Nitrogen Stress Effects on Growth and Nitrogen Accumulation by Field-Grown Tomato
- Johannes Scholberga,
- Brian L. McNeal *a,
- Kenneth J. Booteb,
- James W. Jonesc,
- Sal J. Locasciod and
- Stephen M. Olsone
- 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
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.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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