Production In May Research Articles

RELATIONSHIP BETWEEN DERIVED PRECIPITATION INDICES AND MILLET YIELD IN KANO STATE, NIGERIA

This study examined the relationship between derived precipitation indices and millet in Kano State, Nigeria. Data on monthly rainfall (mm) and millet yield (kg/ha) from 1992-2022 were used for the study. The rainfall data was sourced from NiMet and IITA while the crop yield data was sourced from KNARDA. The data obtained were subjected to correlation analysis in SPSS environment version 20. The result obtained revealed that a relationship exists between precipitation indices and millet at the onset of rainfall (r=0.421, p=0.018) at the significant level of 1% and negative (r=0.059, p=0.753) at the Cessation period. Also, the study revealed that there were low and negative relations between the rainfall data and millet production in May (r= -0.057, p= 0.760) and June (r=0.193) at a 0.05 significant level. In July (r=0.233), and August a very low and positive relationship was observed between rainfall and millet yield (r=0.156, p=0.401). The result of the study further revealed that a very low and positive relationship was observed between A.G.S.R and Millet yield (r=0.298) and between Millet production with LRS (r=0.194, p=0.296). A markedly and negligible negative relationship was observed between SI and millet yield (r=0.010) at a 0.05 significant level. The study concluded that variation occurred in millet production in Kano state between the onset and cessation period of rainfall received. Based on the findings, the study recommends that medium-maturing varieties of millet should be introduced to minimize the effect of precipitation indices.

A Comparative Analysis of Various Simulation Software for grid-connected Residential Building: A Case Study at Jeddah, Saudi Arabia

Saudi Arabia receives significant energy daily from solar radiation, making it one of the best places to use solar energy to meet its energy needs. Grid connected Photovoltaic (PV) systems provide the electrical energy available from the solar radiation into the grid. Different simulation tools are currently available used to assess the performance of solar PV systems. The present study was conducted to design and evaluate the performance of 15 kW grid-connected solar PV system under climatic conditions of in Jeddah, Saudi Arabia. Two simulation models, Helioscope and PVsyst were used in the analysis and the results were then compared. The annual energy production, specific production, energy injected into grid, and annual performance ratio (PR) are evaluated by the software’s around a whole year at the same climatic conditions. Results showed that the maximum annual solar irradiation in May was 2212 kWh/m2. The PR based on PVsyst simulation (78.04 %) was higher than that of the Helioscope simulation (74.8%) by about 4.15%. The maximum energy production in May was about 6.1 kWh. The energy production from the PVsyst and Helioscope is 28.98 and 25.9 MWh/year with 289.8 and 259.13 MWh/year energy injected into the grid, respectively.

Computation of comfort indices for livestock in central Punjab

Climate change imposes detrimental heat stress, which disrupts the thermo-regulatory balance of cattle and buffaloes. Quantifying heat stress through bioclimatic indices is a vital step for identifying suitable mitigation/adaptation strategies. So, the trend of different comfort indices for cattle was computed (2000-2019) and used for estimating milk production as these indices provide a holistic view of the bovine’s thermoneutral status. The trend analysis of seasonal comfort index (CI) through box plot analysis indicated that Black Globe Humidity Index (BGHI) had shifted from ‘Low Impact’ to ‘High Impact’, Temperature Humidity Index (THI) had shifted from ‘Normal’ to ‘Danger’ and Comprehensive Climate Index (CCI) had shifted from ‘No stress’ to ‘Mild stress’ from winter to summer season indicating the impact of heat stress during the latter period. The milk production in April had a significant correlation with BGHI, Heat Load Index (HLI), Respiration Rate (RR), THI, CCI, and Equivalent Temperature Index (ETI). Milk production in May and June had a significant relationship with ETI and THI. Lactation-wise milk production analysis indicated that sixth lactation is related to ETI and HLI. Fourth and second lactation had a significant relation with all indices estimated and the first stage of lactation with BGHI, ETI, and RR. The CI with the highest correlation coefficients were used to develop a regression model for a respective month and lactation stage.

