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Interference of Tifton Burclover Residues with Growth of Burclover and Wheat Seedlings
Author(s) -
Mbũgwa Gatua wa,
Krall James M.,
Legg David E.
Publication year - 2012
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/agronj2012.0036
Subject(s) - allelopathy , shoot , bioassay , agronomy , biology , tifton , soil water , horticulture , germination , botany , chemistry , forage , ecology , genetics
Residues of some Medicago spp. crops exhibit allelopathy and autotoxicity that adversely affect plant growth. This study was conducted to determine whether Tifton burclover [ Medicago rigidula (L.) Allioni] residues exhibit toxicity that directly or indirectly inhibits plant growth. Four laboratory bioassays and two field experiments were conducted in Wyoming, between 2006 and 2007, to investigate the allelopathic and autotoxic effects of aqueous extracts from burclover residue on both burclover and winter wheat ( Triticum aestivum L.) seedlings. Biotic soil (field soil) bioassays resulted in maximum growth inhibition of 53 and 87.9% of wheat shoot and root lengths, respectively, while abiotic soil (autoclaved field soil) bioassays resulted in maximum growth inhibition of 38.2 and 51.1% for wheat shoot and root lengths, respectively. Nitrogen‐amended soil bioassays resulted in maximum growth inhibition of 62 and 75.1% for wheat shoot and root lengths, respectively. Bioassays for soils treated with 1, 2, and 4 g of activated charcoal resulted in maximum growth inhibition of 63.4 and 77.9% for wheat shoot and root lengths, respectively, with the greatest shoot growth inhibition occurring with 4 g of activated charcoal only. Soils treated with burclover leachates resulted in increased PO 4 –P, NH 4 –N, electrical conductivity, total phenolics content, and decreased soil pH. Results from the two field studies were mixed, but drought may have adversely affected these results. Bioassay results showed that the full‐strength leachate of burclover exhibited allelopathy effects on wheat, while growth inhibition of burclover seedlings in the field showed that burclover may have autotoxicity that could reduce productivity.