Evaluation of Ridge Tilling with and without Herbicides

Final Report for FNC92-002

Project Type: Farmer/Rancher
Funds awarded in 1992: $3,885.00
Projected End Date: 12/31/1993
Matching Non-Federal Funds: $4,942.00
Region: North Central
State: Iowa
Project Coordinator:
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Project Information


We have a diversified crop and livestock operation of 480 acres which breaks down to 150 acres of corn, 120 acres of soybeans, 80 acres of pasture, 70 acres of hay and 20 acres of oats annually. We have cow-calf operations averaging 65 stock cows and utilize rotational grazing practices. The farm also consists of a farrow-to-finish hog operation of 60 sows producing 1,100 hogs annually as well as a small commercial tree nursery. Ours is a family farm, which includes my wife, Maria, our sons, David-12, Daniel-10, Mark-7, and one employee.

We changed our farming practices in 1983 by drastically lowering our inputs of fertilizer and chemicals and we have continued to do so ever since. In 1987, we decided to use ridge-tillage as a tool to help in weed control without herbicides. This trial grew out of our continuing attempts to improve weed control without, or with, very little herbicides. Our herbicide bill for the past 11 years has been only $6,795 which amounts to an average of less than $2.50/acre on all row crops.

Shawn Shouse, area extension agricultural engineer, directly assisted in the project by helping to conduct weed ratings for each trial. He also provided general observations and trial evaluations. The local Soil Conservation Service office aided in the promotion of the June cultivation field day.

The primary project goal was to see if we could fine tune ridge-tillage in corn without any herbicides and not suffer any significant yield loss or effectiveness of weed control. We wanted to determine whether or not a band of herbicides was worth the economic and environmental cost of using it in terms of yield, weed control, economics and energy use. We hoped to demonstrate through proper management and timing of planting, rotary hoeing and cultivating that herbicide use even in a narrow band was not needed. In addition, we wanted to see the effects of rotary hoeing on yields and weed control.

What We Did and What We Learned From the Project: We established five treatment trial with the two variables of no herbicides and banded herbicides and also used different numbers of rotary hoeing in the five treatments to determine what effect, if any, the hoeing had. These five treatments were randomized and replicated six times and ran the entire length of the field. Each plot consisted of eight rows or one round with the planter. Total plot size was approximately 10 acres. In August, manual weed ratings of every two rows were taken for the entire plot and were averaged. The plots were harvested and weighed in October with statistical analysis used to ascertain any significant yield differences. Economic cost comparisons of all treatments were figured.

The following diagrams describe the various treatments and plot order:

A= 0 rotary hoeing, 2 cultivations, 0 herbicide
B= 1 rotary hoeing, 2 cultivations, “Dual” grass herbicide, (10” band)
C= 1 rotary hoeing, 2 cultivations, “Bladex” herbicide, (14” band)
D= 0 rotary hoeing, 2 cultivations, “Dual” + “Bladex” comb. (14” band)
E= 2 rotary hoeing, 2 cultivations, 0 herbicide

First strip – EADCB
Second strip – ADECB
Third strip – EBADC
Fourth strip – EBACD
Fifth strip – ACBDE
Sixth strip – EBACD

What Results Were Achieved and How Were They Measured?
The results are found on pages 2-6 of the included supplementary sheets and include the following measurements:
1. Data for each strip, (field length, percentage of moisture, test weight and yield).
2. Average plot yields.
3. Weed control ratings.
4. Production costs comparing our costs to those of ISU, both assuming a yield of 155 bu./acre.
5. Our actual production costs of different treatments.

What Were the Results Expected?
With the extreme weather conditions encountered this past growing season, we feel fortunate to get the kinds f yields that we did. Since we were on the ridge-till system, this allowed us to plant sooner than any of our neighbors using a conventional tillage system. The plots were planted 5/13/93, which was a full two days before anyone else could get out. We were able to achieve weed control just as good using no herbicide as compared to the narrow bands.

This tells us two things for the coming growing season. First, it says that with ridge-tilling, timely hoeing and cultivating can produce good weed control without herbicide use, even in an extremely difficult season as was 1993. It also says that perhaps the herbicide leached down too far because of the rain to be of much value. The trial could have been improved if we had another treatment of broadcasting herbicides or a treatment of post-emerge spray to see if the weed control could have been affected. What our project was really doing was fine tuning ridge-tillage with very little, or no herbicide use. We feel we have made more progress in that. In fact, our next goal is to become certified organic on our farm. We feel more confident that we can drop the option of limited herbicides in favor of no herbicide in order to make certified organics work on our farm. Since there were significant yield differences in the treatments, we feel confident that if properly managed, yields will not decrease when converting to certified organic. What we will have to watch is our fertility since we can no longer use liquid 28% N as a nitrogen source.

Because of the extreme wet conditions, we could not take the late spring soil nitrate tests. The amount of nitrogen used was based on past field history and experience with the test over the last six years. We are confident that the amount of nitrogen applied was within the parameters of the test guidelines. We also feel confident that stricter six-year crop rotations and the use of composted hog and cattle manure will meet the bulk of our fertility needs without the need to purchase much additional organic amendments.

The impact of using ridge-tillage without any herbicides or even with narrow bands of herbicides could have tremendous impact if adoption were more widespread. Herbicide use could be lowered by over two-thirds by banding, and, or course, down to zero in many cases. Production costs with no herbicides was $61.62/acre less than Iowa state University’s estimated cost of production for the same yield goal.

Two scheduled field days were held to tell guests about the project. In addition, one unscheduled tour took place. The first field day was the cultivation field day held in late June with 48 in attendance. ABC World News Tonight with Peter Jennings was present with a crew to tape a segment for their “American Agenda” feature. Their presence was to coordinate a feature story with the National Academy of Science’s Report on the risk of pesticide use to children. With or without their presence, we feel the tour was very successful because we were able to demonstrate first cultivation of corn, and second cultivation or ridging of corn. There was a lot of interest and questions by those attending, many of whom were area farmers. (Only a handful of individuals knew in advance that ABC would cover the event).

The second scheduled field day was our annual PRACTICAL FARMERS OF IOWA field day on 9/2/93. 85 attended this event. We also hosted the National Sustainable Agricultural Advisory Council in early June where participants viewed the trial. We also demonstrated cultivation with a Buffalo cultivator in a strip of corn next to the trial which proved to be the highlight of the tour for the council members.

Results of the trial will be published in the annual PRACTICAL FARMERS OF IOWA experimental result booklet. We will also submit an article for one of the PFI newsletters in early 1994 and will share results with other farmers. How we will go about this has not yet been determined.


Participation Summary
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.