U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            MIMMO, TANJA - U OF BOLOGNA, BOLOGNA, ITitem
                                            GALLETTI, GUIDO - U OF BOLOGNA, BOLOGNA, ITitem
                                            Reeves  Iii, Jamesitem
                                            McCarty, Gregory
  Submitted to: University of Bologna Italy Thesis
                                    Publication Type: Other
                                    Publication Acceptance Date: 2/21/2001
                                    Publication  Date: 3/25/2001
                                    Citation: N/AInterpretive Summary: Spectroscopy utilizes the interaction of light with materials to determine their composition.  The objective of this work was to determine the effects of sample diversity on near-and mid- infrared spectroscopic calibrations (process for relating spectra to compositions) for biological activity in soil. One hundred and  thirty six soil samples were taken from a 20 ha field within a small watershed. The samples were obtained in a grid pattern from the top ten centimeters. Samples were analyzed spectroscopically and by conventional methods for total N, total C, and several measures of biological activity.  Near-infrared based results were not successful for biological measures, but were somewhat successful for total C and total N.  Mid-infrared results were an improvement over the near-infrared results for total N and C and  biological activity as reflected by  three enzymes.  While the mid-infrared results were not as good as found in previous studies using less diverse sample sets, they were much better than achieved using near-infrared spectra for this data set.  In general, the results using mid-infrared spectra were more accurate for the determination of soil parameters than those found using near-infrared spectra.  Also, results using either spectral region indicate that sample diversity has a large and detrimental effect on the ability to accurately determine biological activity in soils.
                                Technical Abstract: The objective of this work was to determine the effects of sample diversity on near-and mid-infrared spectroscopic calibrations for biological activity in soil. One hundred and thirty six soil samples were taken from a 20 ha field consisting of a toposequence within a small watershed. The samples were obtained  in a grid pattern from the top ten centimeters. Samples were analyzed spectroscopically and by conventional methods for total N, total C, alkaline and  acid phosphatase, arylsulfatase, biomass N and biomass C.  Samples were scanned "as is", dried and dried and ground in the near-infrared using a scanning monochromator, and dried and ground in the mid-infrared using a Fourier Transform spectrometer. Near-infrared calibrations were not successful for biological measures as reflected by the three  enzymes, biomass N or C, but were somewhat successful for total C and total N (R2 of approx .6 and .8, resp.).  Mid-infrared results were an improvement over the near-infrared results for total N and C (R2 of approx. 0.85 and .95, resp.)  and biological activity as reflected by the three enzymes, but again were unsatisfactory for measures of biomass N and C.  With the best R2 for the three enzymes in the range of 0.7 the results were not as good as found in previous studies using less diverse sample sets, but were much better than achieved using near-infrared spectra for this data set.  In general, the results using mid-infrared spectra were more accurate for the determination of soil parameters than those found using near-infrared spectra.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov