Life Sciences Commons^™

Effect Of Temperature On Nitrogen Fixation Rates In Seven Clover Cultivars, J R. Crush, B D. Campbell, J R. Caradus

IGC Proceedings (1993-2023)

Seven white clover (Trifolium repens L) cultivars were grown in growth rooms at S different temperatures between S and 2S°C. Plant growth and nitrogenase activity (acetylene reduction) were measured. There were significant effects of temperature on total plant ay matter (DM) accumulation and nitrogenase activity. Temperature x cultivar interactions were significant for DM accumulation, nitrogenase activity per pot and nitrogenase activity/g DM. There was a strong correlation between DM increment/°C rise in temperature over the range 10-20°C, and nitrogenase activity/g DM. Three cultivars had maximum nitrogenase activity/g plant DM at 200C and 4 cultivars peaked at 15° C. These differences …

Growth Of Temperate Perennial Legumes Over Three Cycles Of Defoliation At Different Temperatures, M A.P Duarsa, M J. Hill, J V. Lovett

IGC Proceedings (1993-2023)

Summer-active legumes such as big trefoil (Lollis ped11nc11lat11s), birdsfool trefoil (Lot11s comic11la111s), crownvelch (Coronilla varia) and cicer milkvetch (Astraga/11s cicer) are needed for summer rainfall areas of the perennial pasture zone in eastern Australia where soil conditions and grazing management do not suit lucerne (Medicago sativa). The growth of these species was compared at 4 temperatures regimens (14/10, 18/14, 22/18, 26/22°C, 12:12 h) for 3 cycles of regrowth where soil moisture was serially changed from field capacity (FC) to 50% PC and back to PC in a growth cabinet pot experiment. Growth rates in lucerne always exceeded those of the …

Response Of White Clover To Soil Phosphate Levels At Different Temperatures And Carbon Dioxide Concentrations, R A. Carran

IGC Proceedings (1993-2023)

Nutrient availability is generally managed to remove limitations when the effects of elevated temperature or CO2 concentrations on plants are investigated. Relating the resulls of such experiments to field situations where nutrients are frequently in short supply is difficult. Phosphorous response curves were obtained for white clover (Trifolium repens L,) seedlings grown at temperatures of 18-13 or 28-23°C, nod 350 or 700 ppm CO2. At low P, response to other variables was non-significant and at 18-13° there was no response to increased CO2, Increasing temperature to 28-23° resulted in increased gcowth, apparently due to increased P availability, and at …

Interaction Of Climate Management As Controls On Species Composition, S H. Hillier, F Sutton, J P. Grime, R Colasanti

IGC Proceedings (1993-2023)

A new technique for the manipulation of temperature near the soil surface without the aid of cloches or screens has been developed at UCPE. This system is being used to manipulate the length of the growing season in an experiment in which the critical interaction between growth and the timing of two important meadow management activities - cutting and grazing - is being investigated. The technique has also been used to expose synthesised meadow communities to an artificially induced mild winter. Temperature manipulations of this kind offer a new approach to understanding the role which climate plays as a mechanism …

Comparison Of Photosynthetic Responses To Carbon Dioxide In Pasture Species, D H. Greer, W A. Laing, B D. Campbell

IGC Proceedings (1993-2023)

Thirteen major pasture species were grown in controlled environments at 3 temperatures (12n, 18/13 and 28/23°C) and at 350 nnd 700 ppm CO2 for 4-8 weeks and net photosynthesis measured under these conditions. In C1 cultivars, short-term (within minutes) exposure to elevated CO2 had the greatest effect on photosynthesis, with an average of 55% higher rates than that at ambient CO2. There was also a response to long-term growth at high CO2, with a,1 average of 40% higher rates of photosynthesis than at ambient CO2 (both measured al their growth CO2) and a marked alteration in the temperature dependence Qf …

Climate Change And Grasslands: A Life-Zone And Biota Perspective, Steven Archer

IGC Proceedings (1993-2023)

Grasslands experiencing climatic and atmospheric change may be altered with respect to: (1) geographic extent and location of local/ regional boundaries; (2) productivity, organic matter dynamics and nutrient cycling; and (3) the relative abundance of constituent life forms (woody v. herbaceous), growth forms (tall vs. shorl-statured grasses), and/or photosynthetic physiologies (C3 v. C4). Classification models based on vegetation-climate correlations predict an increase in the global acreage of grassland and savanna at the expense of boceal forest and dry tropical forest. However, extrapolation of these relationships to climates with atmospheric CO2 concentrations without present-day analogues is suspect. Dynamic models of plant …

A Climate Change Perspective On Grasslands, A Barrie Pottock

IGC Proceedings (1993-2023)

Grasslands are the result of interactions between climate, soil, interspecies competition and natural or humnn distucbance. They are vital to human sustenance but vulnerable to human mismanagement and climatic stress.• Thece is now a strong scientific consensus that climate will change during the next century at a rate unprecedented since the end of the last glaciation. Expected climatic changes include not only increasing temperatures, but also changes in total rainfall and its seasonality, and systematic increases in rainfall intensity. Along with the direct effects of increasing carbon dioxide concentrations on plants, and changes in fire frequency, these environmental influences will …

Effect Of Air Temperature On Plant Reserves And Regrowth Potential In Napiergrass (Pennisteum Purpurem), Yeong Chyn Wang, Main Lian Lee

IGC Proceedings (1993-2023)

The response of plant reserves to air temperature and the relationship between these reserves and the regrowth potential of napiergrass (Penniseetum purpurem) after defoliation was examined. Two cultivars, A7007 and Taishiuh No. 1, were cut in Wagner pots and established outside. The plants were moved into the growth chamber for 3 weeks of temperature treatment, from 2 weeks before to 1 week after harvest. Pour temperature combinations were examined: 15-15°C (temperature before-after the harvest), 15-35 °C, 35-15°C and 35-35°C. High temperature (35°C) before the harvest benefited plant growth but was associated with lower plant reserves. The stubble stored more reserves …

Influence Of Climatic Factors On Animal Production In The Humid Pampa Of Argentina, J D. Josifovich, E Frutos

IGC Proceedings (1993-2023)

For any' pasture grazing area it is important lo know the relationship among the climatic parameters, rainfall and temperature, with carrying capacity and minimal gains. The availability of pasture to adjust stocking rates and make provisions for hay or supplementary feed needed for periods of shortage can be estimated from these data. Seven years of monthly rainfall and medium average temperature; and 25 years of forage digestibility and average daily gains were related to cattle i: carrying capacity; Analysis was made using the stepwise regression method. Carrying capacity was evaluated considering animal units (AU) for a 400 kg head gaining …

Production Of Dryland Lucerne In The Western And Southern Cape Regions Of South Africa, J M. Van Heerden

IGC Proceedings (1993-2023)

Cutting trials were conducted with lucerne (Medicago sativa) cv. S A Standard under dryland conditions over a period of 8 (1982 to 1989) years at 2 sites, one each in the western (Elsenburg) and southern (Tygerhoek) Cape. The sites differed in soil type and rainfall distribution. Replicated plots were harvested at 3 set frequencies (4·, 6- and 8- weekly). Production was lowest during summer and highest in late spring and increased with decreased harvesting frequency at both sites. These data were used to derive equations for the extrapolation of the seasonal yield. Inputs into the model 11cc average …

Comparison Of Methods For Assessing Productivity Of Native Pastures In Queensland, K A. Day, G M. Mckeon, D M. Orr

IGC Proceedings (1993-2023)

The relationship between seasonal climatic conditions and observed seasonal pasture growth was examined for 3 native pasture sites in south-east Queensland for periods of up to 5 years. Nine indices of seasonal climatic conditions were considered. Across sites, between year differences in observed growth were best accounted for by the average daily ratio of calculated transpiration and vapour pressure deficit, This index accounted for 83% of the between year variation in observed growl h.

Co2 Enrichment And Temperature Effects On Productivity Of Field-Grown Phalaris And Subterranean Clover, J M. Lilley, T P. Bolger, R M. Gifford

IGC Proceedings (1993-2023)

Pure and mixed swards of Phalaris aquatica and Trifolium subterraneum were exposed to cool (ambient) and warm (cool +3oC) temperatures, at both 380 and 690 ppm CO2 concentrations in field temperature gradient tunnels for 5 months. In general, clover and the mixture had similar forage productivity in each treatment, while phalaris was less productive. Elevated CO2 increased clover production 40% in the monoculture and the mixture. Higher temperatures reduced clover regrowth at ambient CO2 and reduced the response to elevated CO2 in the monoculture but not in the mixture. In contrast, phalaris regrowth in the monoculture was not increased by …

Biophysical, Grazing-Season Management, And Animal Traits Effects On Individual Animal Performance Of Cow-Calf Systems: Insights From A Long-Term Experiment In The Us Western Great Plains, G. Irisarri, P. A. Cipriotti, L. Castro Sardiña, M. Mortenson, J. D. Derner

IGC Proceedings (1993-2023)

Beef grazing systems require information on management, biophysical, and individual animal influences on performance metrics. However, long-term controlled experiments are lacking to comprehensively ascertain these individual and likely interacting influences. We used a legacy data set from the USDA Agricultural Research Service where individual weight gains were determined from on and off weights of Hereford cows and calves grazing native northern mixed-grass prairie, during the June through September season, from 1975-2001 near Cheyenne, Wyoming, USA. The herd size varied from a minimum of 10 to a maximum of 48 pairs across years. Management (on and off grazing dates and stocking …

Southeast Kansas Climate Summary For 2023, Matthew Sittel

Kansas Agricultural Experiment Station Research Reports

Temperature and rainfall are important factors influencing agricultural performance. This report summarizes weather conditions in southeast Kansas. Comparisons to long-term records are used to indicate deviations from historical averages. Overall, in 2023 the southeast region had below average precipitation and above normal temperatures.

Weather Information For Garden City, 2023, Anthony Zukoff

Kansas Agricultural Experiment Station Research Reports

Summary of 2023 weather for research conducted at the research locations included in the 2024 Western Kansas Agricultural Research report.

Weather Information For Tribune, Ks 2023, Amanda Burnett

Kansas Agricultural Experiment Station Research Reports

Summary of 2023 weather for research conducted at the research locations included in the 2024 Western Kansas Agricultural Research report.

Germination And Seedlings Heterotrophic Growth Of Cocksfoot (Dactylis Glomerata L.) In Response To Temperature, Abraham Escobar-Gutiérrez, L. Q. Ahmed

IGC Proceedings (1993-2023)

In the context of climate change, grasslands are considered, similar to forest, as an important sink for atmospheric CO₂. However, environmental change seems to go faster than species adaptation to survive on site. Germination and heterotrophic growth are key phases for plant, and consequently, communities’ establishment and structure. They are under genetic control and affected by temperature. The objective of this study was to analyze the intra-specific variability of six accessions of Dactylis glomerata in their responses to eight constant temperatures (5 to 40˚C) during germination and initial heterotrophic growth. The novelty of this work comes from the …

L-Grassf: A New Model For Simulating The Genetic Environment Interactions On The Reproductive Phenology Of Grasses, S. Rouet, Jean Louis Durand, D. Combes, A. Escobar Gutiérrez, D. Leclercq, R. Barillot

IGC Proceedings (1993-2023)

Predicting the reproductive phenology in perennial grasses is a major concern because it determines the quantity and quality of forage. It varies a lot depending on site, year and cultivar. Projections of future climates suggest significant changes in seasonal temperature pattern, with new combinations of temperature and photoperiod, whose consequences on the floral induction of perennial grasses are unknown. L-GrassF is a new Functional Structural Plant Model simulating genetic variability of the phenology of perennial ryegrass in order to better understand the perenniality of grasslands and better anticipate the effects of climate change. L-GrassF stems from a previous model (L-Grass) …

