Navigation Links
Illinois Soil Nitrogen Test measures microbial nitrogen
Date:5/11/2009

MADISON, WI, May 4, 2009--Contrary to the prevailing view, cereal crops derive the majority of their nitrogen from the soil, not fertilizer. Soils differ considerably in microbial activities that determine nitrogen-supplying power, and these differences must be taken into account if nitrogen fertilizers are to be used efficiently. The Illinois Soil Nitrogen Test (ISNT) was developed for this purpose, and involves estimation of gaseous ammonia liberated by heating the soil with strong alkali in a Mason jar. Several studies have provided evidence that the ISNT is predictive of yield response by corn to nitrogen fertilization, but there have also been negative evaluations in which concern has been raised that test values represent a constant proportion of total soil nitrogen rather than a microbial fraction that would be potentially available.

A study was conducted from 2004 to 2006 at the University of Illinois to clarify the chemical nature of what the ISNT measures and its relationship to microbial growth in agricultural soils. A multifaceted approach was taken, involving recovery tests with pure organic nitrogen compounds, statistical analyses of different nitrogen fractions measured for 26 Illinois agricultural soils, and incubation studies to determine incorporation of labeled nitrogen into soil nitrogen fractions. Results from the study were published in the May-June issue of the Soil Science Society of America Journal. The research was funded by the USDA and the Illinois Council on Food and Agricultural Research (C-FAR).

Recovery tests did not support the concept that the ISNT estimates total soil nitrogen. Rather, the results confirmed that the ISNT is selective for certain forms of microbial nitrogen, and differs from conventional acid-hydrolyzable fractions in the proportions of these compounds that are detected. Specifically, amides and the amino sugars in bacterial cell walls were detected, but not alpha-amino acids or fungal chitin. When the findings were applied in a statistical analysis of data from soil nitrogen fractionation, the ISNT was estimated to recover 95% of the nitrogen in bacterial amino sugars and 43% of amide-nitrogen. The incubation studies showed that labeling was more rapid for nitrogen recovered by the ISNT than in hydrolyzable amino sugars, again indicating a dominance of bacterial over fungal nitrogen recoveries by the ISNT.

Taken together, these findings suggest that the ISNT mainly detects bacterial amino sugars and implicates this form of soil nitrogen in the test's effectiveness for predicting the response of corn to nitrogen fertilization. Because the ISNT also detects some amide nitrogen, the bacterial amino sugar nitrogen signal can be obscured in soils where these components are highly variable.


'/>"/>

Contact: Sara Uttech
suttech@soils.org
608-268-4948
Soil Science Society of America
Source:Eurekalert

Related biology news :

1. Human aspects of climate change to be focus of conference at Illinois
2. NSF funds research at Illinois on sustainable biofuels infrastructure
3. NSF funds new Center for the Physics of Living Cells at Illinois
4. 2 University of Illinois researchers named HHMI investigators
5. Tree species composition influences nitrogen loss from forests
6. Researchers call for nitrogen and phosphorus reductions to combat eutrophication in aquatic systems
7. Cropland diversity reduces nitrogen pollution
8. Lichens function as indicators of nitrogen pollution in forests
9. Nitrogen applied
10. A little nitrogen can go a long way
11. EPA releases science assessment on health effects of nitrogen oxides
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/15/2016)... New York , June 15, 2016 /PRNewswire/ ... a new market report titled "Gesture Recognition Market by ... and Forecast, 2016 - 2024". According to the report, ... USD 11.60 billion in 2015 and is estimated ... reach USD 48.56 billion by 2024.  ...
(Date:6/2/2016)... 2016 The Department of Transport Management ... 44 million US Dollar project, for the , ... Personalization, Enrolment, and IT Infrastructure , to ... and implementation of Identity Management Solutions. Numerous renowned international vendors ... Decatur was selected for the most compliant and ...
(Date:5/20/2016)... , May 20, 2016  VoiceIt is ... partnership with VoicePass. By working together, ... experience.  Because VoiceIt and VoicePass take slightly different ... engines increases both security and usability. ... excitement about this new partnership. "This ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... ... June 27, 2016 , ... Cancer experts from Austria, Hungary, ... be a new and helpful biomarker for malignant pleural mesothelioma. Surviving Mesothelioma has ... it now. , Biomarkers are components in the blood, tissue or body ...
(Date:6/27/2016)... , ... June 27, 2016 , ... ... for Amgen, will join the faculty of the University of North Carolina ... professor of strategy and entrepreneurship at UNC Kenan-Flagler, with a focus on the ...
(Date:6/24/2016)... , June 24, 2016  Regular discussions on a range ... place between the two entities said Poloz. Speaking ... Ottawa , he pointed to the country,s inflation ... federal government. "In ... "Both institutions have common economic goals, why not sit down ...
(Date:6/24/2016)... NC (PRWEB) , ... June 24, 2016 , ... Researchers ... the most commonly-identified miRNAs in people with peritoneal or pleural mesothelioma. Their findings are ... to read it now. , Diagnostic biomarkers are signposts in the blood, lung ...
Breaking Biology Technology: