|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
ABSTRACT
Phosphorus was extracted by 10 methods from soils in Minnesota supporting stands of red pine (Pinus resinosa Ait.) to find those methods most suitable for estimating site index. The amount of phosphorus extracted from the surface 25 cm of mineral soil by H2O, 0.002N H2SO4, or 0.01N HCl was related at the 1% level (r2 = .47 to .53) to site index. Considerably weaker relationships with site index were obtained with organic P, total P, and phosphorus extracted by 0.5N NaHCO3, 0.4N HCl, 0.025N HCl + 0.03N NH4F, 0.10N HCl + 0.03N NH4F, or 0.05N HCl + 0.025N H2SO4. No improvement in the estimation of site index was made by including phosphorus extracted from deeper layers of the soil. Foliar phosphorus concentration was significantly related to site index and to the amount of phosphorus extracted from the surface soil by H2O, 0.002N H2SO4, or 0.01N HCl.
1 Contribution from the North Central Forest Exp. Sta., Forest Service, USDA, St. Paul, Minn. 55101.
2 Research Soil Scientist, USDA Forest Service, North Central Forest Exp. Sta., Northern Conifers Lab., Grand Rapids, Minn. Laboratory maintained in cooperation with the University of Minnesota.
Received for publication October 20, 1971. Accepted for publication March 22, 1972.
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |