A Strip-till Planting System for No-till Fallow

Chapter 2 – Systems and Equipment, No. 3, Fall 1988

Don Wysocki

No-till chemical fallow can provide better protection against water and wind erosion than traditional summer fallow. However, several problems are associated with chemical fallow systems. Among these problems are: increased difficulty with fertilizer application and seeding, plugging of equipment, delayed seedling emergence and uneven stands. These problems are addressed in the design of several no-till grain drills. Some of these drills use large heavy coulters, while others use shanks or chisels to open untilled soil for placement of seed and fertilizer, One method of no-till planting that is being researched by Floyd Bolton of the Crop Science Department, Oregon State University, is the rotary strip-till planter.

The strip-till system combines seedbed preparation, fertilizer and herbicide application, and seed placement into one field operation. The seedbed is prepared by roto-tilling strips 4 inches wide and spaced 16 inches apart. Depth of tillage can be varied to a maximum of 7 inches depending upon the depth to moist soil. A representation of the strip tillage system is shown in Fig. 1. According to Bolton the system provides effective erosion control because only 25 percent of the surface is disturbed and the residue between the rows remains intact. Also the tilled seed rows help to collect and infiltrate surface runoff.

Bolton’s strip-till planter has been in development since1977. After each planting season, its operation was evaluated. Adjustments and modifications were then made to improve its performance. The current version, which has performed well for the past 2 years, is being considered for production by a commercial manufacturer. The present unit consists of a heavy duty tiller modified to achieve the desired row spacing and area of tillage. Double disk openers are mounted on a tool baron the rear of the unit. Seed is distributed from a standard drill box by a hydraulic motor. A spray boom attached to the ti-ont of the planter applies liquid fertilizer-herbicide materials. Each double disk also has tubes for application of liquid starter fertilizer or water into the seed zone. The experimental unit was constructed 8 feet wide for ease of transport. However, the manufacturer is proposing widths up to 20 feet.

Bolton has evaluated the performance of the strip-till planter from several aspects. Data in Table 1 area comparison of performance of the unit under different levels of surface residue. The strip till planter performed equally well under these different conditions which demonstrates that it can operate successfully in heavy crop residues. Bolton points out that the difference of 10 bushels under the highest level of residue was not statistically different from the other yields, He attributes the difference to lack of nitrogen because all plantings received the same rate of fertilizer nitrogen. Bolton compared the strip-till method of fertilizer application (liquid between the rows) to broadcasting before seeding (Table 2). Spraying liquid fertilizer between the rows was equivalent to broadcasting. However, using liquid fertilizer allows simultaneous application of herbicide solutions, thus saving extra application costs. Bolton has further evaluated the system in regard to herbicide rates, Cercosporella foot rot and water injection.

The strip-till system has produced grain yields of winter wheat equal to other systems over the past 6 years. A comparison is shown in Table 3. All systems were in a wheat-fallow rotation. The strip-till system was chemical fallowed; the others were conventionally fallowed. All systems received equal rates of nitrogen and seed. Bolton explains the slightly lower yield observed in the stubble mulch system was probably caused by grassy weeds. The conventional and strip-till systems were observed to have fewer grassy weeds during crop growth than the stubble mulched system.

Table 1. Seedling emergence and grain yield of strip-till plantings under different levels of surface residue, Moro, OR (Bolton, OSU).

Table 2. Response of strip-till plantings to different methods of nitrogen fertilizer application, Moro, OR (Bolton, OSU).