Margaret Livingston - Academia.edu (original) (raw)

Uploads

Papers by Margaret Livingston

I also wish to thank Dr. Donovan Wilkin for his help with preparation and review of this manuscri... more I also wish to thank Dr. Donovan Wilkin for his help with preparation and review of this manuscript. Special thanks to Steven for his continual encouragement and support throughout the study, and to Mary, Ken, and Betsy for their helpful hands during construction of the research plots.

Journal of the American Society for Horticultural Science

Single plant selections from a diverse guayule (Parthenium argentatum Gray) breeding population w... more Single plant selections from a diverse guayule (Parthenium argentatum Gray) breeding population were evaluated for rubber and resin concentration, rubber and resin yield, and 12 growth characteristics. Thirty-seven superior selections (≈9% of the total of 421 single plant selections) exhibit combinations of satisfactory biomass production, high rubber yield, and strong regeneration and survival after harvesting by clipping the branches at a height of 0.10 m. Rubber concentration (%) was not highly correlated with the 12 plant characteristics measured. In contrast, rubber yield (g/plant) was highly correlated with plant dry weight and other plant characters related to biomass production. Twelve of the 37 superior selections had yields >125 g of rubber per plant, and the rubber concentration of seven of these 12 plants exceeded the mean (7.1%) of the 37 superior selections. Selection for high rubber concentration and yield with strong top regrowth after clipping appears to be feasi...

Urban environments present unique challenges for landscape designers wishing to incorporate wildl... more Urban environments present unique challenges for landscape designers wishing to incorporate wildlife attractants into their designs. Cities such as Tucson, Arizona that are surrounded by relatively large expanses of native vegetation provide many opportunities for effectively enticing native wildlife into urban spaces. Patches of landscape can be designed that mimic vegetation composition found on the peripheral edges and may potentially lure wildlife by providing food and cover. These areas may also provide regenerative patches of native vegetation within the urban matrix, thereby offering connectedness to larger areas of native vegetation. Such corridors encourage wildlife movement and may aid in the retention of wildlife populations. The purpose of this paper is to describe and illustrate design techniques used to create these vegetation patches specifically for attracting songbirds, hummingbirds, and butterflies within urban spaces in Tucson. Design strategies that address plant...

An understanding of the various influences of urbanisation on plant communities is critical for p... more An understanding of the various influences of urbanisation on plant communities is critical for planning a sustainable future for the planet. For example, landscape practices and sense of place driven by aesthetic influences often dominate in the design of built landscapes, resulting in strikingly different vegetation communities from that of the surrounding communities. Furthermore, these built landscapes in metropolitan areas often markedly influence an inhabitant's impressions of a region's biotic foundation and sense of place. Inhabitants may not consider or understand the ecological impacts of practices that are typically dominated by contemporary cultural aesthetics. Do these cultural aesthetic drivers result in relatively similar landscapes in terms of appearance, regardless of region? The purpose of this study was to document general trends in landscape structure and composition from two distinct, different regions. Specifically, we addressed the questions: how do th...

Natural open spaces adjacent to developing cities are frequently affected by advancing urban spra... more Natural open spaces adjacent to developing cities are frequently affected by advancing urban sprawl. It requires a delicate balancing act to conserve habitats while developing new environments for city inhabitants. As landscape architects, planners, and managers of these areas, we continue to explore mitigation strategies for habitats affected by development. One strategy focuses on creating new spaces within development that can fulfil some of the functions previously provided by natural areas and serve as resource links among remaining peripheral natural areas (Forman and Godron, 1986). Previous research has shown that created open spaces, such as parks and golf courses may provide critical habitat functions associated with natural areas if planned appropriately (Mannan and Boal, 2000; Shaw et al, 1998). However, few studies have evaluated the specific characteristics associated with created open spaces for their wildlife habitat value. This research addresses the following questi...

