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Articles 2431 - 2460 of 2464

Full-Text Articles in Ecology and Evolutionary Biology

Webworm And The Weather, J A. Button Jan 1962

Webworm And The Weather, J A. Button

Journal of the Department of Agriculture, Western Australia, Series 4

FOR many years farmers have remarked on the cyclic occurrence of webworm outbreaks in their cereal crops.

Webworm, the State's most serious pest of cereals, has frequently assumed a role of major importance for one or two seasons, and then not been troublesome for a number of years.

A research programme being carried out by the Entomology Branch aims to give a better understanding of the effects of weather conditions on the seasonal incidence of webworm, and should lead to more effective control of this pest.


Grazing To Control Pasture Composition, R A. Bettenay Jan 1962

Grazing To Control Pasture Composition, R A. Bettenay

Journal of the Department of Agriculture, Western Australia, Series 4

APART from grazing management, there are a number of means by which the farmer can influence pasture composition.

With the exception of grazing, all of these processes involve recurring costs, so it is important to exert the utmost possible control through the grazing animal.


Perennial Atriplex Of Utah And The Northern Deserts, Craig A. Hanson Jan 1962

Perennial Atriplex Of Utah And The Northern Deserts, Craig A. Hanson

Theses and Dissertations

Atriplex is a genus in the Chenopodiaceae, the perennial members of which are ecologically important in western North America. Seventeen species and one subspecies of perennial Atriplex occur in Utah and the northern deserts. Three of these species and the subspecies were described by the writer in a recent publication as a result of extensive field work leading to this study. These are A. welshii, A. navajoensis, A. bonnevillensis, and A. cuneata ssp. introgressa. This study is an investigation of the systematics and phytogeography of the perennial Atriplex in Utah and the northern deserts, with emphasis on the A. gardneri …


List Of The Smut Fungi Of Arkansas, George E. Templeton Jan 1962

List Of The Smut Fungi Of Arkansas, George E. Templeton

Journal of the Arkansas Academy of Science

No abstract provided.


Volume Tables For Aspen In Colorado, Geraldine Peterson Aug 1961

Volume Tables For Aspen In Colorado, Geraldine Peterson

Aspen Bibliography

No abstract provided.


An Ecological Study Of An Exclosure In The Mountain Brush Vegetation Of The Wasatch Mountains, Utah, Elray S. Nixon Aug 1961

An Ecological Study Of An Exclosure In The Mountain Brush Vegetation Of The Wasatch Mountains, Utah, Elray S. Nixon

Theses and Dissertations

This is a comparative study of the vegetation and soils of an exclosure in the mountain brush vegetation of the Wasatch Mountains, Utah. The exclosure was fenced and initially analyzed during the summers of 1949-1950. The study area is located in Pole Canyon in the Uinta National Forest, a few miles northeast of Provo, Utah. The dominant woody species of the vegetation in the exclosure are big toothed maple (Acer grandidentatum) and Gambel oak (Quercus gambelii). After settlement of the area in and around Provo, Pole Canyon became overgrazed by livestock. Since 1949 the area has been protected from grazing. …


Dwarf Fruit Trees, Frank Melville Jan 1961

Dwarf Fruit Trees, Frank Melville

Journal of the Department of Agriculture, Western Australia, Series 4

IN this country where most fruits and particularly apples and pears are grown without irrigation, heavy crops and summer stress restrict tree size.

The aim of most growers therefore, has been to grow larger trees and little interest has been shown in trees with dwarfing tendencies.

However, in countries with ideal conditions for growth, trees tend to grow too big and become uneconomic in terms of labour costs.


Revised And Annotated Catalogue Of The Grasses Of Arkansas, Dwight M. Moore Jan 1961

Revised And Annotated Catalogue Of The Grasses Of Arkansas, Dwight M. Moore

Journal of the Arkansas Academy of Science

No abstract provided.


Ligneous Flora On Contrasting Sites At Longpool, Pope County, Arkansas, Lowell A. Logan Jan 1960

Ligneous Flora On Contrasting Sites At Longpool, Pope County, Arkansas, Lowell A. Logan

Journal of the Arkansas Academy of Science

No abstract provided.


Some Aspects Of Regeneration Silviculture In Spruce-Aspen Stands In Alberta, L. A. Smithers Jul 1959

Some Aspects Of Regeneration Silviculture In Spruce-Aspen Stands In Alberta, L. A. Smithers

Aspen Bibliography

Surveys of spruce-aspen stands in Northern Alberta have shown that natural regeneration of white spruce is generally a failure on areas which have been logged but not burned (Candy 1951).


Growth Of Alberta White Spruce After Release From Aspen Competition, L. A. Smithers, G Ontkean Jan 1959

Growth Of Alberta White Spruce After Release From Aspen Competition, L. A. Smithers, G Ontkean

Aspen Bibliography

At the present time spruce sawtimber is the most important single commodity produced from the forests of Alberta.


Effect Of Time Of Cutting On Yield And Botanical Composition Of Prairie Hay In Southeastern Nebraska, Elverne C. Conard, Vincent H. Arthaud Nov 1957

Effect Of Time Of Cutting On Yield And Botanical Composition Of Prairie Hay In Southeastern Nebraska, Elverne C. Conard, Vincent H. Arthaud

Nebraska Agricultural Experiment Station: Historical Research Bulletins

Approximately three and one-third million acres of native prairie are harvested annually in Nebraska for hay. In the four-year period 1948-1951, the State ranked first in wild hay production with an average yield of more than two and one-quarter million tons per year. This crop is an important natural resource in Nebraska's livestock industry. Studies were initiated in 1945 to determine the effects of time of cutting on the yield and feeding value of prairie hay in southeastern Nebraska. The studies were continued through the summer of 1952 to determine the effects of different cutting treatments on the vigor and …


Aspen Leaf Blight In The Intermountain Region, James L. Mielke Mar 1957

Aspen Leaf Blight In The Intermountain Region, James L. Mielke

Aspen Bibliography

No abstract provided.


The Growth And Yield Of Aspen In Saskatchewan, C. L. Kirby, W. S. Bailey, J. G. Gilmour Jan 1957

The Growth And Yield Of Aspen In Saskatchewan, C. L. Kirby, W. S. Bailey, J. G. Gilmour

Aspen Bibliography

No abstract provided.


Field Guide To Aid In Recognition Of Natural Triploid Aspen, Philip N. Joranson, Dean W. Einspahr, J P. Van Buijtenen Jan 1957

Field Guide To Aid In Recognition Of Natural Triploid Aspen, Philip N. Joranson, Dean W. Einspahr, J P. Van Buijtenen

Aspen Bibliography

Swedish experience with the genetic improvement of the European aspen (Populus tremula L.), a species which is closely kin to our North American quaking aspen (P. tremuloides Michx.), suggests that the rate of volume increment and the length of fiber tracheids might both be increased in North American aspen by finding or producing trees which possess a triple set, rather than the usual double set, of "chromosomes". Chromosomes (Figure 1) are found within and inner region--the nucleus--of each of the millions of cells formed during the growth of a tree.


The Succession Of Vegetation On A Southern Utah Sand Dune, Elias S. Castle Aug 1954

The Succession Of Vegetation On A Southern Utah Sand Dune, Elias S. Castle

Theses and Dissertations

The sand dunes lying ten miles northwest of Kanab in Kane County, Utah, support a sparse plant cover with four species dominating the vegetation: Psoralea stenostachys, Sophora stenophylla, Oryzopsis hymenoides, and Wyethia scabra var. attenuata. Of these Psoralea and Wyethia are endemic to the dunes or to a limited area which includes the dunes. The pineer species gain a start in the valleys between dunes and occupy the area only until sand covers them or until sand is blown away from their roots. Stabilization of the soils is not permanently in the interdune valleys and the dunes continue to wander. …


Moss: Flora Of Maine, Robert N. Miller Jan 1951

Moss: Flora Of Maine, Robert N. Miller

Maine Collection

Moss: Flora of Maine

by Robert N. Miller

Gorham State Teachers College, Gorham, Maine, 1951.

Contents: What Are Mosses? / Moss Groups / Suggestions for Collecting, Mounting and Preservation of Moss Specimens / Over-All Pictures of the Capsules and Setae / Types of Leaves / Glossary / Outline Key to Some Maine Mosses


Early Release From Aspen Improves Yield Of Pine Plantations, E.I. Roe Jan 1951

Early Release From Aspen Improves Yield Of Pine Plantations, E.I. Roe

Aspen Bibliography

No abstract provided.


Aspen Management Problems Of The Lake States, Z.A. Zasada Jun 1950

Aspen Management Problems Of The Lake States, Z.A. Zasada

Aspen Bibliography

No abstract provided.


How To Control Undesirable Trees And Shrubs, Maurice W. Day May 1950

How To Control Undesirable Trees And Shrubs, Maurice W. Day

Aspen Bibliography

No abstract provided.


Microorganisms And Soil Structure, T. M. Mccalla Mar 1950

Microorganisms And Soil Structure, T. M. Mccalla

Department of Agronomy and Horticulture: Faculty Publications

SUMMARY

Laboratory tests were made to determine the effectiveness of different compounds and microbial groups in increasing the stability of Peorian loess lumps against the action of falling water drops. The influence of these on percolation tests in the laboratory was also determined.

Many organic substances-dextrose, sucrose, starch, peptone, cullulose, and gum arabic-did not themselves contribute directly to soil-structure stability, though these substances do furnish energy material for soil microorganisms, which can convert them readily into either microbial tissue or decomposition products that increase soil-structure stability. Lignin, proteins, oils, fats, waxes, resin, and paraffin increased the stability of lumps of …


Aspen Defiberization And Refining Of Product, Robert Craig Jr. Mar 1948

Aspen Defiberization And Refining Of Product, Robert Craig Jr.

Aspen Bibliography

Because of the great demand for wood fiber and because there is an abundance of aspen available1/ for this purpose, its conversion into a usable fiberized material offers possibilities. It also affords an outlet for low-quality bolts developed in any aspen logging operation or from land of poor quality.


