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CTIC News Release
Contact: Dan Towery Tel: 765 494-9555
Email: towery@ctic.purdue.edu
Date: November 12, 1998
Strip-till – A practical solution for conservation tillage corn
With strip-till, corn growers can capitalize on the cost reduction
benefits of conservation tillage without the production problems associated with wet, cool
spring conditions.
What is strip-till? Think of it as hybrid between no-till and
ridge-till, takes much of the risk out of planting ‘no-till’ corn in Iowa,
Illinois, Indiana, Ohio, Michigan, Minnesota, Missouri and other areas with traditionally
wet springs.
Corn growers who successfully use strip-till usually rely on ammonia
injection knives to till and raise (4") the seedbed in the fall. Many apply any
needed Phosphorous and/or Potash simultaneously. Seed is then planted into this tilled
area the following spring.
Other growers use variations of strip-till in the spring instead of the
fall. These include the "Grow Zone," various residue managers and various
combinations of multiple coulters. The spring variations are usually completed at least a
week prior to planting.
With either approach, the rest of the row (two-thirds or more of the
row’s width) remains covered with residue so growers still benefit from soil
microbial activity that builds organic matter. Over time this helps improve soil tilth
critical to retaining soil moisture and retard drought conditions later in the summer.
Strip-till fundamentals
- The strip-till toolbar must exactly match planter size
(ie.
8-row-30" or 12-row-30") and needs row markers.
- Soil temperatures of at least 50° F are needed to germinate most
hybrids. Soil in the "raised strip" warms faster and may be five to eight
degrees warmer than the rest of the row.
- Excessive moisture also inhibits soil warming. Since the raised strip has
been aerated, moisture levels are lower than between strips.
- Uniform seed depth and inter-row distances are also important for a
uniform stand and provide the best potential for optimum yield. Because the seedbed is
worked early and left to ‘mellow" over time, planter seed placement accuracy is
improved compared to traditional no-till conditions.
- Starter fertilizer placed ‘2x2’ (two inches below the surface
and two inches either side of the seed) is also vital to getting seedlings off to a good
start. (Be sure to include this application and rate into the Crop Nutrient Management
plan.
- A seed treatment will also improve stand. Under cool, moist conditions,
pythium may be a problem. Most treatments protect seed from this fungus.
- Of course, as is always the situation, hybrid selection is key: Select a
hybrid with an excellent cold-germ rating. If a cold-germ rating is not available, select
for emergence and seedling growth.
- Fall application of anhydrous ammonia should be delayed until the soil
temperature reaches 50°F. A nitrification inhibitor is always recommended to increase
nutrient efficiency.
- And, remember, if you’re conducting an on-farm test, be sure to use
comparable hybrids and fertility levels. The rest of the management system will differ
little from the management system used with reduced or intensive tillage systems.
Economic benefits of strip-till
University of Illinois research on strip-till in 1996 and 1997 (1998
figures not available) showed a two year average increase in yield of 35 bpa for
strip-till over no-till and 3 bpa for strip-till over conventional tillage, on heavy black
prairie soils. On-farm trials in Iowa and Illinois show strip-till out-yields no-till in
cool, wet soil conditions. These farm trials report yields similar to conventional
tillage.
In addition to yield, there is also strong evidence that banding P and K
in the fall with the anhydrous ammonia application can increase fertilizer efficiency. It
can also replace the cost of separate applications. These benefits plus the elimination of
time consuming secondary tillage in the spring help optimize planting efficiency.
The 1998 survey collected data about tillage practices and crops planted
on the more than 293 million acres of cropland in the United States. The survey is
coordinated, compiled and reported by the Conservation Technology Information Center, a
non-profit, national public-private partnership. |
