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

This Article Figures Only Full Text Free Full Text (PDF) Free 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 Naeve, S. L. Search for Related Content PubMed Articles by Naeve, S. L. Agricola Articles by Naeve, S. L. Related Collections Soil Fertility and Productivity Crop Growth and Development Soybean Plant and Environment Interactions Plant Nutrition

Production Papers

Iron Deficiency Chlorosis in Soybean

Soybean Seeding Rate and Companion Crop Effects

Department of Agronomy and Plant Genetics, Univ. of Minnesota, 411 Borlaug Hall, 1991 Upper Buford Cir., St. Paul, MN 55108

^* Corresponding author (naeve002{at}umn.edu)

Received for publication March 29, 2006. Iron deficiency chlorosis (IDC) is an important production problem in soybean [Glycine max (L.) Merr.] grown in the upper Midwest. Although IDC-tolerant varieties are available to producers, even tolerant cultivars suffer from IDC-related stresses. Several cultural methods have been utilized in an attempt to reduce IDC losses. Interplant competition from increased soybean seeding rates or companion crops appears to reduce IDC symptoms. Two related studies were established to examine increased seeding rates and the planting of companion crops to reduce IDC of soybean in eight IDC-prone environments. In one study, soybean was planted at five seeding rates from 432 000 to 926 000 seeds ha^–1. In a second study, a glyphosate-resistant soybean variety was planted as a sole crop or with companion crops of glyphosate-susceptible soybean or oat (Avena sativa L.). Seeding rate treatments affected IDC scores and yield, but these effects were confounded by environmental interactions. Overall, yield increases from higher seeding rates tended to be small and inconsistent, but among seven environments exhibiting mild to moderate IDC symptoms, increasing seeding rates from 432 000 to 926 000 seeds ha^–1 increased yields by 281 kg ha^–1 (16%). Blending of a glyphosate-susceptible with a glyphosate-resistant variety seemed to have little positive effect on yield of soybean (yield gains varied from –333 to + 566 kg ha^–1). Likewise, using oat interseeded with soybean to reduce IDC symptoms and increase soybean yields is unlikely to be a profitable practice for soybean producers.

Abbreviations: AE, acid equivalent • Fe-EDDHa, Fe-ethylenediamine (o-hydroxyphenylacetic)acid • IDC, iron deficiency chlorosis • Susc., susceptible