scholarly journals Soil properties across a chronosequence of Ailanthus altissima in semiarid plantations

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Hamed Aghajani
Keyword(s):  
Soil Properties ◽  
Soil Quality ◽  
Large Scale ◽  
Management Practice ◽  
Main Tool ◽  
Total Carbon ◽  
Stand Age ◽  
Ailanthus Altissima ◽  
Forest Park ◽  
Almost All

Afforestation is a main tool for preventing desertification and soil erosion in arid and semiarid regions of Iran. Large-scale afforestation, however, has poorly understood consequences for the future ecosystems in the term of ecosystems protection. The objective of the present study is to identify changes in soil properties following different intervals of planting of Ailanthus altissima (tree of heaven) in semiarid afforestation of Iran (Chitgar Forest Park, Tehran). For this purpose, sand, silt and clay ratios, bulk density, soil moisture, pH, electrical conductivity, phosphorus, potassium, magnesium, calcium, sodium, total soil N, and total carbon was measured. Our study highlighted the potential of the invasive trees by A. altissima, to alter soil properties along chronosequence. Almost all soil quality attributes showed a declining trend with stand age. A continuous decline in soil quality indicated that the present land management may not be sustainable. Therefore, an improved management practice is imperative to sustain soil quality and maintain long-term productivity of plantation forests. Thinning activity will be required to reduce the number of trees competing for the same nutrients especially in a older stand to protect forest soils.

A comparison of indexing methods to evaluate quality of horticultural soils. Part II. sensitivity of soil microbiological indicators

Soil Research ◽  
2014 ◽  
Vol 52 (4) ◽  
pp. 409 ◽  
Author(s):  
Romina Romaniuk ◽  
Lidia Giuffré ◽  
Alejandro Costantini ◽  
Norberto Bartoloni ◽  
Paolo Nannipieri
Keyword(s):  
Soil Properties ◽  
Soil Quality ◽  
Quality Indicators ◽  
Production Systems ◽  
Management Practice ◽  
Great Influence ◽  
Organic Amendments ◽  
Biological Indicators ◽  
Biological Properties ◽  
Microbiological Indicators

Soil is a non-renewable natural resource, considered as the basis for food production. Changes in soil properties may indicate potentially beneficial or degradative effects of a given management practice, so it is important to select the most sensitive soil properties to act as quality indicators. This research evaluated different approaches to selecting soil quality indicators in the construction of soil quality indices (SQIs). The sensitivity of integrative SQIs, constructed by considering diverse chemical, physical, and biological properties, was compared with biological SQIs, using only biochemical and microbiological indicators, to assess soil quality in an intensive horticultural production system under short- and long-term organic and conventional management. The results provided by the SQIs showed that plots under organic management had increase soil quality compared with the conventionally managed plots, independent of the number of years under production. The SQIs integrated by physical, chemical and biological indicators were more sensitive than indices composed only of biological indicators, as they did not reflect the physical properties of the studied plots. The organic amendments had a great influence on the microbial community; therefore, microbiological indices could not provide reliable information on soil quality in production systems with high inputs of organic materials.

scholarly journals Determining the effects of the forest stand age on the soil quality index in afforested areas: A case study in the Palandöken Mountains

2021 ◽  
Author(s):  
Emre Çomaklı ◽  
Bülent Turgut
Keyword(s):  
Soil Quality ◽  
Quality Index ◽  
Aggregate Stability ◽  
Principal Component ◽  
Erosion Control ◽  
Soil Samples ◽  
Total Carbon ◽  
Stand Age ◽  
Soil Quality Index ◽  
Score Functions

Afforestation is an essential strategy for erosion control. The objective of this study was to determine the soil quality index (SQI) in established afforested areas of different ages for erosion control in Erzurum, Turkey. Three afforested areas were selected as plots considering their establishment periods: + 40 years old (AA<sub>&gt;40</sub>), 10–40 years old (AA<sub>10–40</sub>), and less than 10 years old (AA<sub>&lt;10</sub>). Forty soil samples were taken in each plot area over the 0–15 and 15–30 cm depths. The soil samples were analysed for the texture, mean weight diameter, aggregate stability, pH, electrical conductivity, total nitrogen, total carbon, and total sulfur contents. These properties were used as the soil quality indicators, whereby the analytic hierarchy process (AHP) and principal component analysis (PCA) were used to establish their relative importance for describing the soil quality. The indicators were scored using the linear score functions of “more is better” and “optimum value”. For determining the SQI, the additive method (SQI<sub>A</sub>), the weighted method with AHP (SQI<sub>AHP</sub>), and the weighted method with PCA (SQI<sub>PCA</sub>) were used. The SQI scores of the plots showed statistically significant differences. In all three methods, the highest SQI value was obtained from the AA<sub>&gt;40</sub> plots.

