Table 7. Effect of P rates and K rates on corn and soybean grain yields under two tillage systems for two locations in southern Illinois, 2001-04.

Illinois Fertilizer Conference Proceedings
January 26-28, 2006

Variable	Dixon Springs						Belleville						Over– all Ave.
Variable	01	02	03	04	05	Ave	01	02	03	04	05	Ave	Over– all Ave.
	----------bu⁄acre Grain Yield-------
Chisel Tillage Corn
AP & AK	176	120	146	133	163	148	192	159	153	230	197	186	167
BP & BK (corn)	172	136	137	133	158	147	189	170	154	233	192	188	167
BP & BK (soy)	162	107	125	125	129	130	194	167	164	215	189	186	158
BP(corn) & BK(soy)	170	115	138	135	137	139	181	165	167	240	198	190	165
BP(soy) & BK(corn)	181	108	136	137	163	145	185	163	160	225	193	185	165
LSD	15.4	27.0	18.7	18.4	NS		12.1	NS	NS	NS	NS
No–Till Corn
AP & AK	175	126	119	168	120	142	187	171	200	202	193	191	166
BP & BK (corn)	171	117	112	151	121	135	195	165	200	214	193	193	164
BP & BK (soy)	165	115	106	158	121	133	170	167	194	191	195	183	158
BP(corn) & BK(soy)	165	115	104	138	118	128	189	158	200	200	190	187	158
BP(soy) & BK(corn)	173	114	133	155	122	139	191	169	210	205	193	194	167
LSD	NS	NS	16.9	20.1	NS		20.6	NS	NS	NS	NS

† Rates for Dixon Springs CT were 1.5× P rates and 2× K rates at other locations. In 2004, rates for NT at DS increased to 1.5× P and 2× K rates.

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