Randomized block trial demonstrates improved trunk growth and foliar nitrogen uptake under fertigation in Thuja occidentalis, highlighting rainfall-dependent nitrate retention.
Key Points
Evaluate the effects of granular fertilization, drip fertigation, and a hybrid delivery system on growth, aesthetic quality, foliar nitrogen, and soil nitrate dynamics in field-grown Thuja occidentalis.
Conducted a two-year field study using a randomized complete block design (RCBD) across two commercial nursery sites in Quebec, Canada.
Tested three nitrogen delivery methods (conventional granular fertilization, drip fertigation, and a hybrid approach) across varied nitrogen rates, including 150 kg N ha⁻¹.
Monitored plant height, trunk caliper, aesthetic grade, foliar nitrogen levels, soil nitrate flux, root depth distribution, and soil water uptake via time-domain reflectometry.
Application of 150 kg N ha⁻¹ significantly increased trunk diameter and aesthetic foliage quality without significantly altering tree height growth across application methods.
Drip fertigation numerically increased foliar nitrogen concentration by up to 17% relative to granular fertilization, supplying immediate bioavailable nitrate to the root zone.
Active roots and primary water absorption were confined to the upper 30 cm of soil, where simulated precipitation events exceeding 50 mm displaced nitrate beyond the root zone.