scholarly journals Understory vegetation relationships with soil element contents in a northern boreal forest ecosystem near a phosphate massif

2019 ◽  
Author(s):  
Laura Matkala ◽  
Maija Salemaa ◽  
Jaana Bäck
Keyword(s):  
Leaf Litter ◽  
Understory Vegetation ◽  
Forest Understory ◽  
Nutrient Contents ◽  
Humus Layer ◽  
P Content ◽  
Relationship Of ◽  
The Relationship ◽  
Total P ◽  
Better Than

Abstract. We studied the relationship of forest understory vegetation with nutrient contents of soil and tree leaves near Sokli phosphate ore in northern Finland, where the soil contains naturally high variation in phosphorus (P) contents. At most study plots boreal dwarf shrubs, bryophytes and lichen formed a dense mat under a mixture of sparsely growing Pinus sylvestris, Picea abies and Betula pubescens. However, some plots were dominated by B. pubescens and had a higher variety and number of forbs and grasses in the understory. The total P content in the soil humus layer explained the abundance and species composition of the vegetation slightly better than the total nitrogen content. The spatial variation in contents of soil elements was high both between and within plots, emphasizing the heterogeneity of soil. High contents of P in the humus layer (max. 2600 mg kg−1) were measured from the birch-dominated plots. As the P contents of birch leaves and leaf litter were also rather high (2580 mg kg−1 and 1280 mg kg−1, respectively), this may imply that the leaf litter of birch forms an important source of P to the soil.

THE DISTRIBUTION OF ORGANIC PHOSPHORUS IN BRITISH COLUMBIA SOILS AND ITS RELATIONSHIP TO SOIL CHARACTERISTICS

1965 ◽  
Vol 45 (1) ◽  
pp. 87-95 ◽  
Author(s):  
M. K. John ◽  
P. N. Sprout ◽  
C. C. Kelley
Keyword(s):  
Organic Phosphorus ◽  
Chemical Properties ◽  
The Other ◽  
Organic P ◽  
Significant Relationships ◽  
P Content ◽  
Wide Range ◽  
Relationship Of ◽  
The Relationship ◽  
Total P

The relationship of organic phosphorus content to a number of chemical properties was studied in the surface horizons of 38 soils of six different soil orders in British Columbia.The concentration of organic P ranged from 1.8 to 77.7% of the total P with amounts varying from 21 to 802 p.p.m. The forested soils of the Podzolic and Brunisolic Orders contained the least organic P. However, the wide range in organic P content within some soil orders indicated that its distribution was not entirely characteristic of the soil order.Simple correlation studies between organic P and nitrogen, carbon, pH, per cent base saturation, total P, and free iron in all soils before assigning them to groups indicated that only nitrogen and carbon were significantly related to organic P. Significant relationships between the other variables and organic P were restricted to specific soil orders. The organic P content has been found to be primarily dependent on nitrogen and pH, since the inclusion of the other independent variables in the multiple regression did not significantly change the coefficient of determination.The range of C/organic P and N/organic P ratios for the 38 samples was between 46 and 648 and 5.5 to 57.6 respectively. Soil pH was the only variable studied which could account for the wide variation of these ratios.

scholarly journals Estimation of C∗-Integral for Central Cracked Plate Under Biaxial Loading

2020 ◽  
Vol 12 (07) ◽  
pp. 2050079
Author(s):  
Yanwei Dai ◽  
Fei Qin ◽  
Yinghua Liu ◽  
Weizhe Feng ◽  
Guian Qian
Keyword(s):  
Loading Condition ◽  
Biaxial Loading ◽  
Classical Method ◽  
Creep Crack ◽  
Cracked Plate ◽  
Reference Stress ◽  
Creep Time ◽  
Relationship Of ◽  
The Relationship ◽  
Better Than

The reference stress method (RSM) is a classical method to estimate [Formula: see text]-integral of creep crack. An extended reference stress method (ERSM) is given for the central cracked plate (CCP) under biaxial loading in this paper. The applicability and verification for the proposed ERSM is given. The study finds that the solutions with the proposed ERSM agree better than those of RSM under biaxial loading condition. A theoretical form to predict the relationship of [Formula: see text]-integral between biaxial loading and uniaxial loading is discussed. Relation between [Formula: see text]-integral and creep time under biaxial loading is validated and discussed.

