Physical Sciences and Mathematics Commons^™

Tropical Hydrology And Critical Infrastructure In The Caribbean: The Impact Of The Prwreri, Walter F. Silva

Sustainability Seminar Series

The Caribbean region is prone to natural hazards including hurricanes, floods, landslides and droughts. These natural phenomena carries impacts in the society, the infrastructure and the economy of this region. Puerto Rico was impacted by two major destructive hurricanes in 2017 (Hurricane Maria) and in 2022 (Hurricane Fiona). The consequences are still seen, and recovery is undergoing Rural communities struggle to maintain essential services operating 24/7; however, there is much to be done to have robust and resilient communities in Puerto Rico. Efforts to increase resilience and reduce risk are performed by several groups, including a collaborative project between Montclair …

Effect Of Crop Age On Seed Yield Of Arachis Pintoi At Two Sites In Costa Rica, Pedro J. Argel, Alfredo Valerio

IGC Proceedings (1977-2023)

Arachis pintoi is a forage legume well adapted to the humid tropics of Costa Rica. Seed production studies were carried out at two contrasting localities within the country, Gulipiles (very humid tropics) and San Isidro (seasonal evergreen tropical forest). The accessions CIAT 18748, 18744 and 17434 cv. Amarillo of A. pinloi were vegetatively planted at both sites. Seed yields were measured at 8, 12, 16 and 20 months post- planting inGulipiles, and at·8, 16 and 20 months in San Isidro. Mean seed yields among accessions were similar in San Isidro but significantly different in Gulipiles; however, the contrary occurred in …

Efficient Nitrogen Fertilization In Grass Seed Crops With Regard To Soil Mineral Nitrogen Content And Analyzing Grass Tillers In Spring, W Schoberlein, H J. Wahl

IGC Proceedings (1977-2023)

When applying the Nmln method in grass seed crops analogously lo that in cereal crops we proceed from the experience that for a mean level of mineralisation, the sum total of soil-borne Nm1n available to plants at the beginning of the growth period and Nd Input in the form of fertiliser will provide sufficient N to the crop. The total quantity of mineral soil-borne N and fertiliser N is considered as the nominal value. The required N input can be derived from the difference between nominal value and mineral soil-borne N (Nd = nominal value• Nrnin>· For Dactylis glomerata …

Effects Of Aneuploidy On Seed Production In Autopolyploid Forage Crops, A Elgersma

IGC Proceedings (1977-2023)

Between the selection of a population and its commercial use, several generations of multiplication are necessary. The essential feature in variety maintenance is that no genetic changes occur during multiplication. In seed-propagated species, however, during each multiplication cycle natural selection takes place at ihe gamete, zygote, seed and plant level. In induced autopolyploids high frequencies of aneuploids can occur. Aneuploidy not only affects the seed yield level, but also the selection processes that occur during multiplication. It may cause genetic shift and affect variety stability. Species differ in their tolerance to aneuploids. It is not possible to eliminate aneuploidy by …

Effects Of Ratooning And Protection From Diseases And Birds On Seed Production In Guinea Grass, Okoro Oji, F N. Madubuike, F.O C. Ezedinma

IGC Proceedings (1977-2023)

Effects of ratooning and protection from diseases and birds on seed production in guinea grass (Pannicum maximum L.) were assessed in a study from October 1986 to April 1987. Treatments included ratooning and mancozeb application with or without protection from birds (netting). Highest yield occurred with combined netting and mancozeb application. Mancozeb sp,aying without netting gave lower seed yield than netting without fungicide spraying. Seed yield, which generally decreased with ratooning, was lowest among unnetted and unsprayed crops. Prom anthesis to seed maturation lasted, on average, 9 days, and seeds borne on the upper part of the panicle matured …

Potential For Improved Honey Bee Pollination Efficiency From Easy-To-Trip Lucerne, L R. Teuber, E E. Knapp

IGC Proceedings (1977-2023)