Integrating technology to support data management abstraction of adverse events (AE) and concomitant medications (ConMed) from the electronic health record (EHR) to sponsor electronic data capture (EDC) systems using design thinking (DT) methodology.

e13624 Background: Manual abstraction of data from a site’s EHR to pharmaceutical sponsor’s EDC system is labor intensive and inefficient. To reduce the time and effort of this process for data managers (DM), a web-based application, Clinical Trials Data Hub (CTDH), was developed using Design Thinking methods. It extracts and consolidates AE and ConMed data from the EHR and displays it in a user friendly, automated, and consolidated view for easy entry into EDC forms. Methods: Following DT methodology to develop CTDH, we interviewed 12 DMs to identify data entry bottlenecks, and ideated solutions for what is now CTDH. To evaluate CTDH’s value, we built a functioning prototype using Splunk and conducted pilot A/B testing with 6 DMs for 2 use cases (Case I: basic easy to find ConMed linked to the AE, and Case 2: complex, where the ConMed linked to the AE was buried in a 33-page document) using their current workflow (A) versus CTDH (B) where a 5-minute training of CTDH occurred prior to testing. We hypothesized that CTDH would outperform current workflows across 3 primary outcomes: 1) correct data identification, 2) time to identify data, and 3) using a modified Single Ease Question (SEQ) rating scale to assess how difficult users found the task. This study was conducted in Jan-Aug 2022 at a large single-center cancer hospital. Results: DMs spend ~20 hours/week on data entry; the majority of which is spent searching the EHR for which ConMeds are associated with an AE. A/B testing results are noted in Table I (see below). Use case 2 showed that DMs using CTDH reduced the time to find one ConMed linked to an AE by 148%, saving ~5 minutes in one task. 5 of 6 participants preferred CTDH to existing clinical systems. Conclusions: Our findings suggest that CTDH allows DMs to 1) identify AE and ConMed data required for EDCs more quickly than in current workflow, 2) identify data more accurately to be entered in sponsor EDCs, and 3) perceive the task of identifying this data to be easier. CTDH reduces the time DMs spend searching clinical systems and documents and has the potential to save meaningful time per patient per study. CTHD will launch into production in May 2023. Digital tool product development using DT methodology has the potential to improve operational efficiency and the clinical staff user experience. This is particularly important in an industry that has struggled with burnout, cost containment, and high turnover. [Table: see text]

Wetland Availability and Salinity Concentrations for Breeding Waterfowl in Suisun Marsh, California

Availability of wetlands with low salinities during the breeding season can influence waterfowl reproductive success and population recruitment. Salinities as low as 2 ppt (3.6 mScm–1) can impair duckling growth and influence behavior, with mortality occurring above 9 ppt (14.8 mScm–1). We used satellite imagery to quantify the amount of available water, and sampled surface water salinity at Grizzly Island, in the brackish Suisun Marsh, at three time-periods during waterfowl breeding (April, May, July) over 4 years (2016–2019). More water was available and salinity was lower during wetter years (2017, 2019) than during drier years (2016, 2018), and the amount of water in wetlands decreased 73%–86% from April to July. Across all time-periods and years, the majority (64%–100%) of wetland habitat area had salinities above what has been shown to negatively affect ducklings (> 2 ppt), and up to 42% of wetland area had salinities associated with duckling mortality (> 9 ppt). During peak duckling production in May, 81%–95% of available water had salinity above 2 ppt, and 5%–21% was above 9 ppt. In May of the driest year (2016), only 0.5 km2 of low-salinity water (< 2 ppt) was available to ducklings in the study area, compared to 2.6 km2 in May of the wettest year (2017). Private duck clubs own the majority of wetland habitat at Grizzly Island and consistently had a greater percentage of land flooded during summer than did publicly owned wetlands, but private wetlands generally had higher salinities than public wetlands, likely because they draw from higher-salinity water sources. By July, few wetlands remained flooded, and most had salinities high enough to impair duckling growth and survival. Local waterfowl populations would benefit from management practices that provide fresher water during peak duckling production in May and retain more water through July.

Breeding Waterbird Populations Have Declined in South San Francisco Bay: An Assessment Over Two Decades

Availability of wetlands with low salinities during the breeding season can influence waterfowl reproductive success and population recruitment. Salinities as low as 2 ppt (3.6 mScm–1) can impair duckling growth and influence behavior, with mortality occurring above 9 ppt (14.8 mScm–1). We used satellite imagery to quantify the amount of available water, and sampled surface water salinity at Grizzly Island, in the brackish Suisun Marsh, at three time-periods during waterfowl breeding (April, May, July) over 4 years (2016–2019). More water was available and salinity was lower during wetter years (2017, 2019) than during drier years (2016, 2018), and the amount of water in wetlands decreased 73%–86% from April to July. Across all time-periods and years, the majority (64%–100%) of wetland habitat area had salinities above what has been shown to negatively affect ducklings (> 2 ppt), and up to 42% of wetland area had salinities associated with duckling mortality (> 9 ppt). During peak duckling production in May, 81%–95% of available water had salinity above 2 ppt, and 5%–21% was above 9 ppt. In May of the driest year (2016), only 0.5 km2 of low-salinity water (< 2 ppt) was available to ducklings in the study area, compared to 2.6 km2 in May of the wettest year (2017). Private duck clubs own the majority of wetland habitat at Grizzly Island and consistently had a greater percentage of land flooded during summer than did publicly owned wetlands, but private wetlands generally had higher salinities than public wetlands, likely because they draw from higher-salinity water sources. By July, few wetlands remained flooded, and most had salinities high enough to impair duckling growth and survival. Local waterfowl populations would benefit from management practices that provide fresher water during peak duckling production in May and retain more water through July.

The approach to the development of a probabilistic model to determine the optimal mechanism for an unfinished oil well fund subsidising

In the context of the coronavirus pandemic and quarantine measures taken by the international community, energy demand declined significantly in the second quarter of 2020. In April, oil prices fell to a record low of $13-$14 per barrel. In order to restore oil prices, OPEC+ imposed strict restrictions on production in May. This has in turn decreased the number of drilling wells significantly and has had a negative impact on oilfield service companies. The decline of the oilfield services can lead to a loss of skills in the development of hard-to-recover reserves and to a loss of global market share. In order to reduce risks and ensure accelerated recovery of production volumes, a number of countries are developing and introducing methods of state subsidising to stimulate the construction of oil wells up to the moment of their completion. In Russia, the Ministry of Industry and Trade is also developing a plan to provide preferential loans to oilfield service organisations, and then oil companies will redeem finished wells. Given the recession in the global economy, the high volatility of macro parameters, the risk of the second wave of coronavirus and the new OPEC+ restrictions, makes it necessary to determine the best and most sufficient, but not excessive, mechanism for supporting oilfield services and stimulating the optimal pace of construction of oil wells depending on the type of oil fields and their remoteness from world markets’ sales. In view of the high uncertainty of model parameters, this paper proposes to use probabilistic methods and Bayesian methods to solve the above problems.

The Buchan Field, Blocks 20/5a and 21/1a, UK North Sea

Abstract The Buchan Oilfield is a large mature field, now suspended, located in the Moray Firth. The field is situated 153 km NE of Aberdeen in water depths of c. 122 m. The reservoir comprises an overpressured and fractured Upper Devonian–Early Carboniferous fluvio-lacustrine sandstone. Production was via high permeability channel sandstones and permeable faults and fractures. The Buchan Field was brought onto production in May 1981 by BP Petroleum Development Ltd via the Buchan Alpha semi-submersible floating production vessel (FPV). The oil column is c. 2000 ft in height with a matrix stock tank oil initially in place (STOIIP) range of 322–471–668 MMbbl. Production from the ten vertical development wells was driven by pressure depletion (over 5000 psi since first oil) coupled with weak aquifer influx. Production from the Buchan Field ceased on 13 May 2017 after having produced 147.8 MMbbl. The Buchan FPV was subsequently taken off-station during August 2017. A new facility or tie-back redevelopment option will be required to access the remaining resources which are in the range of 20–90 MMbbl depending on the STOIIP, the production mechanism and the potential development plan.

