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Effects of Phosphorus on Growth and Mycorrhizal Development of Douglas‐fir in Greenhouse Pots
Author(s) -
Heilman Paul E.,
Ekuan Gorden
Publication year - 1980
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/sssaj1980.03615995004400010024x
Subject(s) - tsuga , human fertilization , phosphorus , seedling , western hemlock , greenhouse , horticulture , nutrient , agronomy , dry weight , biology , botany , zoology , chemistry , ecology , organic chemistry
Results of this study confirmed that P deficiency is a cause of poor growth and poor mycorrhizal development in greenhouse grown Douglas‐fir seedlings [ Pseudotsuga menziesii (Mirb). Franco] in certain horizons of two pedons of an Andic Haplumbrept from western hemlock stands ( Tsuga heterophylla ) of the coastal area of Washington. The phosphorus levels in foliage of 9‐month old seedlings without supplemental P were as low as 0.04%. Phosphorus treatment at the rate of 300 kg P/ha increased foliar P levels to an average of 0.19% P compared with an average of 0.08% P in untreated seedlings. In contrast, foliar N levels were reduced by P fertilization. Highest response to P treatment occurred on one of the Al horizons where seedling dry weight at 9 months was increased from an average of 0.31 to 1.89 g. In addition, P fertilization significantly increased development of mycorrhizal roots on seedlings. In the absence of field results confirming P deficiency in these soils, the practical implications of this study are tentative. However, the results of this experiment indicate need for field study of P fertilization of forests in the coastal area of Washington and perhaps also in Oregon and British Columbia.