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INTRODUCTION

The term "opener" is a generic term used to describe a soil-engaging device, which places seed and/or fertilizer in the soil as part of the seeding or planting operation. Furrow openers are the business end of a larger machine such as a press drill or air seeder. Rogers and Dubetz (1960) in discussing openers said "The function of a seed drill furrow opener assembly is to place seed in the soil at a regulated depth in relation to either moisture or soil surface, and also to manipulate the soil in such a manner as to obtain maximum emergence."

The terms "regulated depth" and "maximum emergence" suggests the concept of opener performance and are usually part of such an assessment. Various other agronomic factors such as rate of emergence, dumber of tillers, number of heads seed size (1000 kernel weight) and other are often considered. These may be useful in following the morphological development of the crop but are usually integrated in the final yield, the factor most producers are interested in. However, one must be careful in using yield as the sole criteria of opener assessment since it is influenced by other factors such as seed rate and row spacing (J. Bauder, 1990).

Another important component of seeding equipment is the press wheel or packing mechanism. Huntgreen et al., (1990) noted the effect of packing pressure on plant emergence, a very important part of crop growth. It may also be a significant factor in determining yield (Djokoto et al., 1961).

This paper summarizes the results of zero-till drill assessments conducted at the Swift Current Research Station and results done by other agencies which were funded by Agriculture Canada and Energy mines and Resources programs administered through the Research Station. The tests were done on various commercial and prototype seed drills having given opener, packer wheel and row spacing featured by that particular machine. The data presented summarizes research which focused on seed placement only and data which focuses on seed and fertilizer placement.

In addition some discussion of future research on this topic is heading at the Swift Current Research Station.

EXPERIMENTS CONDUCTED

Field tests were laid out in the traditional randomized plot design with multiple replicates. Recommended rates of seed and fertilizer were applied and held constant for all treatments in a given test. The seeding equipment and some feature or combination of features are the main controlled variables and will be listed for each experiment. Performance factors such as plant counts, seeding depth and grain yield were measured.

Experiment 1:

The Swift Current zero-till drill test (1982-85) assessed the following machines:

1. The Haybuster 1206 double disc drill with 6-inch row spacing.

2. The SCOT (Swift Current zero-till offset disc) disc drill with 7-inch row spacing and 1 3/4 x 26 inch steel packer wheels (Dyck 1980, 1982; Dyck andTessier, 1986).

3. The Versatile Noble 2000 zero-till hoe drill with 8-inch row spacing.

4. The Versatile Noble 2000 zero-till disc drill with 8-inch row spacing. Fertilizer was broadcast prior to seeding. Results are presented in Table 1.

Experiment II:

A similar zero-till drill test 1986-88 assessed the following drills:

1. Airseeder knife - a 16-foot Morris chisel plow equipped with Dutch fertilizer banding knifes, a Beline two compartment granular applicator modified to handle seed and fertilizer, and rear mounted gangs of Conservapak poly packers. Row spacing is 12 inches.
2. SCOT disc as defined in experiment I.
3. Noble hoe as defined in experiment I.
4. SCOT hoe - a prototype zero-till hoe drill featuring a narrow opener using the Thompson slim line knife. Soil disturbance is approximately mid-way between the SCOT disc and the Noble hoe. It has 7-inch row spacing and 13/4 x 26 steel packer wheels the same as the SCOT disc drill.

Experiment III:

Equipment for the zero-till seeding of winter wheat. The same equipment was used as in experiment II. Fertilizer was broadcast. Results are presented in Table 4.

Experiment IV:

Results of two separate tests conducted it Saskatoon (Foster, 1988) using the Haybuster 1206 and the Versatile Noble 2200 zero-till hoe drill are presented in Tables 5 and 6.

Experiment V:

The Prairie Agricultural Machinery Testing Institute at Portage, Manitoba evaluated three zero-till drills under contract (May et al., 1987). The machines were:

1. The Amazone VNT 375 hoe drill.
2. The Lilliston 9680 end wheel double disc drill with a leading coulter.
3. The SCOT disc drill.

The results are presented in Tables 7 and 8.

Experiment VI:

Fertilizer placement study for zero-till seeding. The following treatments were evaluated:

1. Fertilizer placed by deep banding at five inches deep prior to seeding with a 3-point hitch machine equipped with narrow banding knives at 12-inch spacing. The seeding was then done with a Versatile Noble 2000 zero-till hoe drill.
2. The same as in one except the seeding is done with the Versatile Noble 2000disc drill.
3. Seed and fertilizer placed in the same operation with a Versatile Noble 2000 zero-till hoe drill equipped with side banding boots. All the fertilizer is placed one-inch below the split seed row (approximately a two-inch split).
4. Seed and fertilizer placed in the same operation with a Versatile Noble 2000 series hoe drill equipped with a prototype three disc side banding opener (patterned after the design described by Dyck 1982, 1986). The fertilizer is placed about one inch below and 3/4 inch to the side of the seed.
5. All seed and fertilizer placed together through the main opener boot of the Versatile Noble 2000 zero-till hoe drill.
6. All seed and fertilizer placed together through the main opener boot of the Versatile Noble 2000 zero-till disc drill.

Experiment VII:

Evaluation of zero and minimum tillage seeding equipment for seed and fertilizer placement.

After Experiment VI was completed it was decided to run another fertilizer placement study using urea fertilizer (46-0-0) as the main source of N for the following reasons:

1. It was suggested ammonium nitrate would be discontinued or hard to get.
2. Urea was a more economical source of N
3. No testing had been done with mid-row banding.
4. The Conservapak (now the Valcon) side-banding air seeder appeared on the market, claiming substantial yield increases.
5. A broadcast treatment had not been included in the previous test.

The following equipment was tested:

1. The SCOT disc drill with various combinations of seed placed and mid-row banded fertilizer. Treatments 1-5 of Table 10.
2. The Versatile Noble 2000 zero-till hoe drill with the side banding boot. Treatments 6 and 7 of Table 10.
3. The Conservapak airseeder which sidebands the fertilizer one inch below and one inch to the side of the seed. This was a plot size unit with nine rows at nine-inch spacing equipped with standard Conservapak opener and packerwheel assemblies and additional packers at the rear to retain furrow geometry. It was equipped with a Beline granular air applicator modified to meter seed and fertilizer. Treatments 8 and 9 of Table 10.
4. The Conservapak airseeder equipped with a knock on sweeps. It now places the fertilizer with the seed and functions similar to a conventional minimum till air seeder. Treatment 10 of Table 10.
5. A Cereal Implements discer followed by coil packers. The fertilizer is placed with the seed. Treatment 11 of Table 10.

OBSERVATIONS AND CONCLUSIONS

A careful study of the data in Tables I through 12 suggest the following:

1. Under conditions of moisture stress openers and operations exhibiting minimum soil disturbance (such as the Haybuster 1206 disc, the Scot disc and hoe and seed placed fertilizer) result in better yields. Note years 82-83 Table 1, years 87-88 Table 2, Table 3, Table 4 stubble and continuous W.W., bottom of Table 9, 1984-85 dry years. It is believed that the yield differences are due to greater moisture loss as a result of greater soil disturbance exhibited by the hoe opener (Experiments I and 11) and the banding operations in Experiment VI. Converting the yield difference to equivalent water (Table 3) required to )reduce this yield difference amounts to one inch of water in the worst case. A significant amount if this hypothesis is valid.
2. Under conditions of lesser moisture stress these differences are not evident. DO NOT expect significant yield difference between machines unless significant functional problems exist, such as very poor residue clearance, inadequate penetration, severe hair pinning of residue and poor seed placement, etc.
3. When moderate amounts of N are required all fertilizer may be seed placed particularly if ammonium nitrate is used.
4. Side banding and mid-row banding are feasible and practical ways of placing all fertilizer requirements at the time of seeding.
5. Broadcasting all fertilizer requirements as compared to banding may result in yield losses (Table 11) in a zero-till environment. However, seed placing P and partial N requirements aid broadcasting the remainder may be a viable option, particularly when total cost is considered. (Campbell et al. 1991).

