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Effects of Added Nitrogen on the Availability of Phosphorus to Slash Pine on Two Lower Coastal Plain Soils
Author(s) -
Maftoun M.,
Pritchett W. L.
Publication year - 1970
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/sssaj1970.03615995003400040040x
Subject(s) - slash pine , soil water , human fertilization , phosphorus , nitrogen , fertilizer , incubation , nutrient , slash (logging) , chemistry , zoology , agronomy , pinus <genus> , botany , biology , ecology , biochemistry , organic chemistry
Applications of 50 to 400 ppm N as NaNO 3 or (NH 4 ) 2 SO 4 suppressed growth, total P uptake, and recovery of fertilizer P by young slash pine ( Pinus elliottii var. elliottii Engelm.) in two P‐deficient coastal plain soils. At the higher N rates (200 and 400 ppm) growth was limited severely by (NH 4 ) 2 SO 4 and all seedlings were killed by these rates of NaNO 3 in pot experiments. Growth suppressions following N fertilization were associated with reductions in P availability, as measured by total P uptake. Reducations in total P uptake apparently were not a result of anion antagonism, as there were only small differences in P uptake associated with the two N sources. Incubation studies indicated very low rates of nitrifications in these soils and N applications did not increase microbial activity (CO 2 production), which could have temporarily reduced P availability. Root development was restricted by the N fertilizers to a greater extent than was top growth. The root suppression evidently resulted from increased concentrations of Na or total salts in the soil. Although it appeared from these studies that Na was involved in the reduction in P uptake by the seedlings, it was not clear whether the small suppressions following N fertilization were associated with reductions in P uptake.