Incorporating high-sugar varieties of honeylocust (Gleditsia triacanthos L.) or black walnut trees (Jugulans nigra L.) into pasture systems may improve soil and water quality, increase biodiversity, and diversify farm incomes. Studies of productivity and management are needed to understand the trees' potential. Research was conducted in the agroforestry demonstration plots at Virginia Tech's Kentland Farms to 1) estimate both the variability of seedpod yield and nutritive value from juvenile Millwood honeylocust trees, 2) measure changes in nutritive value and digestibility over-winter in Millwood and wild-type honeylocust seedpods, and 3) estimate black walnut biomass productivity, timber quality, nut production, and kernel quality in response to tree density and topography within an emulated silvopasture. Ground Millwood seedpods were comparable to whole-ear dent corn in terms of nutritive value. Both ground pods and seeds were highly digestible (78.7 and 96.3%, respectively) and low in fiber and lignin. Seeds, with over 20% crude protein (CP), have potential as a CP supplement. Millwood trees displayed alternate bearing patterns with 3-yr average yields of approximately 12 kg tree-1. Total aboveground biomass for black walnut trees planted on toe-slopes (109.0 kg) was 72% greater than at back slopes (63.2 kg) and nearly 3-fold more than at shoulder-slopes (37.6 kg). Nut yields ranged from 0 to 7.9 kg of dried, hulled nuts tree-1 year-1. All walnut trees displayed alternate nut bearing patterns and nut production was marked by high variability. / Master of Science

No description available.

Call number: LD2668 .T4 1978 B37 / Master of Science

Distributed rainfall-runoff models are gaining widespread acceptance; yet, a fundamental issue that must be addressed by all users of these models is definition of an acceptable level of watershed discretization (geometric model complexity). The level of geometric model complexity is a function of basin and climatic scales as well as the availability of input and verification data. Equilibrium discharge storage is employed to develop a quantitative methodology to define a level of geometric model complexity commensurate with a specified level of model performance. Equilibrium storage ratios are used to define the transition from overland to channel-dominated flow response. The methodology is tested on four subcatchments in the USDA-ARS Walnut Gulch Experimental Watershed in southeastern Arizona. The catchments cover a range of basins scales of over three orders of magnitude. This enabled a unique assessment of watershed response behavior as a function of basin scale. High quality, distributed, rainfall-runoff data were used to verify the model (KINEROSR). Excellent calibration and verification results provided confidence in subsequent model interpretations regarding watershed response behavior. An average elementary channel support area of roughly 15% of the total basin area is shown to provide a watershed discretization level that maintains model performance for basins ranging in size from 1.5 to 631 hectares. Detailed examination of infiltration, including the role and impacts of incorporating small-scale infiltration variability in a distribution sense, into KINEROSR, over a range of soils and climatic scales was also addressed. The impacts of infiltration and channel losses on runoff response increase with increasing watershed scale as the relative influence of storms is diminished in a semi-arid environment such as Walnut Gulch. In this semi-arid environment, characterized by ephemeral streams, watershed runoff response does not become more linear with increasing watershed scale but appears to become more nonlinear.

Phellinus weirianus (Aphyllophorales: Hymenochaetaceae) causes a white heartrot of living Juglans and is the major cause of decay in Arizona black walnut. Infection is caused by germinating basidiospores. Tissue isolates fruit in culture, but single basidiospore isolates do not. The growth of tissue and single-spore isolates is slow to very slow. Cultural morphology is quite variable even among single-spore isolates derived from a single, culturally produced basidiocarp. Single-spore isolates, presumed to be homokaryotic, are derived from uninucleate spores that germinate and develop hyphae with paired nuclei. Lack of fruiting in homokaryons suggests that P. weirianus is heterothallic. Tissue isolates derived from basidiocarps produced in nature are assumed to be heterokaryotic. Hyphae of tissue isolates have nuclei that are not paired and are more numerous than those in single-spore isolates. Interaction zones are formed in pairings of heterokaryons, pairings of homokaryons, and pairings of homokaryons with the parent heterokaryon. Homozygous matings do not form an interaction zone. Agar-block decay tests show that single-spore isolates exhibit no appreciable differences in decay capacity from tissue isolates. Phellinus weirianus readily decays woods of associated riparian species (Arizona alder, velvet ash, southwestern chokecherry, netleaf oak, and Arizona sycamore) in standard wood test blocks although it is not known on these hosts in nature.