The principal pollinator of lucerne (Medicago sativa L.) in California, USA is the honey bee (Apis mellifera L.). However, honey bees are notoriously inefficient pollinators of lucerne because they learn to avoid tripping the floret. Easy-to-trip lucerne florets could reduce this problem. These studies were designed to determine the inheritance of ease of tripping and assess the effect of ease of tripping on the rate of outcrossing. Both additive and digenic variance for ease of tripping were significant, resulting in a heritability of 34.0:1:16.2%. Ease of tripping had no influence on outcrossing rate, which was estimated to average …

Effect Of Final Cutting For Fodder On Seed Yield And Seed Quality In Berseem, S L. Saini, R K. Chowdhury

IGC Proceedings (1977-2023)

The study was conducted to determine the appropriate time of final culling (closing) for fodder to optimise the seed yield and seed quality in berseem (Trifolium alexandrinum L.). Based on 2 years' experimentation, the maximum seed yield was obtained when the final cut for fodder was taken in mid•March and the crop was then closed for seed. Seed yield was reduced drastically when the final cut was delayed to late March•April. The seed quality parameters of standard germination, seed weight and vigour index were also reduced when the final cut for fodder was delayed to late March•early April. Based …

Effect Of Post-Harvest Management Practices On Seed Yields On Fine-Leaf Fescue, Gale A. Gingrich, William C. Young Iii, Thomas B. Silberstein

IGC Proceedings (1977-2023)

Public opposition and legislative actions have restricted the practice of open-field burning of grass seed fields in Western Oregon's Willamette Valley. Finding economically acceptable alternatives to straw residue removal has become a priority for valley grass seed growers. Trials using 4 residue management practices were established on 2 commercial fine fescue (Festuca rubra) seed fields. Seed yields varied significantly between residue management practices. Seed yields from thermal-treated plots were equal or significantly greater than yields from the non-thermal treatments. Fertile tiller number was also greater with thermal treatments. Most fine fescue fields produce 4-6 seed crops before replanting, …

Floret Site Utilization Of White Clover, A H. Marshall, D H. Hides

IGC Proceedings (1977-2023)

Plants of white clover (Trifolium repensL.) cv. Olwen were grown in an open glasshouse at 20°C and ovule growth and development measured. Differences in the rate of growth of ovules within ovaries were observed as early as 2 days after pollination. Ovules reached a maximum size after 8 days, with the smallest only half the size of the largest. After 8 days the smallest ovules became flaccid and shrivelled. Ovule position within the ovary had no effect on the frequency of seed set. Inflorescence position and floret position on the inflorescence had a significant effect on the number …

Influence Of Harvest Date On The Yield And Quality Of Seed Of Phalaris, K Reddy, W R. Scott, R J. Lucas

IGC Proceedings (1977-2023)

Grasslands Maru phalaris (Phalaris aquatica L,) was harvested every third day commencing 12 days after mid-anthesis (DAA) to define the optimum time of harvest for seed yield and quality. Harvesting earlier than 21-24 DAA reduced 1000-seed weight and viability. Delaying harvest until 24 days reduced seed yield due to shattering but had no detrimental effect on seed weight and viability. Heavy seed losses occurred 24 DAA when seed moisture fell below 40%. The results of this experiment suggest that Maru phalaris should be harvested 21-24 DAA when the seed moisture is in the range of 40-42% to reduce the …

Annual Bluegrass And Rat's Tail Fescue Control In Perennial Ryegrass, M E. Mellbye, William C. Young Iii, George W. Mueller-Warrant

IGC Proceedings (1977-2023)

Annual bh1egrass (Poa annua L.) and rat's-tail fescue (Vulpia myruros (L.) C.C. Omel.) are common weed contaminants in seed from perennial ryegrass fields Lolium perenne L. grown in Oregon. A trial was conducted to evaluate post-harvest residue removal methods and herbicides to reduce the level of these impurities. The best weed control was obtained from herbicides following crew-cut management, a comparatively thorough non-thermal nppronch to residue removal. Control was good with sequential herbicide treatments, especially when an effective pre-emergence herbicide such as pendimethalin was used, although no treatment completely eliminated annual bluegrass and rat's-tail fescue from threshed seed samples …