FUTURE RESEARCH

While useful, the summary of the research just given of field scale, replicated plot testing of particular equipment leaves many questions unanswered. For example, is the yield variation cited between SCOT disc and the Noble hoe really due to moisture loss as suggested? If so, was it due to the greater soil disturbance of the hoe opener, or was it due to excessive packing of wide steel V-shaped press wheel? The resulting compaction levels over a larger surface area may continue to conduct soil moisture to the soil surface where it is evaporated throughout the growing season. Or, was it simply due to the difference in row spacing? The latter seems unlikely - the wider row spacing should favor the Noble hoe in a dry year. Effort to measure the loss of moisture throughout the growing season by intensive gravimetric sampling or by use of moisture flux transducers have not been successful. At the end of the growing season both plots were dry to four feet but the yield difference was still there. How can one track the moisture loss? Perhaps a field scale lysimeter is the answer but is it practical?

To try to provide answers to some of the questions cited we are shifting our research endeavors to look at opener and packer wheel performance on a more controlled basis and on a micro scale. A self-propelled tool bar (Fig. 1) is being developed, on which we can readily change the furrow openers and packer wheels (and pressures) to determine which combination performs best in terms of emergence and plant establishment. Complimentary instrumentation has been developed by Tessier et al., (1990) (Fig. 2) to characterize furrow opener and packer wheels in terms of soil disturbance and compaction levels. These can be related to the emergence data and hopefully one can optimize parameters which will give the best performance. One can also measure vertical and draft forces and achieve some optimum solution in that area.

Some experimental work, using this approach, and a simple 3-point hitch tool has been done at Swift Current. The results for two opener and packer wheel combinations are shown in Figures 3, 4 and 5. the results are encouraging and we intend to pursue this approach.

Does one need to do yield testing? We believe so. The tool bar can be equipped with a full set of a given type of opener and packer wheels to seed yield plots. All other variables such as row spacing, seed metering mechanism, fertilizer rates, etc., can be held constant and perhaps more definitive data and therefore a better assessment of particular opener and packer combinations can be achieved. This information will be useful to designers and manufactures of seeding equipment and to producers as a guide in equipment purchasing.

Table 1. Swift Current Zero-till Drill Test 1982 - 1985

Means with the same letter are not significantly different (5% significance level)

* For these two years the S.C. offset disc drill was a modified John Deer LTB drill with the offset disc opener (Dyck 1980, 1982). For the 1984 and onward the S.C. drill is the new prototype (Dyck and Tessier 1986)

Table 2. Swift Current Zero-till Drill Test 1986-1988

Means with the same letter are not significantly different (5% significance level)

Table 3. Effect of 0-Till drill design on establishment, yield and moisture use for continuous spring wheat at Swift Current, Sask.

* Plant Density - plants/sq. meter Grain Yield - bu/ac

** Moisture Use difference for the yield difference between drills as determined by a yield equation (Campbell et al., 1988).

Means with the same letter are not significantly different 0.05 level of probability (Duncan's New Multiple range test).

Table 4. Main effects of seed drills on the establishment and grain yield of Winter wheat (cv Norstar) in southwestern Saskatchewan (1985-86 to 1987-88)

Means with the same letter are not significantly different (5% significance level)

Table 6. Effects of seeding implements on hard red spring wheat, seeded on stubble at Saskatoon, Sask. (1985-1988) (Foster 1988 Research Report)

* Direct seeded with no pre-seeding tillage for all years.

Table 7. Seed drill performance for hard red spring wheat at Portage la Prairie, Manitoba (May et al., 1987)

Means with the same letter are not significantly different (5% significance level).

Table 8. seed drill performance for direct seeded Nortstar winter wheat, Portage la Prairie, Manitoba. (et al. 1987)

Means with the same letter are not significantly different (5% significance level).

Table 9. Zero-Till Ammonium Nitrate Fertilizer Placement Test 1983-1987 at Swift Current.

Means with the same letter are not significantly different (5% significance level).

