ISSUE 4 May 23, 2002
SALINE AREAS- ITíS REALLY NOT LINGERING SNOW!
In many areas of our state, areas of surface salinity are showing up as expansive white areas. Some people that I have talked to have commented that they have not seen these areas as large as they are now. Although we experienced some dry weather last year, it was apparently not enough to reduce water tables deeply enough to prevent these salts from percolating to the surface. Our subsoil moisture is again high in many areas, and there is no prospect for easily ridding fields of this menace. In most areas, gypsum (calcium sulfate) is our major salt within these areas. Another common salt is epsom salts (magnesium sulfate). Less commonly, chloride salts of calcium and magnesium and even sodium will surface, mostly west of the Grand Forks area.
What can be done to reduce these areas? If we had a method to improve drainage, these could be attempted. The salts are present because of local and sometimes regional high water tables. By increasing the depth to the water table, the concentration of salts at the surface will be reduced. Sometimes, the problem lies in poor depth of the roadside ditches. Sometimes areas of natural drainage have been obstructed. But most of the problem is simply too much water.
Invest in ways to use the water whenever possible. Some farmers have weeds growing in areas or areas marginal to the white areas and till these under like a summer fallow. What they create is- summer fallow (!) which as you recall is conducted to - increase water retention in the field (!). That is opposite of what needs to be done. Let the weeds grow and mow them to prevent seeding and allow them to remain green as long as possible. Dead weeds use no moisture, but green ones will. If for some reason areas experience prevented planting, try to seed some kind of cover crop into the field to use some of the water. Otherwise the field will be susceptible next year not only for another round of prevented planting, but increased danger and expanse of saline areas.
- Things to avoid- adding more gypsum, deep tillage.
- Things only marginally and short-term successful (sometimes)- adding manure. Manure can dilute the problem temporarily, but adds to the problem in the long run.
METHODS TO SPEED UP FERTILIZING AND SEEDING
Although some areas of the state are finishing up seeding, many areas still have a long way to go. Here are a few ways to speed up the process of fertilizing and seeding.
1. One-pass seeding/fertilizing- This method requires the "plumbing" to allow fertilizer to apply fertilizer either in the seed furrow, or with fertilizer and seed separation. There are some crops which allow more fertilizer with the seed, such as wheat and corn, and other which tolerate little, such as flax, canola and soybeans. In corn, in a band 2 inches to the side and 2 inches below (2 by 2 band), the rate of N that can be applied is limited only by the fertilizer N recommended, unless you want a "starter" effect. N levels above 50 lb/acre in a 30 inch row band will cause roots to shy away from the fertilizer until ammonia levels from transforming urea are low. By then, it will be too late for a starter effect. Ammonia can be applied while seeding nearly any crop as long as lateral distance from the seed is at least 3 inches.
2. Preplant ammonia/seeding in the same day- Although by the book the waiting period is from 5-10 days (depending on the book), practically there is no time where ammonia is truly safe as a preplant operation. So if you throw away the book, make sure that the ammonia is applied at some angle to the intended direction of seeding. Some plants will not emerge when the planter rows cross the application trenches, but if you seed correspondingly at a heavier rate, the stand will be OK. If you seed in the same direction as ammonia application, it is highly possible that long lengths of row and gaps of unemerged plants will result.
3. Side-dress- Most of our row crops, including sunflowers and corn are easily side-dressed using ammonia, 28-0-0 and sometimes urea if you have attachments rigged to a cultivator. It will take some time later, but timely seeding is most important.
4. Top-dress- Non-row crops can be top-dressed, although in this region it may be more risky counting on rainfall than it would in some places. I would suggest you check out Chaffer bars, originally manufactured in Europe and now in our region, probably available from local distributors. I have talked in the past about "straight-stream" orifices that could be rigged up to reduce burning and concentrate liquid N so that volatilization could be minimized, but these Chaffer bars attach easily to existing nozzle assemblies, making the whole conversion operation a matter of minutes rather than hours as we used to do back in my former life. You still need a rain, but burning dangers are greatly reduced, and the volatilization rate of the urea in the liquid N is slower than broadcast.
SOIL CONSERVATION REVISITED
As you travel around the state this spring, take note as I have of the mini-disasters which we tend to ignore and forget later on when the crop is growing. It has been a long time since we had this windy a spring, but surely it is not the first or last time that this has occurred. Note that the fields which have no soil (I guess itís dirt now) in the ditch are the ones thick with residue; the ones not "clean-plowed"; the ones with hedges closely spaced on wind erosion susceptible soils; the ones with an established cover crop from last fall. As growers conceivably have to replant sand-blasted acres of sugarbeets and other crops, is it really the winds fault? Or is it their failure to plant cover crops, the reluctance to try strip seeding or trash whippers on the seeders, or failure to replace the hedge rows that have come out during the last 10 years? If people are not interested in soil conservation for the benefit of future generations, how about soil conservation to preserve this yearsí crop?
NDSU Extension Soil Specialist