No abstract

The authors are solely responsible for the content of this technical presentation. The technical presentation does not necessarily reflect the official position of ASAE, and its printing and distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not subject to the formal peer review process, therefore, they are not to be presented as refereed publications. Citation of this work should state that it is from an ASAE Section Meeting paper. EXAMPLE: Author's Last Name, Initials. 2004. Title of Presentation. ASAE Section Meeting Paper No. 0 St. Joseph, Mich.: ASAE. For information about securing permission to reprint or reproduce a technical presentation, please contact ASAE at hq@asae.org or 269-429-0300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA). (EC a) and penetration resistance expressed as cone index (CI) for soil compaction was investigated with Veris 3100 and Veris 3000 sensing technologies. The study was conducted at the research farm located near Williston, ND on a sandy loam soil (Sandy, mixed, frigid Entic Haplustoll). Measurements of soil EC a were taken using Veris 3100 guided by a parallel swathing light bar monitored with the Trimble Ag132 DGPS unit providing spatial coordinates for each measurement at shallow (0-30 cm) and deep (0-90 cm) depths. A Veris 3000 equipped with the GPS unit was also used to collect measurements of EC a and CI that were recorded in 2 cm intervals to a depth of 90 cm on a grid sampling system. The experimental plot area mapped with this technology was approximately 1.4 ha. The EC a data from both Veris 3100 and Veris 3000 exhibited similar spatial trends across the field that may characterize the variability of soil for a variety of important physical and chemical properties. The coefficient of variations of EC a from Veris 3100 and Veris 3000 were 19.2 and 11.3%, respectively. However, the averages of EC a measurements for Veris 3100 and Veris 3000 were 4.92 and 3.31 mS/m, respectively. The EC a mean difference, M d between these two devices was also significantly different from zero (M d = 1.71 mS/m; t=34.23, n=138; pr<0.01). Geostatistical tools were used to evaluate spatial dependency and assess the overall soil variability. It was found that soil ECa and CI parameters were spatially distributed and presented weak to medium spatial dependency within the mapped field area. Further, EC a measurements from both sensors exhibited approximately log normal distribution and the CI values were normally distributed using probability distribution functions. The spatial data produced from this new direct sensing technology can be used as baseline for precision farming and making future management decisions.