scholarly journals Hourly Relationship between Reference Evapotranspiration and Shoot Shrinkage in Walnut Trees and Pomegranate under Deficit Irrigation

Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 31
Author(s):  
Eduardo Salgado ◽  
Nieggiorba Livellara ◽  
Esteban Chaigneau ◽  
Fernando Varas ◽  
Italo F. Cuneo
Keyword(s):  
Water Potential ◽  
Deficit Irrigation ◽  
Reference Evapotranspiration ◽  
The Novel ◽  
The Past ◽  
Slope Analysis ◽  
Daily Scale ◽  
Relationship Of ◽  
The Relationship ◽  
Better Than

Diameter fluctuations of branches, shoots, or fruits are related to plant transpiration and water potential. In the past, several models have related dendrometric variables and evapotranspiration on a daily scale. However, trunk–branch shrinkage occurs only between dawn and midday, while evapotranspiration occurs most of the day from sunrise to sunset. Previous models have failed to incorporate this key fact. The objective of the present study was to assess the relationship of hourly daily shrinkage (HDS) between dawn and the next 4 h to the hourly reference evapotranspiration (EToh) of the same period in walnut trees and pomegranate plants under different irrigation regimes. Our data show that the relationship between EToh and HDS is much better than several previous models that included maximum daily shrinkage (MDS) and reference evapotranspiration (ETo). The novel slope analysis of the relationship between HDS versus time used here corresponds to the velocity at which the HDS occurs, which depends on the ETo intensity at that moment. This new method of analyzing this type of data calls for a revision of these models and sets a new baseline for future analysis.

scholarly journals 85 Impact of teat order on feed consumption in swine from birth to nursery

2019 ◽  
Vol 97 (Supplement_1) ◽  
pp. 32-32
Author(s):  
Callan A Lichtenwalter ◽  
Jason K Apple ◽  
Elizabeth B Kegley ◽  
Tsung Cheng Tsai ◽  
Elizabeth Palmer ◽  
...  
Keyword(s):  
Phase 1 ◽  
Average Daily Gain ◽  
Feed Consumption ◽  
Feed Ratio ◽  
Nursery Pigs ◽  
Total Ghrelin ◽  
Relationship Of ◽  
The Relationship ◽  
Daily Gain ◽  
Total P

Abstract This study evaluated the relationship between teat order and its impact on feed consumption in pigs through nursery. Pigs were observed 48 h after birth to be in either a cranial, middle, or caudal teat position. Growth performance data, and active and total plasma ghrelin concentrations (determined by radioimmunoassay) were analyzed from 2 pigs in each position from 6 litters (n = 36) at 7 d of age, 21 d of age (weaning), and 62 d of age (end of the nursery stage) to determine a relationship with teat order. At weaning, pigs were moved to an off-site nursery and housed 2 pigs/pen based on teat position and litter, resulting in 6 pens/teat position. Overall, no effect of teat order was found on average daily gain (ADG; P = 0.91), average daily feed intake (ADFI; P = 0.67), gain-to-feed ratio (G:F; P = 0.33), or body weight (P = 0.94) among pigs from each teat position. A linear relationship was found between teat order and ADG (P = 0.01) as well as G:F in nursery phase-1 (P = 0.01) with caudal pigs gaining more rapidly and being more efficient than cranial pigs. Yet, in nursery phase-2, cranial pigs had the greatest ADFI (linear, P = 0.05). No difference was seen in active (P = 0.18) or total (P = 0.63) ghrelin concentrations or the active to total ghrelin ratio (P = 0.68) in relation to teat order, although there were differences in active (P = 0.04) and total (P < 0.01) ghrelin concentrations among the sampling days with the least concentrations being on d 21 for active and total ghrelin. Further study should investigate what factors would contribute to these data contradicting previous inferences about the relationship of teat order and feed consumption in pigs

Phosphorus diffusion in soils in relation to some edaphic factors and its influence on P uptake by maize and wheat

1986 ◽  
Vol 107 (2) ◽  
pp. 335-341 ◽  
Author(s):  
G. S. Bahl ◽  
N. T. Singh
Keyword(s):  
Moisture Content ◽  
Buffer Capacity ◽  
Significant Negative Correlation ◽  
P Uptake ◽  
Stages Of Growth ◽  
Soil Variables ◽  
Extractable P ◽  
P Content ◽  
Relationship Of ◽  
The Relationship