Aspen Properties And Uses, Zigmond A. Zasada May 1947

Aspen Properties And Uses, Zigmond A. Zasada

Aspen Bibliography

Because of the large demand for lumber during the last 10 years, and particularly during the war period, aspen has entered many new fields of use. At present there is widespread interest in the possibilities of building new industries and extending the life of old ones by increased use of aspen. Many people are interested in becoming familiar with this wood. This report has been prepared to give general information on the properties and present uses of aspen and also to help in correcting some of the existing erroneous ideas about this wood.


Seeding Grass On Deteriorated Aspen Range, A. Perry Plummer, George Stewart Oct 1944

Seeding Grass On Deteriorated Aspen Range, A. Perry Plummer, George Stewart

Aspen Bibliography

The herbaceous undercover on much of the aspen range in the Intermountain region is badly deteriorated. These areas, naturally highly productive, when revegetated can contribute greatly towards a much needed supply of range forage. One of the major obstacles to successful seeding has been the difficulty of getting the seeds covered with soil since both standing and fallen trees interfere with the use of drills, harrows, or other machinery. In the search for methods to overcome this difficulty, it was found that for open aspen stands the covering of seeds is unnecessary when the right precautions are taken in other …


How To Reseed Utah Range Lands, A. Perry Plummer, Richard M. Hurd, C. Kenneth Pearse Jun 1943

How To Reseed Utah Range Lands, A. Perry Plummer, Richard M. Hurd, C. Kenneth Pearse

Aspen Bibliography

Additional low cost forage is urgently needed by Utah's range livestock industry. Seeding of depleted tracts in accordance with recently developed methods and principles will help supply this forage and is entirely feasible. Where the value of the increased forage will repay the cost of planting, careful reseeding of selected sites is fully justified.

The important part that reseeding can play in restoring ranges to their former capacity has been demonstrated. Although satisfactory results can be obtained on many sites during average or better years, much more study is needed to insure consistent success in abnormal years and to extend …


The Effect Of Fomes Ignarius On Populus Tremuloides In The Gallatin National Forest Of Montana, Marvin F. Kelly Jun 1941

The Effect Of Fomes Ignarius On Populus Tremuloides In The Gallatin National Forest Of Montana, Marvin F. Kelly

Aspen Bibliography

No abstract provided.


Weather And Plant-Development Data As Determinants Of Grazing Periods On Mountain Range, David F. Costello, Raymond Price May 1939

Weather And Plant-Development Data As Determinants Of Grazing Periods On Mountain Range, David F. Costello, Raymond Price

Aspen Bibliography

Fundamental in economical range-resource management is the determination of proper grazing periods. It is of prime importance to be able to establish a date in the spring when the range has produced sufficient feed to keep livestock in thrifty condition, when it is reasonably safe from excessive trampling and packing of the soil, and when the more important key forage plants have attained sufficient development to withstand grazing use. Such opening dates, as well as the time to defer and rotate grazing and to remove livestock from the range, are dependent in part on the prevailing weather conditions and on …


The Influence Of Overgrazing On The Density And Number Of Palatable And Unpalatable Desert Forage Plants, John H. Mcguire Jan 1937

The Influence Of Overgrazing On The Density And Number Of Palatable And Unpalatable Desert Forage Plants, John H. Mcguire

Theses and Dissertations

The data for this problem were collected at the Desert Range Experiment Station and on adjoining public domain lands during the summer of 1934, for the purpose of studying the influence of overgrazing on the increase of palatable and unpalatable desert forage plants. A vegetative description of the two areas studied has been prepared and presented.


Effects Of Overgrazing On The Mortality Of Desert Browse Of The Utah West Desert, Charles W. Menzies Jan 1935

Effects Of Overgrazing On The Mortality Of Desert Browse Of The Utah West Desert, Charles W. Menzies

Theses and Dissertations

During the summer of 1934 this investigation was conducted to determine the effect of overgrazing on the mortality of desert browse in the vicinity of the Desert Range Branch experiment station. Range lands of western United States have, as a whole been subjected to overgrazing. Utah has about 24 million acres of public acres of public domain that can only be utilized from grazing. An effort has been made to put this area under control. The "Taylor Grazing Act" passed by Congress June 28, 1934 is a big step in the direction of the control of this vast area of …


Grazing Periods And Forage Production On The National Forests, Arthur W. Sampson, Harry E. Malmsten Sep 1926

Grazing Periods And Forage Production On The National Forests, Arthur W. Sampson, Harry E. Malmsten

Aspen Bibliography

Stockmen in the West have always had confidence in the adequacy of the native forage crop to provide pasturage for their livestock. Indeed, under normal climatic conditions this enormous natural resource has not failed the grazier, except where it has been called upon to meet unreasonable demands. The productivity of the range has declined sharply, however, wherever the requirements of plant growth have been disregarded for many years in succession. Where there has been too early or too frequent and to heavy grazing, undue trampling, or some other unsatisfactory feature of range use, the results have been uniformly bad. Many …