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| Seminars |
Welcome to the Crop and Soil Sciences Seminar Series. Following is a list of the seminars scheduled for the Fall of 2003 and Spring 2004. Unless otherwise noted, all seminars are on Thursday, from 12:20 PM to 1:10 PM in 135 Emerson Hall.
Crop and Soil Sciences
9/2/03 - Do Environmental Factors Trigger BSE (Mad Cow) and Other Prion Diseases? (Murray McBride, Professor, Department of Crop and Soil Sciences, Cornell University). Abstract: A number of important facts about BSE and other “transmissible spongiform encephalopathies” (TSE’s) not explained by the widely-accepted “infective prion” theory suggest that environmental or nutritional factors in certain geographic regions are at least a predisposing, and perhaps even a causative, factor in BSE and other TSE’s such as scrapie in sheep and chronic wasting disease (CWD) in elk and deer. These facts have led to a hypothesis that clusters of sporadic TSE’s are initiated by trace metal imbalances in soils and food chains, particularly excess Mn and deficient Cu. Evidence in support of an environmental explanation of TSE’s, and against transmissibility of prion diseases under natural conditions, will be presented.
9/16/03 - Relativism, environmental sciences and policy-making (Philippe Baveye, Associate Professor, Department of Crop and Soil Sciences, Cornell University). Abstract: Relativism, as a philosophical school of thought, has bad press these days, to say the least. This is especially the case among scientists. Yet, increasingly, environmental scientists of different backgrounds are coming to the conclusion that a form of relativism is unavoidable, given the complexity and the spatio-temporal heterogeneity of the systems they are dealing with. More often implicitly than explicitly, a brand of relativism is nevertheless apparent in studies dealing with such environmental issues as biodiversity, environmental equity or justice, sustainability, habitat deterioration, etc. In this seminar, I will try to explain in detail, via examples, the various reasons why this trend came about, and to analyze some of its potential consequences for the way environmental policies are developed.
9/23/03 - Combining an optical strip-assay biosensor with ribotyping for microbial source tracking of Enterococcus faecalis in the Lower Hudson River Basin (John Reilly, MS Candidate, Department of Crop and Soil Sciences, Cornell University. Abstract: Increased occurrence of fecal pathogens in the water supply drives the need to develop highly specific, inexpensive, portable, and accurate bioanalytical devices that can be used to detect the presence of particular pathogens. Determining the presence/absence of fecal bacteria and their sources continues to be important for water quality managers monitoring bacterial contamination of public water bodies. Enterococcus faecalis is a fecal indicator bacterium currently being tested as a means to distinguish contamination arising from humans and birds from that derived from other animals. Two complementary molecular methods used to detect and fingerprint these bacteria will be described; an optical biosensor and ribotyping of isolates.
9/30/03 - Experiential Learning: Lessons from an Agroecosystems Analysis Course in the Midwest (Gary Fick, Thomaz Rein, Karman Lhendup and Christian Peters, Department of Crop and Soil Sciences, Cornell University. Abstract: Eight students and one teacher from Cornell University took part in a field course in the Midwest this past August. The subject was “Agroecosystems Analysis” and the teaching method was “experiential learning.” Students in the course came from Cornell University, Dordt College, Iowa State University, the University of Minnesota, the University of Nebraska, and the University of Wisconsin, and will get credit from their home institution. The functional teachers of the course were the farmers visited on their farms in Minnesota, Nebraska, and Iowa. Six professors served as consultants, and the students were provided background readings before the course began and placed in charge of their own learning process. Six teams of three or four students finished the course with a group presentation followed in four weeks with a group report and an individual learner document. The four presenters of this seminar were participants in the course, and they will relate their insights on what it was like to be a professor who gave no lectures, a student required to write one’s own course outline, and a visitor in the Midwest experiencing novel agricultural systems. The focus question of the course was how to appraise agricultural sustainability, and we will also cover some of our impressions of the sustainability of Midwest agriculture.
10/7/03 - Applying Plant Population Ecology - Increasing the Suppression of Weeds by Cereal Crops (Jacob Weiner, Department of Ecology, Royal Veterinary and Agricultural University). Abstract: Recent advances in our understanding of the advantage of initial size in competition among individual plants ("size-asymmetric competition") suggest that the potential for many crops to suppress weeds is much greater than generally appreciated. We hypothesize that this potential can be realized if: (i) the crop density is increased significantly; and (ii) the crop is regularly (uniformly) distributed in two-dimensional space rather than sown in traditional rows. We tested these hypotheses by sowing four varieties of spring wheat Triticum aestivum at three densities (200, 400 and 600 / m2) and in two spatial patterns (normal rows and a uniform grid-like pattern) in the presence of high weed pressure. There were strong and significant effects of both crop density and spatial distribution on weed growth. The treatment with high crop density and the grid sowing pattern contained 60% less weed biomass and produced 60% higher yield than the treatment closest to normal sowing practices (crops sown in rows at 400 / m2). While weed biomass decreased monotonically with density for all varieties, a significant variety x density interaction suggests that the attributes resulting in good weed suppression at high crop density may not be the same as those most advantageous at low crop density. A more crowded, uniform distribution of some crops can contribute to a strategy to reduce the use of herbicides and energy-intensive forms of weed control.
10/21/03 - Increasing the suppression of weeds by cereal crops - possibilities and limitations (Lars Kristensen, Visiting Fellow, Cornell University). Abstract: In continuation of the presentation by Jacob Weiner October 7th, Lars Kristensen will present further work on crop spatial pattern, crop density and weed suppression in cereal crops, exploring possibilities and limitations of the increased density/increased uniformity approach. The presentation will mainly focus on two further aspects of pattern-density and weed suppression relations, a) impact of nitrogen fertilization on weed suppression in different pattern density combinations, and b) impact of different degrees of uniformity - obtained by different sowing techniques - on weed suppression in different pattern density combinations.
10/28/03 - Through protection to prevention: Pollution control in sustainable agriculture (Irina Birman, Research Scientist/Associate Professor, NYS Department of Health/School of Public Health, SUNY at Albany). Abstract: Waterborne outbreaks may result in simultaneous infection of a high proportion of the community and, thus, the importance of safe and reliable drinking water cannot be overemphasized. Without undermining the significance of conventional water treatment technologies, the concentration will be given to source water protection as an effective means of preventing the risks, associated with contaminated water supply. Irresponsible manure spreading, inadequate storm water management, excessive use of agricultural chemicals and improper timber harvesting, all these factors can contribute to either intentional or non-intentional source water impairment and, therefore, create public health risks. To reduce the load of nutrients and pathogens, protect aquatic habitat and maintain reservoirs in a healthy mode, ‘the multiple barrier approach’ is being taken in the unfiltered New York City water supply. Used as an example, this system will discussed to demonstrate the need for balancing risks and benefits in sustainable agriculture.
11/11/03 - Ecosystem Restoration: role of arbuscular mycorrhizal fungi (Sigurdur Greipsson, Assistant Professor, Troy State University). Abstract: Natural processes during primary succession can provide valuable information for restoration strategies. An example is given from natural plant colonization on the volcanic island Surtsey where arbuscular mycorrhizal fungi (AMF) play a key role in regulating primary succession. The pioneer sand stabilizing grass Leymus arenarius grew significantly better when inoculated with native AMF compared to commercial AMF inocula or added phosphorus. Eleven species of AMF were isolated from sandy soils in Iceland of which three species are probably new to science. Restoration sites and native dunes in primary succession were deficient in AMF propagules. Management of AMF populations is critical in restoration and emphasis is put on the use of native AMF isolates.
11/18/03 - SPEAR PROGRAM - Nutrient management research, extension and teaching at Cornell (Quirine Ketterings, Assistant Professor, Department of Crop and Soil Sciences, Cornell University). Abstract:
Quirine Ketterings joined the faculty of the Department of Crop and Soil Sciences, Cornell University, in August 2000, to provide leadership for the nutrient management extension program of the college and to conduct research that improves our understanding of nutrient cycling and aids in agronomic and environmentally sound nutrient management of farms. Quirine received her MS from Wageningen Agricultural University and her PhD from The Ohio State University. She established and leads the Nutrient Management Spear Program, an applied research, teaching and extension program for field crop and manure management, that aims to improve grower and agricultural industry awareness of crop nutrient needs, crop quality, management of organic wastes, environmentally sound nutrient management practices, and overall soil fertility management. The current research program includes studies on phosphorus dynamics on field and whole-farm scales and best management practices to control P losses from farms, calibration of a new soil nitrogen test, and fertilizer recommendations for brown mid-rib sorghum sudangrass. Research findings are extended to NY stakeholders through extension bulletins, web-based tools (
11/25/03 - Soil and Crop Sciences Graduate Student Poster Session (Graduate Students, Department of Crop and Soil Sciences, Cornell University).