Flowering And Seed Production Of Centrosema Spp. In Relation To Day Length And Temperature, R.J M. Gonzalez, R J. Clements, L R. Humphreys

IGC Proceedings (1977-2023)

The effcc1s of variation in daylength and temperature on the flowering processes leading to seed production were studied in genotypes of 5 Centrosema spp. Short days (11 h) enhanced flowering in accessions of C. virginatum from low latitude but flowering of lines from high latitude was more prolific in 16-h days. A quantitative long-short day response was evident in 2 intermediate latitude accessions. The critical photoperiod for flowering·varied: C. virginianum cross 31 flowered in 13.5 h or less, C. pubescens, C. pascuorum and C. macrocarpum in 12 h or less, and C. schiediam Oowcred only in a 10.5 …

Herbicide Treatments For Non-Thermal Grass-Seed Production, George W. Mueller-Warrant, William C. Young Iii

IGC Proceedings (1977-2023)

Legislation phasing down open-field burning in the Willamette Valley of Oregon is forcing grass seed growers to alter crop production piactices. Adoption of new mechanical means for straw removal has increased reliance on herbicides. Volunteer seedling control and crop tolerance for 15 herbicide treatment sequences were evaluated in established tall fcscue (Festuca arundinacea) and perennial ryegrass (Lolimn perenne) stands during 2 growing seasons using 5 methods of residue removal. Pre-emergence pendimethalin was extremely safe yet fairly effective on volunteer seedlings in both crops. For perennial ryegrass subsequently treated with post-emergence herbicides, pre-emergence metolachlor was slightly more …

A Development Scale For Perennial Ryegrass, Miriam L. Martin, Roger J. Field

IGC Proceedings (1977-2023)

Vernalised plants of perennial ryeg ra ss (Lolium prenne L. cv. Orasslonds Nui) were grown under controlled conditions and apical development followed by regular excision of apices, which were examined by light and scanning electron microscopy. A 12-point scale describing apical development from the vegetative stage to ear emergence has been produced that is presented in 2 forms: a developmental sequence describing organogenesis events at specific stages, and a commentary on easily recognised features of each stage. The developmental scale provides a detailed analysis that is of value as a botanical description and as a practical aid to those involved …

Seed Yield Potential Of White Clover: Characteristics, Components And Compromise, P.T P. Clifford, I J. Baird

IGC Proceedings (1977-2023)

Nd relationship between leaf size and any of the measured variables was found for 63 agronomically superior white clover (Trifolium repens L.) plants of relatively diverse morphological and physiological characteristics, Predominantly crown-flowering plants gave more than double the seed yield of stolon-lip 'flowerers. High seed yields were also associated with delays in peak flowering, harvest date and increased harvest dry matter. Similar associations were evident for inflorescence density. Increased dry matter accumulation was associated with increases in both floret numbers and seeds/ inflorescence.

Studies In Germination And Thousand-Seed Weight In Chicory Cv. Grasslands Puna, W J. Archie, J S. Rowarth, B R. Guy

IGC Proceedings (1977-2023)

A strong, positive correlation was found between 1000-seed weight (TSW) and germination in chicory (Cichorium intybus L.) cv. Grasslands Puna. Low TSW tended to be associated with empty or immature seed; empty seed was associated with exclusion of bees. No significant differences in seed characteristics were found between seeds harvested from different positions (top, middle or bottom third) on the plant. Optimum harvest lime was 4 weeks after peak flowering.

Seed Production Of Plantain (Plantago Lanceolata L.), J S. Rowarth, M P. Rolston, W J. Archie

IGC Proceedings (1977-2023)

Seed development studies showed that seed maturity in plantain (Plantago lanceolata L,) occurred 6 weeks after anthesis; maximum seed yields were obtained 8 weeks after anthesis. This is consistent with the fact that seed heads take approximately 17 days to complete flowering. Fertiliser nitrogen increased plantain seed yield. Time of closing, timing of nitrogen application and different stand densities did not significantly affect seed yield, probably because plantain can adapt to and compensate for the treatments imposed.

