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2005 Annual Report: Tillage Systems in Soybeans

Objective

The objective of this demonstration is to evaluate the effect of different tillage systems on soybean yields and profitability. This is the 5th year for this demonstration.

Methods and Materials

The four most common tillage systems practiced in this region were used for this demonstration. The tillage systems used were: Fall Chisel and Spring Disk, No-till, Spring Disk, and Fall and Spring Disk.

Each plot consisted of eight rows spaced 30 inches apart and 250 feet long. Yield results were taken from the center six rows of each plot. The plots were planted on May 20, 2005 with a population of 188,500 seeds/acre into a field that was planted in corn in 2004. Harvest was conducted on October 27, 2005.

Results

In 2005, the highest yielding system was the No-till plots with a yield of 64.6 bu/ac. The lowest yielding system was the Fall and Spring Disk plot which yielded 50.9 bu/ac. The average for the four systems was 60.7 bu/ ac with a standard deviation of 6.6 bu/ac. Yield results for all four tillage systems are shown in Table 1 and Figure 1.

Soybean Tillage SystemHarvest Moisture %Yield at 13.0%
Moisture bu/acre
Fall Chisel and Spring Disk12.164.5
No-Till12.164.6
Spring Disk12.162.8
Fall & Spring Disk12.150.9
   
Trial Averages12.160.7
Standard Deviation 6.6

Table 1 - Soybean tillage systems yield results.

If you compare the data obtained over the five years of the study, the No-till treatment has had the highest average yield for any of the tillage methods with an average of 53.8 bu/acre per year. The Fall and Spring Disk treatment had the lowest average yield for any of the treatments with an average of 51.1 bu/ac per year. These averages are shown in Figure 2.

Fig 1 - 2005 Soybean tillage systems yield
Fig 1 - 2005 Soybean tillage systems yield

With five years of data, you can see a trend developing in the yields for each tillage method. This longer term collection of data allows the weather variable to be minimized since we had varying weather patterns during this time period.

The economic analysis follows the trend we have seen in the corn tillage demonstrations. The application of the fertilizer, herbicides, seed, planting and harvesting were identical for each of the tillage methods used. The economic difference is a result of the tillage procedures conducted on each plot and the associated costs.

It is very difficult to estimate tillage costs as producersís operating costs will be different. Age and size of the equipment, field shape and size, and soil type will all effect the tillage costs. A large variable this past season was fuel costs. We estimated an average cost but most will agree it is below average.

Soybean Tillage System5 Year Yield
Ave bu/acre
Gross Income
@ $5.50/bu
Tillage Costs per AcreGross Income
less Tillage
Fall Chisel/Spring Disk52.7$289.93$19.69$270.24
No-Till53.8$296.16$0.00$296.16
Spring Disk52.4$287.99$8.32$279.67
Fall and Spring Disk51.1$281.12$16.64$264.48

Table 2. Gross income per acre minus tillage costs over a 5 year period.

Figure 2 - Soybean tillage 5 year yield averages
Figure 2 - Soybean tillage 5 year yield averages

One factor not considered in the economic analysis is labor. It is almost impossible to place a value on a producerís labor per hour. Therefore, no labor costs are included in the analysis.

Table 2 provides a summary of the gross income per acre minus the costs for the tillage work that was conducted. For the five years of this study, the No-till plots grossed between $16.49 and $31.68 per acre more than the other tillage systems assuming a price of $5.50 per bushel for soybeans.

Another important factor that is sometimes not considered is the benefit to the environment of different tillage practices. Notill programs greatly reduce the amount of soil erosion caused by wind and water runoff. Soil particles are the number one contaminant found in the rivers and streams of Northwest Missouri. These particles not only cloud the water but they also may have other pollutants (herbicides, insecticides, fertilizer) adhered to them which may contaminate the water.