Table of Contents
ISRN Agronomy
Volume 2012 (2012), Article ID 359284, 9 pages
http://dx.doi.org/10.5402/2012/359284
Research Article

Evidence, Regulation, and Consequences of Nitrogen-Driven Nutrient Demand by Turfgrass

Department of Soil Science, University of Wisconsin, 1525 Observatory Drive, Madison, WI 53706-1299, USA

Received 21 October 2011; Accepted 13 November 2011

Academic Editors: J. T. Tsialtas and H. Zhang

Copyright © 2012 Wayne R. Kussow et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Nutrient uptake is strongly influenced by plant growth rate. Accelerated growth leads to nutrient levels incapable of sustaining the optimal growth rate, resulting in shoot to root signaling for increased nutrient absorption. The factors controlling nutrient demand in turfgrass and its consequences have not been investigated. The objectives of this research were to verify that turfgrass exhibits the principal characteristics of demand-driven nutrient uptake and to identify the primary factor controlling nutrient demand via regulation of growth rates. Kentucky bluegrass clipping production increased linearly up to annual fertilizer N rates of 600 kg ha−1 and to 1000 kg N ha−1 for creeping bentgrass. At the typical annual N fertilization rates of 150 to 300 kg ha−1 for the two grasses, N supply was the primary determinant of turfgrass growth rate, plant nutrient demand, and nutrient uptake. Nitrogen uptake accounted for over 88% of uptake of all other nutrients. Uptake of P and K were strongly related to tissue N content irrespective of soil test levels. Variations in turfgrass species and cultivar nutrient requirements and nutrient use efficiencies were found to be directly related to differences in growth rates and, by inference, to differences in nutrient demand.