Changes in the energy status of water that occurred in Milville silt loam and in bean (Phaseolus vulgaris L.) plants growing on it , during two consecutive 6-day periods while being irrigated with saline solutions, were studied. Total soil water potential (Ψ soil) (measured with thermocouple psychrometers), matric-potential (Ψm) (measured with tensiometers) were considered. In leaf samples, the total water potential (leaf) and the osmotic potential (Ψπ)--after freezing-- were determined with thermocouple psychrometers; by difference, the pressure potential (Ψp) was obtained. There is no evidence of close relationship between changes taking place in the values of the leaf water potential (or its components) and changes that occur in the energy status of the soil solution. Also, there is a lack of close relationship between the concentration of the solutions added and the resulting water potentials in the soil solution. Results indicate that the soil water potential exerts increasing control of leaf water potential as it decreases. In addition, there is a smaller range of values of leaf water potentials when the saltier solutions (C and D) are used for irrigations. Also, the osmotic potential is higher in leaves of plants grown in pots watered with saltier water. High values of pressure potentials (Ψp)--low turgor-calculated for leaf samples, where no wilting symptoms were visible, suggest that there are differences among plant species with regard to the turgor level at which wilting occurs.

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Ng Chi Chung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 126-143). / Abstract --- p.i / Acknowledgements --- p.iii / Lists of Tables --- p.vii / Lists of Figures --- p.ix / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Importance of soil physical properties to plant growth --- p.2 / Chapter 1.3 --- Importance of organic matter to soil physical properties --- p.5 / Chapter 1.4 --- Chemical composition of sewage sludge and spent sawdust litter and their disposal --- p.6 / Chapter 1.5 --- Objectives --- p.9 / Chapter 1.6 --- Significance of the study --- p.10 / Chapter Chapter 2 --- Literature Reviews / Chapter 2.1 --- Influence of organic wastes on soil organic matter --- p.12 / Chapter 2.2 --- Influence of organic wastes on soil aggregate stability --- p.15 / Chapter 2.3 --- Influence on bulk density and total porosity --- p.21 / Chapter 2.4 --- Influence on field capacity and water holding capacity --- p.23 / Chapter 2.5 --- Influence on soil water intake and in situ soil moisture content --- p.27 / Chapter 2.6 --- Influence on mechanical resistance --- p.28 / Chapter Chapter 3 --- Methodology / Chapter 3.1 --- Study site --- p.30 / Chapter 3.2 --- Treatments --- p.30 / Chapter 3.3 --- Soil sampling --- p.32 / Chapter 3.4 --- Methodology / Chapter 3.41 --- Organic carbon --- p.33 / Chapter 3.42 --- Aggregate stability --- p.34 / Chapter 3.43 --- Bulk density --- p.37 / Chapter 3.44 --- Field capacity --- p.37 / Chapter 3.45 --- Water characteristics curve --- p.38 / Chapter 3.46 --- Infiltration --- p.38 / Chapter 3.47 --- Water release property --- p.39 / Chapter 3.48 --- Mechanical resistance --- p.39 / Chapter 3.5 --- Statistical analysis --- p.39 / Chapter Chapter 4 --- Effect on Soil Aggregate Stability / Chapter 4.1 --- Introduction --- p.41 / Chapter 4.2 --- Results / Chapter 4.21 --- Effect on soil organic matter content --- p.45 / Chapter 4.22 --- Change in organic matter content under continuous cultivation --- p.46 / Chapter 4.23 --- Effect on aggregate stability under continuous cultivation --- p.47 / Chapter 4.24 --- The relationship between percentage aggregate stability and the amount of organic matter --- p.49 / Chapter 4.3 --- Discussion --- p.52 / Chapter 4.4 --- Conclusions --- p.60 / Chapter Chapter 5 --- "Effect on Bulk Density, Total Porosity and Mechanical Resistance" / Chapter 5.1 --- Introduction --- p.62 / Chapter 5.2 --- Results / Chapter 5.21 --- Change in bulk density and total porosity --- p.65 / Chapter 5.22 --- Change in bulk density and total porosity under continuous cultivation --- p.66 / Chapter 5.23 --- Change in bulk density and total porosity in relation to organic matter content and aggregate stability --- p.67 / Chapter 5.24 --- Change in mechanical resistance --- p.69 / Chapter 5.3 --- Discussion --- p.71 / Chapter 5.4 --- Conclusions --- p.77 / Chapter Chapter 6 --- Effect on soil water retention / Chapter 6.1 --- Introduction --- p.80 / Chapter 6.2 --- Results / Chapter 6.21 --- Field capacity and change between the second and the fourth harvest --- p.82 / Chapter 6.22 --- Relationship between field capacity and organic matter content --- p.84 / Chapter 6.23 --- Water characteristics curve --- p.84 / Chapter 6.24 --- Change in water characteristics curve between the second and the fourth harvest --- p.88 / Chapter 6.25 --- The relationship between water holding capacity and organic matter content --- p.91 / Chapter 6.26 --- Change in available water capacity and its relationship with organic matter content --- p.92 / Chapter 6.3 --- Discussion / Chapter 6.31 --- Change in field capacity --- p.95 / Chapter 6.32 --- Change in water holding capacity and available water capacity --- p.97 / Chapter 6.4 --- Conclusions --- p.100 / Chapter Chapter 7 --- Effect on Infiltration and Water Release Property / Chapter 7.1 --- Introduction --- p.102 / Chapter 7.2 --- Results / Chapter 7.21 --- Infiltration and its change under continuous cultivation --- p.103 / Chapter 7.22 --- Water release property --- p.109 / Chapter 7.3 --- Discussion --- p.112 / Chapter 7.4 --- Conclusions --- p.117 / Chapter Chapter 8 --- Conclusion / Chapter 8.1 --- Summary of findings --- p.118 / Chapter 8.2 --- Implication of the study --- p.122 / Chapter 8.3 --- Further studies --- p.123 / References --- p.126

Typescript (photocopy). / Digitized by Kansas Correctional Industries

It has been generally recognized that the surface phenomena of the solid particles such as shrinking and swelling, water- holding capacity, water' movement, and cation exchange are important in understanding the physical properties of the soil. Clay is the most prevalent material in the colloidal fraction of many soils. Because of the complex nature of the surface of clays and the small size of the particles, the direct study of surface phenomena is difficult. Thermodynamic functions change in accordance with changes and organization within the system. Thus, an examination of the thermodynamics of surface phenomena provides some understanding of the reactions.

Bibliography: p. 182-197. The objectives of this study are: selection and construction of four narrow sowing points, evaluation of these points in terms of draught requirements and wear rates, comparison of the points in direct drilling systems and their effects on soil physical properties.

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 293-308).