12/2/03 - A Project on Apple Replant Disease - A challenge for all who get bored by conventional who-done-it mysteries (Angelika Rumberger, Post Doctorate, Department of Horticulture, Cornell University).
12/9/03 - Decreasing Bioavailability of Soil Zinc Under Flooded Conditions: Implications for Rice Production and Soil Testing (Sarah Johnson, PhD Candidate, Department of Crop and Soil Sciences, Cornell University). Abstract: Zinc deficiency is the most common micronutrient problem in paddy rice production across Asia, resulting both in reduced yield and in low content on Zn in grain, leading to lack of Zn in the rice-based human diet. There has been some debate in the literature about whether Zn deficiency in rice is caused by chemical changes in flooded soils affecting Zn2+ or by competition between Zn2+, Fe2+, and HCO3- for plant uptake. In the present study, DTPA extractions of wet soil samples indicated a decrease in plant-available Zn as the soil progressed from oxidized to reduced condition during the flooded season. Rice growth studies indicated decreased plant uptake of Zn from reduced as compared to oxidized soils, even with high levels of Zn fertilizer added to the soil prior to flooding. X-ray adsorption spectroscopy (specifically EXAFS) revealed chemical changes in Zn upon reduction of the soil, although Zn2+ is not itself oxidized or reduced. The conclusion is that Zn deficiency in rice is caused by a combination of soil chemical changes involving Zn and by competition for Zn uptake into plant roots. Implications for rice production include ideas about how Zn might be effectively added to rice, since incorporation of Zn fertilizer into soil prior to flooding is largely ineffective. The implication for soil testing is that Zn availability to rice must be tested when the soil is still in its reduced state, rather than after air-drying.
12/16/03 - Role of Plant Nutrition in Suppression of Radopholus similis Nematode Populations and Damage in Banana Production (David Bwamiki, PhD Candidate, Department of Crop and Soil Sciences, Cornell University). Abstract: Bananas have been one of the few foods enjoyed on a truly worldwide scale, on tables of families, from the highest-income to the lowest-income in all parts of the world. Yields of this important crop have been declining due to many abiotic and biotic factors among which nematodes are paramount. The Burrowing nematode Radopholus similis is the major nematode pest of bananas worldwide. As chemical control becomes unpopular due to its effects on the environment, toxicity to the users in addition to being expensive, alternative methods of control have gained importance. Plant nutrition, although frequently unrecognized, is very important in plant defense against diseases and pests. In the present study, nutrient balances involving half the recommended levels of K, Mg, Ca, S and micronutrients, indicated a decrease in nematode populations, damage and an increase in growth parameters and yield of bananas. The form of nitrogen (NH4 or NO3) supplied to the banana plants influenced both nematode reproductive potential and plant growth. The conclusions are that nutrient imbalance may be just as detrimental as nutrient deficiency or excess in influencing plant defense and potassium application to banana plants under nemataode stress should not be as high as in nematode free environments.
1/15/04 - Plant Salt Tolerance: Genes and Functions (Dr. Huazhong Shi, Department of Horticultre and Landscape Architecture, Purdue University). Dr. Shi is a faculty candidate for the Plant Genomics, Molecular Biology of Abiotic Stress position, through the Crop and Soil Sciences Department, Cornell University.
1/29/04 - Tracing Nutrients from Soil to Humans: the example of zinc, rice and the nutritional status of children in Bangladesh (Anne-Marie Mayer, Graduate Student, Nutrition Department, Cornell University). Abstract: The idea that nutritional deficiency in humans can have its origin in the soil is not new, but has received little recent research attention. In Bangladesh, soil zinc deficiency is widespread and the population is at risk of zinc deficiency due largely to poor dietary intake. Using the example of zinc, studies were designed to trace this nutrient from soil to rice, to processed rice, to the whole diet and finally to the nutritional status of children. The various challenges on this journey will be presented.
