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ARS Home » Plains Area » Las Cruces, New Mexico » Range Management Research » Research » Publications at this Location » Publication #333743

Research Project: MANAGEMENT TECHNOLOGIES FOR CONSERVATION OF WESTERN RANGELANDS

Location: Range Management Research

Title: Improved estimation of nitrogen uptake in grasslands using the nitrogen dilution curve

Author
item Reyes, Julian Jon
item Schellberg, Juergen - University Of Bonn
item Siebert, Stefan - University Of Bonn
item Adam, Jennifer - Washington State University
item Ewert, Frank - University Of Bonn

Submitted to: Agronomy for Sustainable Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/9/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary: Farmers and ranchers need simple, yet robust tools and resources to effectively manage nutrients on their farms and surrounding landscapes. The nitrogen dilution curve (NDC) serves as an empirical relationship that tracks the amount of nitrogen as a plant grows, which can be used as a management tool. This paper is a reply to a letter to the editor that continues discussion on NDC and its usefulness in nutrient management.

Technical Abstract: The critical nitrogen concentration (CNC) is a simple yet robust relationship that describes the changes in crop N during growth. We applied the concept of CNC to calculate N uptake across various cutting regimes. While it is well-established that decreasing cutting frequency changes growth rates, the parameters of the CNC equations may need to be adjusted based on the grass physiological age (i.e., vegetative versus reproductive stage). We do not question the validity of the CNC during vegetative growth; however, we recognize that there is research needed to test the effects of cutting date on composition and internal partitioning of N as it relates to the CNC. Moreover, we focus on the applicability of the CNC for use in process-based models for better understanding of the CNC for different crop ages and management considerations.