SummaryLaboratory studies were conducted on four soils to ascertain the effect of P content and texture on the capacity factor (P buffering capacity) of soils and in turn the effect of these factors combined with moisture content of soil on the diffusion coefficient of P (Dp). A glasshouse experiment was conducted to study the relationship of Dp with P uptake by maize and wheat. The buffer capacity decreased by the application of P in all four soils. There was a significant negative correlation between buffer capacity and Olsen's extractable P but positive correlation with other soil factors. The relative influence of different soil variables on the buffer capacity was in the order: free iron > percentage clay > exchangeable aluminium. The Dp value increased significantly with applied P, the maximum (3·2-fold over control) being in Tolewal loamy sand. The increase in clay and moisture content of soil also increased the Dp value. The drymatter yield and P uptake was significantly correlated with Dp, the r value being higher at later stages of growth of maize and wheat.

CASSAVA LEAF LITTER ESTIMATION IN ON-FARM TRIALS

2004 ◽  
Vol 40 (3) ◽  
pp. 315-326 ◽  
Author(s):  
R. J. CARSKY ◽  
M. A. TOUKOUROU
Keyword(s):  
Leaf Litter ◽  
Rainy Season ◽  
Dry Matter ◽  
Cropping Systems ◽  
First Year ◽  
Litter Production ◽  
Nutrient Contents ◽  
K Fertilizer ◽  
3.0 T ◽  
The Relationship

Cassava (Manihot esculenta) returns organic matter and nutrients to the soil through leaf litter and these amounts need to be quantified to help understand and design sustainable cropping systems. Our objectives were to estimate dry matter and nutrient contents in cassava leaf litter and to derive relationships between litter fall and easily measurable cassava yield components. Litter traps (1 m2) were placed in farmers' fields for monthly monitoring during a three year period. Maximum monthly leaf litter production ranged from 0.5 to 1.0 t ha−1, and occurred at the end of the first rainy season and at the onset of the next rainy season. In the first year, the mean dry matter of leaves collected during 12 months of growth was 3.4 t ha−1 for the unamended treatment, and 4.1 t ha−1 when N-P-K fertilizer was applied. The totals were 2.4 and 3.0 t ha−1 in 2000–2001 and 1.6 and 2.5 t ha−1 in 2001–2002, respectively. Annual differences were apparently related to rainfall. The relationship with fresh root yield was best described using one slope and yearly intercepts giving an r2 of 0.63. This relationship can be exploited for estimating litter dry matter in agronomic experiments when rough estimates are sufficient, keeping in mind that the relationship may not be the same for cultivars of differing architecture. Otherwise, the use of litter traps gives the best estimate of annual litter production.

scholarly journals STUDY ON TEMPERATURE FIELD OF ASYMMETRIC LARGE-SPAN ARCH SHEDS UNDER LOW-TEMPERATURE ENVIRONMENT

2020 ◽  
pp. 239-248
Author(s):  
Kai Zhou ◽  
Zhiwei Meng ◽  
Jialin Hou ◽  
Min Wei ◽  
Tianguo Jin ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Wind Speed ◽  
Low Temperature ◽  
Storage Capacity ◽  
Heat Storage ◽  
Large Span ◽  
Distribution Uniformity ◽  
Relationship Of ◽  
The Relationship ◽  
Better Than

In order to improve the effective sunshine time, heat storage capacity and temperature distribution uniformity of traditional arch shed under low temperature, this paper designed a large-span arch shed which has larger sunny side span and east-west orientation. According to the numerical and measured data, it is concluded that the heat storage capacity and temperature distribution of asymmetrical arch shed are better than those of symmetrical arch shed within a certain range of the ratio between sunny and shaded side. After that, ten different asymmetric arch sheds were designed. It is concluded that the structure of 11+9 m along north-south direction has the best heat storage capacity. Besides that, the analysis of outside wind speed and opening size of top vent were carried out. It is found that the outside wind and top vent can effectively promote convection and exchange of the air, and then achieve the purpose of reducing the temperature. At the end of this paper, in order to identify the relationship of temperature with the structure of arch shed, outside wind speed, and opening size of top vent, a mathematical model was built based on response surface methodology, which would provide theoretical guidance for the design of arch sheds.

