The effect of pH, liming, moisture and temperature on the activity of nitrifiers in a soil under pasture

Soil Research ◽  
1989 ◽  
Vol 27 (4) ◽  
pp. 711 ◽  
Author(s):  
RGV Bramley ◽  
RE White
Keyword(s):  
Moisture Content ◽  
Soil Temperature ◽  
Soil Ph ◽  
Marked Change ◽  
Quadratic Equation ◽  
Ph Optimum ◽  
Ph Values ◽  
Significant Relationships ◽  
The Mean ◽  
The Relationship

A short-term nitrification assay (SNA) was used to measure the activity of soil nitrifiers in the field in relation to soil pH and seasonal changes in soil temperature and moisture content. At roughly two-monthly intervals over two successive years, samples of the Tokomaru Silt Loam which had been limed in 1982 and/or 1987 were analysed in addition to an unlimed control. The SNA analysis was carried out for a range of pH values between 4.5 and 7.5, obtained by amending the incubation medium with small amounts of HCl or KOH. A quadratic curve was fitted to a plot of SNA value v, incubation pH. The fitted equations were used to calculate the pH optimum for nitrification (pHopt), the SNA value at pHopt (SNAopt) and the SNA value at the soil pH at sampling (SNApH). Values of pHopt and the mean soil pH over the year were higher in soil limed in 1982 than control soil; neither variable showed marked change in either soil over the first 320 days of observation. The addition of lime in 1987 raised the mean soil pH and pHopt in unlimed soil, but had negligible effect on either variable in soil limed five years previously. A covariance-type analysis demonstrated that the same quadratic equation could be fitted to each plot of SNA v. incubation pH for each soil treatment by changing the intercept parameter (C), i.e. the relationship between nitrifier activity and pH in the four soils remained constant over the year. No significant relationships could be found for the four soils between soil pH, pHopt, SNA, soil moisture content, soil temperature and C. However, the slight fluctuation in pHopt tended to follow the variation in soil pH. Values of SNAopt and SNApH showed a more obvious seasonal trend and showed a 1 : 1 relationship over a range of values from 0.015 to 0.110 �mol g-1 h-l; i.e. the nitrifier activity in the soil, irrespective of variations that were random (unknown influences) or associated with seasonal variables (temperature and moisture), was near the optimum with respect to pH. Nitrification activity is dynamic and changes quickly in response to changes in the soil environment. The implications of this with respect to nitrate leaching models include the likelihood that it may not be possible to produce a definitive model which works for all soil types.

Soil pH and aluminium and their spatial variation in Western Australian acidic soils

1990 ◽  
Vol 30 (5) ◽  
pp. 637 ◽  
Author(s):  
PJ Dolling ◽  
WM Porter ◽  
AD Robson
Keyword(s):  
Spatial Variation ◽  
Soil Ph ◽  
Surface Soil ◽  
Acid Soils ◽  
Poor Correlation ◽  
Ph Values ◽  
Coefficients Of Variation ◽  
Subsurface Soil ◽  
The Relationship ◽  
Surface Soil Ph

Thirty-eight sites on acid soils (pH<5.5, 1:5 in water) in the medium rainfall region of Western Australia were sampled to examine spatial variation in soil pH and 0.01 mol/L CaCl2-extractable aluminium. We also examined the relationship between (i) the A1 and A2 horizon soil pH, (ii) the A1 and A2 horizon extractable aluminium, (iii) surface and subsurface soil pH and (iv) surface soil and subsurface soil-extractable Al. Soil at each site generally had a light-textured layer overlying a clay layer at varying depths (30-70 cm) and was classified as either Dy 5.21 or Dy 5.41 (Northcote 1979). Over 80% of the sites had surface soil pH values 4.8 or lower and extractable aluminium concentrations 2 �g/g or higher. There was a very poor correlation (r2 = 0.21) between the A1 horizon soil aluminium extracted in 0.01 mol/L CaCl2 and the pH measured in 0.01 mol/L CaCl2 over 1 ha sites. The relationship was slightly improved in the A2 horizon (r2 = 0.49). The coefficients of variation of soil pH varied from 1.2 to 5.1%, while the coefficients of variation for CaCl2-extractable aluminium varied from 10 to 50%. At many of the sites, low pH values and high aluminium concentrations extended down to 35-45 cm. At the B horizon the pH values generally increased and the aluminium concentrations decreased. The surface soil pH and extractable aluminium were not good indicators (r2 = 0.09-0.60) of the subsurface soil pH and extractable aluminium.