scholarly journals Retrieving Forest Canopy Elements Clumping Index Using ICESat GLAS Lidar Data

2021 ◽  
Vol 13 (5) ◽  
pp. 948
Author(s):  
Lei Cui ◽  
Ziti Jiao ◽  
Kaiguang Zhao ◽  
Mei Sun ◽  
Yadong Dong ◽  
...  
Keyword(s):  
Large Scale ◽  
Forest Canopy ◽  
Remote Sensing Data ◽  
Alternative Methods ◽  
High Signal ◽  
Laser Altimeter ◽  
Waveform Data ◽  
Forest Park ◽  
Clumping Index ◽  
The Impact

Clumping index (CI) is a canopy structural variable important for modeling the terrestrial biosphere, but its retrieval from remote sensing data remains one of the least reliable. The majority of regional or global CI products available so far were generated from multiangle optical reflectance data. However, these reflectance-based estimates have well-known limitations, such as the mere use of a linear relationship between the normalized difference hotspot and darkspot (NDHD) and CI, uncertainties in bidirectional reflectance distribution function (BRDF) models used to calculate the NDHD, and coarse spatial resolutions (e.g., hundreds of meters to several kilometers). To remedy these limitations and develop alternative methods for large-scale CI mapping, here we explored the use of spaceborne lidar—the Geoscience Laser Altimeter System (GLAS)—and proposed a semi-physical algorithm to estimate CI at the footprint level. Our algorithm was formulated to leverage the full vertical canopy profile information of the GLAS full-waveform data; it converted raw waveforms to forest canopy gap distributions and gap fractions of random canopies, which was used to estimate CI based on the radiative transfer theory and a revised Beer–Lambert model. We tested our algorithm over two areas in China—the Saihanba National Forest Park and Heilongjiang Province—and assessed its relative accuracies against field-measured CI and MODIS CI products. We found that reliable estimation of CI was possible only for GLAS waveforms with high signal-to-noise ratios (e.g., >65) and at gentle slopes (e.g., <12°). Our GLAS-based CI estimates for high-quality waveforms compared well to field-based CI (i.e., R2 = 0.72, RMSE = 0.07, and bias = 0.02), but they showed less correlation to MODIS CI (e.g., R2 = 0.26, RMSE = 0.12, and bias = 0.04). The difference highlights the impact of the scale effect in conducting comparisons of products with huge differences resolution. Overall, our analyses represent the first attempt to use spaceborne lidar to retrieve high-resolution forest CI and our algorithm holds promise for mapping CI globally.

scholarly journals Impact of Sustainable Land Management Practices on Soil Properties: Example of Organic and Integrated Agricultural Management

Land ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 8
Author(s):  
Rok Mihelič ◽  
Jure Pečnik ◽  
Matjaž Glavan ◽  
Marina Pintar
Keyword(s):  
Soil Properties ◽  
Soil Quality ◽  
Management Practices ◽  
Visual Assessment ◽  
Agricultural Management ◽  
Vegetable Production ◽  
Modified Method ◽  
Food And Agriculture ◽  
River Terraces ◽  
Food And Agriculture Organization

Maintaining good soil quality is crucial for the sustainability of agriculture. This study aimed to evaluate the effectiveness of the visual soil assessment (VSA) method by testing it on two soil types and two agricultural management practices (AMP) (organic and integrated) that are considered to protect soil quality. We selected two farms with plots on two river terraces with different soil properties. The test was based on the modified method Annual Crops Visual Quality Assessment developed by the Food and Agriculture Organization of the United Nations and supported by a standardized soil physical and chemical analysis. This study showed that the assessed score is highly dependent on the type of farming practice and how soils are managed. The soil type also plays an important role. The results for Calcaric Fluvisol showed that the effects of selected agricultural management practices on the visual assessment of soil quality could be almost undetectable. The time of assessment also plays a significant role in VSA scoring. Different crops and agricultural activities with significant impacts on the soil occur throughout the year (especially in vegetable production). It was observed that a higher score for the soil cover indicator had a beneficial effect on the total VSA rating.

