Clone-Specific Response in Leaf Nitrate Reductase Activity among Unrelated Hybrid Poplars in relation to Soil Nitrate Availability

Table 1

Site and soil characteristics at the two riparian sites: elevation, mean aboveground poplar dry biomass (including leaves), soil drainage class, pH, and nutrient supply rate (μg 10 cm⁻² 15 d⁻¹). The NO₃⁻  :  NH₄⁺ nutrient supply rate molar ratio is also indicated. For nutrient supply rate, PRS-Probes were buried during a 15 day period in late August 2007.

Sites	Elev.; (m)	Poplar biomass; (kg tree^−1)^1	Drainage^2	pH^1	NO3^−	NH4^+	NO3^−  :  NH4^+	P	Ca	K	Mg	Mn
Bromptonville	140	58.9	Good	6.36	69.2	11.4	1.8	8.37	1291	506	254	2.8
Magog	208	12.2	Imperfect	5.81	24.7	16.7	0.4	4.24	710	102	492	17.8
SE	—	—	—	0.03	9.7	1.0	—	1.16	57	19	23	—
𝑃<	—	—	—	0.001	0.01	0.01	—	0.05	0.001	0.001	0.001	NS

¹Poplar aboveground biomass per tree data and pH data were taken from Fortier et al. [1].
²Soil drainage classes were obtained from Cann and Lajoie [40].