The pH of Puerto Rican Soils Used for Principal Crops

1969 ◽  
Vol 46 (2) ◽  
pp. 107-119
Author(s):  
George Samuels
Keyword(s):  
Puerto Rico ◽  
Puerto Rican ◽  
Soil Ph ◽  
Acid Soils ◽  
Soil Series ◽  
Root Crop ◽  
Ph Values ◽  
Ph Range ◽  
The Relationship ◽  
Acid Range

The pH values of the soils of Puerto Rico were determined with the following results: 1. About 80 percent of the soils were acid (below pH 7) and 50 percent were below pH 6, which was acid enough to require liming. 2. Most of the soils planted to bananas were pH 6 and above. 3. The pH range for brushland was wide, extending from acid to alkaline. 4. Eighty percent of the soils of the coconut plantations were above pH 6. 5. Coffee soils, in general, were acid, with 63 percent below pH 6, of which 49 percent were in the range pH 5.0 to 5.9 and 13 percent in the very acid range of pH 4.0 to 4.9. 6. The pH of soils planted to corn varied widely. 7. The small cotton acreage had a pH range of 5.0 to 5.9. 8. The soils planted to grapefruit had 57 percent of their acreage at pH 4.0 to 4.9 and 29 percent in the range pH 5.0 to 5.9. 9. The natural pastures had 75 percent of their soil at pH below 6, whereas improved and rotational pastures had only 39 percent below pH 6. 10. Pineapples were planted in acid soils, 75 percent of which were below pH 6. 11. The majority, 68 percent, of the plantains were grown in acid soils below pH 6. 12. Root-crop soils had a systematic distribution throughout the range of pH from below 4 to above 8. 13. Most soils used for soilage (cut grass) had a pH above 6. 14. Eighty-one percent of the sugarcane acreage was found to be in the range of pH 5 to 8. About 36 percent of the cane acreage was below pH 5.5 and in need of liming. 15. Tobacco was grown primarily on acid soils, with 61 percent of its acreage on those below pH 6. 16. No vegetables were found in soils with a pH below 5, and 50 percent were planted in soils with a pH above 6. 17. The pH range for woodland soil was distributed rather evenly from a pH 5 to 7.9. 18. The average pH and range of pH of the soils of Puerto Rico are presented, by soil series, and several examples are given of the relationship between soil pH and soil series.

41 DETERMINATION OF THE RELATIONSHIP BETWEEN VULVAR SKIN TEMPERATURES AND TIME OF OVULATION IN SWINE USING DIGITAL INFRARED THERMOGRAPHY

2010 ◽  
Vol 22 (1) ◽  
pp. 178 ◽  
Author(s):  
S. Scolari ◽  
R. Evans ◽  
R. Knox ◽  
M. Tamassia ◽  
S. Clark
Keyword(s):  
Infrared Thermography ◽  
Marked Change ◽  
Control Group ◽  
Thermal Imager ◽  
Promising Tool ◽  
Significant Difference ◽  
Estrus Detection ◽  
The Mean ◽  
Change In Mean ◽  
The Relationship