Land Use Change Effects on Soil Quality in Prince Edward County, ON

2018 ◽  
Author(s):  
Kelsey Watts
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Land Use Change ◽  
Bulk Density ◽  
Soil Quality ◽  
Water Holding Capacity ◽  
Total Carbon ◽  
Prince Edward County ◽  
Effects Of Land Use ◽  
Water Holding

Soils play a critical role to society as a medium that facilitates crop production and also contributes to the energy and carbon balance of the Earth System. Land-use change and improper land-use is one of the dominant factors affecting soil erosion and nutrient loss in soils. We examined the effects of land-use change on an Elmbrook clay/clay-loam soil on a farm in Ameliasburg on the northern part of Prince Edward County. Three cover types were examined: a sod field (established for over 10 years), a wheat field (part of a wheat/corn/soybean rotation for 30 years) and an undisturbed deciduous forest. Under each land-use type, cores to a depth of 40 cm were collected along three random 30 m transects (at 8, 16 and 24 m), then divided them into 10 cm increments, combining all similar depth increments along one transect. Soil quality was assessed by analyzing various soil physical and chemical properties. Bulk density of the soil was much higher (1.55 vs. 0.95 g/cm3) in both agricultural ecosystems compared to the forest, but only in the 0-10 cm layer. Soil moisture at 60% water holding capacity was much greater for the forest than the sod and wheat soils. Soil pH was slightly lower in the forest compared to the sod and wheat fields. The sod and wheat fields showed losses of ~52% and ~53% organic matter, respectively, in contrast to the forested area. The greatest differences in organic matter and total carbon were found in the top 10 cm, likely due to the greater accumulation of litter at the ground surface in the forest compared to the agricultural sites. It appears that long-term (10 year) agricultural production has led to a decline in some, but not all, soil quality measures, particularly soil organic matter, bulk density and water holding capacity. These findings are consistent with much of the literature concerning the effects of land-use change on soil quality, and highlight the need to develop improved management systems to minimize losses in soil quality that can lead to declines in the productivity potential of soils over time.

RESEARCH OF EXTERNAL MASS TRANSFER PROCESSES FOR ADSORPTION FROM SOLUTIONS IN A APPARATUS WITH STIRRING

2021 ◽  
pp. 11-20
Author(s):  
V. Solovej ◽  
K. Gorbunov ◽  
V. Vereshchak ◽  
O. Gorbunova
Keyword(s):  
Mass Transfer ◽  
Energy Spectrum ◽  
Energy Dissipation ◽  
Large Scale ◽  
Isotropic Turbulence ◽  
Wave Number ◽  
Wave Form ◽  
Local Isotropy ◽  
Stirred Vessel ◽  
Almost All

A study has been mode of transport-controlled mass transfer-controlled to particles suspended in a stirred vessel. The motion of particle in a fluid was examined and a method of predicting relative velocities in terms of Kolmogoroff’s theory of local isotropic turbulence for mass transfer was outlined. To provide a more concrete visualization of complex wave form of turbulence, the concepts of eddies, of eddy velocity, scale (or wave number) and energy spectrum, have proved convenient. Large scale motions of scale contain almost all of the energy and they are directly responsible for energy diffusion throughout the stirring vessel by kinetic and pressure energies. However, almost no energy is dissipated by the large-scale energy-containing eddies. A scale of motion less than is responsible for convective energy transfer to even smaller eddy sires. At still smaller eddy scales, close to a characteristic microscale, both viscous energy dissipation and convection are the rule. The last range of eddies has been termed the universal equilibrium range. It has been further divided into a low eddy size region, the viscous dissipation subrange, and a larger eddy size region, the inertial convection subrange. Measurements of energy spectrum in mixing vessel are shown that there is a range, where the so called -(5/3) power law is effective. Accordingly, the theory of local isotropy of Kolmogoroff can be applied because existence of the internal subrange. As the integrated value of local energy dissipation rate agrees with the power per unit mass of liquid from the impeller, almost all energy from the impeller is viscous dissipated in eddies of microscale. The correlation for mass transfer to particles suspended in a stirred vessel is recommended. The results of experimental study are approximately 12 % above the predicted values.

Why Do People Stay Poor?

2021 ◽  
Author(s):  
Clare Balboni ◽  
Oriana Bandiera ◽  
Robin Burgess ◽  
Maitreesh Ghatak ◽  
Anton Heil
Keyword(s):  
Occupational Choice ◽  
Large Scale ◽  
Choice Model ◽  
Effective Means ◽  
Threshold Level ◽  
Poverty Traps ◽  
Asset Transfer ◽  
Small Livestock ◽  
Program Costs ◽  
Almost All

Abstract There are two broad views as to why people stay poor. One emphasizes differences in fundamentals, such as ability, talent, or motivation. The other, the poverty traps view, emphasizes differences in opportunities which stem from access to wealth. To test between these two views, we exploit a large-scale, randomized asset transfer and an 11-year panel of 6,000 households who begin in extreme poverty. The setting is rural Bangladesh and the assets are cows. The data supports the poverty traps view—we identify a threshold level of initial assets above which households accumulate assets, take on better occupations (from casual labor in agriculture or domestic services to running small livestock businesses), and grow out of poverty. The reverse happens for those below the threshold. Structural estimation of an occupational choice model reveals that almost all beneficiaries are misallocated in the work they do at baseline and that the gains arising from eliminating misallocation would far exceed the program costs. Our findings imply that large transfers which create better jobs for the poor are an effective means of getting people out of poverty traps and reducing global poverty.

Opuntia ficus-indica (prickly pear).

2021 ◽  
Author(s):  
Nick Pasiecznik
Keyword(s):  
Vitamin C ◽  
Large Scale ◽  
Time Lag ◽  
Prickly Pear ◽  
Invasive Weeds ◽  
Historical Records ◽  
Opuntia Ficus Indica ◽  
Actual Risk ◽  
Invasive Spread ◽  
Almost All

Abstract O. ficus-indica is highly valued as a fruit-producing cactus, also yielding 'leaves' that are used as a vegetable and browsed by livestock. It has been introduced widely from its native Mexico to almost all countries where the climate is suitable. The fruit is very rich in vitamin C and is exploited commercially in many areas. Many countries, especially in Asia, have recently established large-scale commercial plantations. However, O. ficus-indica, like several other species of Opuntia, have been known to spread and become invasive weeds. Historical records, however, appear to indicate a time-lag of about 100 years between introduction and the beginnings of invasive spread thus the actual risk may be low.

What Kind of Friction Model Is Needed to Predict Brake Squeal?

2012 ◽  
Author(s):  
Tore Butlin ◽  
Jim Woodhouse
Keyword(s):  
Large Scale ◽  
Dynamic Properties ◽  
Theoretical Work ◽  
Friction Model ◽  
Coupled Systems ◽  
Brake Squeal ◽  
Model Framework ◽  
Wide Range ◽  
Pin On Disc ◽  
Almost All

Predictive models of friction-induced vibration have proved elusive despite decades of research. There are many mechanisms that can cause brake squeal; friction coupled systems can be highly sensitive to small perturbations; and the dynamic properties of friction at the contact zone seem to be poorly understood. This paper describes experimental and theoretical work aimed at identifying the key ingredients of a predictive model. A large-scale experiment was carried out to identify squeal initiations using a pin-on-disc test rig: approximately 30,000 squeal initiations were recorded, covering a very wide range of frequencies. The theoretical model allows for completely general linear systems coupled at a single sliding point by friction: squeal is predicted using a linearised stability analysis. Results will be presented that show that almost all observed squeal events can be predicted within this model framework, but that some subsets require innovative friction modelling: predictions are highly dependent on the particular choice of friction model and its associated parameters.

scholarly journals The influence of cactus spine surface structure on puncture performance and anchoring ability is tuned for ecology

2018 ◽  
Vol 285 (1891) ◽  
pp. 20182280 ◽  
Author(s):  
S. B. Crofts ◽  
P. S. L. Anderson
Keyword(s):  
Surface Structure ◽  
Large Scale ◽  
Biological Materials ◽  
Morphological Features ◽  
Ecological Functions ◽  
Defensive Mechanisms ◽  
Evolutionary Convergence ◽  
Almost All

Spines are common morphological features found in almost all major biological groups offering an opportunity to explore large-scale evolutionary convergence across disparate clades. As an example, opuntioid cacti have spines with barbed ornamentation that is remarkably similar in form and scale to that found on porcupine quills, suggesting specific biomechanical convergence across the animal and plant kingdoms. While the mechanics of porcupine quills as defensive mechanisms has been previously tested, the mechanics of cactus spines (which have evolved to fill a number of functions including defence, climbing and dispersal) has not been characterized. Here we study the puncturing and anchoring ability of six species of cactus, including both barbed and non-barbed spines. We found that barbed spines require less work to puncture a variety of targets than non-barbed spines. Barbed spines also require more work than non-barbed spines to withdraw from biological materials, owing to their barbs engaging with tissue fibres. These results closely match those found previously for barbed versus non-barbed porcupine quills, implying biomechanical convergence. The variation in performance of barbed versus non-barbed spines, as well as between barbed spines from different species, is probably tied to the diversity of ecological functions of cactus spines.

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