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The Effect of Controlled‐Availability Nitrogen Fertilizers on Mature Pecan Trees
Author(s) -
Sullivan D. T.,
O'Connor G. A.,
HerreraAguirre E.
Publication year - 1976
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1976.03615995004000030046x
Subject(s) - human fertilization , fertilizer , nitrogen , urea , juglandaceae , sulfur , yield (engineering) , nitrogen fertilizer , nut , chemistry , horticulture , agronomy , botany , biology , fruit tree , materials science , organic chemistry , structural engineering , metallurgy , engineering
Two controlled‐availability N fertilizers, sulfur‐coated urea (SCU) and NH 4 NO 3 plus N‐Serve, were compared with NH 4 NO 3 alone applied to 30‐year‐old pecan trees ( Carya illinoensis Koch) in a 2‐year study. Leaf N contents were increased in both years by N fertilization, but yield and nut weight were not significantly affected. Yields in 1973 were correlated with 1972 leaf N contents, but not with 1973 leaf N contents. The SCU treatment was effective in controlling N release in 1973, but not in 1974. The N‐Serve treatment was ineffective both years of the study. The ineffectiveness of the controlled N sources were attributed to: (i) poor incorporation of the materials, (ii) inherent slow response of mature pecan tree to N fertilization, and/or (iii) sufficient variability within treatments to mask fertilizer source difference.