Almost all runoff-producing rainfall on small watersheds (100 square miles and less) in southeastern Arizona results from air-mass thunderstorms. On large watersheds (1,000 square miles and greater) frontal systems which may include thunderstorm activity or snowmelt produce the major flood peaks as well as much of the annual runoff. Air-mass thunderstorms are of short duration and limited areal extent, and generally occur in the late afternoons and early evenings in July, August, and September. Runoff-producing rainfall may occur from frontal-convective systems at any time although they are most common in southeastern Arizona in September. Rainfall and runoff records have been collected from the 58- square-mile Walnut Gulch rangeland watershed near Tombstone in southeastern Arizona by the Agricultural Research Service since 1954. These data represent the best information available on thunderstorm rainfall-runoff relationships in the Southwest. At present there are 95 recording rain gages and 22 permanent runoff-measuring stations on the Walnut Gulch watershed. Runoff-producing thunderstorm rainfall is extremely variable both in time and space, and is therefore difficult to measure accurately and define precisely. Isohyetal mapping for rainfall from individual thunderstorms both for total rainfall and shorter durations within the storm provides good qualitative information, and also provides some quantitative limits on storm movement, intensities and volumes, and areal extent. Runoff records from Walnut Gulch and other Arizona watersheds indicate that peak discharge and runoff volume from individual thunderstorms decrease with increasing watershed size because of the limited areal extent of runoff-producing thunderstorms and because cf the increasing channel abstractions with increasing watershed size. Channel abstractions greatly alter runoff hydrographs as flood surges move through the ephemeral channel system. Five major runoff-producing thunderstorms on Walnut Gulch between 1957 and 1967 were used to develop a model for the maximum expected rainfall in southeastern Arizona. The model was based on maximum 30-minute point rainfalls within the average 60-minute runoff-producing thunderstorm. Over 2.5 inches of rainfall has been recorded in 30 minutes on Walnut Gulch during 3 thunderstorms in 15 years of record (1955-1969). A thorough search of U.S. Weather Bureau and other records indicated that no storms of this combined intensity and magnitude have been recorded in Arizona. Therefore, for design purposes, the expected mean 30-minute rainfall for southeastern Arizona was estimated as 3 inches. Regression analysis was used to estimate peak discharges for major runoff events on Walnut Gulch and to develop a rainfall-runoff model for Walnut Gulch. Peak discharges were correlated with the maximum 30-minute rainfall, which was considered the core of runoff-producing rainfall for major runoff events. Antecedent channel conditions and distance between watershed outlet and runoff-producing rainfall had little effect on the correlation. The coefficients of determination for the regression equation correlating thunderstorm rainfall and peak runoff were 0.92 and o.84 for watershed 5 (8 square miles) and watershed 1 (58 square miles), respectively. With the model for maximum expected rainfall and the rainfall-runoff model for estimating peak discharge from maximum 30-minute rainfall, maximum discharge for the 58-square-mile Walnut Gulch watershed was 23,000 c.f.s. Assuming a normal distribution of errors, within 95 percent confidence limits, the limits were 19,000 and 27,000 c.f.s., and assuming the Chebyshev inequality, the limits were 15,000 and 31,000 c.f.s. Recurrence intervals for 20-, 50-, and 100-year storms and the maximum peak discharges were developed for small watersheds (100 square miles and less) from Walnut Gulch data. The curves were compared to a family of curves for Arizona watersheds up to several hundred thousand square miles. The family of curves based on Walnut Gulch data were much steeper, strongly suggesting that there are 2 families of curves, one steeper family for the small watersheds (100 square miles and less) which is based on runoff peaks from air-mass thunderstorms, and another flatter family of curves for the large watersheds (1,000 square miles and greater) which is based on runoff peaks from frontal-convective systems and snowmelt. The 2 families of curves probably intersect between 100 and 1,000 square miles.

Master of Science / Food Science - Human Nutrition / Delores Chambers / Researchers evaluated the flavor characteristics of seven black walnut (Juglans nigra L.) cultivars: Brown Nugget, Davidson, Emma K, Football, Sparks 127, Sparrow, and Tomboy using descriptive sensory analysis. Seven trained panelists developed a lexicon for the black walnuts and scored the intensities of the samples for 22 flavor and taste attributes. Results showed that the 7 samples differed significantly (P ≤ 0.05) on 13 of the attributes. For the majority of the attributes, only Emma K differed from the rest of the cultivars by being characterized with lower scores for black walnut ID, overall nutty, nutty-grain-like, nutty-buttery, floral/fruity, oily, and overall sweet. It also was higher in acrid, burnt, fruity-dark, musty/earthy, rancid, and bitter attributes. Researchers then incorporated the black walnut cultivars into a simple cookie recipe and evaluated the samples for differences in flavor attributes using the same trained panelists. Nine of the 25 attributes differed significantly across cultivars: black walnut ID, overall nutty, nutty-buttery, brown, toasted, acrid, rancid, overall sweet, and sweet (P ≤ 0.05). Lower mean scores in black walnut ID, overall nutty, and sweet and higher mean scores in rancid and acrid characterized the Emma K cookie. A PCA biplot revealed that cookies with Football, Sparks 127, and Sparrow walnuts related with one another and the attributes nutty-woody, leavening, and piney. A consumer acceptance test for six of the cookies (Tomboy cultivar was excluded) was also performed. There were four significant clusters of consumers that differed in their acceptance of the cookie samples. Cluster 1 preferred Football, clusters 2 and 3 each showed no overall preference, and cluster 4 preferred Emma K suggesting a set of niche consumers for black walnut cookies. Results presented in this paper can assist black walnut growers in determining which cultivars to plant and harvest. By knowing which cultivars have the most desirable flavor characteristics, growers can focus time and resources on select cultivars, therefore resulting in higher quality black walnuts as products to be sold to consumers in various formats. By consciously choosing which cultivars to harvest, black walnut growers can meet market demand and increase profit.

Typescript. / Digitized by Kansas Correctional Industries

Thesis (M.S.)--Youngstown State University, 2008. / Includes bibliographical references (leaves 37-39). Also available via the World Wide Web in PDF format.

Thesis (D. Min.)--Perkins School of Theology, Southern Methodist University, 1985. / Abstract. Includes bibliographical references (leaves 147-150).