Table 10. Effects of seed and fertilizer placement on establishment and yield of spring wheat at Swift Current, Sask.

*Plant density - plants/sq. meter Grain yield - bu/ac.

**Rates shown are actual nutrient values, products are urea (46-0-0) and MAP (11-51-0).

Means with the same letter are not significantly different 0.05 level of probability (Duncan's New Multiple range test).

Table 11. Effects of fertilizer placement on spring wheat yields (bu/ac) at Swift Current Sask.

Means with the same letter are not significantly different 0.05 level of probability (Duncan's New Multiple range test)

*Broadcast at the time of seeding with the SCOT drill.

**All of the SSCOT mid-row banding, the VN side banding and the CP side banding treatments are averaged.

Table 12. Growing season rainfall (mm)

REFERENCES

Campbell, C.A., Zentner, R.P., Selles, F., McConkey, B.G. and Dyck, F.B., 1992. Nitrogen management for spring wheat grown annually on zero- tillage yields and N use efficiency. Agron. J. (Submitted).

Campbell, C.A., Zentner, R.P., McConkey, B.G. and Selles, F. 1992. Effect of nitrogen management on moisture use by spring wheat grown annually on zero-tillage. Can. J. Soil Sci. (Submitted).

Djokoto, I.K., Bigsby, F.W. and Lal, R., 1961. Soil compaction by agricultural land packers and models. Can. Soc. Agric. Eng. 13:46-50.

Dyck, F.B. 1980. Design considerations for zero-till drills. Proc. Zero Tillage Symposium, Bismarck, N.D., Sept. 9-11, 1980.

Dyck, F.B. 1982. Zero-till seeding equipment for research. Paper No. 82- 310. CSAE-AIC Annual Meeting, Vancouver, BC, July 11-15, 1982.

Dyck, F.B. and Tessier, S. 1986. Zero-till drill developments at the Swift Current Research Station. Paper No. 86-210, Annual Meeting, Can. Soc. Agric. Eng., July 6-10, 1986, Saskatoon, Sask.

Dyck, F.B. 1986. Fertilizer placement equipment developed at the Swift Current Research Station 1966-1986. Paper No. 86-211, Annual Meeting, Can. Soc. Agric. Eng., July 6-10, 1986, Saskatoon, Sask.

Foster, R.K. 1988. Tillage systems and related agronomy research. In: Research 88, A Report of the Crop Development Centre of Crop Science and Plant Ecology. Univ. of Sask., Saskatoon. S7N OWO.

Foster, R.K. 1988. Energy conserving practices. Final Report Contract No. 01916-2-EC25. Agr. Canada Res. Sta., Swift Current, Sask., Canada.

Huntgreen, G., Kushwaka, L., Foster, K., and Fowler, B. 1990. Designing a suitable packer for air seeders. In: Air Seeding 90, Proc. of an international Symposium on Pneumatic Seeding for Soil Conservation Systems in Dryland Areas. F.A. Holm, B.A. Hobin and W.B. Reed (Editors). Extension Div., Univ. of Sask., Saskatoon, Sask. S7N OWO. ISBNO-88880-243-9.

May, D.J., Ominichinshi, G.M., Inerson, A.T., Stobbe, E.H. 1987. A study of no-till/minimum till drill performance data for farm management decisions. Final Report AERD Contract No. 0186.01706-4-ME35 Agriculture Canada, Research Branch, Lethbridge, Alta. Canada.

Rogers, R.B., and Dubetz, S. 1980. Effect of soil-seed contract on seed imbibition, Can. Agric. Eng. 2:89-92.

Tessier, S., Saxton, K.E., Papendick, R.I., and Hyde, G.M. 1988. Measurement of the physical properties of the soil-seed environment. CSAE Paper No. 88-215 presented to CSAE. 1988 Annual Meeting, Aug. 1988, Calgary, Alberta.

Tessier, S., Saxton, K.E., Hyde, G.M. and Papendick, R.I. 1990. Seed row compaction and crust meter. Transactions of the ASAE (Vol. 33, No. 1, pp. 91-94, 1990).

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