Environmental Measurement

Field Methods for Ferrous Iron (and Dissolved Manganese) Analysis in Monitoring Wells
This document decribes recommendations and precautions for ferrous iron and manganese sampling and analysis. Iron and manganese measurements are often used as indicators of alternate electron acceptor use at contaminated sites, but can be problematic because of sample oxidation. The author describes various sampling techniques and discusses the use of the CHEMetrics "snapper"sampling device to collect in-situ samples.

Scaling Leaf Level Gas Exchange Measurements to Canopy...
by Dr. Xuejun Dong

This document presents a case study for scaling growth chamber leaf level gas exchange data to full scale prairie conditions. Specifically, the purpose of this study was to estimate the appropriate values of gLa for grasslands near Streeter, ND, so to facilitate the scaling of leaf-level measurements to the canopy level, which is directly related to the quantitative evaluation of grassland water and carbon budgets.

The Impact of Clouds on Hourly Solar Radiation on Prairieby Dr. Xuejun Dong

This document presents a case study for calculating the influence of clouds on hourly variations in solar radiation, based on past weather data. The author planned to find out, on an average non-rainy day, during the 6 high radiation hours from 10 am to 4 pm, what is the probability that radiation changes at least once between two adjacent hours. Calculations and MINITAB macros are included.

Fate On the Recalcualtion of Microbial Biomass Data
by Dr. Xuejun Dong

This document presents a case study for calculating the microbial biomass in soils from a grazing intensity study site at the Central Grasslands Research Center, Streeter, ND. The soil microbial biomass was tested using the chloroform fumigation method. The measurement is based on the flush of CO2 and NH4+ in the fumigated sub-sample as compared to the unfumigated control sub-sample. Methodology and calculations are explained and results are presented.


Using Two Simple True Basic Programs for Handing Raw Data From LI-COR 6400 Portable Photosynthesis System Li-ExtractOK.pdf (81.4 Kb)
by Dr. Xuejun Dong

The LI-COR 6400 Portable Photosynthesis System is widely used for measuring gas
exchange parameters from plant leaves in agricultural and environmental studies. It is also being used for measuring soil respiration rate. In typical field studies, many measurements are usually made. This report describes a method that can be used for automated manipulation of the numerous small files that come from the LI-COR 6400 system.