2/5/04 - Land-based opportunities for mitigation of greenhouse gas emissions in New York State (John Duxbury, Professor, Department of Crop and Soil Sciences, Cornell University). Abstract: This seminar is the first in a series of four that will explore land based opportunities for mitigation of greenhouse gas (GHG) emissions in NY State. The GHG emissions by agriculture in NY will be presented and discussed within the context of Governor Pataki's task force report on GHG sources and mitigation options for NY. The possibilities for carbon sequestration in soils and forest biomass to contribute to mitigation of GHG's, and for agriculture to move into the energy sector will be introduced. Subsequent seminars will discuss some of these options in more detail.
2/12/04 - Sustainability of short-rotation woody crops grown for bioenergy and bioproducts (Tim Volk, SUNY College of Environmental Science and Forestry, Syracuse, NY). Abstract: Global energy use projections predict that biomass will be an important component of primary energy sources and a main source of renewable energy in the coming decades. Short-rotation woody crops (SRWC) will be a major component of this biomass. However, questions and concerns have been raised about the sustainability of SRWC.
A suite of common criteria has emerged from the different international groups that have convened to define sustainable forestry. These include conservation of biological diversity, conservation of soil and water resources, maintenance of forest ecosystems contribution to global carbon cycles, forest ecosystem productivity and health, socio-economic benefits. These criteria are used to show how willow biomass crops in the northern temperate zones, as an example of SRWC, are moving society towards sustainability.
The biological characteristics and management of willow crops creates a structurally diverse habitat for an array of species both above and belowground. The perennial nature of willow crops, their rapid growth and extensive root system contributes to the improvement of soil and water quality relative to annual agricultural crops. Biomass from SRWC can be used to produce energy with no net addition of CO2 to the atmosphere, making a significant contribution to global carbon cycles. Both research and experience from commercial operations indicates that the implementation of good management practices will maintain productivity of willow crops over multiple rotations. Rural development and environmental benefits associated with deployment and use will accrue to the local community because of SRWCs short supply chain.
Using these internationally agreed upon forest sustainability criteria as benchmarks, the answer is clearly yes, SRWC are sustainable. The recognition and economic valuation of these benefits are necessary for the deployment of SRWC, which in turn can help move society along the path of sustainability.
2/19/04 - Land Use and Climate Change Seminar Series: Grass biofuel for rural America, New York forests as carbon sink (Jerry Cherney, Professor, Department of Crop and Soil Sciences, Cornell Univeristy; Christine Goodale, Department of Ecology and Evolutionary Biology, Cornell University). Abstract:
Grass Biofuel for Rural America: Pelletized grass biofuel has the potential to become a major unsubsidized fuel source capable of meeting home and small business heating requirements in rural communities at less cost than all available alternatives. In addition, grass biofuel pellets emit 80-90% less greenhouse gasses than conventional energy sources. Perennial grass can be pelleted and used successfully as a heating source as long as the ash content of the grass is low. Preliminary research in 2003 investigated management strategies to produce low-ash biomass from perennial grass in New York State. This system can make a positive contribution to sustainable agriculture through increasing farm diversification and increasing the land base under perennial cover, and is ideal for nutrient management, soil conservation, maintaining open spaces, and compatible with wildlife nesting opportunities. Our overall goal is to address and resolve the remaining outstanding issues facing this cost-effective, environmentally-friendly, low-technology, small-scale biomass production system for reducing energy imports and stimulating rural economic development.
NY forests as a carbon sink: Carbon cycle science suggests that forests of the eastern U.S. make important contributions to the global terrestrial carbon sink. A review of patterns and mechanisms suggest that changes in land use and recovery from past disturbance are the primary causes of these carbon sinks. In New York and elsewhere across the Northeast, forest re-growth from past clearing for agriculture presently provides a substantial net carbon sink, partly offsetting the regions CO2 emissions. The persistence and trajectory of this forest carbon sink into the future depends largely on intentional and unintentional land management decisions, but likely represents a transient sink of finite capacity.
2/26/04 - Land Use and Climate Change Seminar Series, Panel discussion (Panelists: Duane Chapman - Economist (Applied Economics and Management, AEM), Steve DeGloria - GIS/land-use (Crop and Soil Sciences, CSS), John Gaunt - Soil Scientist (Crop and Soil Sciences, CSS/GY Associates), Neil Schwartzbach - Community Development (Community and Rural Development Institute, CaRDI)).
