Chlorosis of plants from a lack of available iron is one of the most common plant nutrient problems of the calcareous soils of the west. The disease is characterized by a yellowing of the plant leaves and is accompanied, in severe cases, by a partial root death and premature defoliation (3). In addition to reducing growth, the disease greatly reduces the quality and yield of plants. Many types of plants are affected by iron chlorosis. In Hawaii and Porto Rico rice, sugar cane and pineapple are susceptible, while in California and Arizona, citrus trees are seriously affected. In Utah apples, peaches, plums, prunes, apricots, pears, grapes, raspberries and many ornamental plants are affected (27). The problem of iron chlorosis, therefore, is of great importance to agriculture in the west. Chlorosis has been studied for more than one hundred and fifty years, but until recently, little progress has been made toward finding the solution to the problem. Although these past studies have not solved the problem of iron chlorosis, they have shown many factors to be closely related to the occurrence of the disease. These factors include an unbalanced ratio of available manganese to iron in the growth medium (9, 23, 29); chlorotic leaves are high in potassium, nitrogen in the form of ammonia (21), and in ferric iron and are low in total calcium and ferrous iron in comparison with green leaves (12, 13, 14, 17, 25, 26). The climatic factors of light, soil temperature and soil moisture also appear to be of fundamental importance in chlorosis. It is a common observation that fruit trees are more chlorotic during the early spring when the temperature of the soil is low and the moisture level high. Many investigators have noted that chlorosis tends to be most severe in the poorly drained portions of fruit orchards when water tends to accumulate. However, the work on the affect of climatic conditions on chlorosis has been limited largely to observations. The purpose of this investigation was to study, under controlled conditions, the effect of light, soil temperature and soil moisture on a lime-induced chlorosis.

Many factors that influence the growth and quality of sugar beets behave in one way under one set of conditions and in quite another under other conditions. Consequently, these factors should be considered together under a dynamic situation to find their interrelations and their influence on sugar beet yield. This study is a statistical analysis of the interaction of fertilizer and soil moisture potential with the yield of sugar beets grown in a crop rotation under different regimes of irrigation conducted over a period of seven years. The data are available for the years 1949 through 1956, from an intensive field experiment conducted under Western Regional Research Project W-29, entitled Soil-Water-Plant Relations under Irrigation. There is need of a complete statistical analysis of third order interaction for the whole cultural rotation. This third order interaction has been examined for the sugar beet crop grown in the seven years of the general cultural rotation, which includes peas, first year alfalfa, second year alfalfa, potatoes, and sugar beets.

During 1966 and 1967, a range plant clipping study was conducted at two locations in central Utah's Ephraim Canyon. It was found that extreme clipping treatment resulted in a significant increase in soil moisture due to a presumed decrease in transpiration during 1967. At the lower location, 7,100 feet elevation, a difference of 5.4 inches over a 5 foot soil profile was noted between the extreme and control clipping treatments in 1967. At the upper location, 10,000 feet in elevation, a savings of 3.6 inches soil moisture was observed over the 5 foot soil profile in 1967. Other clipping intensities also showed water savings in terms of reduced depletion values over the control plots, although these differences were not in all cases statistically significant.

The importance of nitrogen in world agriculture has been known for many years. But in the past few decades the enormity of the problem of nitrogen economy has been recognized. Along with the recognition of this problem there has developed a great increase in the use of nitrogen fertilizers. Coupled with the increased use of nitrogen there has come about an increasing awareness of the problem involved in the use of nitrogen fertilizers.

The object of current efforts at investigating catchment response is to derive a physically based stochastic model of the watershed. Recent studies have, however, indicated that a limiting factor in deriving such models is the dependence of hydrologic response on initial soil moisture. The dependence affects the distributions and moments of the hydrological processes being investigated. A stochastic model of soil moisture dynamics is developed in the form of a pair of stochastic differential equations (SDE's) of the Ito type. The sources of stochasticity are linked to the random inputs of rainfall and evapotranspiration (ET). One of the SDE's describes the "surplus" case, in which sufficient infiltration always occurs to allow for moisture depletion by the processes of drainage through and ET out of the root zone. The other SDE represents the "deficit" case, in which lack of adequate moisture leads only to an ET-controlled depletion process. Sample functions and moments of moisture evolution are obtained from the SDE's. From the general model of soil moisture, a specific model of initial soil moisture (the moisture at the beginning of a rainstorm event) is developed and its moments are derived. Furthermore, the probability distribution of initial moisture is postulated to permit the assessment of how initial moisture affects the estimation of hydrologic response. The moisture dynamics model reveals that the stochastic properties of moisture ae sensitive to initial conditions in the watershed only for less permeable soils under the "surplus" state but are practically insensitive to such conditions for more permeable soils. The stochastic properties are also less sensitive to initial conditions for all soil types whenever under the "deficit" state. These results suggest that hydrologic processes, such as precipitation excess and infiltration, depend on initial moisture only in regions where the soils are generally less permeable and where the climate tends to sustain a "wet" environment, whereas in arid or semi-arid regions, such processes would not depend on initial moisture. These conclusions imply that, in arid regions, an effective value of initial moisture such as the mean can be used to estimate the properties of the hydrologic processes, whereas in "wet" environments, more accurate values of the properties must be "weighted" based on the probability distribution of initial soil moisture.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Meteorology and Physical Oceanography, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND LINDGREN. / Bibliography: leaves 136-139. / by Dale Richard Durran. / Ph.D.

