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

This Article 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 HighWire Citing Articles via Google Scholar Google Scholar Articles by Borges, R. Articles by Mallarino, A. P. Search for Related Content PubMed Articles by Borges, R. Articles by Mallarino, A. P. Agricola Articles by Borges, R. Articles by Mallarino, A. P.

Field-Scale Variability of Phosphorus and Potassium Uptake by No-Till Corn and Soybean

Department of Agronomy, Iowa State Univ., Ames, IA 50011

*Corresponding author (apmallar{at}iastate.edu).

ABSTRACT

Use of precision farming technologies requires better understanding of nutrient variability in soils and plants. This study assessed patterns of spatial variability of plant P and K content of no-till corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] on eight fields that had varied histories of fertilization. One hundred composite whole-plant samples (five corn plants and 10 soybean plants at V5 to V6 growth stages) were collected in late spring from 2.2-m² areas spaced 3.05 m along two intersecting transects. Dry weight (DW) and total P and K concentrations were measured in all samples. Plots of observed values, variography, and fast Fourier transform (FFT) analyses revealed clustering of values and periodic patterns of DW and nutrient content in most fields. The patterns of variability varied greatly among fields and directions within a field. The diversity of patterns probably results from nonuniform distribution of fertilizers and animal manures. Patterns of plant K uptake (KU) followed patterns of plant K concentration (KC) in some fields and those of DW in others. Patterns of plant P uptake (PU), however, usually followed those of DW. Implementation of plant analysis for no-till fields should address situations with high spatially structured variability of cyclic or clustered structure. The results show that the structure of the variability in P and K uptake is site specific and that both the sampling scheme and the optimal separation distance between sampling positions would vary greatly among fields. The results suggest that plant analysis would have similar sampling problems to those of soil testing for representing the P and K supplies of corn and soybean fields.

Journal paper J-16742 of the Iowa Agric. and Home Economics Exp. Stn., Ames; Project 3233. This work was supported in part by the Iowa Soybean Promotion Board and the Leopold Center for Sustainable Agriculture.

Received for publication March 13, 1996.

This article has been cited by other articles:

				J. Sawchik and A. P. Mallarino Variability of Soil Properties, Early Phosphorus and Potassium Uptake, and Incidence of Pests and Weeds in Relation to Soybean Grain Yield Agron. J., September 8, 2008; 100(5): 1450 - 1462. [Abstract] [Full Text] [PDF]

				A. N. Kravchenko and D. G. Bullock Spatial Variability of Soybean Quality Data as a Function of Field Topography: I. Spatial Data Analysis Crop Sci., May 1, 2002; 42(3): 804 - 815. [Abstract] [Full Text] [PDF]

				J. Wu, W. A. Norvell, D. G. Hopkins, and R. M. Welch Spatial Variability of Grain Cadmium and Soil Characteristics in a Durum Wheat Field Soil Sci. Soc. Am. J., January 1, 2002; 66(1): 268 - 275. [Abstract] [Full Text] [PDF]

				J. P. Schmidt, R. K. Taylor, and G. A. Milliken Evaluating the Potential for Site-Specific Phosphorus Applications Without High-Density Soil Sampling Soil Sci. Soc. Am. J., January 1, 2002; 66(1): 276 - 283. [Abstract] [Full Text] [PDF]