The purpose of the panel discussion is to further examine land-based opportunities for GHG mitigation in NY State (short rotation wood biomass, grass pellets, forest biomass, biofuels). Audience participation welcomed
3/4/04 - Micronutrients status in agricultural soils of Bhutan (Karma Lhendup, Graduate Student, Department of Crop and Soil Sciences, Cornell University). Abstract:Micronutrients deficiencies have been found to be widespread in South Asia. To date, no comprehensive analysis on the levels of micronutrients in soils of Bhutan have been carried out. In the present study, soils samples from 371 agricultural fields across five different Agro-ecological zones (AEZ) and two land use types have been sampled in 1999 and analyzed for five micronutrients (B, Zn, Cu, Fe and Mn). The distribution of the micronutrients and their association with other important chemical and physical properties were investigated. Spatial patterns were observed with boron but not the other micronutrients.
3/11/04 - Conservation and Change: A Comparison of In-Situ and Ex-Situ Conservation of Jala Maize Germplasm in Mexico (Ellie Rice, Graduate Student, Department of Crop and Soil Sciences, Cornell University). Abstract: Conservation efforts have targeted the giant maize from the town of Jala, in the Mexican state of Nayarit, for decades. This population genetic study employs microsatellite marker analysis to compare the Jala variety found in farmers' fields today with the Jala variety found in genebank accession (1944, 1951, 1952, 1968, and 1988). The study has implications for understanding how varieties change with time, both in farmers' fields and in genebanks. Results based on eight farmers' fields, as a composite of modern Jala, show remarkable similarity across the valley within a given year. Furthermore, the balanced data set allows comparisons between farmers' fields, Jala genebank accessions, diverse landrace accessions and teosinte relatives in order to address questions about distribution and management of diversity.
3/18/04 - Light Interception and Soil Water Dynamics After Pasture Degradation in the Brazilian Amazon: Effects of Pasture Management and Secondary Forest Regrowth (Steve Welch, Graduate Student, Department of Crop and Soil Sciences, Cornell University). Abstract: In the Brazilian Amazon, forest cleared for ranching often results in abandonment of degraded pastures. Pastures are frequently abandoned because the forage grasses cannot maintain adequate leaf area and lose canopy dominance to more aggressive invasive species. Phosphorus and calcium have been indicated as nutrients limiting to pasture growth. We tested their effects on light and soil water resource capture by Brachiaria humidicola, the principal pasture grass in the region. We also tested the hypothesis that a gypsum amendment will enhance fertilizer effects and deepen the rooting zone by deeply incorporating limiting nutrients. Primary forest and degraded pastures have distinctly different light interception and soil water dynamics which can have profound effects on the hydrological cycle and local heat budgets. The rate at which secondary forest growth restores these important processes is not known. Evaluation of leaf area indices and soil water stocks of secondary forests, pastures and primary forests demonstrate how secondary forest matures and the degree to which hydrology is restored.
4/1/04 - The MAUP: a universal problem without a universal "solution"? (David Wong, Associate Professor, George Mason University, Fairfax, Virginia). Abstract: The modifiable areal unit problem (MAUP) is one of the two major methodological problems in analyzing spatial data (the other is spatial autocorrelation). It is a rather stubborn problem because it has been identified for more than half a century, but we still have not developed viable solutionsyet. It is a pervasive problem because it will emerge as long as spatial data are involved. In this presentation, I will briefly define the MAUP and identify its source. Then I will discuss its impacts on some major areas of analysis. It will be followed by an overview of major approaches to handle the MAUP. Finally, I will discuss some potential methods for specific application analyses.
4/8/04 - Weed dynamics in maize planted on Terra preta de Indio and adjacent soils of the central Brazilian Amazon (Julie Major, Graduate Student, Department of Crop and Soil Sciences, Cornell University). Abstract: Soils in the Amazon basin are generally considered to be nutrient-impoverished. However, there are areas of black, highly fertile anthropogenic soils, called Terra Preta de Índio (Indigenous Black Earth, TP) that are distinctly different from the dominant, nutrient-poor adjacent soils (AS). These areas were likely formed by activities of indigenous peoples in Pre-Columbian times. Surprisingly, TP soils have generally maintained their high fertility levels, allowing for more intensive crop management and reducing the need to frequently clear surrounding forest. The TP system also affords a unique opportunity to study the effect of high fertility on weed-crop competition under tropical growing conditions. The primary focus of this work was to compare weed population dynamics and crop growth in TP and AS soils. From January to July 2003, field studies were conducted at four different locations near Manaus (Amazonas, Brazil), on land that had been prepared using traditional slash-and burn techniques. At each location, two maize (Zea mays L.) plantings were carried out, one on TP and one on AS. Data from these field trials will be presented.