Calsweet watermelons were irrigated at two levels, utilizing a drip irrigation system for accurat... more Calsweet watermelons were irrigated at two levels, utilizing a drip irrigation system for accurate rate measurements. Number and weight of harvested melons were recorded for four harvest dates. There were no significant differences in weight per melon, number of melons and total mean weight for the water treatments within the four harvest dates. For the entire season, number and total weight of melons were higher in the wet treatment; the weight per melon was higher in the dry treatment. INTRODUCTION With water in the Southwest becoming increasingly limited for agricultural crops, new water delivery systems for horticultural crops are becoming increasingly important. PROCEDURES This study was conducted at the Campus Agricultural Center, Tucson, Arizona. The experimental design was a randomized, complete block with 2 treatments and 4 replications per treatment. Each plot had 4 beds, 80" on center, with 5 transplants per bed, spaced 5 feet apart. The field was 140 ft. by 35 ft.; ...

Calsweet' watermelons were irrigated at three levels using a drip irrigation system. Number a... more Calsweet' watermelons were irrigated at three levels using a drip irrigation system. Number and weight of melons were recorded for three harvest dates. The low water treatment had significantly lower average melon weight than the medium and high treatments. There were no significant differences between the number of melons produced for each treatment. INTRODUCTION Due to increasing water costs, efficient irrigation of high wateruse crops, such as watermelons, is a growing concern for many Arizona farmers. Drip irrigation applies water more effectively than conventional irrigation systems; drip may reduce overall crop water use. The amount of water applied to individual plants is easily regulated, and unnecessary irrigation of areas between plants may be limited with drip system. This study was conducted to determine the irrigation level needed for increasing yield of 'Calsweet' watermelons and to examine the use of drip irrigation in watermelon production. PROCEDURES Thi...

Tasks for Vegetation Science, 2016

DESCRIPTION

Design with the Desert, 2016

Landscape Urban Plan, 2009

Germination and establishment was evaluated in Arizona cottontop (Digitaria californica (Benth.) ... more Germination and establishment was evaluated in Arizona cottontop (Digitaria californica (Benth.) Chase), bush muhly (Muhlenbergia porteri Scribn.) and plains lovegrass (Eragrostis intermedia Hitchc.) from southern Arizona. Germination was determined in different aged seed harvested from native and irrigated plots of various populations. Results indicated variability in germination characteristics of study species that appeared unrelated to afterripening or dormancy. Germination ranged from 62 to 96% for Arizona cottontop, 34 to 99% for plains lovegrass, and 75 to 99% for bush muhly. Bush muhly had highest average velocity of germination (58.0 ± 4.1), followed by plains lovegrass (35.9 ± 1.91), and Arizona cottontop (31.4 ± 1.13). Effects of 3 surface treatments (furrows, gravel, litter) and 2 cultivation treatments on establishment of study species and yellow bluestem (Bothriochloa ischaemum (L.) Keng var. ischaemum) was investigated in the field. Bush muhly did not emerge and plains lovegrass had minimal emergence. Arizona cottontop had similar emergence in cultivated and uncultivated plots whereas yellow bluestem had greater emergence in cultivated plots. Litter promoted greater survival of Arizona cottontop. Lower survival in furrows may have resulted from fewer days with available soil moisture and interference from greater density of non-seeded species. Soil covers appear to positively influence survival rather than emergence. Effect of rainfall distribution on germination was investigated using 2 seed retrieval methods. Arizona cottontop and bush muhly germinated after at least 3 days of available soil moisture. Plains lovegrass seeds did not germinate in the field but retrieved seeds had 83% germination, possibly due to light exposure under laboratory conditions. Another study determined whether species have different density and cover under overstory species compared to open areas. Arizona cottontop had either greater, less, or no differences in density under canopied versus open areas. Cover of Arizona cottontop was greater or similar among canopied and open areas. Plains lovegrass had lower or similar density and cover under canopies than in open areas. Bush muhly had greater density and cover under canopies. Overall, studies suggested that species are easily germinated, but accept relatively narrow ranges of environmental conditions for establishment. Establishment may be enhanced by sowing species when rainfall is consistent, extending available moisture through use of soil covers, or mimicking microsites where a species occurs naturally

Conservation and Sustainable Development, 2016

Symposium on Scheduling of Irrigation for Vegetable Crops under Field Condition, 1990

Journal of Range Management, 1992