EFFECT OF LIMING ON THE DISTRIBUTION OF ALUMINUM AND ALUMINUM UPTAKE BY MAIZE GROWN IN A COARSE TEXTURED SOIL

11th International Multidisciplinary Scientific GeoConference SGEM2011, www.sgem.org, SGEM2011 Conference Proceedings/ ISSN 1314-2704, June 20-25, 2011, Vol. 2, 1071-1078 pp

ABSTRACT

The phytoavailability of aluminum (Al) in Al-rich acid podzolic soils is of particular concern in many Quebec agricultural areas due to its toxic effect on plant growth.
Liming materials may mitigate Al phytoavailability and toxicity depending on Al pool
and plant part, respectively. Our objective was to determine the effect of dolomitic limestone on the distribution of Al species in soil and to evaluate the uptake and distribution of Al in the different parts of maize (Zea mays L.). Maize was grown in 40-
cm high and 15-cm diameter columns filled with Morin series loamy sand [Orthic Humo-Ferric Podzol (Haplorthod)]. The amount of exchangeable Al (1 M MgNO3, pH7) was very low (< 0.6%). Exchangeable and carbonate fractions represented less than 9
% of total Al. Most Al was in the oxide fraction (63%). Exchangeable soil Al (Al-exch) was the most significantly affected by liming. Al-exch was negatively correlated with soil Ca-exch and Mg-exch (0.5 M BaCl2-TEA, pH 8.2) (r = -0.914*** and -0.944***,
respectively), soil pH (r = -0.958***) and concentrations of Ca in stems (r = -0.960***), leaves (r = -0.920***), flowers (r = -0.660**), ears (r = -0.850***) and roots (r = -0.881***). On other hand, Al-exch was positively correlated with concentration of Al instems (r = 0.754**), leaves (r = 0.936***), flowers (r = 0.926***), ears (r = 0.825***)
and roots (r = 0.925***). Plant roots accumulated more Al than shoots. After corn harvest, soil pH ranged from 5.4 (without limestone) to 6.4 (highest limestone rate).
Liming soil to pH 6.4 maximized shoot biomass yield while reducing Al-exch to 0.13
cmolc/kg and the ratio of Al-exch to exchangeable Ca+Mg to 0.01 in the 0-10 cm soil
layer. Tissue Al concentrations ranged from 10.7 to 34.7 mg/kg in stems and from 25.9
to 57.1 mg/kg in leaves, well below the critical toxicity limit of 80 mg/kg for most
agricultural crops, whatever soil pH and the level of Al-exch.

Keywords: dolomitic limestone, soil Al fractions, exchangeable Ca and Mg