Navigation Links
A little nitrogen can go a long way
Date:9/3/2008

MADISON, WI, SEPTEMBER 2, 2008 Varying the rate of crop production inputs such as fertilizer and seed makes intuitive sense, as farmers have long observed differences in crop yield in various areas of a single field. The availability of spatial yield information from combines equipped with yield monitors has provided a good resource for improved management.

So, optimizing inputs to match yield potential of different areas within fields may increase profit and reduce the environmental impact associated with over-application of fertilizer or pesticides. With recent substantial increases in grain and fertilizer prices, even small changes in management may have the potential to significantly impact profit from a field.

Scientists with the University of Nebraska-Lincoln (UNL) compared an approach to site-specific nitrogen and seed density management for irrigated maize, based on soil properties and yield potential zones, to whole field uniform management based on current University of Nebraska best management practices (BMPs).

The researchers wanted to know if the site-specific approach could increase yield or nitrogen-use efficiency (the amount of grain produced per kilogram of nitrogen applied), and the effect of site-specific management on profitability. The study was conducted on two irrigated maize fields in Nebraska in 2003 and 2004 -- a total of four site-years.

Four treatments were then compared each year in field length strips, evaluating uniform management of nitrogen and seed density (current BMP), variable nitrogen rate plus uniform seed density, uniform nitrogen rate plus variable seed density, or both variable nitrogen rate and seed density. The variable nitrogen rate was based on yield potential within each zone, spatial patterns of soil organic matter within each zone, and zone-average residual soil nitrate-nitrogen values, using the University of Nebraska recommendation algorithm for maize.

Yield levels in both years generally followed the order of historical yield zones, though at Site 1 in 2003 average grain yields were not different among yield zones. Uniform nitrogen and seed density management resulted in high yields for all four site years, and site-specific management strategies resulted in no or small yield increases. Only at Site 1 in 2003 were there small but statistically significant yield increases with variable rate nitrogen management. There were no significant effects of seed density on yield, nor any interactions between seed density and nitrogen rate.

Fertilizer nitrogen use efficiency (NUE) was high in all site-years and well above national averages. NUE was particularly influenced by the amount of residual nitrate-nitrogen present in the soil profile prior to planting. At Site 1, NUE tended to be highest with the strategy that combined variable rate nitrogen with uniform seed density. At Site 2 in 2003, there was no advantage to variable rate nitrogen in NUE, while in 2004 a variable rate strategy which applied more nitrogen in high-yielding areas of the field resulted in the highest NUE.

At Site 1 in 2003, variable rate nitrogen management increased the gross economic return above fertilizer costs. However, for the other three site-years, there were no significant effects of site-specific management on profitability.

The conclusion of the study was that, using the strategies the researchers selected, they could not demonstrate consistent significant economic benefits to site-specific management. One site-year did indicate an economic benefit to site-specific management, but this was before costs associated with collecting and analyzing site-specific information were included. However, this economic analysis was conducted using 2004 values of grain and fertilizer.

With significant increases in the price of fertilizer and the value of grain in 2007 and 2008, the value of using site-specific management is likely to have increased for those locations where site-specific management has a significant impact on yield, NUE, or both.

The researchers believe variable rate nitrogen application will be most profitable in situations with relatively wide maize to nitrogen fertilizer price ratios, and where a significant yield increase over uniform management is likely. They found little benefit to variable seed density, likely due to plasticity in yield components in response to different plant populations. Site-specific adjustment of seed density in irrigated environments is probably best applied to areas of known low yield potential in order to reduce seed cost.


'/>"/>

Contact: Sara Uttech
suttech@agronomy.org
608-268-4948
American Society of Agronomy
Source:Eurekalert

Related biology news :

1. Mothers little helpers
2. Choosing dry or wet food for cats makes little difference
3. Book on little-known species and conservation provides guidance to managers and others
4. Ancient lemurs little finger poses mystery
5. Variety is the spice of life: too many males, too little time...
6. Too much or too little weight gain poses risks to pregnant mothers, babies
7. Getting better with a little help from our micro friends
8. MSU researcher uses grant to study little-known but largely useful microbes
9. Little teeth suggest big jump in primate timeline
10. Building a stronger roof over your head: 3 little pigs project begins first tests
11. Nitrogen -- the silent species eliminator
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/8/2017)... Feb. 7, 2017 Report Highlights ... 2021 from $8.3 billion in 2016 at a compound ... 2021. Report Includes - An overview of the ... trends, with data from 2015 and 2016, and projections ... Segmentation of the market on the basis of product ...
(Date:2/6/2017)... , Feb. 6, 2017 According ... security are driving border authorities to continue to ... reports there are 2143 Automated Border Control (ABC) ... currently deployed at more than 163 ports of ... 2013 to 2016 achieving a combined CAGR of ...
(Date:2/2/2017)... , Feb. 2, 2017  EyeLock LLC, a market ... new white paper " What You Should Know About ... of ensuring user authenticity is a growing concern. In ... of users. However, traditional authentication schemes such as username/password ... Biometric authentication offers an elegant solution to the ...
Breaking Biology News(10 mins):
(Date:2/24/2017)... , Feb. 24, 2017  OncoSec Medical Incorporated ("OncoSec") ... will host a Key Opinion Leader event to highlight ... oral and poster presentation at the upcoming 2017 ASCO-SITC ... KOL event will be held in-person and via live ... / 9:00 AM PST at the Lotte New York ...
(Date:2/23/2017)... Calif. , Feb. 23, 2017  MIODx ... license for two key immunotherapy technologies from the ... technology provides a method to monitor a patient ... as PD-L1 and CTLA-4.  The second license extends ... a patient is likely to have an immune-related ...
(Date:2/23/2017)... (PRWEB) , ... February 23, ... ... Inc., announced today that in a published evaluation of multiple immunoassay-based threat ... U.S. Department of Energy Laboratory, PathSensors’ CANARY® biosensor threat detection technology was ...
(Date:2/23/2017)... 23, 2017 Aviva Systems Biology Corporation ... acquisition of GenWay Biotech Incorporated, a protein solutions ... product offering for both the research and diagnostic ... and enhance capabilities for both entities. GenWay,s 18 years ... will nicely complement ASB,s objective to become a ...
Breaking Biology Technology: