Paul G. Johnson

Effects of Irrigation and Mowing on Species Diversity of Grass and Wildflower Mixtures for the Intermountain West

Grass and wildflower mixtures can be aesthetically appealing, water-conserving, low-maintenance alternatives to conventional turfgrass. One problem with these mixtures is loss of species diversity over time. We examined the effects of irrigation and mowing on the species diversity of 3 grass and wildflower mixtures. The nonirrigated and non-mowed treatment combination maintained diversity most effectively whereas the irrigated and mowed treatment combination was least effective. Generally, when the irrigation treatment was significant (P

The 2011 Great Flood in Thailand: Climate Diagnostics and Implications from Climate Change

AbstractSevere flooding occurred in Thailand during the 2011 summer season, which resulted in more than 800 deaths and affected 13.6 million people. The unprecedented nature of this flood in the Chao Phraya River basin (CPRB) was examined and compared with historical flood years. Climate diagnostics were conducted to understand the meteorological conditions and climate forcing that led to the magnitude and duration of this flood. Neither the monsoon rainfall nor the tropical cyclone frequency anomalies alone was sufficient to cause the 2011 flooding event. Instead, a series of abnormal conditions collectively contributed to the intensity of the 2011 flood: anomalously high rainfall in the premonsoon season, especially during March; record-high soil moisture content throughout the year; elevated sea level height in the Gulf of Thailand, which constrained drainage; and other water management factors. In the context of climate change, the substantially increased premonsoon rainfall in CPRB after 1980 and the...

FLAVIN‐SENSITIZED PHOTOOXIDATION OF HISTIDINE*

Flavins are known to sensitize the aerobic photooxidations of amino acids (Galston, 1950; Frisell et al., 1959). For aromatic amino acids, there is some evidence that triplet flavin produces singlet oxygen, which reacts with the aromatic ring (Penzer, 1970). In particular, Tomita et al. (1969), who studied the flavinsensitized photooxidation of histidine, demonstrated that a 1,Ccycloaddition of singlet oxygen to the imidazole ring produced a cyclic peroxide, which decomposed to give aspartic acid via at least 17 intermediates. This photosensitized decomposition of amino acids by flavin can be used to induce a chemical modification of proteins (Penzer, 1970; Taylor and Radda, 1971). More importantly, the naturally bound coenzyme in a flavoprotein can act as a photosensitizer, causing reaction of nearby amino acid residues and thus helping to elucidate the environment of the binding site (McCormick, 1970; Tu and McCormick, 1973). Recently, several flavin-containing enzymes have been shown to have a histidine residue at the active site. Succinate dehydrogenase (Walker and Singer, 1970), D-6-hydroxynicotine oxidase (Mohler et al., 1972), and sarcosine dehydrogenase (Patek and Frisell, 1972) actually have the N-3 nitrogen of the imidazole ring of the histidine moiety covalently attached to the 8a-position ofa FAD. An absorption spectral study on glucose oxidase (Miiller et al., 1970) allows for the presence of a histidine near the FAD-binding site, but, in this case, the imidazole ring is not covalently attached to the flavin. These developments prompted us to study the ability of the light-excited flavin to oxidize histidine, as was done previously for other aromatic amino acids (Wu and McCormick, 1971). Flavinyl histidines, pre-

AMELIORATION OF ZINC DEFICIENCY OF CORN IN CALCAREOUS SOILS OF THAILAND: ZINC SOURCES AND APPLICATION METHODS

A variety of zinc (Zn) fertilizer sources are applied with varied responses on calcareous soils in Thailand. Seed treatment is an alternative method to deliver Zn to corn and alleviate Zn deficiency. To address this Zn delivery methods we conducted greenhouse studies on corn grown in three calcareous soils of Thailand to three Zn fertilizer sources [zinc sulfate (ZnSO4), Zn-ethylenediaminetetraacetic acid (EDTA) and Zn citrate]. We also evaluated effectiveness of soaking corn seed in three concentrations of ZnSO4 (0.4, 0.8 and 1.6%) prior to planting compared to soil applied methods. Applications of zinc increased the growth, dry matter yield and zinc uptake of corn with few differences observed among the types of fertilizers. Seed soaking with ZnSO4 solution also increased Zn uptake, growth rate and yield comparable to soil-applied Zn. Seed soaking prior to planting is an effective and efficient method to supply Zn to corn grown in Zn deficient calcareous soils of Thailand.

