The Effects of AlCl₃Additions on Rhizosphere Soil and Fine Root Chemistry of Sugar Maple (Acer Saccharum)

Abstract

Abstract. Increased Al mobilization and Ca and Mg leaching have been linked to nutritional imbalances in sugar maple across the northeastern US and Canada. The susceptibility of sugar maple fine roots to Al stress is poorly understood, in part because roots respond to Al stress by altering the chemistry of the rhizosphere. AlCl 3 was applied to plots of sugar maple at the Hubbard Brook Experimental Forest, NH. After two years of treatment, we sampled fine roots of sugar maple, rhizosphere soil, and bulk soil in the Oa horizon and the upper 10 cm of the mineral soil. AlCl 3 treatments resulted in significantly less Ca (21%) and Mg (30%) in fine roots from the organic horizon, but had no significant effect on fine root Al. Fine root (Ca+Mg):Al ratios were 42% lower in AlCl 3 plots than in controls, though most roots had ratios above critical toxicity thresholds developed for hydroponically grown sugar maple seedlings. In the mineral horizon, roots differed only in Mg concentration, which was 22% lower in AlCl 3 plots. In the AlCl 3 treated plots, rhizosphere soil in the organic horizon had 47% greater Al and 29% less Mg than in controls. Combining data from both treatments we found significantly less Al and organically bound Al in rhizosphere soil than in bulk soil, possibly due to leaching of Al from the rhizosphere by organic acids released by roots. These results suggest that increased mobilization of Al in soil lowers (Ca+Mg):Al ratios in sugar maple fine roots, though roots may minimize Al stress by leaching Al from the rhizosphere.

Response of Soil Respiration to Acid Rain in Forests of Different Maturity in Southern China

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Phosphate addition enhanced soil inorganic nutrients to a large extent in three tropical forests

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Phosphorus transformation in root zone environment under semi tropical agro ecosystem in sandy clay loam soil

“…The lowest availability was seen in the harvest stage of maize. When looking into the significant differences among the rhizosphere and non rhizosphere soil, the former was pertained to show 5.8% more P availability than the later irrespective of the crop growth period which was in line with Phillips and Yanai, (2004). Increased organic matter decomposition caused by increased microbial populations in the MILASHECHKINA ET AL S625 rhizosphere might have resulted in higher nutrient concentrations in the rhizosphere solution were found in alignment with Leyval and Berthelin, (1993); Drever and Vance, (1994); Wang and Zabowski, (1998).…”