Table 4. Effect of direct application (in 2005) of P rates and K rates on soybean trifoliate leaf P and K concentrations under two tillage systems for two locations in southern Illinois, 2005.

Illinois Fertilizer Conference Proceedings
January 26-28, 2006

Variable	Trifoliate Leaf P Concentration				Trifoliate Leaf K Concentration
	Dixon Springs		Belleville		Dixon Springs		Belleville
	CT	NT	CT	NT	CT	NT	CT	NT
	-------- % P Concentration -------				------ % K Concentration --------
Check(no P or K)	0.42	0.36	0.34	0.34	1.80	1.86	1.90	2.09
P Rate‡
0 lb⁄a P₂O₅	0.40	0.39	0.34	0.35
40(60†)	0.40	0.40	0.33	0.34
80(120)	0.43	0.41	0.33	0.35
120(180)	0.42	0.41	0.33	0.35
K Rate‡
0 lb⁄a K ₂O					2.39	2.43	2.52	2.45
40(80†)					2.34	2.62	2.28	2.27
80(160)					2.49	2.51	2.26	2.42
120(240)					2.40	2.60	2.28	2.56
ANOVA	---------------------------Significanceξ-------------------------------
Ck vs others	NS	*	NS	NS	***	***	***	**
P Rate
P linear	NS	NS	NS	NS	N/A	N/A	N/A	N/A
P quadratic	NS	NS	NS	NS	N/A	N/A	N/A	N/A
K Rate
K Linear	N/A	N/A	N/A	N/A	NS	NS	**	NS
K quadratic	N/A	N/A	N/A	N/A	NS	NS	**	NS

† Rates in parentheses for Dixon Springs CT and NT.

‡ Means for P rates averaged across K rates and means for K rates averaged across P rates.

ξ *, **, *** refer to significance at the 10%, 5%, and 1% levels, respectively.

NS = non-significant. N/A means not available (not measured).