scholarly journals Analyzing the spatial-temporal influence of built environment on taxi ridership

2020 ◽  
Vol 66 (4) ◽  
pp. 1-9
Author(s):  
Que Yuhua
Keyword(s):  
Built Environment ◽  
Regression Models ◽  
Transportation System ◽  
Critical Dimensions ◽  
Taxi Service ◽  
Global Regression ◽  
Temporal Influence ◽  
Relationship Of ◽  
The Relationship ◽  
Better Than

Taxi is an important component in urban transportation system, which covers wide area and maintains 24h available. Exploring the relationship of taxi and built environment is very important to manage taxi service and improve transportation system. The issue is addressed by capturing the influence of built environment on taxi ridership considering spatial and temporal non-stationarities. The grid cells are developed as analysis units and the global regression model is adopted for preliminary exploring. Then the GWR are implemented considering spatial heterogeneity and the GTWR is used to analyze the spatiotemporal influence of built environment on taxi ridership. An empirical study conducted in Hong Kong Island using one-week taxi’s GPS data demonstrates the effectiveness of the regression models. It’s verified that GWR performs better than OLS, and GTWR outperforms the rest two regression models, indicating both time and space are critical dimensions.

MANEUVERING OF BIOMIMETIC FISH BY INTEGRATING A BUOYANCY BODY WITH MODULAR UNDULATING FINS

2007 ◽  
Vol 04 (04) ◽  
pp. 671-695 ◽  
Author(s):  
K. H. LOW
Keyword(s):  
Field Trials ◽  
Biomimetic Robots ◽  
Laboratory Tank ◽  
The Individual ◽  
Relationship Of ◽  
Phase Angles ◽  
The Relationship ◽  
Undulating Fin ◽  
Better Than ◽  
Buoyancy Control

Biomimetic robots borrow their senses and structure from animals, such as insects, fishes, and human. Development of underwater vehicles is one of the areas where biomimetic robots can potentially perform better than conventional robots. In this paper, an undulating fin mechanism has been developed and used as the propulsion system of fish in various fin types. The layout and workspace of the modular fin segments are considered and analyzed. The relationship of the individual fin segment and phase angles with the overall fin trajectory is also discussed. A gymnotiform knifefish robot, as an example, has been developed to demonstrate the design methodology and prototype performance. The maneuvering and the buoyancy control can be achieved by the integration of a buoyancy tank with the undulating fin. Experiments were conducted in the laboratory tank and the variation of velocity with respect to several swimming parameters was analyzed. Field trials have also been conducted in an outdoor pool to demonstrate the swimming capability of the knifefish robot and its buoyancy performance in 4 m deep water.

Relationship of Preservice Music Teachers’ Primary Instrument Background and Teaching Effectiveness in Brass and Woodwind Techniques Classes

2017 ◽  
Vol 27 (3) ◽  
pp. 38-50 ◽  
Author(s):  
Sean R. Powell ◽  
Molly A. Weaver ◽  
Robin K. Henson
Keyword(s):  
Teaching Effectiveness ◽  
Music Teachers ◽  
Music Teacher ◽  
Music Teacher Education ◽  
Brass Players ◽  
Study Participants ◽  
Relationship Of ◽  
The Relationship ◽  
Better Than ◽  
Primary Instrument

The purpose of this study was to examine the relationship between preservice music teachers’ primary instrument background and their teaching effectiveness in brass and woodwind techniques classes. Study participants ( N = 135) were preservice music teachers enrolled in secondary instrument techniques courses (brass and woodwinds) from fall 2011 through spring 2015 in three universities. Participants taught a 10-minute video recorded lesson to a beginning-level university student on a brass or woodwind instrument at the end of the semester. All videos were subsequently assessed by two researchers using a researcher-designed rubric. The results of analyses of variance showed that brass-teaching scores tended to be higher than woodwind-teaching scores for all groups. Brass players taught brass more effectively than woodwind players, and woodwind players taught woodwinds better than brass players. Brass and woodwind players scored higher than percussionists, vocalists, pianists, and string players in both brass and woodwind teaching. Implications for music teacher education are discussed.

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