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

This Article 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 Google Scholar Articles by Sawchik, J. Articles by Mallarino, A. P. PubMed Articles by Sawchik, J. Articles by Mallarino, A. P. Agricola Articles by Sawchik, J. Articles by Mallarino, A. P. Related Collections Soybean Field-Scale Studies Spatial Variability Site-Specific Analysis Soil Fertility and Productivity

SITE-SPECIFIC ANALYSIS & MANAGEMENT

Variability of Soil Properties, Early Phosphorus and Potassium Uptake, and Incidence of Pests and Weeds in Relation to Soybean Grain Yield

^a Inst. Nacional de Investigaciones Agropecuarias (INIA), La Estanzuela, Colonia, Uruguay
^b Dep. of Agron., Iowa State Univ., Ames, IA 50011

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

Successful crop management requires understanding relationships between site characteristics and crop yield. We studied intercorrelations among soil and crop properties using factor analysis (FA) and principal components analysis (PCA), and their relationships with soybean [Glycine max (L.) Merr.] within-field yield variability. Site variables (22) measured on 0.2-ha cells of 12- to 20-ha areas of five Iowa fields were: elevation; soil texture; extractable nutrients; incidence of soybean cyst nematode (Heterodera glycines) (SCN), diseases, and weeds; soybean dry weight (DW), height, and P and K uptake at V5; plant height at R5; and grain yield. Agronomic interpretations of interrelationships among site variables were more straightforward for FA than for PCA. The factors conditions for early growth and nutrient uptake and intrinsic soil properties were present in all fields, plant P and K availability was present in three fields, and the factor soybean pests, weeds or plant growth was present in the other fields. Factor analysis and PCA accounted for 62 to 64% of the yield variability in the field with the largest yield CV (30%) and 5 to 35% in the other fields (CV 2.8 to 5.9%). Two factors related significantly to yield in two fields (plant P and K availability and intrinsic soil properties) while others were specific to one field. Factor analysis identified groups of interrelated site variables, showed how they accounted for yield variability, and showed that single measurements seldom account for most yield variation in a field.

Abbreviations: BSR, brown stem rot • CEC, cation exchange capacity • DGPS, differential global positioning systems • DW, dry weight • FA, factor analysis • GIS, geographical information systems • OM, soil organic matter • PCA, principal components analysis • PCs, principal components • SCN, soybean cyst nematode • STP, soil-test P • STK, soil-test K

All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.

Received for publication September 8, 2007.