Humic substances effect on moisture retention and phosphorus uptake in Intermountain West putting greens

Humic substances are often used as an amendment in putting greens to improve turf health, but little is known regarding their effects on soil moisture retention. Commercial humic substance products and pure organic acids were applied to three golf course putting greens in Utah in 2006 and the Utah State University research putting green in 2006 and 2007. These treatments were evaluated for effects on soil volumetric water content, phosphorus uptake, and chlorophyll content of creeping bentgrass (Agrostis stolonifera L.). Three irrigation levels — 80%, 70%, and 60% — of reference evapotranspiration (ETo) were imposed on the turf at the research putting green. Humic substances did not increase moisture retention in putting green soils as pure humic acid significantly decreased soil volumetric water content compared to the control. Both humic acid and fulvic acid-treated plots had lower soil moisture content readings than the control at a depth of 10 to 15 cm during the growing season. Uptake of P by creeping bentgrass was significantly decreased with the application of humic acid, and no differences were observed for chlorophyll content of the turf with any humic substance treatment. While they may provide other benefits, humic substances may not provide superintendents with benefits of reducing water or P fertilizer on putting greens. Turf Management and Humic Substances Creeping bentgrass (Agrostis stolonifera L.) is the predominant cool-season grass grown and managed on putting greens in the Intermountain West region of the United States. While adapted to golf course conditions, both the climate and calcareous soils of the region can impose difficult growing conditions for this and other turfgrass species. The large transpiration gradient created by warm temperatures and low humidity during the summer can create stressful conditions for bentgrass growth. Plus, sand root zones have low water holding capacity that requires frequent irrigation. The calcareous sand commonly used in the Intermountain West has a relatively high pH (~ 7.5 to 8.5), making phosphorus and some micronutrients less available to the turf. In addition to these challenges, many golf course superintendents are expected to reduce water use, especially during droughts, and minimize fertilizer use while still maintaining high quality turf. Thus, they are always seeking ways to be more efficient with their management practices while improving turf health. In order to meet these challenging demands, one management practice that is often implemented is the use of natural organic products, such as those containing humic substances. However, many questions exist regarding their effectiveness and what exactly these products can do for putting green turf (9). Humic substances are a component of soil humus, which can be divided into fractions of fulvic acid, humic acid, and humin depending on their solubility as a function of pH (17). These fractions represent an operationally defined heterogeneous mixture of organic materials (12) that are characterized as being yellow or black in color, of high molecular weight, and refractory (1). Humic substances have been studied and used on a variety of agricultural crops for 6 October 2008 Applied Turfgrass Science years, but only in the last twenty years have they been studied on turfgrass systems. Of the humic substances that have been studied, humic acid is the most common, but results with creeping bentgrass have been highly variable (5). Humic substances have caused hormone-like effects on plant growth and metabolism (3). Growth responses may also result from increased nutrient availability (15), including bioavailability of phosphorus (6), increased tissue levels of iron (4), zinc (4), and manganese (11). However, less growth effects from humic substances have been reported on creeping bentgrass when adequately supplied with nutrients (5). Humic substances increased photosynthesis in creeping bentgrass (11,20) and root mass (11) and length (5) in controlled studies. However, similar responses have not been observed in the field (8). The lack of responses on turf when using humic substances in the field may be attributed to the difficulty in isolating the effects of nutrients and other ingredients often included in humic substance products, and the confounding effects of the variability and uncontrolled nature of field conditions. Regardless of the inconsistencies that have been reported, products containing humic substances are common in the turf industry, with claimed benefits including the ability to increase soil moisture and nutrient availability. While positive growth effects of humic substances on creeping bentgrass have been well documented, scientific literature on improved moisture retention in putting greens has not. This study tested organic acids, including a pure humic acid and commercial humic substance products, on established putting greens to test their effects on (i) increased water retention, and (ii) uptake of phosphorus by creeping bentgrass in sand putting greens. Testing Effects of Humic Substances on Putting Greens Two experiments were conducted. One involved three golf courses in Utah, and the other at a research putting green at Utah State University. Organic acids, including a pure humic acid and commercial humic substance, products were applied to established creeping bentgrass putting greens. Evaluations were done during the summer growing season (June, July, and August) of 2006 and 2007 at the research putting green at Utah State University, and in 2006 at the three golf courses in Utah. The research sites for this experiment were the Utah State University Greenville Research Farm in North Logan, Birch Creek Golf Course in Smithfield, The Country Club in Salt Lake City, and Talons Cove Golf Course in Saratoga Springs. At the golf courses, plots were laid out on practice putting greens. The root zones consisted of primarily calcareous sands. None of the putting greens were built to USGA recommendations, with the research putting green being the closest of all the sites. At the research putting green, the sand mix contained higher percentages of fine (14%) and very fine (9%) sand particles. The Talons Cove putting green was built to California style specifications. The Country Club and Birch Creek greens were native soil pushup green with sand topdressing applied. In all locations, the putting green turf was predominantly creeping bentgrass (Agrostis stolonifera L.) with varying percentages of annual bluegrass (Poa annua L.) (Table 1). Cultural practices at all of the locations were considered typical for the Intermountain West region of the United States. Details of the management are outlined in (Table 1). At the three golf courses, the putting greens were used extensively by golfers, but no traffic was applied on the research putting green at Utah State University. 6 October 2008 Applied Turfgrass Science Table 1. Site characteristics and turf management practices at the golf course and research putting green locations. v Ratio of bentgrass to annual bluegrass. w Ratio of sand to organic matter in the root zone mix. x Mowing height was gradually lowered during the summer evaluation period at all locations. y Weekly foliar fertilization at the USU site was not done in July 2007. z Number of irrigations that occurred during the 91 day evaluation period (June 1 to August 31). Experimental design. Both experiments were laid out as a split-split-plot design. The experiment with the golf courses had location as the whole-plot factor, organic treatment the sub-plot factor, and observation date the sub-subplot factor. The experiment at the research putting green had irrigation level as the whole-plot factor, organic treatment the sub-plot factor, and observation date the sub-sub-plot factor. Individual organic treatment plots measured 1.5 × 1.5 ft with three replications. At the research putting green only, each block of organic treatments was centered in a 10.7 × 10.7 m plot irrigation block where different irrigation levels were applied. Irrigation treatments were randomized in a Latin square consisting of 80%, 70% and 60% of reference Birch Creek 2006 The Country Club 2006 Talons Cove 2006 Research putting green 2006 Research putting green 2007 Turf Type Penncross Many old bentgrasses L-93 and Southshore Dominant blend Dominant blend Bent: P. annuav 50:50 60:40 99:1 80:20 80:20 Soil Type Loamy sand Loamy sand Loamy sand Loamy sand Loamy sand Root zone mixw 100:0 80:20 100:0 90:10 90:10 pH 7.65 7.50 7.81 7.52 7.52 ECe (dS/m) 0.4 0.8 0.8 0.3 0.3 Manage -ment Mowing heightx (mm) 3 to 3.5 2 to 3 3 to 3.3 3 to 3.5 3 to 3.5 Fertilizery 6/10/06: 10-2-4, N at 183 kg/ha, &