Reproductive Initiation, Closing Dates, Nitrogen Requirements And Harvesting Of Smooth Brome Cv. Grasslands Tiki, J S. Rowarth, W J. Archie

IGC Proceedings (1977-2023)

Reproductive initiation, closing dates, nitrogen requirements and optimum harvest time were investigated for seed production of Grasslands Tiki smooth brome (Bromus inermis Leyss.) in the South Island of New Zealand. Reproductive initiation began in late June, spikelet initiation in mid-September and ear-emergence in mid­October. Seed yield was not affected detrimentally by mowing to 5 cm in mid-September but decreased 24% by mowing in mid-October. Seed yield tended to increase with increasing amounts of N. However, although the highest seed yields were achieved with 50 kg/ha of N in autumn plus I 00 or 150 kg/ha in spring, they did not …

Evaluation Of Non-Thermal Residue-Removal Equipment Used By Willamette Valley Seed Growers As A Substitute For Open-Field Burning, William C. Young Iii, David O. Chilcote, Thomas B. Silberstein

IGC Proceedings (1977-2023)

Recent legislation reducing open-field burning in Oregon has caused many grass seed producers to experiment with non-thermal residue management alternatives. On-farm test sites were selected to evaluate 4 post-harvest residue removal treatments common at 7 locations. Seed yield did not differ significantly when residue management treatments were applied to new stands of perennial ryegrass (Lolium perenne) and tall fescue (Festuca arundinacea) after harvest of the first seed crop. Control of weeds and volunteer crop seedlings was poorest where increased amounts of crop residue remained on the soil surface.

Sowing Rate And Row Spacing In Pure Stand Establishment Of Smooth Meadowgrass For Seed Production, Trygve S. Aamlid

IGC Proceedings (1977-2023)

Seed production of smooth meadow grass (Poa pratensis L.) cv. Lavang was compared at 3 sowing rates (2.5, 5.0 and l0.0 kg/ha) and at 2 row spacings (16.5 and :n cm), the wider used in conjunction with carbon banding. Results varied between fields according to temperature after planting and the weed content of the soil, but, on average, 5.0 kg/ha proved to be the optimal sowing rate. 33 cm row spacing and carbon banding caused a higher proportion of tillers to develop panicles and gave a higher seed yield with a better weed control in the first and third …

Role Of Galega Seed In Forage Production, H Raig

IGC Proceedings (1977-2023)

The effects of different soil types and seeding rates and row spacing on the yield of galega (Galega orientalis) have been determined in long-term trials. Over 10 years al the Estonian Research Institute of Agriculture, IO00-seed weight was 6.7-8.4 g. Ten-yenr average seed yield (kg/hn) was 241, 305 nnd 424 on soils of pH 5.6, 6.0 and 6,3, respectively. Seed yields of galega were about 6 times those of alfalfa in the soil at pH 6.3. Seeding rate and now spacing hnd little effect on seed yields. In south Sakhalin, galega was winter-hardy at - 47°C and survived drought …

Effect Of Paclobutrazol On Seed Yield In The Subtropical Grass Digitaria Eriantha, L Ramirez, J B. Hacker

IGC Proceedings (1977-2023)

Lodging of Digitaria erlantha can reduce seed yield of well-fertilised seed crops. This experiment was designed to assess the effect of the growth retardant paclobutrazol on seed production and its components in a spring crop of D. erialllha cv. Premier. Paclobutrazol decreased lodging, reduced tiller height and weight and tended to increase seed set, seed weight and seeds per panicle. However, it also tended to reduce panicle density. Treatment with 0.75 kg ai/ha applied at initial panicle emergence was optimal, increasing pure seed yield from 305 to 462 kg/ha. Paclobutrazol has potential for increasing seed yield in D. erantlta through …

Seed Shattering In Tall Fescue, Mario Falcinelli

IGC Proceedings (1977-2023)

