TABLE 3.

Concentration of nutrients in the tissue of lettuce in experiment 2.

Nutrient	Units	Treatment
		Control	Recycle
N	(mg⋅g–1)	37.6 (1.29) a	24.3 (0.70) b
P		5.4 (0.11) a	2.7 (0.20) b
K		42.0 (1.15) a	25.4 (1.01) b
Ca		10.7 (0.40)	11.0 (0.34)
Mg		5.2 (0.20)	5.3 (0.27)
S		3.2 (0.17)	3.0 (0.12)
Na		1.9 (0.08) b	3.2 (0.20) a
B	(mg⋅kg–1)	38.8 (2.37)	33.4 (1.79)
Zn		43.1 (2.72)	39.8 (3.16)
Mn		91.8 (5.24)	77.7 (8.65)
Fe		74.2 (8.41) a	46.3 (5.73) b
Cu		13.2 (1.56) b	20.0 (2.68) a
Al		47.4 (9.01)	53.6 (15.44)

Mean values for nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), sodium (Na), boron (B), zinc (Zn), manganese (Mn), iron (Fe), copper (Cu) and aluminum (Al) are shown. Means followed by the same letter within a measurement are not statistically different (P ≤ 0.05). Values in parenthesis indicate standard error of mean.