4/15/04 - CANCELLED - Simulating water and tritium fluxes in a mixed forested watershed in the South Eastern US (Karin Rebel, PhD Candidate, Environmental Information Science, Cornell University). Abstract: A simple, spatial, dynamic model of water uptake by trees in a watershed was developed using the PCRaster Environmental Modeling Software. We are using this model to simulate water uptake and subsurface lateral movement
in a coniferous and a mixed hardwood - coniferous forest on Coastal Plain soils of the southern United States. These soils are characteristically sand overlying slowly permeable clays found at depths of 30 to 200 cm. Temporary perched water tables can develop. Twenty-five hectares of the watershed we are modeling is periodically irrigated with tritium enriched water, which we use to validate the model.
Methods for determining in the field if tree species differ in where they take up water in the soil profile are limited, as are methods to determine root distribution for modeling purposes. Modeled and measured tritium activity in the transpiration water were compared, as well as the measured differences between tree species. The measured tritium activity in the transpiration water followed the simulated tritium activity well. Differences in measured tritium activity in the transpiration water was most apparent between understory and overstory trees, comparing the same species as well as among species. These results imply that roots of
individual trees and tree species were taking up water in different parts of the soil profile. On a stand basis the root distribution estimated using inverse modeling techniques appeared to well represent water and tritium uptake.
4/15/04 - Soil Composition and Properties at Medieval Archaeological Sites in Russia (Dr. Olga Yakimenko, Department of Soil Science, Moscow State University, Russia).
4/22/04 - Influence of photoperiod and maize competition on reproduction, seed germination, and seedling vigor in the annual Abutilon theophrasti Medic (Rob Nurse, Graduate Student, Department of Crop and Soil Sciences, Cornell University). Abstract: Abutilon theophrasti Medic. is a troublesome annual weed in many maize and soybean cropping systems of the United States and Canada. Seeds of A. theophrasti exhibit physical dormancy. Differences in the growing environment of parent plants may influence the germinability of seeds and vigor of seedlings produced. Thus, the effects of photoperiod and maize competition on A. theophrasti seed germination and seedling vigor were examined under field conditions from 2000 to 2003. The experiment was designed as a split-split-split plot design with four replications. The main plot factor was environment (maize vs. velvetleaf monoculture), the sub plot factor was photoperiod length (13.5, 14, amd 15 hours), and the sub-sub-plot factor was transplant date (competitive environment) of A. theophrasti (14 Days Before maize Emergence, 0 DAE, 14 DAE). Abutilon theophrasti is a quantitative shortday plant that is highly competitive within a maize canopy. Previous research suggests that A. theophrasti maturing under shorter photoperiods (i.e. 14 hrs) and high maize competition should respond with rapid flowering and allocate fewer resources to seed dormancy and seedling vigor. In support with this hypothesis, A. theophrasti in this study that matured under shorter photoperiods and in competition with corn (i.e 13.5 hrs and 14 DAE) had higher germinability (60%) than seeds produced under longer 15 hour photoperiods (90%). Seedling vigor was determined by measuring radicle length for six days following germination. There was no significant difference found between treatments for seedling vigor with all treatments averaging radicles of 125 mm in length. Abutilon theophrasti were smaller, flowered faster and produced fewer seeds under shorter daylengths (14 hr). Additionally, a 1.5g reduction in seed weight was found in the shortday/high competition treatments when compared to the longday treatments under both competitive levels. The seed germination and seedling vigor results for A. theophrasti grown under different photoperiods may provide a unique opportunity to more effectively manage this problem weed; especially for A.theophrasti emerging and maturing under shorter daylengths found late in the maize growing season.