Projected Increase in Hydropower Production in India under Climate Change

Hydropower is a valuable renewable energy resource in India, which can help in climate change mitigation and meet the increasing energy demands. However, the crucial role of climate change on hydropower production in India remains unexplored. Here using the observations and model simulations, we show that seven large hydropower projects experienced a significant (p-value < 0.05) warming and a decline in precipitation and streamflow during the observed period of 1951–2007. However, all the hydropower projects are projected to experience a warmer and wetter climate in the future. Multimodel ensemble mean annual average temperature (precipitation) is projected to rise up to 6.3 ± 1.6 °C (18 ± 14.6%) in the catchments upstream of the other reservoirs by the end of the 21st century under representative concentration pathway (RCP) 8.5. Due to the projected increase in precipitation, mean annual streamflow (up to +45%) and hydropower (up to +25%) production are projected to rise under the future climate. However, significant warming (6.25 ± 1.62 °C) is projected to result in a decline in streamflow and hydropower production in May- June for snow-dominated Nathpa Jhakri and Bhakra Nangal hydropower projects. Our results provide insights into the development and planning of hydropower projects in India under the current projected future climate.

Efecto de dos sistemas de cosecha de la caña de azúcar sobre la calidad del suelo en el Cantón Milagros Ecuador

Basic aspects of yield and production of ornamental horticulture are unknown in Tabasco, Mexico. Therefore, this study aim to evaluate the production of Red and Pink Ginger ( Alpinia purpurata ) flowers in the municipalities of Comalcalco, Centro and Teapa, Tabasco. The production was evaluated in six clumps per variety and per planting on each municipality. Quantitative production traits for flowers, commercial stems and clumps were assessed every two weeks for one year. Comalcalco had the highest production of Red and Pink Ginger stems and flowers per clump with 48.2 Red and 24.7 Pink commercial flowers. Both varieties concentrated about 23% of the commercial flower production in May. In Centro, Red and Pink Ginger commercial flowers were 11.9 and 12.5 per clump with 42.0% and 34.7% concentrated in May. In Teapa, the production of Red Ginger commercial flowers was 10.6 per clump per year with 34.8% of the production recorded in June.

Production of Red and Pink Ginger [ Alpinia purpurata (Viell.) K. Schum] in three municipalities of Tabasco, Mexico

Basic aspects of yield and production of ornamental horticulture are unknown in Tabasco, Mexico. Therefore, this study aim to evaluate the production of Red and Pink Ginger (Alpinia purpurata) flowers in the municipalities of Comalcalco, Centro and Teapa, Tabasco. The production was evaluated in six clumps per variety and per planting on each municipality. Quantitative production traits for flowers, commercial stems and clumps were assessed every two weeks for one year. Comalcalco had the highest production of Red and Pink Ginger stems and flowers per clump with 48.2 Red and 24.7 Pink commercial flowers. Both varieties concentrated about 23% of the commercial flower production in May. In Centro, Red and Pink Ginger commercial flowers were 11.9 and 12.5 per clump with 42.0% and 34.7% concentrated in May. In Teapa, the production of Red Ginger commercial flowers was 10.6 per clump per year with 34.8% of the production recorded in June.

Europe

The Eurozone economy may have lost some momentum in the course of Q2, based on business surveys for the period. Admittedly, the falls in the composite PMI in May and June were pretty small and on past form the PMIs still point to slightly stronger quarterly GDP growth than the 0.2% recorded in Q1. But given the sharp falls in German, French, Italian and Spanish industrial production in May and subdued Eurozone retail sales figures for the first two months of the quarter we suspect that Eurozone GDP growth is unlikely to have picked up in Q2…

Impact of sea‐ice processes on the carbonate system and ocean acidification at the ice‐water interface of the Amundsen Gulf, Arctic Ocean

From sea‐ice formation in November 2007 to onset of ice melt in May 2008, we studied the carbonate system in first‐year Arctic sea ice, focusing on the impact of calcium‐carbonate (CaCO3) saturation states of aragonite (ΩAr) and calcite (ΩCa) at the ice‐water interface (UIW). Based on total inorganic carbon (CT) and total alkalinity (AT), and derived pH, CO2, carbonate ion ([CO32−]) concentrations and Ω, we investigated the major drivers such as brine rejection, CaCO3 precipitation, bacterial respiration, primary production and CO2‐gas flux in sea ice, brine, frost flowers and UIW. We estimated large variability in sea‐ice CT at the top, mid, and bottom ice. Changes due to CaCO3 and CO2‐gas flux had large impact on CT in the whole ice core from March to May, bacterial respiration was important at the bottom ice during all months, and primary production in May. It was evident that the sea‐ice processes had large impact on UIW, resulting in a five times larger seasonal amplitude of the carbonate system, relative to the upper 20 m. During ice formation, [CO2] increased by 30 µmol kg−1, [CO32−] decreased by 50 µmol kg−1, and the ΩAr decreased by 0.8 in the UIW due to CO2‐enriched brine from solid CaCO3. Conversely, during ice melt, [CO32−] increased by 90 µmol kg−1 in the UIW, and Ω increased by 1.4 between March and May, likely due to CaCO3 dissolution and primary production. We estimated that increased ice melt would lead to enhanced oceanic uptake of inorganic carbon to the surface layer.

Mapping Interstitial Urban Spaces through Performing the City

The project investigates how public perception of interstitial urban spaces could be elicited and recorded through Performing the City - participatory ‘walkabout’ performance practices produced and staged for specific urban sites. Interstitial urban spaces are ‘forgotten’ underused spaces awaiting public re-imagination and interventions. Following an ethnographic study of the UK theatre company Slung Low's Mapping the City production in May 2011, the authors reflect on how the research propositions should be refined to better capture the transient transformative potential of spatial urban mapping through performing the city.

Production of Herbivore-Induced Plant Volatiles is Constrained Seasonally in The Field but Predation on Herbivores is not

Natural enemies of herbivorous insects utilize numerous cues to locate and identify their prey. One class of such cues is volatile organic compounds (VOCs) often produced by plants after attack by herbivores (hereafter herbivore-induced plant volatiles or HIPVs). Under simplified laboratory conditions, natural enemies often make clear choices between different HIPV blends, but such clear choices may be more difficult in more complex field environments. We studied the impact of VOC production by the undomesticated species, Datura wrightii on predation of eggs and larvae of Lema daturaphila by the omnivore, Geocoris pallens in the field. HIPV production in D. wrightii is developmentally and seasonally constrained to the early stages of plant growth even though L. daturaphila and G. pallens inhabit plants throughout the plant's growing season. We, therefore, asked if predation of L. daturaphila by G. pallens might be similarly constrained seasonally. Higher levels of VOC production were associated with higher levels of predation throughout the growing season, and the greater quantities of VOC production in May caused greater increases in predation than did VOC production later in the season (June-September). However, predation in the absence of VOC production ranged from 60-70% in June-September compared to only 14% in May, probably because plants were already colonized by predators later in the season. High levels of VOCs in response to herbivore damage by D. wrightii therefore may aid in the discovery of herbivore-damaged plants early in the season but the seasonal decline in VOC production does not limit predation of L. daturaphila by G. pallens later in the season.

The influence of black locust (Robinia pseudoacacia) flower and leaf fall on soil phosphate

To investigate the influence of black locust (Robinia pseudoacacia) flower and leaf fall on soil phosphate, we monitored litterfall, litter decomposition, and soil membrane phosphate in a R. pseudoacacia forest on Mt. Ilzasan, Seoul, Korea. R. pseudoacacia flower litter was 30–50% of total litter production in May and the flowers decomposed rapidly. More than 11% of R. pseudoacacia leaf litter decomposed from February to May, while that of Quercus spp. decomposed very little. Fast decomposition of R. pseudoacacia flower and leaf litter significantly increased membrane phosphate in the soil. The rapid nutrient-cycling of R. pseudoacacia through flower litterfall and rapid decomposition benefits the plant itself in the growing season when nutrients demand is increasing. Rapid nutrient-cycling might be a strategy that helps R. pseudoacacia to persist in poor soil environments.

Redução na produção de látex da seringueira provocada pela infestação de ácaros

O ataque dos ácaros Calacarus heveae Feres e Tenuipalpus heveae Baker em seringueira pode causar intenso desfolhamento precoce das plantas. É provável que a queda de folhas antes do período de senescência normal resulte em diminuição da capacidade fotossintética e como conseqüência, da produção. Este trabalho teve por objetivo avaliar o efeito do desfolhamento provocado por ácaros sobre a produção de látex da seringueira. O experimento foi desenvolvido no município de Reginópolis, SP, com o clone PB 235, no período de setembro de 2002 a agosto de 2003, com dois tratamentos: área tratada com defensivos agrícolas para evitar o desfolhamento e área sem pulverização. As plantas foram submetidas ao sistema de sangria 1/2 S d/5 6d/7. 10m/y. ET 3.3% 4/y e a produção foi pesada mensalmente. As amostragens dos ácaros foram realizadas com intervalo de 7 a 10 dias. O desfolhamento foi avaliado pela medição, com auxílio de um luxímetro, da intensidade de luz sob a copa das plantas. Houve diferença significativa na ocorrência dos ácaros. Para C. heveae, a média geral, de todas as avaliações, foi de 0,34 ácaros/cm² na área tratada e de 0,93 ácaros/cm², na área sem tratamento. Para T. heveae esses valores foram de 0,06 e 1,09 ácaros/cm², respectivamente. Como consequência, houve diferença significativa com relação ao desfolhamento e à produção nos meses de maio, junho, julho e agosto.

Photosynthetic features and primary productivity of phytoplankton in the Oyashio and Kuroshio-Oyashio transition regions of the northwest Pacific

Diel and seasonal changes in the photosynthetic physiology of phytoplankton and primary productivity were investigated during 2005, together with community composition in the Oyashio (OY) and Kuroshio – Oyashio transition (TR) regions of the northwest Pacific. In both regions, diel changes in the maximum photosynthetic rate (P* max) and the light saturation index (Ek) in the photosynthesis – irradiance (P –E) curve were observed, due to diel differences in photo-physiology. In the OY region, the highest values of chlorophyll a concentration, depth-integrated primary production and the maximum quantum yield of carbon fixation in photosynthesis (Fc max) were observed in May when diatom blooms occurred. Furthermore, a higher water-column light utilization efficiency (C) of photosynthesis for phytoplankton was found in the OY region in both May and September. In contrast, in the TR and warm-core ring regions, Fc max was nearly constant, while depth-integrated primary production in May was significantly lower than in the OY region. These results show that the spring phytoplankton assemblages in OY waters had a higher light utilization ability during photosynthesis. Such a high photosynthetic property would contribute to the highest seasonal biological drawdown of surface pCO2 among the world’s oceans (Takahashi, T., Sutherland, S. C., Sweeney, C. et al. (2002) Global sea – air CO2 flux based on climatological surface ocean pCO2, and seasonal biological and temperature effects. Deep-Sea Res. II, 49, 1601– 1622).

