Author
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Kitchen, Newell |
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GOULDING, KEITH - IACR-ROTHAMSTED, UK |
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Submitted to: Book Chapter
Publication Type: Book / Chapter Publication Acceptance Date: 5/31/2001 Publication Date: N/A Citation: N/A Interpretive Summary: Movement of nitrogen (N) off of crop production fields and into ground and surface water remains a challenge for farmers and agronomists. The visual and subsequent yield response to inexpensive N fertilizer reinforces farmers' reliance on it for profitable production. Some of the biggest problems occur when animal manures are poorly utilized, and here progress has been slow. Governments have responded with guidelines, standards, regulations, and in some cases fines when off-field losses of N have not been reduced. This chapter reviews various old and new technologies and practices that are available to farmers for improving N use in crops. Tools for assessing N in the soil as well as tools that assess the N health of the growing crop are reviewed and compared. We predict by the year 2005 crop and soil images from satellites and airplanes will be commonly used in crop N management in the U.S. and European countries. Whenever animal feeding is a component of an agriculture production operation, we strongly encourage whole-farm nutrient planning. "On-farm" implies that farmers will be at the center of implementing change; "change" means N management options will motivate farmers to action. Opportunity for improvement in N management in crops largely lies with technologies that enable timely, quick, and accurate measurement of the spatial variability of crop yield potential, soil N availability, and within season indication of crop N health. These same tools used under these conditions will grant the greatest environmental benefit. Technical Abstract: Modern agriculture has come to embrace the concepts of environmental stewardship as a necessary component of crop production. Nitrogen from soil, fertilizer, and manure sources is inefficiently used (30 to 60% of annual input) in most crop production systems. As a consequence, unused inorganic N can move off crop fields and contaminate surface and ground water resources. Governments have responded with guidelines, standards, regulations, and in some cases fines when off-field losses of N have not been reduced. Numerous technologies and time-proven practices are available for producers to employ that will result in improved crop N use efficiency. We review in this chapter tools currently available, or that are soon to be available, to help producers make better N management decisions. Soil and crop measurements are considered and compared. New technologies such as airborne or satellite remotely sensed images are being aggressively tried. Internet-accessibly N management tools for on-farm decisions were listed and reviewed for their appropriate applications. Soil N excess and deficiency can exist on the same field. Thus, opportunity for improvement in N management in crops largely lies with technologies that enable timely, quick, and accurate measurement of the spatial variability of crop yield potential, soil N availability, and within season indication of crop N health. Tools that indicate N in excess of crop needs for the year in question may have little economic appeal to producers, because of inexpensive N, but these same tools used under these conditions will grant the greatest environmental benefit. |
