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Accueil du site → Doctorat → Royaume-Uni → 1989 → Water storing polymers as aids to vegitation establishment in arid soils

University of Liverpool (1989)

Water storing polymers as aids to vegitation establishment in arid soils

Woodhouse, Joanna Margaret

Titre : Water storing polymers as aids to vegitation establishment in arid soils.

Auteur : Woodhouse, Joanna Margaret.

Université de soutenance : University of Liverpool

Grade : Doctor of Philosophy (PhD) 1989

The high permeabilities and poor moisture-storage properties of coarse-textured, sandy soils hinder plant establishment and growth. Water-storing, gel-forming synthetic polymers have recently been introduced as aids to vegetation establishment on such drought-prone substrates. These polymers are capable of absorbing large quantities of water and have been designed to act as reservoirs in the soil from which developing plants can extract moisture as required. The polymers have major potential applications as water conservation aids in arid and semi-arid regions to aid the establishment and growth of trees, shrubs and crops. In more temperate countries, the polymers may be useful in both agricultural and horticultural situations where they could reduce failure rates of newly-planted trees and maintenance and irrigation costs. The research reported in this thesis is an investigation of the technical efficacy of hydrophilic polymers for improving plant growth in arid soils. The first part of the thesis is an examination of the effects of soluble salts in irrigation waters on the volume of water which the polymers can absorb. The salts examined were those found commonly in irrigation waters in Middle Eastern and African regions. The major fertilizer ions likely to be found in soil solutions were also included in this study because addition of fertilizers to soils will lead to these ions being in contact with polymers. In the second part of the thesis, an examination of physical aspects of water storage and loss by polymers is reported. The rates of water loss from polymers and polymer-treated soils and the effects of polymers on plant-available soil water supplies were investigated. The plant-available water supply of a polymer is a direct consequence of the binding tension with which the polymer holds water and several polymers were found to bind most of their water in the plant-available range. The third part of the thesis is a detailed examination of the effects of polymers on a range of different plants. The approach used was to examine how useful the polymers were in growing situations at the stages of germination/establishment, young plant and in the production of vegetable crops under glass. The effects of polymers on tree growth, both in the UK and in the Sudan, were studied. The effects of the polymers on crop growth under field conditions were tested using sorghum in the Sudan. In general, there were benefits of the polymers to plant growth at all growth stages and to the water use efficiencies of many of the soil-plant growing systems studied. Performance of polymers under field conditions was, however, found to be difficult to forecast from the results of glasshouse experiments.

Mots clés : Agronomy Plant diseases Horticulture Agricultural engineering Soil

Présentation : EThOS (UK)

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