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 Sivakumar, M. V. K. Articles by Shaw, R. H. Search for Related Content PubMed Articles by Sivakumar, M. V. K. Articles by Shaw, R. H. Agricola Articles by Sivakumar, M. V. K. Articles by Shaw, R. H.

Top and Root Relations of Field-Grown Soybeans¹

Field data describing both the top and root growth of soybeans [Glycine max L. (Merr.)] at different morphological stages are very limited. Such quantitative data are essential far analyzing or simulating growth patterns of whole soybean plants.

Soybean top and root growth studies were conducted at the Western Iowa Experimental Farm on Ida silt loam soil [fine, silty, mixed (calcareous) mesic family of typic Udorthents]. Plant height, dry matter distribution of above-ground plant parts, leaf area index, root length, and root dry weight distribution were measured at different physiological stages.

Toproot ratio of soybeans was 3.8 when the plants were in stage V6, and the ratio increased to 9.0 by the time that the plants reached stage V15R2. From the root length and leaf data, the total length of roots required to supply water and nutrients to each m² leaf area was calculated. These root lengths increased from 630 m/m² leaf area when the plants were in V6 stage to 1,190 m/m² at V13R2 stage then decreased to 345 m/m² at stage V15R2 as the soil dried. Root length in a specific layer decreased whenever soil was drier than –2 bars or volumetric water content was below 16%.

Plant height and leaf area were positively correlated (r = 0.95). Most of the leaf area was concentrated in the upper portions of the soybean canopy when leaf area was maximum.

Key Words: Soil water content • Leaf area index • Root length

² Formerly graduate research assistant, presently scientist, Int. Crops. Res. Inst. for the Semi-arid tropics, 1-11-26 Begumpet, Hyderbad 500016, India: soil scientist and professor of agronomy, North Central Region, ARS/USDA; and professor of agricultural climatology, Agronomy Dep., Iowa State Univ., Ames, IA 50011.

Received for publication August 4, 1976.

This article has been cited by other articles:

				D. B. Myers, N. R. Kitchen, K. A. Sudduth, R. E. Sharp, and R. J. Miles Soybean Root Distribution Related to Claypan Soil Properties and Apparent Soil Electrical Conductivity Crop Sci., July 30, 2007; 47(4): 1498 - 1509. [Abstract] [Full Text] [PDF]

				J. M.-F. Johnson, R. R. Allmaras, and D. C. Reicosky Estimating Source Carbon from Crop Residues, Roots and Rhizodeposits Using the National Grain-Yield Database Agron. J., April 11, 2006; 98(3): 622 - 636. [Abstract] [Full Text] [PDF]