An Examination Of The Diurnal Variability In Nitrous Oxide Emissions, B. P. Hyde, A. F. Fanning, M. Ryan, O. T. Carton

IGC Proceedings (1993-2023)

It is generally assumed in field experiments, that the measurement of nitrous oxide (N₂O) using enclosed chambers for a period of 1 hour can be used to provide an estimate of daily emission rates. In the majority of studies, emission measurements are conducted between 0900 and 1300 h. However, clearly defined diurnal cycles in N₂O emission rates have been observed from both agricultural and forest soils in temperate regions as a consequence of diurnal fluctuations in temperature (Blackmer et al., 1982; Ball et al., 1999; Baggs et al., 2002). The objective of this …

Net Photosynthesis Rate And Chlorophyll Content Of Caucasian And White Clover Leaves Under Different Temperature Regimes, A. D. Black, R. J. Lucas, D. J. Moot

IGC Proceedings (1993-2023)

In spring and summer in intensive temperate pastures, Caucasian clover (Cc) (Trifolium ambiguum) has higher dry matter (DM) production rates than white clover (wc) (Trifolium repens) (Black et al., 2003). An examination of the physiological basis for these differences can provide a greater insight into the suitability of Cc for inclusion in temperate pastures. Specifically, leaf photosynthesis rate is a major driver of seasonal growth and is strongly regulated by temperature and chlorophyll content. This study aimed to compare the net photosynthesis rate (Pn) and chlorophyll content of Cc and wc leaves under different temperature …

Climate Long-Term Trends Impacting Wheat Production Systems In Kansas, Octavia M.M. Tavares, Fábio Marin, Romulo Lollato, Bruno C. Pedreira

Kansas Agricultural Experiment Station Research Reports

Winter wheat production is of major importance in Kansas. The purpose of the study was to verify the evidence of climate change in a long-term weather data series from Wellington and Parsons, KS, to understand whether climate change has been affecting yield production.

Quantifying The Effects Of Abiotic Stress On Early Season Growth, Development, And Physiological Characteristics In Corn, Charles Hunt Walne

Theses and Dissertations

Corn is one of American agriculture's greatest success stories, where we have witnessed incredible increases in yield potential over the last half-century. However, abiotic stress is still the primary limiting factor preventing plants from reaching their true yield potential. In addition, agriculture is not exempt from the deleterious effects of changing weather patterns and the altered climate our world will face as time progresses. Thus, increasing our understanding of how crops interact with their environment both above and below the soil will be crucial to increasing production on a global scale while maximizing profitability at a local level. Five studies …

Southeast Kansas Weather Summary - 2020, G. F. Sassenrath, M. Knapp, X. Lin

Kansas Agricultural Experiment Station Research Reports

This is a summary of the weather conditions in southeast Kansas during the 2019/2020 growing season. The wet weather pattern that began in 2019 continued into the spring of 2020, creating adverse conditions for spring crop establishment. Dry conditions dur­ing the summer and fall limited crop and pasture production. Temperatures were very near the 10-year averages at each location.

Maize And Soybean Root Front Velocity And Maximum Depth In Iowa, Usa, Raziel A. Ordóñez, Michael J. Castellano, J. L. Hatfield, M. J. Helmers, Mark A. Licht, Matt Liebman, Ranae Dietzel, Rafael Martinez-Feria, Javed Iqbal, Laila A. Puntel, S. Carolina Córdova, Kaitlin Togliatti, Emily E. Wright, Sotirios V. Archontoulis

Department of Agronomy and Horticulture: Faculty Publications

Quantitative measurements of root traits can improve our understanding of how crops respond to soil and weather conditions, but such data are rare. Our objective was to quantify maximum root depth and root front velocity (RFV) for maize (Zea mays) and soybean (Glycine max) crops across a range of growing conditions in the Midwest USA. Two sets of root measurements were taken every 10–15 days: in the crop row (in-row) and between two crop rows (center-row) across six Iowa sites having different management practices such as planting dates and drainage systems, totaling 20 replicated experimental treatments. …

Precision Drought Stress In Orchards: Rootstock Evaluation, Trunk Hydration And Canopy Temperature, Lance V. Stott

