Effect of grinding on the decomposition of soil organic matter—I. The mineralization of organic nitrogen in relation to soil type     

E.T. Craswell  S.A. Waring 《Soil biology & biochemistry》1972

The effect of grinding on aerobic nitrogen mineralization in ten soils of widely different properties was studied. The aerobic mineralization of nitrogen was increased in seven of ten soils when they were ground to < 0.18 mm and < 0.05 mm; these seven soils contained more clay than the other three soils. Five soils with montmorillonite clay showed larger proportional increases in mineralization due to grinding than did the two soils with kaolin clay. The implications of these findings are discussed in terms of the inability of some previous workers to find increases in the rate of organic matter decomposition when soils are physically disrupted and the importance of clay protection in the resistance of soil organic matter to decomposition.  相似文献   

THE TRIPLE POINT OF WATER     

Waring W 《Science (New York, N.Y.)》1943,97(2514):221-222

(1) A common error in text-books on physical chemistry is pointed out. It is hoped that the correct value for the triple point temperature, +.0098 degrees C, will be given in new books and in succeeding editions of the books surveyed above. (2) Inconsistencies in the vapor pressure values for ice and for liquid water near 0 degrees C are pointed out. (3) The equilibrium vapor pressures for ice and liquid water under two different sets of equilibrium conditions are compared with the triple point pressure.  相似文献   

Antigenic relationship of the picorna-like virus of larval barramundi, Lates calcarifer Bloch to the nodavirus of larval striped jack, Pseudocaranx dentex (Bloch & Schneider)     

BL MUNDAY  T NAKAI  HD NGUYEN 《Australian veterinary journal》1994,71(11):384-385

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A study of the effect of variation in the calorie‐protein ratio of a medium energy diet and a high energy diet containing sucrose on the efficiency of egg production in caged layers     

W. O. Brown  J. J. Waring  E. Squance 《British poultry science》1965,6(1):59-66

Literature pertaining to the variation in the protein content of layers’ diets is discussed and the lack of information on the effect of calorie‐protein ratio on food conversion is mentioned. The experiment described in the present paper was designed to test the effect of variations in calorie‐protein ratio on food conversion on a diet of high energy content (1340 k cal/lb.) based on sucrose supplementation and on a medium energy diet (1160 k cal/lb.). At the same time three types of pullet, Thornber 606, Thornber 404 and Light Sussex x Brown Leghorn pullets were compared on the two types of diet, each being fed at three nominal protein levels of 13, 15 and 17 per cent giving a total of eighteen treatments. The pullets were individually recorded for egg production, egg weight and food consumption. Meta‐bolisable energy crude protein determinations were carried out on each of the six diets employed and the actual calorie‐protein ratios calculated.

There was no significant effect on egg production when the calorie‐protein ratio of the diet was raised from 69 (i.e. k cal M.E./lb. per 1 per cent protein) to 90 but an increase to 103 reduced production and egg weight. It was found that maximum efficiency of food conversion was realised at ratios of 76 to 78.

The efficiency of conversion of dietary energy was unaffected by energy concentration in the diet.

The lightweight hybrid (Thornber 606) produced eggs more efficiently than either the Thornber 404 or the crossbred type.  相似文献   

Phillip Frank Lewis 1919–2015          下载免费PDF全文

HD Middleton  R Lowden 《Australian veterinary journal》2016,94(1-2):3-3

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Why is the productivity of Douglas-fir higher in New Zealand than in its native range in the Pacific Northwest,USA?     

Richard Waring  Alan Nordmeyer  David Whitehead  John Hunt  Michael Newton  Christoph Thomas  James Irvine 《Forest Ecology and Management》2008,255(12):4040-4046

Douglas-fir (Pseudotusga menziesii (Mirb.) Franco), a native to the Pacific Coast Range in North America, is recognized as a tree that is long-lived and can grow rapidly to standing volumes that approach the highest recorded for temperate conifers. Managed plantations in western Oregon register maximum periodic annual increments (PAI) at ages between 20 and 40 years of ∼30 m³ ha⁻¹ year⁻¹. The same seed source, when planted in New Zealand and elsewhere in the Southern Hemisphere, may attain a PAI of ∼50 m³ ha⁻¹ year⁻¹. Is this higher productivity mainly related to climate or to isolation from native pests? To evaluate the role of climate, we obtained meteorological data from plantation sites in New Zealand and Oregon, from which we established relationships between mean monthly temperature extremes and solar irradiance, air humidity deficits, and frost frequency. Using these empirical relationships, long-term weather records were converted to the meteorological variables required to drive a process-based forest growth model, 3-PG, for sites approaching the most productive in New Zealand and in Oregon. Annual precipitation is similar in both areas, but sites in Oregon receive only 10% during the growing season, resulting in humidity deficits 30% larger than those recorded in New Zealand. According to sensitivity analyses and direct measurements, the more productive Douglas-fir forests in Oregon avoid the limiting effects of summer drought by obtaining water from the subsoil and fractured bedrock. If such forests were under a reduced evaporative demand similar to that in New Zealand, we show that they would exhibit comparable productivity.  相似文献   