Seed shattering in many commercial grass seed crops is a serious problem which makes seed harvesting difficult and which is often a major cause of high losses in seed yield. 2880 plants of tall fescue (Festuca arundinacea) belonging to 48 natural populations collected at sites scattered from northern (46° 10'N) to southern (39°05'N) Italy and 60 plants of the cultivar Fawn were grown in Perugia (Italy) as spaced plants. Al peak anthcsis, 5 panicles from each plant were randomly chosen and 40 days later they were evaluated for seed retention capability. Ten plants, belonging to 9 different populations, …

Achieving Potential Herbage Seed Yields In Species Of Temperate Regions, Franco Lorenzetti

IGC Proceedings (1977-2023)

The potential seed yield (PSY) of a crop is represented by the total number of ovules present at anthesis in a unit area and is very high for nil forage species. However, seed yield or the agricultural realised seed potential (ARSP) is very low especially if compared with major grain crops (e.g., 15% vs 40% of PSY, respectively). The need for obtaining primarily high yield of high quality forage indicates that seed yield should be increased by improving the efficiency of the reproductive system rather than increasing its size. Seed setting and development and seed shattering are the characters to …

Graph Regularized Sparse L2,1 Semi-Nonnegative Matrix Factorization For Data Reduction, Anthony Rhodes, Bin Jiang, Jenny Jiang

Mathematics and Statistics Faculty Publications and Presentations

Non-negative Matrix Factorization (NMF) is an effective algorithm for multivariate data analysis, including applications to feature selection, pattern recognition, and computer vision. Its variant, Semi-Nonnegative Matrix Factorization (SNF), extends the ability of NMF to render parts-based data representations to include mixed-sign data. Graph Regularized SNF builds upon this paradigm by adding a graph regularization term to preserve the local geometrical structure of the data space. Despite their successes, SNF-related algorithms to date still suffer from instability caused by the Frobenius norm due to the effects of outliers and noise. In this paper, we present a new L2,1 SNF algorithm that …

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Local Hydroclimate Alters Interpretation Of Speleothem Δ18o Records, E. W. Patterson, V. Skiba, A. Wolf, M. L. Griffiths, D. Mcgee, T. N. Bùi, M. X. Trần, T. H. Đinh, Q. Đỗ-Trọng, Gregory R. Goldsmith, V. Ersek, K. R. Johnson

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Oxygen isotopes (δ¹⁸O) are the most commonly utilized speleothem proxy and have provided many foundational records of paleoclimate. Thus, understanding processes affecting speleothem δ¹⁸O is crucial. Yet, prior calcite precipitation (PCP), a process driven by local hydrology, is a widely ignored control of speleothem δ¹⁸O. Here we investigate the effects of PCP on a stalagmite δ¹⁸O record from central Vietnam, spanning 45 – 4 ka. We employ a geochemical model that utilizes speleothem Mg/Ca and cave monitoring data to correct the δ¹⁸O record for PCP effects. The resulting record …

Approval Letter For The Butte Priority Soils Operable Unit (Bpsou) Revised Draft Final Quarterly Operations And Maintenance Report Butte Treatment Lagoon System – Fourth Quarter 2022 (Dated July 3, 2024), Emma Rott

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.

Comment Letter For Draft Final Bpsou Quarterly Operations And Maintenance Report Butte Treatment Lagoon System – First Quarter 2024 (Dated June 26, 2024), Emma Rott

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.

Manifestations Of Sulfuric Acid Speleogenesis In The Mulapampa Travertine, Central Andes Of Peru: Evidence From The Gruta Con Lago, Andrzej Tyc, Krzysztof Gaidzik, Justyna Ciesielczuk, Katarzyna Wątor

International Journal of Speleology

Sulfuric acid speleogenesis (SAS) is a form of hypogene speleogenesis characterized by the formation of caves in carbonate rocks due to the presence of sulfuric acid. This study focuses on the Gruta con Lago, one of three caves identified in the Mulapampa travertine, located in the central Andes of Peru. These caves are accessed through collapse sinkholes, and much of their morphology results from roof breakdown. The bottom of the studied cave is situated at the current water table. Despite the absence of typical solutional features associated with SAS caves, mineralogical and geochemical evidence of speleogenesis involving H₂SO …