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This article in AJ

  1. Vol. 92 No. 1, p. 159-167
     
    Received: Feb 22, 1999
    Published: Jan, 2000


    * Corresponding author(s): blm@gnv.ifas.ufl.edu
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doi:10.2134/agronj2000.921159x

Nitrogen Stress Effects on Growth and Nitrogen Accumulation by Field-Grown Tomato

  1. Johannes Scholberga,
  2. Brian L. McNeal *a,
  3. Kenneth J. Booteb,
  4. James W. Jonesc,
  5. Sal J. Locasciod and
  6. Stephen M. Olsone
  1. a Soil and Water Science Dep., Univ. of Florida, Gainesville, FL 32611-0510 USA
    b Agronomy Dep., Univ. of Florida, Gainesville, FL 32611-0510 USA
    c Agricultural and Biological Engineering Dep., Univ. of Florida, Gainesville, FL 32611-0570 USA
    d Horticultural Science Dep., Univ. of Florida, Gainesville, FL 32611-0690 USA
    e North Florida Research and Education Center, Route 3 Box 4370, Quincy, FL 32351-9529 USA

Abstract

There are few growth studies evaluating within-season effects of N on vegetative growth and N accumulation of tomato (Lycopersicon esculentum Mill.). Growth analysis of field-grown tomato for a number of Florida locations and management systems is presented here. Severe N stress resulted in fewer and smaller, but thicker, leaves. With increasing N, average leaf area index (LAI) increased from ≈0.75 to ≈3, but radiation use efficiency (RUE) typically increased less then 30%. Lower RUE under N-limited conditions reflected a decrease in N concentration of the most recently matured leaves from 40 mg g−1 to as little as 15 mg g−1 Over the life of well-fertilized crops, leaf N concentrations dropped from 55 to 65 mg g−1 during initial growth to 20 to 35 mg g−1 at final harvest. Corresponding N concentrations for fruit and for stems were 30 to 35 mg g−1 and 15 to 25 mg g−1 Severe N stress affected leaf and stem N concentrations most drastically, whereas N in fruits was less variable. With lower N supply (N < 180 kg ha−1) under careful management, nitrogen use efficiency (NUE) for field-grown tomato was ≈0.4 Mg fresh fruit (kg N)−1 and average crop N accumulation increased from 37 to 210 kg N ha−1 as N fertilization increased from 0 to 333 kg N ha−1 As a fraction of the fertilizer N applied N fertilizer recovery ranged from 0.36 to 0.74 and 0.61 to 0.96 for drip-irrigated and subirrigated crops, respectively.

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Copyright © 2000. American Society of AgronomySoil Science Society of America