Irrigation × post-infiltration aeration interaction on root activity (as mg triphenyl formazan per g fresh root per hour) of potted single tomato plants (n = 3) measured at 57, 85, and 99 days after sowing (DAS).

Notes: Aeration treatment means at each irrigation level (n = 3) not followed by the same letter are significantly different at the 5% level. The t-test was used to compare 2 irrigation treatment means (n = 3) for each aeration treatment period. The asterisk indicates significantly different means (* for p ≤ 0.05) and (** for p ≤ 0.01, otherwise not significant (ns).
Aeration treatments (i.e. none or 2.5 liter aeration applied during 5 different periods) at the low and high irrigation levels (i.e. subsurface drip-irrigation to maintain soil at 60 to 70% and 70 to 80% of volumetric field capacity).