Vernon Hofman, Extension Agricultural Engineer, NDSU

INTRODUCTION

Establishing a good small grain stand is the basic requirement of a seeding system. The selection of seeding machinery that will perform adequately in each farmer's particular condition is of prime concern. The selection of a seeder requires a knowledge of field conditions, how a machine will perform under those field conditions and an understanding of crucial seeding requirements.

A producer should look at the seeding operation as the most important field operation. If the seed isn't placed at the proper depth and into moisture, crop emergence may be delayed which will probably result in reduced yield. Directing more attention to or purchasing a better seeding implement may be more important or as important as having good harvest equipment. If seed isn't placed properly, a lower yield will probably result which will produce fewer bushels to harvest.

PRESEEDING TILLAGE

North Dakota farmers have traditionally used preseeding tillage in the spring to obtain a uniform seedbed and weed control. In addition, extra tillage operations may be done in the spring or fall to incorporate herbicides and/or reduce crop residues.

During the eighties, concerns about soil conservation and the cost of fall and preseeding tillage brought into question these practices. At the same time improved seeding equipment and the availability of new herbicides opened up the possibility for good seeding practices with reduced tillage.

For a lot of farmers in North Dakota, the double disc press drill is the standard seeding implement. Standard double disc press drills will not penetrate hard soils or cut through moderate or heavy trash conditions. As a result preseeding tillage is required to allow proper seed to soil contact in a firm seedbed. Other reasons for preseeding tillage include: weed control, warming up cold soils, drying wet soils and incorporating preemergent chemicals.

Spring tillage should be done only to depths no greater than seeding depth. The firm soil will help limit the operating depth of double disc press drills. Many times tillage is done to 3 to 5 inches deep which loosens the soil causing it to dry out to the tillage depth. Placing small grain seed below 2 1/2 to 3 inches tends to reduce or slow emergence. If emergence is slowed, part of the growing season is lost. For best emergence, small grain should be planted 1 to 1 1/2 inches deep and into moisture.

Double disc press drills do not maintain a uniform seeding depth as the disc openers do not contain any method to limit operating depth. Press springs push the openers into the soil and when operating in a loose soil, the discs may sink into the hub. Operating at this depth can place seed 4 to 5 inches deep. Faster travel speeds may cause excessive variation in operating depth. When discs hit clods or firm soil, the discs may almost bounce out of the soil and in soft soil sink in too deep. Some means of depth control is needed. Double disc press drills can be equipped with depth bands but this often creates problems with mud, rocks and residue. Other methods of depth control besides slower speeds and shallow spring tillage are not available. As drills wear out, producers should purchase seeders that have positive depth control. Many new types of seeders are available that have much better depth control than double disc press drills.

The development of new seeding technology during the past 10-15 years reduced the need for preseeding tillage leaving weed control, soil warming and chemical incorporation as the major reasons for tillage. Preseeding tillage does provide weed control, however the soil disturbance caused by the operation also stimulates the germination of some weed species and dries out the seedbed to the working depth. Cold soils are usually only a problem in heavy textured soils. If soils are slow to warm in the spring, tillage for residue reduction should probably be done in the fall. Only enough fall tillage should be done so enough residue remains on the soil surface to control erosion. Then, the next spring, a shallow tillage and seeding operation can be done. An alternative is the use of a direct seeding drill such as an air seeder or other unit that does tillage and seeding. Weed control may best be done with a burn down herbicide prior to seeding or with post emergent herbicides.

SEEDING EQUIPMENT REQUIREMENTS

Small grain seeding equipment has made dramatic improvements in seed placement and depth control. They have been designed to seed into firm, moist soils with a residue cover. Some drills will operate in more residue than others and producers should look at this closely before purchasing a seeding unit. Some seeders have little residue clearance while others have considerable front-to-back, side-to-side and vertical clearance. Extra clearance will stretch out units which will place load carrying wheels farther apart reducing depth control accuracy. Seeders with gage wheels next to the opener should have the best depth control. Wheels placed directly behind the opener should also gage depth well but may not be quite as responsive and press wheels are necessary to firm soil around the seed.

The following is a list of features a producer should consider when purchasing a drill:

1. Good depth control to provide proper seed placement.

2. Good seed to moist soil contact.

3. The ability to cut through and clear residue.

4. Even penetration in firm soil.

5. Adequate packing.

6. Rock protection.

7. Accurate metering system for seed and fertilizer.

8. Ability to seed a wide range of crops.

9. Ease of transport

10. Draft of implement and horsepower required.

11. Rugged construction with a minimum of complexity.

12. Cost effective.

13. Ease of maintenance.

FERTILIZER AND PLACEMENT

Soil nutrient deficiencies need to be corrected to achieve maximum economic yields. Nitrogen typically becomes depleted in all continuous cropping systems including direct seeding. There are many types of nitrogen fertilizer and methods of application. Anhydrous ammonia, liquid and granular nitrogen (ammonium nitrate and urea) are the common nitrogen sources. Application methods include fall or spring banding, side banding, seed placed mid-row banding, below seed row banding, fall or spring broadcasting and postemergence broadcasting, dribbling or spraying. The choice of nitrogen source will depend on the application method and timing, local availability, cost, farmer preference and type of seeding equipment.

Side banding, seed placing, mid-row and below row banding are all "one pass" systems which generally result in efficient nitrogen use. One of the major drawbacks of these application methods is the fact that all fertilizer requirements are handled at the time of seeding. Some farmers find this cumbersome, particularly if high nitrogen application rates are required. One other concern with side banding, mid-row banding and below row banding is high power requirements. As the fertilizer is placed below the seeding depth more power is required to seed and place the fertilizer at the lower depth than would be required if seeding only.

CONCLUSION

There is no simple answer to the question of what is the best minimum seeder as no single implement will probably meet the needs of all farmers. Most seeders will do the job under the right circumstances so it is important to do a complete evaluation of both the requirements of the farm and of the design of the machine. The investment in seeding equipment is high and the producer cannot afford to make a purchase and trade it off in two years time because it doesnÃt do the job. Purchase decisions should only be made after careful thought, studying PAMI reports, discussions with other farmers who have experience with the unit and seeing the unit in operation if possible.