Sexual Activity, Seminal Characteristics, and Reproductive Organs in Sexually inexperienced Castrate Rabbits Following Testosterone Implantation

Summary Males castrated at 2.5 mo of age were supplied immediately with testosterone-filled implants (210.5-mm2 vs 421-mm2 inside surface area). Plasma testosterone levels, libido, and sexual development tended to parallel implant size. Other males castrated for 26 days before receiving testosterone implants were delayed in development, but otherwise responded similarly to testosterone therapy. Libido and semen volume were higher in control males than in other groups despite the fact that plasma testosterone in controls averaged 1.52 ng/ml compared to 2.41 ng/ml for bucks with 2-cm implants and 1.33 ng/ml for bucks with 1-cm implants. This result indicates that testicular products, in addition to testosterone in controls, were involved in producing normal sexual development and activity. The authors are grateful to Glenn Coulter, Linda Pierro, Michael Simkin, and Jacqueline VanWie for valuable technical assistance.

Phylogenetic relationships among low ploidy Poa species using chloroplast sequences

Species of the genus Poa are taxonomically and genetically difficult to delineate owing to high and variable polyploidy, aneuploidy, and challenging breeding systems. Approximately 5% of the proposed species in Poa are considered to include or comprise diploids, but very few of those diploids are represented in seed collections. Recent phylogenetic studies of Poa have included some diploid species to elucidate Poa genome relationships. In this study, we build upon that foundation of diploid Poa relationships with additional confirmed diploid species and accessions, and with additional chloroplast sequences. We also include samples of P. pratensis and P. arachnifera to hone in on possible ancestral genomes in these two agronomic and highly polyploidy species. Relative to most species of Poa, Poa section Dioicopoa (P. ligularis, P. iridifolia, and P. arachnifera) contained relatively large chromosomes. Phylogenies were constructed using the TLF gene region and five additional chloroplast genes, and the placement of new species and accessions fit within chloroplast lineages previously reported better than by taxonomic subgenera and sections. Low-ploidy species in the P chloroplast lineage, such as P. iberica and P. remota, grouped closest to P. pratensis.