TABLE 4.

Means over 18 days for concentrations of water-soluble nutrients and water-soluble organic carbon in leachate after filtration (0.22-μm pore size), and for turbidity of leachate samples, as affected by core type, soil type, and manure application^a

Variable compared	Type	Nitrate (μg ml −1)b	Ammonium (μg ml−1)b	Phosphate (μg ml−1)b	W.S.O.C. (μg ml−1)c	Turbidity (OD405)c
Core type	Intact	13.55 A	1.16 B	4.87 A	1.66 B	0.82 B
	Disturbed	13.20 A	2.71 A	4.63 A	1.82 A	0.93 A
Soil type	Sandy loam	14.26 A	1.88 A	4.90 AB	1.70 A	1.02 A
	Silt loam	13.64 A	2.12 A	5.46 A	1.72 A	0.85 B
	Clay loam	10.67 B	1.98 A	3.71 B	1.82 A	0.75 C
Manure applied	Yes	14.13 A	2.08 A	4.93 A	1.77 A	0.89 A
	No	12.67 B	1.92 A	4.60 A	1.72 A	0.87 A

^aSamples from all replicates and time points were compared in a linear model to determine overall treatment effects. Letters following the means are from least-significant-difference comparisons (LSDs using SAS proc GLM). Mean comparisons with different letters are significantly different. 

^bWater-soluble nitrate, ammonium, and phosphate concentrations generally decreased in leachate over time. 

^cWater-soluble organic carbon (W.S.O.C.) concentrations and turbidity (optical density at 405 nm) were generally constant in leachate over time.