HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Mattos, D. Articles by Alva, A. K. Search for Related Content PubMed Articles by Mattos, D., Jr. Articles by Alva, A. K. Agricola Articles by Mattos, D. Articles by Alva, A. K. Related Collections Best Management Practices Isotopes Nitrogen Nutrient Management

DIVISION S-4—SOIL FERTILITY & PLANT NUTRITION

Biomass Distribution and Nitrogen-15 Partitioning in Citrus Trees on a Sandy Entisol

^a Centro de Citricultura Sylvio Moreira- IAC, Via Anhanguera, km 158, 13490-970 Cordeirópolis-SP, Brazil
^b Univ. of Florida, Soil and Water Science Dep., 106 Newell Hall, P.O. Box 110510, Gainesville, FL 32611-0510
^c ARS-USDA, 24106 N Bunn Rd., Prosser, WA 99350-0000

^* Corresponding author (ddm{at}centrodecitricultura.br)

The area under citrus production in Florida is 332 000 ha, with a production of 10 to 12 million metric tonnes of fruit annually. Nutrient management recommendations are needed to increase N uptake efficiency and to minimize nitrate leaching below the root zone. The objectives of this study were (i) to evaluate biomass distribution of 6-yr-old ‘Hamlin’ orange trees [Citrus sinensis (L.) Osbeck] on ‘Swingle citrumelo’ [Poncirus trifoliata (L.) Raf. x C. x paradisi Macfad.] rootstock grown in a sandy soil under low volume irrigation, and (ii) to estimate partitioning of ¹⁵N fertilizer applied to the soil during early spring into different tree components. We evaluated biomass of tree components (leaves, twigs, trunk, taproot, roots, and fruit), and N recovery and distribution of ¹⁵NH₄¹⁵NO₃ (AN) and ¹⁵N-urea (UR) (10 atom % ¹⁵N) applied to the soil surface. About 70% of dry matter biomass of trees was aboveground (AG). Length density of feeder roots was concentrated at a depth of 0 to 15 cm below the soil surface and varied from 1.87 to 0.88 cm cm^-3 at 0.5- and 1.5-m distance from the trunk, respectively. Total recoveries of ¹⁵N by trees were 25.5% for UR and 39.5% for AN at fruit harvest, 280 d after fertilization. Mean accumulation of applied ¹⁵N in recent leaf flush was 4.2% and that of older leaves was 2.5%. Accumulation of ¹⁵N was low in woody tissue. Since fruit represented a large sink for N (10.2 and 18.4% recovery of ¹⁵N applied as UR and AN, respectively), we confirmed the importance of N fertilization before fruit development.

Abbreviations: AG, aboveground • AN, ammonium nitrate • BG, belowground • BMP, best management practice • DAF, days after fertilization • Ndff, N in plant components derived from the labeled fertilizer • PVC, polyvinyl chloride • UR, urea

This article has been cited by other articles:

				W.-L. Liang, K. Kosugi, and T. Mizuyama Heterogeneous Soil Water Dynamics around a Tree Growing on a Steep Hillslope Vadose Zone J., November 20, 2007; 6(4): 879 - 889. [Abstract] [Full Text] [PDF]

				K. T. Morgan, T. A. Obreza, J. M. S. Scholberg, L. R. Parsons, and T. A. Wheaton Citrus Water Uptake Dynamics on a Sandy Florida Entisol Soil Sci. Soc. Am. J., December 2, 2005; 70(1): 90 - 97. [Abstract] [Full Text] [PDF]