The continuous similarity model of bulk soil-water evaporation

The continuous similarity model of evaporation is described. In it, evaporation is conceptualized as a two stage process. For an initially moist soil, evaporation is first climate limited, but later it becomes soil limited. During the latter stage, the evaporation rate is termed evaporability, and mathematically it is inversely proportional to the evaporation deficit. A functional approximation of the moisture distribution within the soil column is also included in the model. The model was tested using data from four experiments conducted near Phoenix, Arizona; and there was excellent agreement between the simulated and observed evaporation. The model also predicted the time of transition to the soil limited stage reasonably well. For one of the experiments, a third stage of evaporation, when vapor diffusion predominates, was observed. The occurrence of this stage was related to the decrease in moisture at the surface of the soil. The continuous similarity model does not account for vapor flow. The results show that climate, through the potential evaporation rate, has a strong influence on the time of transition to the soil limited stage. After this transition, however, bulk evaporation is independent of climate until the effects of vapor flow within the soil predominate

The desorptivity model of bulk soil-water evaporation

Available models of bulk evaporation from a bare-surfaced soil are difficult to apply to field conditions where evaporation is complicated by two main factors: rate-limiting climatic conditions and redistribution of soil moisture following infiltration. Both factors are included in the "desorptivity model', wherein the evaporation rate during the second stage (the soil-limiting stage) of evaporation is related to the desorptivity parameter, A. Analytical approximations for A are presented. The approximations are independent of the surface soil moisture. However, calculations using the approximations indicate that both soil texture and soil moisture content at depth significantly affect A. Because the moisture content at depth decreases in time during redistribution, it follows that the A parameter also changes with time. Consequently, a method to calculate a representative value of A was developed. When applied to field data, the desorptivity model estimated cumulative evaporation well. The model is easy to calculate, but its usefulness is limited because it requires an independent estimate of the time of transition between the first and second stages of evaporation. The model shows that bulk evaporation after the transition to the second stage is largely independent of climatic conditions

A preliminary report on the fouling characteristics of Ponce de Leon Tidal Inlet, Daytona Beach, Florida

In December 1941, the writers visited the exposure location of the North Florida Test Service on Ponce de Leon Inlet, near Daytona Beach, Florida, for the purpose of examining the extent of borer attack in this locality, and to determine the station\u27s suitability for exposure tests on treated piling and for tests in the related field of marine fouling. Arrangements were effected for exposing a series of gum pine blocks throughout the year 1942 to record the progressive borer attack, and simultaneously, to record the growth of all marine fouling organisms prevalent at this location

Following the contour (How to strip-crop Iowa land)

Many Iowa farmers are now farming around the hills instead of up and down them. The results of many investigations have justified for some time this practice as a soil- and water-conserving measure, but until comparatively recently there was little contour farming practiced in the state. Since contour farming has been adopted on many Iowa farms in the last few years, its value under real Iowa conditions can be appraised on the basis of actual experience. “The proof of the pudding is in the eating,’’ according to the old English proverb, and so it is with contour farming. Farmers have found it to be a wise and feasible practice as shown by the fact that only a very few of those who have given it a fair trial have abandoned it. The reasons why contour farming helps to conserve soil and water are obvious. Every row running around the hill acts as a little barrier which checks the velocity of the surface runoff, causing it to unload its silt and to flow more slowly from the land so that more of the water will have time to soak into the soil. Strips of close-growing, soil-binding crops, planted alternately between strips of contour row crops, likewise lessen the amount of the slope exposed by the clean tillage. The close-growing crop will check the velocity of any runoff from the cultivated strip above and cause it to drop its load of silt. The soil covered by the soil-binding crop will be held against erosion, and the continuous extension of rills and gullies through the field will be checked

Interdisciplinary research on the application of ERTS-1 data to the regional land use planning process

The author has identified the following significant results. Although the degree to which ERTS-1 imagery can satisfy regional land use planning data needs is not yet known, it appears to offer means by which the data acquisition process can be immeasurably improved. The initial experiences of an interdisciplinary group attempting to formulate ways of analyzing the effectiveness of ERTS-1 imagery as a base for environmental monitoring and the resolution of regional land allocation problems are documented. Application of imagery to the regional planning process consists of utilizing representative geographical regions within the state of Wisconsin. Because of the need to describe and depict regional resource complexity in an interrelatable state, certain resources within the geographical regions have been inventoried and stored in a two-dimensional computer-based map form. Computer oriented processes were developed to provide for the economical storage, analysis, and spatial display of natural and cultural data for regional land use planning purposes. The authors are optimistic that the imagery will provide revelant data for land use decision making at regional levels

The use of ERTS-1 data for the inventory of critical land resources for regional land use planning

Computer-generated spatial and statistical comparisons of critical land resource data derived from conventional sources, RB-57 photographs, and ERTS images, for an eastern Wisconsin test site, suggest that certain critical land resource data can be mapped from ERTS images on a statewide basis. This paper presents one of the biotic resources, wetlands, as an example of the use of ERTS imagery to inventory land resources

An investigation into how tree characteristics and species composition associated with veteran and ancient trees influences invertebrate species

Veteran and ancient trees have distinctive characteristics that act as microhabitats: such as tree cavities and deadwood. These trees and their microhabitats are keystone features for specialised communities of invertebrates, fungi, and epiphytes. However, due to limited species data, there are still uncertainties around the relative importance of veteran and ancient trees and their associated microhabitats on these invertebrate species. This investigation aims to assess how the tree characteristics of veteran and ancient trees affect the species richness and composition of the three taxa (i) invertebrates, (ii) fungi, and (iii) epiphytes. Epiphytes, fungi, and invertebrates on the tree trunk were recorded and identified; pitfall traps were also installed and collected after 48 hours for identification in the lab. The most significant tree host characteristics that impacted species richness and community structure were the tree size, measured as the diameter at breast height (m) and the number and quality of tree cavities found only on veteran and ancient trees. Due to the low sample size, the ancient tree was combined with veteran trees for data analysis. Tree size significantly affected the variation in the number of microhabitats between tree species, accounting for 68% of the variation, suggesting that larger trees that are generally older will provide more microhabitats. Although the ancient and veteran trees combined had a higher diversity of invertebrates with a mean of three compared to mature trees with two, it was not statistically significant. Furthermore, tree size and the number of microhabitats did not significantly impact the variation associated with invertebrate species richness. Tree cavities benefit invertebrate species, with the wood mould providing stable levels of moisture, pH, and temperature. However, this was not observable due to the invertebrates being in diapause during the sampling period

Evaluation of the application of ERTS-1 data to the regional land use planning process

The author has identified the following significant results. Employing simple and economical extraction methods, ERTS can provide valuable data to the planners at the state or regional level with a frequency never before possible. Interactive computer methods of working directly with ERTS digital information show much promise for providing land use information at a more specific level, since the data format production rate of ERTS justifies improved methods of analysis

Critique and Design on the Cost of Cataloging

published or submitted for publicatio