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Studies of Intact Shoot‐Root Systems of Field‐Grown Winter Wheat. I. Sampling Techniques 1
Author(s) -
Belford R. K.,
Rickman R. W.,
Klepper Betty,
Allmaras R. R.
Publication year - 1986
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1986.00021962007800050001x
Subject(s) - tiller (botany) , agronomy , loam , shoot , tillage , environmental science , silt , mathematics , horticulture , soil water , biology , soil science , paleontology
The yield component most closely related to wheat ( Triticum aestivum L. em. Thell.) yield in the dryland farming area of the Pacific Northwest is heads per unit area. Tiller survival determines the head population and is therefore a major yield determining factor. A study relating tiller survival to tiller rooting required a sequential sampling of intact shoot‐root systems of field grown plants. As no technique to provide the required samples was found in the literature, a new procedure was devised. Square metal tubes, 0.18 by 0.18 by 1.1 m with removable side, were constructed of 16‐gauge steel. These tubes were forced into the ground with a hydraulic coring machine immediately after emergence of winter wheat (var ‘Stephens’) planted in 0.18‐m rows on 14 Oct. 1981 in field plots on a Walla Walla silt loam (mixed, mesic Typic Haploxerolls). Thermocouples and tensiometers at 0.2‐, 0.4‐,0.6‐, and 0.8‐m depths showed that soil temperatures were not significantly different between the tubes and adjacent field soil, but soil in some tubes was significantly wetter (higher water potential) than adjacent field soil during winter. Tubes were extracted from the field on 23 February, 17 March, 19 April, and 1 June. The removable side was taken off and a fine spray was used to wash soil from the roots. Washed intact plants were floated in water in a shallow tray to separate individual plants, tillers, and their associated roots. These separations were not successful for deep roots for the June sampling date. This technique permits collection of data on rooting habits of plants at different times in the growing season, on associations between shoots and intact field‐grown root systems, and on details of root branching patterns under field conditions.