TABLE 2.

Plant nutritional status of lettuce (cv. Tizian).

Nutrient concentration of shoot dry biomass (DM) of lettuce (cv. Tizian)
		HUB-LTE		DOK-LTE
		HU-org	HU-min	BIODYN2	CONMIN
Macronutrients (g kg–1 shoot DM)
N	35*	31.40 ± 1.51 a	31.51 ± 1.60 a	30.68 ± 0.40 a	32.04 ± 1.21 a
P	3.0*	1.66 ± 0.25 a	2.06 ± 0.09 a	1.75 ± 0.03 a	1.91 ± 0.12 a
K	42*	20.23 ± 3.18 b	33.44 ± 0.58 a	38.11 ± 1.93 a	26.35 ± 1.47 b
Ca	12*	17.46 ± 3.11 a	18.42 ± 1.60 a	14.76 ± 0.45 b	16.59 ± 0.62 a
Mg	1.0*	3.79 ± 0.61 a	3.54 ± 0.21 a	3.53 ± 0.10 b	5.05 ± 0.29 a
S	2.5*	1.79 ± 0.27 a	2.06 ± 0.13 a	2.54 ± 0.08 a	2.36 ± 0.12 a
Na	0.6*	4.08 ± 0.93 a	2.92 ± 0.05 a	3.40 ± 0.35 b	5.59 ± 0.25 a
Micronutrients (mg kg–1 shoot DM)
Cu	2.5**	2.87 ± 0.55 a	3.21 ± 0.41 a	7.10 ± 0.53 a	7.52 ± 0.64 a
Fe	50**	123.63 ± 18.00 a	289.38 ± 122.81 a	841.52 ± 203.32 a	401.24 ± 162.02 a
Mn	20**	63.37 ± 9.78 a	85.91 ± 9.48 a	80.10 ± 5.74 a	81.75 ± 12.19 a
Zn	20**	19.74 ± 2.96 a	26.47 ± 2.00 a	55.37 ± 2.06 a	33.55 ± 3.91 b

The plants were grown in minirhizotron culture for nine weeks in soils with long-term organic (HU-org, BIODYN2) or mineral (HU-min, CONMIN) fertilization history. Data represent means ± standard errors of four independent replicates per treatment. Different lowercase letters indicate significant differences between organic vs. mineral fertilization tested separately for the sites DOK-LTE and HUB-LTE by one-way ANOVA, Tukey’s HSD pairwise test, p ≤ 0.05. *Deficiency threshold macronutrients (g kg^–1 DM). **Deficiency threshold micronutrients (mg kg^–1 DM), (Bergmann, 1988).