PNW CONSERVATION TILLAGE HANDBOOK SERIES
Chapter 2 - Systems and Equipment, No. 1, June-July 1985

Placement of fertilizer near the seed row below the seed depth is an important part of successful cereal production under conservation tillage in the Pacific Northwest. This has been demonstrated by many STEEP researchers and innovative growers as well as private industry throughout much of the region.

STEEP researcher Dale Wilkins, a USDA-ARS agricultural engineer, and other researchers at the Columbia Plateau Conservation Research Center near Pendleton, OR, have been experimenting with deep furrow grain drill openers modified for banding fertilizer below the seed. Some variations of the openers have proven quite successful over the past few years and are now marketed commercially in eastern Washington and eastern Oregon.

Because of the increased length of the opener which is necessary for banding fertilizer 2 inches below the seed, a larger volume of soil was disturbed and deeper furrows were formed, however. This resulted in a higher soil erosion potential on steep slopes in some cases and a higher power requirement to pull the drill.


In 1984, Wilkins and other researchers began working on a new, narrower opener that creates less soil disturbance and reduces the power requirements. Fig. 1 shows how the new knife point for hoe-type openers is designed to place liquid fertilizer 2 inches below the seed. The point is mounted on a John Deere HZ deep furrow opener shank. The slot-forming knife, sharpened on the leading edge, cuts a slot approximately 0.25-inch wide and 3.5 inches deep. Above the knife point, the opener is 1.25 inches wide. This helps move dry surface soil away from the seed row.

Field tests with the opener last fall were encouraging. However, soils with high water contents slightly reduced the seed-fertilizer separation. This was because the opener depends on the soil "flowing" back over the fertilizer before the seed is dropped into the furrow. Soil flow is reduced with increasing soil water content. Depth of furrows created by the new knife point was 2.5 inches compared to 4.5-inch furrows for the earlier versions of

Openers, which were approximately 1.25 inches wide. Wilkins feels that the shallower furrows are more acceptable for seeding on steep slopes and the smoother surface would allow grain harvesting at higher speeds.

Other STEEP researchers are also experimenting with narrow hoe-type drill openers. Gary Hyde and John Simpson, Washington State University agricultural engineers at Pullman, are evaluating a parabolic (carved) knife opener. This opener also places fertilizer 2 inches below the seed. The parabolic knife opener, pictured in Fig. 2, is ~-inch wide except for the %-inch wear-point on the bottom. This experimental opener is capable of placing gaseous anhydrous ammonia, liquid fertilizer, dry fertilizer and seed.
The knife opener has reduced the amount of soil disturbance and power requirements under no-till seeding compared to the wider John Deere HZ openers modified for deep fertilizer banding. The curvature of the knife also helps to clear residue better than the straighter HZ opener, enabling the drill to seed through higher residue levels without plugging. In 1984 no-till winter wheat and spring wheat trials near St. John, WA, no statistical differences in yield were noted between plantings with the knife opener and the double disk seed openers. In both cases ,parabolic knife was used for banding the fertilizer 2 inches below the seed. Washington State University Cooperative Extension Bulletin 1318, No-Tillage Drill Design, reviews some of the WSU research on modifying seed and fertilizer openers over the past few years.
At the University of Idaho in Moscow, agricultural engineers Charles Peterson and Ed Dowding recently developed anew narrow opener for deep banding of fertilizer on their one-pass "Chisel-Planter." Two-inch wide chisel points were previously used on the Chisel-Planter. However, these formed large ridges and furrows that occasionally reduced stands because of nonuniform seeding depths with the trailing double disk seed openers. Seed rows on the ridges tended to be planted too deeply, reducing emergence. Seed rows in the bottom of the furrows sustained rodent damage over the winter in some years.

In 1984, they removed the chisel points and twisted the chisel shanks at a right angle," using the %-inch shank as the fertilizer opener. Fig. 3 shows the shank modification. Commercial knife points %-inch wide have since been added to the shank tips to improve wear and ease of soil penetration. The narrow shank opener significantly reduced the amount of soil disturbance and the power requirement. Extensive Chisel-Planter winter wheat trials
seeded last fall with the narrow shank opener look very promising. A side view of the Chisel-Planter with the new shank openers is shown in Fig. 4. University of Idaho Cooperative Extension Service Current Information Series 476, The Chisel-Planter: A Minimum Tillage System for Winter Wheat, briefly describes the development and design of the Chisel-Planter.

Contact us: Hans Kok, (208)885-5971 | Accessibility | Copyright | Policies | WebStats | STEEP Acknowledgement
Hans Kok, WSU/UI Extension Conservation Tillage Specialist, UI Ag Science 231, PO Box 442339, Moscow, ID 83844 USA Redesigned by Leila Styer, CAHE Computer Resource Unit; Maintained by Debbie Marsh, Dept. of Crop & Soil Sciences, WSU