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Tree fruit crops are of high value, but use a lot of water. Precision irrigation has the potential to save water while simultaneously improving crop quality. The timing and method of precision water stress in various tree fruit crops has been widely studied. However, in order to successfully employ precision irrigation methods in orchards, an accurate measurement of tree water status is required. Currently, stem water potential is the preferred indicator. However, this measurement is tedious and cannot be automated. Because measurements must be taken near solar noon (approximately 1:30 PM MDT in the summer in northern Utah), the number …

Temperature Control Of Node Appearance And Initiation In Soybean, Fatima Amor M. Tenorio

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Soybean demand remains strong and continues to grow as a source of protein and oil for food and feed. Soybean production is expanding into cooler and warmer environments, thus, it becomes critical to expand the current knowledge about the influence of temperature on soybean. Temperature is the main environmental factor effecting node appearance rate (NAR) and node initiation rate (NIR), which are key parameters controlling soybean growth and development. This study aims to assess the response of NAR and NIR to temperature and investigate the coordination between these two processes under controlled and field conditions. Two greenhouse experiments with four …

Agro-Climatic Change, Crop Production And Mitigation Strategies-Case Studies In Arkansas, Usa And Kenya, John Westley Magugu

Graduate Theses and Dissertations

Although climate change impacts vary geographically and temporally, studies at local levels are not readily available for stakeholders to better understand how their local communities would be affected and what remedial measures could be more effective in their local contexts. This dissertation has examined climate change and its impacts in two different local contexts: eastern Arkansas in the USA and Nyando in Kenya. The first part of this dissertation develops agro-meteorological indicators and examines the relationship between agro-meteorological indicators and crop yields in eastern Arkansas between 1960 and 2014. Results reveal that temperature based indicators were more strongly correlated to …

Yield Gap Analysis Of Us Rice Production Systems Shows Opportunities For Improvement, Matthew B. Espe, Kenneth Cassman, Haishun Yang, Nicolas Guilpart, Patricio Grassini, Justin Van Wart, Merle Anders, Donn Beighley, Dustin Harrell, Steve Linscombe, Kent Mckenzie, Randall Mutters, Lloyd T. Wilson, Bruce A. Linquist

Department of Agronomy and Horticulture: Faculty Publications

Many assessments of crop yield gaps based on comparisons to actual yields suggest grain yields in highly intensified agricultural systems are at or near the maximum yield attainable. However, these estimates can be biased in situations where yields are below full yield potential. Rice yields in the US continue to increase annually, suggesting that rice yields are not near the potential. In the interest of directing future efforts towards areas where improvement is most easily achieved, we estimated yield potential and yield gaps in US rice production systems, which are amongst the highest yielding rice systems globally. Zones around fourteen …

Postharvest Degradation Of Microalgae: Effect Of Temperature And Water Activity, Jacob A. Nelson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Though usually a nuisance in swimming pools and ponds, algae has the potential to be a valuable commodity for use as food and fuel. But before algae butter and biofuel become commonplace, issues with harvesting and storing this new crop need to be overcome. Though there has been ample research into how to grow and use algae, scientists have spent little time figuring out what to do after you pull it out of the water and before you eat it (or turn it into biodiesel). Algae, like all food products, starts to spoil as soon as it is harvested.

This …

Synthetic Turf Surface Temperature Reduction And Performance Characteristics As Affected By Calcined Clay Modified Infill, Eric Hall Reasor

Masters Theses

Synthetic turf research plots containing crumb rubber (CR) infill were established in Knoxville, TN in 2012 and 2013. Calcined clay (CC) was amended to CR in several ratios: a 50:50 (vol vol-1) blend; a 50:50 blend with a polymer coating on CC (50 CR:50 CCC); a 15 mm layer of CC under 15 mm of CR (CR over CC); and a 15 mm layer of CC over 15 mm of CR (CC over CR). A 100% CR and a 70:30 blend of CR to sand (70 CR:30 S) were included for comparison. Surface temperature was measured in the summer of …