When most farmers' corn planters have begun gathering dust in their machine sheds, the planter on Thompson Farms is working overtime. For the past two years, Keith Thompson, his son Ben and brother Doug have planted corn after wheat in late June and early July.
The Thompsons, of Osage City, KS, planted 99-day Dekalb 493 BT (now marketed as 4952BT) at 28,500 seeds/acre both years. The 1998 yield on a six-acre field was 72 bu/acre. It was planted June 24. Last year's 20-acre field, planted July 6, yielded 65 bu/acre.
The doublecrop corn is part of an effort by the Thompsons to intensify and diversify their no-till rotation to make the best use of available moisture. They say their silty clay loam soils, no-tilled for the past 10 years, catch and retain more moisture than conventionally tilled fields in the area.
"We started doublecropping to take advantage of otherwise wasted water," Keith says.
Soil moisture was adequate both years to get the corn up without rain. Adequate rainfall continued in 1998 until the corn reached knee height, then no rain fell for 35 days. Precipitation was plentiful throughout the growing season last year, so the Thompsons were banking on more than 100 bu/acre. But a Sept. 18 freeze and hungry deer took a toll. Both fields planted to doublecrop corn were bottom fields. Keith is reluctant to plant doublecrop corn on hill fields because of the limited moisture-holding capacity of the upland soils.
Wheat wasn't emphasized in the Thompsons' cropping program prior to their switch to no-till. It just didn't pay in eastern Kansas, where moisture made more intense water-use crops - corn and soybeans - more profitable. Now, as they move to intensify and diversify their rotations, it has a fit. Combined with corn, it also leaves more residue. Before doublecropping corn, they had doublecropped soybeans, grain sorghum and sunflowers after wheat.
"Corn and grain sorghum are more profitable, but probably more risky," Keith says.
"Lack of weeds in our doublecrop corn surprises a lot of people," says Doug Thompson. He applies a quart of Roundup and a half-pint of 2,4-D to burn down existing weeds, then the crop emerges and canopies quickly, keeping weeds in check.
"Given the number of growing-degree units in July, the corn jumps from 6" to shoulder high before you know it," he says.
The Thompsons expect to inject even more diversity into their no-till program in the future. More and different crops, perhaps canola or even cover crops, will find a place. Their current rotation is wheat and a doublecrop, corn, corn, soybeans, soybeans and back to wheat. Their full-season corn averages 115 bu/acre. They've found that as they've improved their rotations, weed pressures have gone down greatly.