Agriculture Reference
In-Depth Information
Chapter 1
Physiological Basis of Plant Nutrient Use
Efficiency - Concepts, Opportunities
and Challenges for Its Improvement
Martin Reich, Tahereh Aghajanzadeh, and Luit J. De Kok
Abstract Knowledge on the underlying physiological processes and variables
which bias their contribution to nutrient use efficiency (NUE) is crucial to develop
strategies for improvement in agroecosystems. This chapter aims to contribute to
the understanding of the physiological basis of NUE to develop strategies for
improvement by modern breeding, but also conceive the challenges and current
limits to do so. General concepts will be summarized briefly and broken down to the
main components before, in the main part of this chapter, the involved physiolog-
ical processes are reviewed and discussed in their relation to NUE. This is followed
by an identification of the factors that make the individual contributions of these
processes to NUE so variable and impede one general concept for all crops,
environmental conditions and nutrients. The last part of the chapter is dedicated
to a critical analysis of the opportunities and challenges to improve NUE, which
arise from physiological interactions and trade-offs on a whole plant level.
Keywords NUE (nitrogen use efficiency) • Nitrogen • Agroecosystem • MRT
(mean residence time) • Crop yield • Oscillations • Acquisition efficiency • Utilization
efficiency
Introduction
Plants are principally, as are all living organisms, chemical compartments, which
are in thermodynamic disequilibrium with their environment. This is actively
maintained by the utilization of solar energy for driving selective chemical
exchange with the environment. In addition to carbon dioxide and water, which
provide the structural and metabolic backbone elements C, O and H, the complex
functioning of plants requires the uptake of at least 13 additional essential nutrients
from the soil. Nutrients can be classified into two very distinct groups depending on
