This year producers might consider planting corn earlier than normal. Producers, who plant corn early, are concerned about frost, poor emergence, and early plant growth. Producers, who plant later, wonder what maturities to plant, and how late planting affects final grain yield and moisture (more about this in the next WCM issue). Planting full-season hybrids early is highly recommended because the entire growing season can be used. Physiological maturity can be reached before growth stops because of frost, and some field drying of corn can occur allowing greater profit margin. These considerations are important for all corn producers, but are even more important for producers on the northern fringes of the Corn Belt where the growing season often is limiting.

Table 1 shows the effect of planting date on various corn hybrids between 1991 and 1997 at Arlington, WI. In some years, yield was affected by earlier planting dates. However, grower return was typically best early in the planting season. Optimum planting dates range from May 1 to May 7 in southern and northern Wisconsin, respectively.

There is some yield risk with early planting dates, but this is often made up by lower drying costs. If corn is planted prior to 20 and 30 April in southern and northern Wisconsin, respectively, the decision to begin planting should be based on soil temperature and field conditions. After 20 and 30 April, corn planting should proceed as rapidly as possible and be completed by 12 May for southern Wisconsin and 15 May for northern Wisconsin. Otherwise, corn producers will suffer significant yield penalties with further delays in planting.

Table 1. Corn response to planting date between 1991 and 1997 at Arlington, WI.
Year	Planting date	Grain yield	Grain moisture	GrowerReturn
		Bu/A	%	$/A

1997	April 18	198	24	497
	May 05	165	27	406
	May 13	190	26	471
	May 20	172	28	421
	June 02	164	31	392
	June 10	134	27	331
	June 19	107	34	249
	July 01	24	55	67

1996	April 26	178	25	445
	May 01	169	25	420
	May 05	161	26	397
	May 10	173	27	426
	May 20	141	26	350
	June 13	141	30	338

1995	April 20	156	17	413
	May 01	153	17	405
	May 15	152	18	401
	May 19	150	19	393
	May 20	145	20	378
	June 09	105	23	267

1994	April 20	169	19	442
	May 03	167	20	433
	May 10	165	22	423
	May 20	170	24	427
	June 01	137	33	323
	June 10	106	29	256
	June 22	50	45	105

1993	April 23	152	30	367
	April 30	149	31	355
	May 10	131	36	301
	May 19	123	29	300
	June 01	102	35	239
	June 10	97	23	245
	June 22	45	39	101

1992	April 30	180	29	434
	May 07	182	31	431
	May 14	161	33	375
	May 21	129	40	284
	May 28	121	44	258
	June 04	73	49	149
	June 10	64	42	139
	June 23	29	54	58

1991	April 20	168	30	403
	May 01	172	29	416
	May 09	180	32	426
	May 20	158	25	396
	June 01	145	31	346
	June 10	106	29	255
	June 18	90	32	211
Grower return to management = (Grain yield x Grain price) minus treatment costs Assumptions included: Grain price = $2.75 per bushel Drying cost = $0.02 per moisture point above 15.5% Hauling cost = $0.04 per bushel Handling cost = $0.02 per bushel