riparian habitat.


1966 ◽  
Vol 24 ◽  
pp. 101-110
Author(s):  
W. Iwanowska

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.


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