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A Root Tube - Pegging Pan Apparatus: Preliminary Observations and Effects of Soil Water in the Pegging Zone¹

Authors: , ,

Abstract

Soil conditions, especially water deficits in either the pegging or rooting zone or both, affect pod initiation and seed development of peanut (Arachis hypogaea L.). The objectives of this study were to 1) construct a root tube - pegging pan apparatus which would allow for physical separation of the rooting and pegging zones, 2) determine growth and development of peanut when grown in the apparatus, and 3) examine the effects of soil water in the pegging zone on the initiation and development of peanut fruits. An experimental apparatus was constructed to provide a mechanism for separation of the rooting and pegging zones, allowing for independent control of soil water in both zones. Root tubes (1.6 m long and 15 cm in dia.) were constructed of polyvinyl chloride tubing. Watering access tubes were inserted at 0, 0.5 and 1.0 m from the top of the root tube. The top of the root tube was closed with a convex cap having a 5-cm central hole through which a peanut plant was allowed to grow. A pegging pan (50 cm long × 35 cm wide × 20 cm deep) was fitted around the upper portion of the root tube. Preliminary studies demonstrated satisfactory shoot growth and pod development of peanut plants grown in the apparatus provided over-watering was avoided. It also appeared that pods and seeds formed in air-dry pegging zone soil. To examine this in more detail, an experiment was conducted comparing the effects of air-dry vs. moist (7 to 12% water by weight) pegging zone soil on pod and seed formation. The air-dry pegging zone reduced the percentage of tagged pegs which developed into full pods (those having reached full expansion) from 61 to 48% and reduced the growth rate of developing seeds and pods by 18 and 29%, respectively. The root tube - pegging pan apparatus provided a useful technique to gain a better understanding of peanut pod formation as influenced by soil water environments in the pegging zone.

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Keywords: Arachis hypogaea, pod growth, seed growth, soil water deficits, Water stress

How to Cite: Bennett, J. , Sexton, P. & Boote, K. (1990) “A Root Tube - Pegging Pan Apparatus: Preliminary Observations and Effects of Soil Water in the Pegging Zone¹”, Peanut Science. 17(2). doi: https://doi.org/10.3146/i0095-3679-17-2-6

Author Notes

1Contribution from the Dep. of Agronomy, Univ. of Florida. This research was supported in part by funds from the Florida Peanut Check-Off Program. Florida Agric. Exp. Stn. Journal Series no. R-00338.