Assessment of water pollution by airborne measurement of chlorophyll

Remote measurement of chlorophyll concentrations to determine extent of water pollution is discussed. Construction and operation of radiometer to provide measurement capability are explained. Diagram of equipment is provided

Low subsonic dynamic-stability investigation of several planetary-entry configurations in a vertical wind tunnel, part i

Low subsonic dynamic stability data for evaluation of ballistic deceleration vehicle entering Mars atmospher

A laser scanner for 35mm film

The design, construction, and testing of a laser scanning system is described. The scanner was designed to deliver a scanned beam over a 2.54 cm by 2.54 cm or a 5.08 cm by 5.08 cm format. In order to achieve a scan resolution and rate comparable to that of standard television, an acousto-optic deflector was used for one axis of the scan, and a light deflecting galvanometer for deflection along the other axis. The acoustic optic deflector has the capability of random access scan controlled by a digital computer

Crop Production in India

It is rarely that one finds a book on the subject of agriculture of such broad scope, fascinating interest, and so full of the applications of ecology and physiology as Howard\u27s Crop-production in India. In every chapter numerous problems of plant growth in relation to environment are brought before the reader in such a stimulating manner that one can scarcely conclude but that ecology will reach its greatest usefulness in the field of general agriculture. It is a book to which every student of environment should have ready access

Role of Fire in Pasture Management

The practice of burning grass is an old one. It was extensively used by the Indians to attract game animals in early spring and to facilitate hunting. It is also highly probable that a large portion of the prairie was burned periodically during very dry years from natural cause

Experimental Studies of Cultivation of Certain Vegetable Crops

For those who have an interest in the ecology of cultivated plants, Thompson\u27s experimental studies on vegetable crops has a wealth of information. This memoir deals not only with the effect of cultivation on yield, but analyzes the several factors of soil moisture, soil temperature, and the production of nitrates as affected by cultivation, and the effect of weeds on these factors. Finally the root habits are studied, and a correlation is made between the root system and the response of the plant to cultivation

Alfalfa Production in a Grassland Climate

The importance of root extent and activities in relation to the supply of subsoil moisture has again been clearly demonstrated. In fact, it has been shown to be the chief problem in the continued production of alfalfa in a grassland climate. Studies extending over a period of 15 years have shown that the native species of the tall-grass prairie never exhaust the water supply below that available for plant growth, except rarely in the shallower soil. The subsoil is always moist, and plants root deeply. Of 43 species typically representative of the flora, only 14 per cent absorb almost entirely in the first 2 feet of soil; 21 per cent have roots extending well below 2 feet but seldom beyond 5 feet; but 65 per cent have roots that reach depths quite below 5 feet, a penetration of 8 to 12 feet being common, and a maximum depth of over 20 feet sometimes being attained. There is sufficient rainfall to wet the soil very deeply, but it is not too wet for good aeration, while aerial conditions promote high transpiration. This results in deep root penetration

Stabilization of Midwestern Grassland

Table of Contents: Introduction Introduction Upland Communities Preceding And Following The Drought Persistence And Effect Of Western Wheat Grass Development Of Understory Chief Invaders Competition In Drought Relative Penetration Of Water Rate Of Infiltration Relative Amounts Of Soil Moisture 7 Effects On Vegetation Severity Of Competition In DroughtPersistence Of Effects After Drought Effects On Forbs And Seedlings Competition With Big Bluestem Needle Grass Consociation Prairie Dropseed Consociation Indicators Of Delay In RecoveryRole Of Big Bluestem Little Bluestem And The Return Of Its Type Spreading Of Kentucky Bluegrass Establishment Of Seedlings New Soil Mulch And Return Of Understory Return Of Forbs And Re-Establishment Of Societies Summary Literature Cite

Effects of Different Intensities of Grazing on Depth and Quantity of Roots of Grasses

The writer has been interested in prairies, pastures, and root depth and distribution over a period of many years. He had the privilege of examining these relationships in the Palouse prairie of Washington long ago while numerous representative areas still remained in a virgin condition (5, 6). Extensive studies have been made in the hardlands of Colorado, Kansas, and Nebraska many years before, during, and following the great drought of 1933-40 (7, 8, 1, 11). Vegetation and root habits have been studied in sand hills (7, 8, 4), in bluffs of wind-blown loess (12), and wet soils of lowland. The trench and hand pick method was employed throughout and roots in prairie and pasture were measured, compared, and sketched in the field. Their depth, spread, and chief characteristics were recorded. Only general consideration was given to soil type. At that time there was no method of quantitatively comparing one root system with another or the roots from one soil with those of the same species from a different soil. The need for such a method has been felt for a long time and lack of one that could be put into general use has probably greatly retarded root studies

Native Grassland of Southwestern Iowa

Studies of the prairie by the writer and Fitzpatrick during 1922-33 were both extensive and intensive. They were extensive in that they included an area of 60,000 sq. mi. in western Iowa, eastern Nebraska and portions of the four adjoining states. They were intensive in that a record of the kinds and distribution of grasses, the abundance and relative importance of forbs, and other pertinent data were ascertained and recorded separately for each of 135 selected areas. Since most of these prairies were examined two or more times each growing season, and many repeatedly during a five-year period, a clear, concise description of each was secured. In this study it soon became clear that the vegetation receiving an annual rainfall of 30-32 in. was better developed in many ways than that in the drier areas westward and northward with 25-29 in. mean annual precipitation. Some of these differences were pointed out by Weaver avid Fitzpatrick (1932, 1934) but the prairie was considered in its entirety and space did not permit descriptions of individual prairies