Accurate estrus detection is an essential component of a successful AI program in modern swine operations. It is necessary to establish efficacious means of estrus detection and optimize reproductive performance in the herd. Measurement of physiological traits such as body temperature, vaginal electrical resistance, and vulva reddening have been investigated as methods to aid in estrus detection in swine. The relationship between vulvar skin temperature (VST) and ovulation has not been previously investigated. Therefore, the objective of this study was to assess changes in VST that occur during the periovulatory period using digital infrared thermography (IRT). The experiment group consisted of a total of 25 gilts and 27 multiparous sows, and the control group consisted of 30 sows that were 60 days of gestation. All Yorkshire-Landrace females were housed individually in a temperature and humidity controlled environment. VST were measured twice daily at 8-h intervals using the infrared digital thermocamera (Fluke IR FlexCam® Thermal Imager, Fluke Corporation, Everett, WA) while the animals were standing and eating prior to estrus detection. Estrus detection was performed twice daily (at 8-h intervals) with the aid of an adult boar. Once standing estrus was observed, transrectal real-time ultrasound was performed twice daily at 8-h intervals to monitor follicle development and determine the time of ovulation. Ovaries were visualized using an Aloka 500 V ultrasonics machine (Aloka Inc., Tokyo, Japan) fitted with a transrectal 7.5-MHz linear transducer, which was fitted into a rigid, fixed-angle PVC adapter. Average VST and hours were reported in mean ± SEM and compared using an ANOVA and Student’s t-test using SAS software (SAS Institute Inc., Cary, NC, USA). Additionally, pairwise comparisons were performed to compare VST at different times during estrus. Significant differences were reported at P ≤ 0.05. Evidence of CL formation and ovulation was detected at 38 ± 9.3 h after onset of estrus in gilts, and 43 ± 12 h in sows. The mean VST of sows during estrus was significantly higher (P ≤ 0.05) than that of gilts. During estrus, the mean VST of gilts reached a peak of 35.6 ± 0.24°C and then decreased significantly to 33.9 ± 0.32°C 12 h prior to ovulation. This marked change in mean VST was detected between 36 and 12 h prior to ovulation. There was a similar trend in sows with a peak mean VST of 36.1 ± 0.25°C at 24 h prior to ovulation and then dropping to 34.6 ± 0.31°C 12 h prior to ovulation. There was no significant difference (P ≥ 0.05) between VST in gilts and sows at the time of ovulation. This study demonstrated that VST of sows and gilts measured by IRT change significantly during the periovulatory period. Additionally, there are distinct times that VST rises and then falls precipitously in sows compared with gilts. Digital IRT as a predictor for ovulation in swine appears to be a promising tool. Further studies involving predictor models and hormonal assays need to be performed.

scholarly journals The Relationship of Duration of Fast to the Volume and pH of Gastric Contents

1986 ◽  
Vol 14 (2) ◽  
pp. 128-130 ◽  
Author(s):  
B. R. Hutchinson ◽  
A. F. Merry ◽  
C. J. Wild
Keyword(s):  
Vascular Surgery ◽  
Significant Relationship ◽  
Ph Value ◽  
Anaesthetic Induction ◽  
Positive Correlation ◽  
Ph Values ◽  
Gastric Contents ◽  
The Mean ◽  
Relationship Of ◽  
The Relationship

Volume and pH of gastric contents were measured after anaesthetic induction in 99 in-patients undergoing general and vascular surgery scheduled for either morning (50) or afternoon (49) lists. Significantly fewer patients in the morning group had pH values below 2.5. The mean pH value of the morning group was significantly higher than that of the afternoon group. There was a positive correlation between duration of fast and pH (the longer the more alkaline) for the groups combined. No significant relationship could be shown for any factor with volume.

A Time–Motion Analysis of Elite Solo Synchronized Swimming

2008 ◽  
Vol 3 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Teresa Alentejano ◽  
Dru Marshall ◽  
Gordon Bell
Keyword(s):  
Horizontal Distance ◽  
Time Motion ◽  
Significant Relationships ◽  
Time Period ◽  
Synchronized Swimming ◽  
Face Immersion ◽  
The Mean ◽  
The Times ◽  
The Relationship ◽  
Analysis Of Performance