京都大学 / 新制・課程博士 / 博士(農学) / 甲第23525号 / 農博第2472号 / 新制||農||1087(附属図書館) / 学位論文||R3||N5356(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 梅村 研二, 教授 矢野 浩之, 教授 仲村 匡司 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Research is presented which encompasses a study of epoxies based on diglycidyl ether of bisphenol A (DGEBA) cured with 2-ethyl-4-methylimidazole (EMI-24) in the presence of the nonionic surfactant Triton X-100. Interest in this epoxy system is due partially to the potential application as a waterborne replacement for solvent cast epoxies in E-glass laminated printed circuit boards. This research has revealed that the viscoelastic behavior of the cured epoxy is altered when serving as the matrix in a glass composite. The additional constraining and coupling of the E-glass fibers to the segmental motion of the epoxy matrix results in an increased level of viscoelastic cooperativity. Current research has determined that the cooperativity of an epoxy/E-glass composite is also sensitive to the surface chemistry of the glass fibers. Model single-ply epoxy/E-glass laminates were constructed in which the glass was pretreated with either 3-aminopropyltriethoxysilane (APS) or 3-glycidoxypropyltrimethoxysilane (GPS) coupling agents. Dynamic mechanical analysis (DMA) was then used to create master curves of the storage modulus (E') in the frequency domain. The frequency range of the master curves and resulting cooperativity plots clearly varied depending on the surface treatment of the glass fibers. It was determined that the surfactant has surprisingly little effect in the observed trends in cooperativity of the composites. However, the changes in cooperativity due to the surface pretreatment of the glass were lessened by the aqueous phase of the waterborne resin. Moisture uptake experiments were also performed on epoxy samples that were filled with spherical glass beads as well as multi-ply laminated composites. No increases in the diffusion constant could be attributed to the surfactant. However, the surfactant did enhance the final equilibrium moisture uptake levels. These equilibrium moisture uptake levels were also sensitive to the surface pretreatment of the E-glass. / Ph. D.

Student Number : 0418764K - MSc (Eng) dissertation - School of Civil and Environmental Engineering - Faculty of Engineering and the Built Environment / Increasing quantities of finer wastes often contain reactive sulphide minerals and high water contents that pose stability and environmental concerns. This study investigates how electrokinetic process can be improved, to make it more viable towards dewatering finer coal slurries. In the electrokinetic process, a direct current induces the movement of water out of a porous material. A wooden test box was filled up to two-thirds with fine coal slurries. Electrokinetic Geotextiles (EKGs) and brass were used as electrodes. The conducting wires were attached to each electrode and connected to a DC source to form an electro-osmosis cell. Current was passed through the cell and water moved to the cathode where it was withdrawn. The dewatering efficiencies ranged from 13.13 to 109.84 ml/Ah. The energy consumptions ranged from 5.23 to 14.03 kWh/m3 and are in line with those recorded by Johns (2005). Conductivity and pH measurements were taken. EKGs performed better than brass electrodes.

Water is an important parameter for crop growth, and the information about the moisture content in soil at different depths is very useful for farmers to determine the best time to water the soil and to irrigate farmland so as to maximize their yield. This thesis project aims to develop a prototype of a multi-depth moisture sensor probe that is part of a large sensing system used in agriculture. The sensor probe has three sets and is required to last for 6-12 months of usage and to be reproduced at a low cost. The sensor probe consists of three sensor boards, on each of which has two different capacitive based sensors and one analog temperature sensor. The three boards are placed approximately 20 cm from each other in the probe. During this project, the two capacitive based sensors were developed, one with arc-shaped plates operating at a frequency less than 1 MHz, and one with electrodes in the form of annular rings operating at a high frequency, approximately 100 MHz. The moisture content in the soil is calculated based on the measurement of the frequency, which depends on the dielectric constant of the soil. For the implementation of the sensor probe, three printed circuit boards (PCBs) for the sensor boards were designed using Altium Designer and then ordered; an STM32 Nucleo board with low power microcontroller was used and the software was implemented in STM32CubeIDE. The lifetime of the sensor probe was calculated for different duty-cycles. With a duty-cycle of 15 minutes, where the sensor probe is active for 1 minute and in sleep mode for 14 minutes, the lifetime of the sensor probe would only be 16 days. With a duty-cycle of 120 minutes instead, with the sensor probe being active for 1 minute, the lifetime is increased to 130 days (less than4,5 months). Due to challenges with the high frequency capacitive sensor, the multi-depth sensor probe does not fully work, and thus cannot be tested with a large testbed. Further work needs to be conducted on the high frequency capacitive sensor and the communication with the gateway.