Soil-Crop Dynamic Depth Response Determined from TDR of a Corn Silage Field Compared to EMI Measurements

Electromagnetic induction (EMI) techniques have been used to monitor bulk seasonal soil-crop apparent electrical conductivity (ECa) dynamics. Interpreting this information can be complicated by changes in the soil profile such as water content or nutrient leaching. Time domain reflectometry (TDR) measures localized soil EC; therefore, TDR can provide clarification to where in the soil profile the EC changes are taking place. The objective of this study was to determine whether surface or deep EC changes were driving the response measured by EMI during the crop season of a field amended with animal manure. Results indicate that seasonal soil-crop EC dynamics measured by EMI are primarily driven by surface (,0.2 m) changes as opposed to deeper (.0.9 m) changes. These changes appear to be the result of surface ionic dynamics caused by crop-soil interactions and not soil volumetric water content (hv), since no significant correlations were detected between hv and ECa for any treatment, depth or dipole orientation. These findings are consistent with others who reported the EMI signal was driven primarily by changes in nitrate concentration and not by soil water content. The results of this study clarify our understanding of the soil dynamics that drive the ECa response of a manure amended field. The ability to non-intrusively measure nutrient mineralization and crop uptake provides researchers with a powerful tool for understanding soil-crop interactions. Understanding the soil-crop dynamic will facilitate development of management practices for amending soil with manure while protecting the environment from unintended contamination

Soil-Crop Dynamic Depth Response Determined from TDR of a Corn Silage Field Compared to EMI Measurements

Electromagnetic induction (EMI) techniques have been used to monitor bulk seasonal soil-crop apparent electrical conductivity (ECa) dynamics. Interpreting this information can be complicated by changes in the soil profile such as water content or nutrient leaching. Time domain reflectometry (TDR) measures localized soil EC; therefore, TDR can provide clarification to where in the soil profile the EC changes are taking place. The objective of this study was to determine whether surface or deep EC changes were driving the response measured by EMI during the crop season of a field amended with animal manure. Results indicate that seasonal soil-crop EC dynamics measured by EMI are primarily driven by surface (,0.2 m) changes as opposed to deeper (.0.9 m) changes. These changes appear to be the result of surface ionic dynamics caused by crop-soil interactions and not soil volumetric water content (hv), since no significant correlations were detected between hv and ECa for any treatment, depth or dipole orientation. These findings are consistent with others who reported the EMI signal was driven primarily by changes in nitrate concentration and not by soil water content. The results of this study clarify our understanding of the soil dynamics that drive the ECa response of a manure amended field. The ability to non-intrusively measure nutrient mineralization and crop uptake provides researchers with a powerful tool for understanding soil-crop interactions. Understanding the soil-crop dynamic will facilitate development of management practices for amending soil with manure while protecting the environment from unintended contamination

EVALUATING NONLINEAR CROSSED RANDOM EFFECTS MODELS FOR COMPARING TEMPERATURE OF FEEDING PIGS UNDER DIFFERENT THERMAL ENVIRONMENTS

The thermal environment plays a large role in an animal’s ability to convert feed into weight gain. A better understanding of a pig’s metabolism will help swine producers select environmental specifications for optimizing feed conversion. The objectives of this study are to 1) characterize the thermoregulatory responses of pigs during a feeding event 2) compare those responses for three thermal environmental treatments applied in a Latin Square design 3) investigate different procedures for fitting nonlinear mixed-effect models with crossed random effects (NLME function in R, %NLINMIX macro in SAS, random effects modeling in AD Model Builder: ADMB-RE). We found that the threeparameter first-order compartment model provides a reasonable representation of the tympanic temperatures of feeding pigs during feeding events. The thermal environmental treatments (28ºC + High air speed) and (18ºC + Low air speed) are significantly different from the reference treatment (28ºC + Low air speed), at the 5% level. Both NLME and ADMB-RE successfully fit the nonlinear mixed-effects model and produce similar results. The %NLINMIX macro did not converge unless restrictions were placed on the model. The estimates of fixed and random effects from the restricted model using %NLINMIX macro were generally different from those from NLME and ADMB-RE

EVALUATING PEN-DAY INTERACTIONS IN BODY TEMPERATURE BILOGISTIC MIXED MODEL FOR HANDLING OF FEEDLOT HEIFERS DURING HEAT STRESS

Daily activities consume the energy of heifers, subsequently causing an elevation of body temperature, depending on the ambient conditions. A better understanding of the dynamics of body temperature (Tb) would be helpful when deciding how to process and handle heifers. It would also lead to specific recommendations on moving heifers under different ambient conditions, especially during the summer. In this study, a bilogistic mixed model is used to describe the dynamics of Tb during the moving event. Data was taken from heifers in pens located at different distances from the heifer work station on four separate summer days under hot conditions. This bilogistic model has seven biological parameters: initial body temperature, heat challenge rate constant, upper asymptote body temperature, challenge inflection point, baseline body temperature for recovery, recovery rate constant, and recovery inflection point. Pen and day were used as treatment factors in the model. Significant interactions between the factors were found for several parameters, indicating distance moved during the handling event influences the way an animal responds to a thermal challenge. The objectives of this study are to fit a bilogistic mixed model for Tb with the above seven parameters, and to examine fixed and random effects. The main focus is to estimate and interpret the interactions between pens and days for the significant parameters to aid in management decisions involving when to work cattle

EVALUATING LINEAR AND NONLINEAR MODELS FOR THE RESPIRATION RATE OF FOUR BREEDS OF HEAT STRESSED FEEDLOT HEIFERS

Heat stress is a factor that causes loss of production and even death in cattle. Animals differ in vulnerability to heat stress. One reason for the difference may be the coat color associated with different breeds or genotypes. A good measure of the heat stress is respiration rate which increases in response to increasing ambient temperature. The objective of this study is to characterize the respiration rates of four genotypes of heat stressed feedlot heifers. Linear and nonlinear models will be compared to find an appropriate method of detecting differences among genotypes

The German Young Geoscientists Group – promoting exchange and information among the next generation of geoscientists

The group „Young geoscientists” of the Senate Commission for Joint Geoscientific Research (Geokommisson, www.geokommission.de) of the German Research Foundation (DFG), is dedicated towards the development of the working environment, workforce and scientific outcome of the next generation of geoscientists in Germany.Geoscientific research – basic as, well as applied – provides crucial contributions for mastering the economic, environmental and societal challenges of the near and medium-term future. Politics and society call for immediate answers, while geoscientific phenomena are complex and act on a large range of temporal and spatial scales.These demands, together with increases mobility requirements, lead to increasing pressure especially on young geoscientists. In this situation the main goals of the group “Young geoscientists” are:Promotion of networking among young geoscientistsInformation about science policy developments, funding opportunities and other relevant mattersRepresenting the interests of young scientists towards (science)-policy makersThe dynamic development of geoscientific research, particularly collaborations across traditional disciplines, as well as in increasing demands from public and policy, calls for a continuous integration of young scientists. We promote this process by organizing round-table discussions, e.g. on “Guaranteeing good scientific praxis” or on “Hot topics and research funding”, by communicating information via the internet and by identifying structural deficiencies that might hinder the advancement of the geosciences and reporting them to decision makers. In this context, we are looking for:European or international collaboratorsYoung geoscientists wishing to participate in / contribute to our activitiesSuggestions on how to improve working conditions of the young and advancing geoscientists</ul

COMPARING CORRELATED PARAMETER ESTIMATES FOR NONLINEAR PET MODEL

The nonlinear PET model based on Newton\u27s law of cooling can be used to estimate body temperature in cattle, T b challenged by hot cyclic chamber temperatures, T a . The PET model has four biologically meaningful parameters: K, the thermal constant; Δ, the difference between T b and adjusted T a ; Υ the proportion of variation in T b comparable to variation in Ta ; T bini, the initial body temperature. The two parameters Y and Δ are highly correlated in the current version of the model. This study looks at other ways to parameterize the PET model in an effort to reduce the correlation between parameters and improve nonlinear behaviors, such as parameter-effects curvature, bias, excess variance and skewness