Purpose:To determine the total amount and relative time periods of face immersion (FI) in a synchronized swimming solo routine and the relationship between FI, distance covered, and the technical-merit score of the 11 top Canadian soloists at a synchronized swimming national championship (mean age 20 ± 1.8 y, height 173.3 ± 4.1 cm, and body mass 58.3 ± 4 kg).Methods:Videotape and timing of solo performances combined with manual tracking of pool patterns.Results:Analysis of performance revealed that an average of 18 FI periods, mean of 6.8 s, were performed for an average total time of 133.7 ± 27.1 s (range 102.2 to 199.8 s). The average longest FI time period was 25.45 ± 6.2 s (range 18.18 to 38.72 s), and most (10/11) of these were in the first third of the solo. The mean total horizontal distance covered was 57.61 ± 6.84 m (range 48.61 to 68.2 m), and the total horizontal distance covered relative to time was 0.276 ± 0.034 m/s (range 0.235 to 0.340 m/s). No significant relationships were found between any of the FI periods and the distance covered or between the technical-merit score and FI periods. Each solo contained 6 to 8 underwater sequences, none of which were longer than 40 seconds, the cutoff deemed dangerous by FINA (Fédération Internationale de Natation).Conclusion:This study shows that the times underwater for solos in Canada are within safety limits recommended by FINA and that judging in Canada is not related to underwater periods of swimming.

scholarly journals On the determination of soil pH

1965 ◽  
Vol 37 (1) ◽  
pp. 51-60
Author(s):  
Ritva Ryti
Keyword(s):  
Soil Ph ◽  
Salt Content ◽  
Soil Samples ◽  
Liquid Ratio ◽  
Ph Values ◽  
Water Suspensions ◽  
The Mean ◽  
The Difference ◽  
Soil Groups

In the present paper the routine determination of soil pH in the laboratory was studied using a material of 15 soil samples of various kind and in addition, two larger soil groups, consisting of 80 and 406 samples respectively. In comparing the pH values determined in water and in 0.01 M CaCl2 suspensions, the latter proved to be almost independent of the soil/liquid ratio between 1: 2.5 and 1: 10, that markedly affected the pHH2O values. The change with time from the pH values measured after the first hour showed less variation in CaCl2 suspensions than in water suspensions; the constancy observed in pHCaCl2 values indicating that a relatively short equilibration period of 1—2 hours would be sufficient. To sum up these results, the use of 0.01 M CaCl2 would mean easy and accurate measurements well suited to mass pH determinations. A linear relationship and a highly significant positive correlation was found between pHH2O and pHCaCl2 values in a material of 406 soil samples. The difference between the two values, which largely depends on the soils’ own salt content, ranged from 0 to 1.1 pH units, with the mean difference of 0.49. Therefore, the suggested use of a constant correction factor to bring the pHCaCl2 values to the level of the pH measured in water, is not recommendable. The main advantage of using 0.01 M CaCl2 would be the concealing of differences in salt content of a soil. The use of pHCaCl2 values would also offer new ways for getting more information about a soil’s exchange capacities, as it provides the center point for TERÄSVUORI’s (13) soil curve.

Soil acidity in New-South-Wales - Current pH values and estimates of acidification rates

Soil Research ◽  
1990 ◽  
Vol 28 (4) ◽  
pp. 523 ◽  
Author(s):  
KR Helyar ◽  
PD Cregan ◽  
DL Godyn
Keyword(s):  
Soil Ph ◽  
Buffer Capacity ◽  
Sandy Loam ◽  
Low Ph ◽  
Ph Values ◽  
Acid Addition ◽  
South Wales ◽  
Addition Rate ◽  
The Mean ◽  
Ph Buffer