Roncador Field Development: Reservoir Aspects and Well-Development Strategy

This article, written by Technology Editor Dennis Denney, contains highlights of paper OTC 19296, "Roncador Field Development: Reservoir Aspects and Well-Development Strategy," by L. Cysne and M.K. Mihaguti, Petrobras, prepared for the 2008 Offshore Technology Conference, Houston, 5-8 May. The paper has not been peer reviewed. Roncador, a giant field in the deepwater Campos basin, was discovered in 1996. Field development involves an 111-km2 area and water depths from 1500 to 1900 m, with significant oil in place, different types of oil, and variations in geological characteristics. The development strategy comprises four modules. The first module, Module-1A, will produce reservoirs in the hanging wall of a large normal-fault structure. Modules-2, -3, and -4, will produce reservoirs in the footwall block. This paper presents key aspects of the reservoirs, drainage modeling and design, and the strategy for project implementation to overcome major reservoir uncertainties, such as fluid type, connectivity, and net-pay thickness. Introduction The Roncador deepwater oil field is approximately 125 km from the coast of São Tomé Cape, Rio de Janeiro State, Brazil (Fig. 1). Reservoir depths range from 2900 to 3600 m below sea level. Roncador reservoirs are high-quality Cretaceous-age siliciclastic reservoirs with average porosity of 25% and average absolute permeability of 800 md. The field is divided into two large blocks separated by a major normal fault (Fig. 2), with oil gravity varying from 18 to 22°API in the footwall block and 28 to 30°API in hanging-wall block. The field resource volume is approximately 7.5 billion bbl. Estimated total recovery is 3.7 billion bbl of oil equivalent, with proven reserves of 3.0 billion bbl of oil equivalent. Module-1 started production in May 2000 through semisubmersible platform P-36. Unfortunately, in March 2001, P-36 sank. Module-1 was renamed Module-1A and was divided in two phases. Phase-1 production started at the end of 2002 with floating production, storage, and offloading (FPSO) vessel Brasil. Phase 2 of Module-1A (P-52) and Module-2 (P-54), both with 180,000 BOPD capacity, started production at the end of 2007. Peak production of approximately 450,000 BOPD will occur by 2013, when all Modules (-1A, -2, -3, and -4) will be on production. The newest drilling and completion technologies were used to achieve the project goals: field development by constructing good-quality wells with low price in the short term. Technologies and other well-construction strategies that contributed to success in the Roncador development are detailed in the full-length paper.

BIOLOGY OF THE GEOPHYTIC LILY, TRITELEIA LAXA (THEMIDACEAE), IN GRASSLANDS OF THE NORTHERN SACRAMENTO VALLEY

Triteleia laxa (Themidaceae), a liliaceous geophyte common in California at lower elevations with mediterranean climate, was studied during 1998–2004 at four sites in the northern Sacramento Valley. New individual plants were randomly selected each year at one to four of these grassland or open savanna sites to provide a composite study of the biology and life history of the plant. A mature plant produced two leaves after fall rains begin, a new corm on top of the shrinking old corm in spring, and a scape with an umbel of large bluish flowers in late March or April. By seed production in May, above-ground parts were dead, and the new corm and seeds persisted through summer. Mean leaf lengths varied from 22 to 28 cm; no correlation was found with amount of precipitation. Mean scape lengths also varied, from 23 to 32 cm; overall, there was a negative correlation with spring precipitation. Corms of flowering plants had a mean volume of 1.30 cm3, and occurred at a mean depth of 7.27 cm; corm volume was correlated with scape height and with number of flowers. Dry mass increased linearly in the new corm during the spring growth period. Number of flowers per plant varied among sites and the mean varied highly significantly among 5 yr (range 8–12.6). Plants appeared to be largely self-incompatible, but produced a small number of selfed seeds when pollinated by hand. The pollen∶ovule ratio was about 3100∶1. Mean fruit set (range 50–74%) and mean seed set (range 40–58%) were low, and varied significantly among sites and years. Seed mass averaged about 1.7 mg, and seeds showed 100% viability. Germination time was about 4 wk after wetting, with up to 98% of seeds germinating. The seedling was carried downward from the seed by the elongating cotyledon, ultimately producing a single foliage leaf, a lateral contractile root that shortened in April (and in situ doubtless pulls the seedling deeper into the soil), and a corm <4 mm in diameter. Soils occupied in study sites were loams, with 20 to 39% clay particles. This study on T. laxa gives a reasonably complete picture of the biology for a common geophyte, and we hope that this work will provide impetus for additional studies of other widespread or local geophytes.