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United States Department of Agriculture

Agricultural Research Service

Title: The Role of Humic Substances in Plant Growth

Authors
item Clapp, Charles
item Cline, Van - UNIVERSITY OF MINNESOTA
item Hayes, Michael - UNIVERSITY OF BIRMINGHAM
item Liu, Ruilong - UNIVERSITY OF MINNESOTA

Submitted to: International Humic Substances Society Conference
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 1998
Publication Date: N/A

Technical Abstract: Humic substances (HS) are plant growth stimulating agents which have been applied in agricultural and horticultural management in recent years. However, detailed mechanisms of how these materials work in plants are still not well understood, due to their complex structures in nature. There are many reports of their roles in promoting plant biomass, stimulation of root, shoot, and flowering growth, and even direct effects on crop productivity and increases in crop yields. The HS consist of humic acids, fulvic acids and humin. They can be extracted from many natural sources such as peat, soil, and leonardite ore. Application of the humics in golf course and sports turf management has recently been re-discovered. They not only increase fertilizer efficiency and promote plant growth, but can reduce the potential to groundwater contamination. Plant growth research involving HS at the University of Minnesota has centered on both basic and practical components to investigate the 'how and why' of HS interactions with plant and soil ecosystems. Humic substances from several commercial and natural sources have been tested with Creeping Bentgrass (Agrostis palustris c.v. Providence) in growth chamber microsystems experiments. The setup consisted of micro tissue culture plates filled with sand and a filter paper wick to provide water and nutrients from a constant head plastic tray. Preliminary results indicated that the system was sensitive to nutrient and HS dynamics. Specific HS samples gave significant increases in grass root and shoot growth over fertilizer controls. Larger scale greenhouse experiments in simulated golf green mixes of sand or sand/peat showed several HS products to be effective and productive turfgrass growth promoters.

Last Modified: 8/21/2014
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