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

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Haden, V. R. Articles by Kahabka, J. E. Search for Related Content PubMed Articles by Haden, V. R. Articles by Kahabka, J. E. Agricola Articles by Haden, V. R. Articles by Kahabka, J. E. Related Collections Nutrient Management Phosphorus

NUTRIENT MANAGEMENT & SOIL & PLANT ANALYSIS

Factors Affecting Change in Soil Test Phosphorus Following Manure and Fertilizer Application

Dep. of Crop and Soil Sciences, Cornell Univ., Ithaca, NY 14850

^* Corresponding author(qmk2{at}cornell.edu).

In many states, Morgan (M) or Mehlich-3 (M3) extractions are the basis for P fertility recommendations and P runoff risk assessment. The impact of timing of sampling, P source, and extractable Al on agronomic soil test P (STP) and P release to the environment are not well understood. Incubation studies were conducted to determine: (i) changes in M-P, M3-P, and 0.01 M CaCl₂–P with time following Ca(H₂PO₄)₂ addition; (ii) the efficiency of liquid dairy manure, NH₄HPO₄, and Ca(H₂PO₄)₂ in raising M-P and M3-P levels; and (iii) the degree to which initial P and extractable Al impact the efficiency of applied P. Twenty-eight noncalcareous soils were incubated at 23°C, in the dark, at field capacity moisture content. Extractable P decreased over 60 d, with a greater proportion of P being lost from the more labile pools (CaCl₂–P > M-P > M3-P). The increase in STP per unit P added (P-M and P-M3) was affected by P source: NH₄HPO₄ raised P levels more efficiently than Ca(H₂PO₄)₂ or liquid dairy manure. There was a positive linear relationship between P and initial STP. Extractable Al was inversely related to P-M and P-M3 and followed exponential decay functions. Extractable Al was positively and linearly related to the amount of P required to raise M-P and M3-P levels 1 mg kg^–1, with Morgan Al as the most accurate predictor of P. Our results suggest that the New York P index should include guidance on sampling time and account for the higher P sorption capacity of soils inherently high in extractable Al.

Abbreviations: CNAL, Cornell Nutrient Analysis Laboratory • LOI, loss on ignition • M, Morgan extraction • M-P, Morgan extractable phosphorus • M3, Mehlich-3 extraction • M3-Al, Mehlich-3 extractable aluminum • M3-P, Mehlich-3 extractable phosphorus • P, change in soil test phosphorus (Morgan or Mehlich-3) per unit P added • STP, soil test P