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Effects Of Chiselling And Sulfur Fertilization On Infiltration, Soil Water Content, Peak Season Biomass Production, And Botanical Composition In The Ait Rbaa Perimeter, Mohammed Tigma

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study evaluated the effectiveness of chiselling and elemental sulfur fertilization in improving an upland and a swale range site with fine loamy, carbonatic, typic calcixeroll soils in the Ait Rbaa Perimeter of central Morocco. Ponding infiltration, soil water content on a mass basis of the 0- to 10-cm and 10- to 20-cm soil layers, peak season biomass production, and botanical composition were monitored during the two growing seasons following the treatments (1984/85 and 1985/86). Chiselling significantly improved infiltration on both sites, although the improvement was greater on the finer and less stony swale site, where chiselling resulted in more …

Burning, Flaming And Herbicides For Control Of Jointed Goatgrass (Aegilops Cylindrica Host.), Blake D. Willis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Winter wheat stubble and dried plant residue in Conservation Reserve Program (CRP) fields were burned in the fall and spring to evaluate effects on jointed goatgrass (Aegilops cylindrica Host.) seed survival and germination. Laboratory studies were also conducted to determine minimum temperatures and heat duration needed to reduce jointed goatgrass seed viability. Maximum air temperatures attained during various field burns reached from 74 C to over 700 C. Temperatures 2.5 cm above the soil surface remained above 400 C for over 10 seconds and above 600 C for 2 to 8 seconds in burning CRP stubble. Results for the …

The Relationship Between Leaf Area Index And Photosynthetic Temperature Response In Wheat (Triticum Aestivum L.) Canopies, David B. Meek

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The objective of this study was to determine the effect of increasing leaf area index on the photosynthetic temperature response of a wheat canopy. Hard red spring wheat (Triticum aestivum L. cv. Veery-10) was grown hydroponically in a growth chamber, which also served as the gas-exchange chamber. Gas-exchange parameters were measured on single leaves and on wheat canopies at various leaf area indices. The temperature response curves of the canopy shifted from being steeper with a high temperature optimum to being flatter with a lower temperature optimum as leaf area index increased from 0 to 20.0 m²m …

Morphological Responses Of Wheat (Triticum Aestivum L.) To Changes In Phytochrome Photoequilibria, Blue Light And Photoperiod, Charles Barnes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wheat (Triticum aestivum, L.) plants were exposed to three different levels of phytochrome photoequilibria (φ), two different photoperiods, end-of-day far-red radiation, two different levels of blue (400-500 nm) light, three levels of photosynthetic photon flux (PPF), and two types of high intensity discharge lamp types. Tillering was reduced by lowered φ, by reduced amounts on blue light and by end-of-day far-red. Main culm development was increased by lowered φ, by increased PPF, and was reduced by shortened photoperiod and by reduced blue light. Leaf length was increased by increased PPF, lowered φ, and reduced blue light but was …

A Descriptive Study Of Range Livestock Operations In The Somali Central Rangelands, Abdinasir M. Abdulle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Information on livestock operations, particularly what kind of livestock operations are practiced in the Somali central rangelands, and how these operations differ for different herders in different vegetation types and farming systems, could serve as a major tool in making management decisions. This study provides a detailed description of range livestock operations in the Somali Central Rangelands. It also answers some important management questions.

Range livestock operations were inventoried through personal interviews with the owners and herders. Data are supplemented by previous nation-wide and regional survey statistics. Herd productivity data which include herd structures, age, age-related sales, slaughters, gifts, and …

Autecological Characteristics Of Chrysopogon Aucheri And Cymbopogon Jwarancusa, Dominant Rangeland Grasses In Baluchistan, Mohammad Saleem

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Controlled environment experiments were designed to study the germination, seedling development, and defoliation responses of Chrysopogon aucheri and Cymbopogon jwarancusa to better understand their autecology and potential use in range improvement programs in Baluchistan.

In experiment 1, Cymbopogon jwarancusa had greater seed fill and viability than Chrysopogon aucheri. When incubated at six different alternating temperature regimes, seeds of Cymbopogon jwarancusa had greater cumulative germination at five temperature regimes and faster germination at the colder temperature regimes than Chrysopogon aucheri.

In experiment 2, seedling shoot and root development was characterized at 15-day intervals over a 60-day period. Seedlings of …

Forest Canopies: Form And Functional Relationships, Steven B. Jack

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Forest canopy structure is strongly influenced by stand density due to changing competitive interactions among the individual trees and in turn directly influences stemwood volume production. The structure and dynamics of forest canopies, particularly in relation to the production of stemwood, were examined in unmanaged, even-aged stands of two dissimilar tree species, Pinus contorta var. latifolia Engelm. and Abies lasiocarpa (Hook.) Nutt. The analysis of structure-production relationships was guided by a conceptual model which generated hypotheses and led to examination of assumptions incorporated in the model.

Mean crown dimensions were related to stand density through a negative exponential function for …

Carbon Dioxide Toxicity In Wheat, Robert Spanarkel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research was conducted to quantify short- and long-term effects of atmospheric carbon dioxide on wheat. Growth, development, and yield of the spring wheat cultivar Veery-10 were measured in response to CO₂ concentrations of 340 (ambient), 1200, and 2500 μmol moI^-1 of CO₂ air. These 3 CO₂ levels were chosen to provide a control group, a predicted optimal CO₂ environment, and a potentially toxic CO₂environment, respectively. A recirculating hydroponic system provided a near-optimal root-zone environment that was identical for all CO₂ treatment levels. Environmental factors, other than CO₂, were …

The Basis Of Browsing Tolerance In Shrubs Of The Intermountain West: Growth Rates And Meristematic Potential, Jackson L. Wandera

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Relative growth rates (RGRs) and meristematic potential of big sagebrush (Artemisia tridentata, in some experiments ssp. tridentata Nutt. and in other experiments ssp. vaseyana [Rydb] Beetls), bitterbrush (Purshia tridentata [Pursh] DC), serviceberry (Amelanchier alnifolia Nutt.), birchleaf mountain mahogany (Cercocarpus montanus Raf.), curlleaf mountain mahogany (C. ledifolius Nutt.) and big tooth maple (Acer grandidentatum Nutt.) were quantified under both glasshouse and field conditions. The relationships between the RGRs, meristematic potential and regrowth capacity of the shrub species were then determined. Sagebrush exhibited a significantly higher RGR than the other species at both high and low …