An estimate has been made of the mean pH of the surface soils (0-10 or 0-15 cm) of New South Wales by mapping the soil pH (1:2, soil: 0.01 M CaCl2) values of soil samples analysed by the NSW Agriculture & Fisheries soil testing service. Within mapped classes the soil pH values vary around the mean by about 20.4 units for low pH soils (3.8-5.0) to about 20.9 units for high pH soils (>6.0). It is estimated that the areas of surface soils within agricultural holdings in NSW in the pH classes <4.5, 4.51-5 0, 5.01-5 5 and 5.5 1-6.0, are 5 3, 8.4, 5 7 and 5.1 million ha respectively. In general, pH values in the higher rainfall coastal and tablelands areas in the east are below 5.0, with the most acid areas being below 4.25. The latter are usually in the high rainfall zones (>1000 mm) and on low pH buffer capacity soils (sand to sandy loam texture). In the south of the state the area of low pH soils is broader, and extends into lower rainfall zones. Within the mapped pH classes the higher pH buffer capacity clay soils had pH values 0.83 (s.e. 0.6) units higher than the mean, whilst sands and sandy loams had pH values 0.34 (s.e. 0.1) units lower than the mean. Data on the acid addition rates for a number of agricultural systems in NSW and adjacent areas were collated and show net rates of acid addition to the soil profile from near zero to rates of 3-5 kmoles H+ ha-l year-1 over extensive areas. High acid addition rates, of 10-20 kmoles H+ ha-1 year-1, have been measured in some exploitative systems. These acid addition rate values can be used in association with soil pH buffer capacity data to estimate the rate of pH change in the future. At an acid addition rate of 4 kmol H+ ha-1 year-1, the soil pH can decline by one unit, in the surface 30 cm within 30 years for sandy loam soils, and within 120 years for clay soils.

Multi-Center Calibration of the Second Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149R

1991 ◽  
Vol 65 (03) ◽  
pp. 263-267 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Reference Material ◽  
Standard Error ◽  
Standard Errors ◽  
Sensitivity Index ◽  
Long Term Stability ◽  
Significant Bias ◽  
The Mean ◽  
The Relationship ◽  
International Sensitivity Index

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.

Energetic relationships for crushing of soil clods

2006 ◽  
Vol 2 (1) ◽  
pp. 51-72
Author(s):  
István Patay ◽  
Virág Sándor
Keyword(s):  
Moisture Content ◽  
Specific Energy ◽  
Soil Moisture Content ◽  
Energy Requirement ◽  
Clay Content ◽  
Clay Soils ◽  
Rigid Support ◽  
Soil Plasticity ◽  
Specific Energy Requirement ◽  
The Relationship

Clod crushing is a principal problem with soils of high clay content. Therefore, there is a need for determining the conditions for clod breaking and clod crushing. The objective of the work was to develop a special purpose tool for single clod breaking both by rigid support of the clod and by a single clod supported by soil and to develop a machine for clod crushing. Furthermore, the purpose was to determine the relationship between the specific energy requirement for clod crushing in the function of soil plasticity and the soil moisture content by the means of the developed tool and machine. The main result of the experiments is summarized in a 3D diagram where the specific energy requirement for soil clod crushing is given in the function of the moisture content and the plasticity index for different clay soils.

Linking ‘Halal’ Friendly Hotel Attributes and Customer Satisfaction:The Islamic Tourism Sector

2016 ◽  
Vol 4 (4) ◽  
pp. 43
Author(s):  
Lennora Putit ◽  
Mazzini Muda ◽  
Ainul Nadzirah Mahmood ◽  
Nor Zafirah Ahmad Taufek ◽  
Norhayati Wahib
Keyword(s):  
Customer Satisfaction ◽  
Dress Code ◽  
Significant Relationships ◽  
Tourism Sector ◽  
Managerial Implications ◽  
Halal Food ◽  
Increasing Demand ◽  
Islamic Dress ◽  
The Relationship ◽  
Survey Questionnaires

An increasing demand for Islamic tourism has driven the concept of a ‘Halal’ (or permissible) friendly hotel into another level of business insight within the consumers’ travel market. The concept via its unique value proposition has rapidly become very attractive not only to Muslim tourists, but also to non-Muslim tourists globally. This study aims to examine the relationship linking ‘Halal’ friendly hotel attributes and customer satisfaction. Using purposive sampling, a total of 410 survey questionnaires were distributed to targeted respondents with only 323 usable feedbacks and used for data analysis. Regression results revealed that four main “Halal-friendly hotel” attributes have significant relationships with customer satisfaction. These include prayer facilities, Halal food, Islamic dress code and general Islamic morality. Of these four attributes, prayer facilities proved to have the most significant impact on customer satisfaction. Findings and managerial implications were further discussed in this article.

Sign in / Sign up

Export Citation Format

Share Document