4/29/04 - The Computational Agriculture Initiative at Cornell, and the Development of Spatially-Balanced Experimental Designs (Harold van Es, Professor, Department of Crop and Soil Sciences, Cornell University). Abstract: This seminar is will introduce the Cornell Initiative on Computational Agriculture, which focuses on the application of high-performance computing to agricultural problems. Its objectives and projects will be discussed. One of these relates to the development of spatially-balanced designs. Despite the availability of a multitude of advanced experimental designs, most agronomic field studies (at least 90%) are implemented through randomized complete block designs (RCBD). We demonstrated in earlier work that randomized treatment allocation to plots can cause biases and imprecision under most field conditions due to autocorrrelation and trends in field properties. We propose spatially-balanced experimental designs that are inherently robust to nonrandom field variability (autocorrelated or trended), and provide an easier way for researchers to design experiments. In collaboration with the Cornell Intelligent Information Systems Institute we are developing standard CBD's that are spatially optimized. We are using two approaches: a heuristic local search method using simulated annealing, and an exact method using combinatorics.
5/6/04 - Nitrate adsorption in oxisols of the Brazilian Savannas (Thomaz Rein, Graduate Student, Department of Crop and Soil Sciences, Cornell University). Abstract: Contrasting to typical temperate soils, highly weathered tropical soils can adsorb indifferent anions like nitrate, causing a retardation of leaching in the profile, with possible agronomic and environmental implications. Knowledge of the nitrate adsorption capacity of these soils and how to predict it are required if this property is to be considered for purposes of management of nitrogen fertility in cropping systems. Results of studies with samples from representative soil profiles will be presented. The significance of nitrate adsorption to leaching and nitrate uptake by roots is evaluated using simulation models.
Special Seminars
12/16/03, 10:00 AM - 11:00 AM - Carbon Dynamics in Forested Ecosystems of New York State (Mary Killilea, PhD Candidate, Field of Soil and Crop Sciences, Cornell University). Abstract: The spatial extent of forest ecosystems in New York State has increased to over 62% during the past 100 years. Increases in forest biomass in the northern temperate zone are in part offsetting the carbon emitted from fossil fuel use and tropical deforestation. Quantifying the amount of carbon being stored in forests is necessary to make future policy decisions on how carbon and other greenhouse gases should be managed. One method of estimating the amount of carbon assimilated and stored in forest ecosystems is the use of biogeochemical models. In this study, the model BIOME-BGC is used to estimate carbon storage for selected field sites and to produce spatially-explicit estimates of net primary productivity (NPP) for the study area. Model-based carbon storage estimates are driven using daily climate data, soil texture, effective soil depth and vegetation type. Leaf area index (LAI) is an important component of carbon models, and was measured at the field sites. The field measurements of LAI were used along with Landsat ETM+ imagery to create landscape estimates of LAI in the study area. Model validation was performed by comparing field site measurements of LAI with the BIOME-BGC estimates of LAI to assess the accuracy of the model. Further validation of the model was conducted by comparing the simulated county estimates of NPP with estimates of NPP derived from USDA Forest Service forest inventory data. Significant findings indicate: (1) improved methods are required for estimating LAI at variable scales using satellite imagery, (2) NPP at the field sites were between 3.47 to 6.35 MgC/ha/yr while net biome productivity were between -0.03 to 0.09 MgC/ha/yr, (3) county estimates of NPP generated from BIOME-BGC were higher than estimates calculated from the forest inventory data.
2/4/04, 12:20 PM - 1:10 PM - Sheep and Penguins: Organic Grazing Systems in the Falkland Islands (David Parsons, MS/PhD Graduate Student, Department of Crop and Soil Sciences, Cornell University). After graduating from the University of Tasmania in Australia, David Parsons was employed by the Falkland Islands Government as a forage agronomist for the Department of Agriculture. For three years prior to coming to Cornell, Parsons was an agronomist with a corporate farming company in the Murrumbidgee Irrigation Area in Australia, where he was responsible for agronomic decisions on three farms covering 46,000 hectare of dryland and irrigated crops and forages.
Parsons began an MS/PhD program in the fall in the Department of Crop and Soil Sciences and will be working with Jerry Cherney in forage agronomy.
Excellent refreshments can be expected.
COSPONSORS: Management of Organic Inputs in Soils of the Tropics, the Cornell Agroforestry Working Group, the Department of Crop and Soil Sciences, and the Department of Natural Resources
Conferences
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