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Accueil du site → Doctorat → États-Unis → 1987 → Variations and boundary location of static and dynamic soil properties along a desert catena in southern New Mexico

New Mexico State University (1987)

Variations and boundary location of static and dynamic soil properties along a desert catena in southern New Mexico

Al-Dabbagh, Ahmed Assim

Titre : Variations and boundary location of static and dynamic soil properties along a desert catena in southern New Mexico

Auteur : Al-Dabbagh, Ahmed Assim

Université de soutenance : New Mexico State University

Grade : Doctor of Philosophy (PhD) 1987

Résumé
A field experiment was conducted to study variation in soil static and dynamic properties along a desert catena in southern New Mexico. Soil texture, the static property, was determined for samples taken along a 315-m transect at equally spaced intervals of 5-m for the five depths of 10 cm increments. Soil moisture content, the dynamic soil property, was determined by a Neutron-scattering method and measurements were taken on a weekly basis for 20 locations along the same transect at equally spaced intervals of 15 m. Measurements were taken to a depth of 130-cm at 10-cm increments. Eight soils pedons were described in detail to identify the different soil classes along the transect of the study area. Time series analysis was employed in this study as a statistical tool to study soil variations and to test its applicability as a technique. Subsampling variations, were found to be minimal when comparing space to space and/or time to time variations. Variations within soil classes were found to be less than among the classes along the transect. Variation of the soil static property from place to place was found to be greater than that of the dynamic property measured across time. All statistical parameters were found to be far from normality when soil properties were measured in space along the transect ; soil properties within a uniform soil class, however, had normal distribution. Through time series analysis, both static and dynamic soil properties were found to be related in space and in time respectively and exhibited order one autoregressive time series type of processes. Three soil groups based on the static soil property were differentiated with cross-correlation technique. Three different soil groups were identified when the dynamic property was used with the same statistical technique. Boundary points achieved by the cross-correlation technique for both static and dynamic properties were found to match well. Furthermore, they have been found to match well with boundary locations found in the field as well. Nine time series models were identified for the soil static property and for the three designated depths along the transect. Another three time series models have been identified for the dynamic property. All models were order one autoregressive.

Sujets : Soils—New Mexico // Desert soils—New Mexico.

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Page publiée le 13 janvier 2018, mise à jour le 11 novembre 2018