Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Effects of plant spacing and soil moisture on growth and yield of grain sorghum

Auteur : Miyata, Satoru

Université de soutenance : University of Arizona

Grade : Master of Science (MS) 1978

Résumé
The effects of wetting and drying cycles and soluble salt accumulations on the stability and strength of adobe material similar to that of Tumacacori Mission, Arizona, were examined. Cores of a selected soil were exposed to wetting and drying cycles with deionized water and solutions of the chlorides and sulfates of Ca, Mg, K, and Na. Cores were prepared by saturation of the CEC with either Ca, Mg, K, or Na. Stability was evaluated visually. Strength was tested by measuring the unconfined compressive strength of the cores. Potential for surface deterioration of adobe walls exists in (1) wetting and drying cycles ; (2) substitution of Ca and Mg on the CEC by Na and K ; (3) adsorption of hygroscopic and/or hydrated moisture under conditions of high humidity, especially the chlorides ; (4) retention of moisture under normal conditions by MgC^ and CaClgJ and (5) hydration pressures of NagSO^ and CaClg. Practically, deterioration will be confined to surface or near-surface material. Crystallization pressures are a minimal problem. Possible segregation of salts and accumulation limits in adobe wall interiors is discussed, with implications for production of superior adobe material.

Mots clés : Building, Adobe. ; Tumacácori National Historical Park (Ariz.)

Présentation

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