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Effects of soil compaction on phosphorus uptake and growth of Trifolium subterraneum colonized by four species of vesicular–arbuscular mycorrhizal fungi
Author(s) -
NADIAN H.,
SMITH S. E.,
ALSTON A. M.,
MURRAY R. S.,
SIEBERT B. D.
Publication year - 1998
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.1998.00219.x
Subject(s) - trifolium subterraneum , soil compaction , biology , shoot , glomus , agronomy , phosphorus , mycorrhiza , bulk density , horticulture , soil water , inoculation , symbiosis , chemistry , pasture , ecology , genetics , organic chemistry , bacteria
The ability of four species of vesicular–arbuscular mycorrhizal (VAM) fungi to increase phosphorus uptake and growth of clover plants ( Trifolium subterraneum L.) at different levels of soil compaction and P application was studied in a pot experiment. Dry matter in the shoots and roots of clover plants decreased with increasing soil compaction. Colonization by Glomus intraradices Schenck & Smith and Glomus sp. City Beach WUM16 increased plant growth and P uptake up to a bulk density of 1·60 Mg m −3 , although the response was smaller as soil compaction was increased. Glomus etunicatum Becker & Gerdeman and Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe had no effect on the shoot d. wt and P uptake when the bulk density of the soil was 1·40 and 1·60 Mg m −3 , respectively. Soil compaction to a bulk density of 1·60 Mg m −3 had no effect on the percentage of root length colonized by G. intraradices and Glomus sp. City Beach, but total root length colonized decreased as soil compaction was increased. Decreased P uptake and growth of clover plants colonized by G. intraradices and Glomus sp. City Beach, with increasing soil compaction up to a bulk density of 1·60 Mg m −3 , was mainly attributed to a significant reduction in total root length colonized and in the hyphal biomass. Soil compaction, which increased bulk density from 1·20 to 1·75 Mg m −3 , reduced the O 2 content of the soil atmosphere from 0·16 to 0·05 m 3 m −3 . The absence of any observable mycorrhizal growth response to any of the four species of VAM fungi in highly compacted soil (bulk density = 1·75 Mg m −3 ) was attributed to the significant decrease in the O 2 content of the soil atmosphere, change in soil pore size distribution and, presumably, to ethylene production.