Cultivator Design for Interrow Weed Control in No-Till Corn

Abstract

More than 95% of Iowa row crop acres are treated with herbicides. Such extensive use is an environmental concern. Banding of herbicides over the crop row, along with mechanical cultivation to control interrow weeds, has been proposed as a way to reduce herbicide use. Though cultivation is used on 74% of Iowa corn (Zea mays L.) land, herbicides are applied in a band on only 17% of the corn acres. This indicates that cultivation is not relied upon for interrow weed control. The risk that weather conditions will hinder completion of mechanical cultivation seems to discourage the use of herbicide banding. Higher speed cultivation could improve the odds of timely completion of needed cultivation. An experiment was conducted on a Clarion loam soil near Boone, Iowa in 1993 through 1996 to determine the effect of cultivator design and speed, when combined with the banding of chemicals, to control weeds. Three cultivator styles, two bands [19 cm (7.5 in.) and 38 cm (15 in.)], and two speeds were tested. A single cultivation management strategy was used. Data were taken in a no-till continuous corn rotation on 76-cm (30-in.) row spacings. Faster speed did not impede weed control or yield. In two years, the corn yield was greater and weed cover was reduced in plots cultivated at 11.2 km/h (7.0 mph) than in plots cultivated at 6.4 km/h (4.0 mph). Weed populations were greater in the 19-cm (7.5-in.) band than in the 38-cm (15-in.) band three of four years. In three of four years, leaf heights and yields were also significantly less for herbicide applied in a 19-cm (7.5-in.) band than in a 38-cm (15-in.) band. There was no difference between yield in a broadcast treatment and treatments which used a wide band of herbicide and a cultivator with disc hillers. In two years, the sweep and smith fin (a vee-shaped flat sweep with low rake angle) cultivator treatments resulted in less weed cover than the point-and-share treatment. In one year, the sweep and smith fin cultivator treatments had greater yield than the point-and-share treatment. Groundcover among cultivators showed few differences.

Integrating Mechanical and Reduced Chemical Weed Control in Conservation Tillage Corn

“…The best overall weed control, however, was typically achieved with the herbicide‐intensive treatments (Treatments 1–4) with more than a 98% reduction in weed biomass compared to the weedy check treatments. These results agree with previous research showing that the high residue cultivator (with and without other mechanical weed control operations) is not consistently equivalent to herbicide‐intensive systems (Eadie et al, 1992; Buhler et al, 1994, 1995; Paarlberg et al, 1998; Hanna et al, 2000) and will likely need to be supplemented with additional management tactics.…”

“…Other research reported reductions up to 14% in corn population from the rotary hoe in tilled systems (Mulder and Doll, 1993; Vangessel et al, 1995; Cox et al, 1999; Mohler et al, 1997). Inter‐row cultivation using a Danish S‐tine style in conventional tillage systems (Cox et al, 1999; Mulder and Doll, 1993) or a shielded high residue cultivator in reduced tillage systems (Paarlberg et al, 1998) were reported to not produce a measureable reduction in corn populations compared to no‐till systems. Minimizing crop damage from inter‐row cultivation can be achieved by coupling an experienced operator with cultivation aids such as shield and/or automatic guidance systems.…”

“…Minimizing crop damage from inter‐row cultivation can be achieved by coupling an experienced operator with cultivation aids such as shield and/or automatic guidance systems. Automatic guidance systems also facilitate faster operating speeds, which will reduce operation costs associated with cultivation (Paarlberg et al, 1998; Hanna et al, 2000), but may increase soil movement that could result in crop injury.…”

“…(Hooker et al, 1997) and modest weed control performance in no‐till wheat ( Triticum aestivum L.) (Gallagher et al, 2010). High residue inter‐row cultivators are also commercially available, which are modified versions of a standard inter‐row cultivator designed to handle high residue and no‐till conditions (Springman et al, 1989; Bowman, 1997; Paarlberg et al, 1998; Hanna et al, 2000). Previous studies have reported that high residue cultivation alone did not typically provide adequate weed control, but the addition of banded residual herbicides over the crop row provided much needed in‐row weed control in these systems (Eadie et al, 1992; Buhler et al, 1994, 1995).…”

Adjustment of Weed Hoeing to Narrowly Spaced Cereals

“…Melander et al [4] reported that hoeing with goosefoot sweeps at different driving speeds had no significant effect on winter wheat yields in 240 mm wide row spacing. Paarlberg et al [25] investigated different cultivation systems in maize, including mechanical weeding. The authors concluded that the hoeing blade style had less distinct effects on yield.…”