A process model analysis of environmental limitations on the growth of Sitka spruce plantations in Great Britain     

Waring  R.H. 《Forestry》2000,73(1):65-79

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A serological survey on the prevalence of infectious bovine rhinotracheitis in Buckinghamshire, Berkshire and Oxfordshire.     

F D Kirby  H T Martin  M J Waring 《The Veterinary record》1978,103(7):134-136

Of the 2368 cattle sera from herds in Buckinghamshire, Berkshire and Oxfordshire examined for infectious bovine rhinotracheitis antibody by an indirect haemagglutination test, 162 (6.8 per cent) proved positive. Positive titres were more prevalent in older cows and they tended to show higher titres. There was little evidence of infection in the bulls tested. The percentage of positive animals in Berkshire and Oxfordshire was 4.7 compared with 10.5 in Buckinghamshire. The infection was not known to be associated with any clinical disease.  相似文献   

Growth response of chicks following addition to the diet of various sources of nitrogen     

R Blair  J J Waring 《British poultry science》1969,10(1):37-44

Two experiments involving a total of 320 day‐old Chunky P male chicks were conducted. In the first experiment chicks were divided into 6 groups and given one of the following diets ad libitum for 6 weeks: A, with determined essential amino acids at minimal required levels; B, with published values for essential amino acids at minimal required levels; C, conventional broiler diet; D, A+1.5 per cent diammonium phosphate (DAP); E, A+3.0 per cent DAP; and F, A+4/4 per cent DAP. Adding 1.5 per cent DAP gave a significant increase in live‐weight at 4 weeks, but adding 3.0 or 4.4 per cent DAP depressed weight significantly at 4 or 6 weeks. Weights of birds receiving diet B were significantly lower than those of birds receiving diets A or C.

In the second experiment chicks were divided into 5 groups and given one of the following diets ad libitum for 4 weeks: GA (similar to A) or GA supplemented with the equivalent of 2 per cent crude protein in several forms. In HM the form was herring meal and in GG, DS and DP it was glycine+glutamic acid, diammonium sulphate and DAP, respectively. Body weights of birds receiving HM were greater (though not significantly) than those receiving GA but were significantly poorer than those fed GG, DS or DP.  相似文献   

Does overshoot in leaf development of ponderosa pine in wet years leads to bark beetle outbreaks on fine-textured soils in drier years？     

Wendy Peterman Richard H Waring 《中国林学(英文版)》2014,(4):214-226

Background： Frequent outbreaks of insects and diseases have been recorded in the native forests of western North America during the last few decades, but the distribution of these outbreaks has been far from uniform. In some cases, recent climatic variations may explain some of this spatial variation along with the presence of expansive forests composed of dense, older trees. Forest managers and policy makers would benefit if areas especially prone to disturbance could be recognized so that mitigating actions could be taken. Methods： We use two ponderosa pine-dominated sites in western Montana, U.S.A. to apply a modeling approach that couples information acquired via remote sensing, soil surveys, and local weather stations to assess where bark beetle outbreaks might first occur and why. Although there was a general downward trend in precipitation for both sites over the period between 1998 and 2010 （slope =-1.3, R2 = 0.08）, interannual variability was high. Some years showed large increases followed by sharp decreases. Both sites had similar topography and fire histories, but bark beetle activity occurred earlier （circa 2000 to 2001） and more severely on one site than on the other. The initial canopy density of the two sites was also similar, with leaf area indices ranging between 1.7-2.0 m2. m-2. We wondered if the difference in bark beetle activity was related to soils that were higher in clay content at site I than at site II. To assess this possibility, we applied a process-based stand growth model （3-PG） to analyze the data and evaluate the hypotheses. Results： We found that when wet years were followed by drier years, the simulated annual wood production per unit of leaf area, a measure of tree vigor, dropped below a critical threshold on site I but not on site II. Conclusion： We concluded that the difference in vulnerability of the two stands to beetle outbreaks can be explained largely by differences in gross photosynthesis attributed to the fact that an equivalent amount of stored wat  相似文献