Reminders for managing salts in soils this spring
Saline areas of farm fields aren't unusual because of last year's wet conditions.
Farmers have been sending me photos and calling about saline areas — which makes sense: The soil profiles were mostly full of water this fall, and as the soils are drying out at the surface this spring, the salts are being pulled up to the surface and sticking around after the water carrying them evaporates. A couple reminders for management this spring for salt-affected areas:
First, do some surface ditching if the soil conditions are right (not saturated) and you have time. Be careful not to drain wetlands or other protected areas. Also clean out the ditches to avoid standing water that causes ditch-effect salinity (salts around the edge of the field). If you aren’t able to get to this now, put it on a list to take care of later. Standing water leads to opportunities for salt movement — keep the water moving.
Then, divide the field. Do not plant salt-sensitive crops (soybeans, edible beans, corn) on saline parts of the field and do plant something like a small grain which is more tolerant. Notice I said, “saline parts of the field,” because you don’t have to plant an entire quarter to one crop. Focus the salt-sensitive crops on the good parts of the field to get the most out of those areas for proven yield. Take the saline areas (you likely know where they are because they haven’t been producing as well for years), square those parts of the field off, and plant them to a crop that does better in saline soils, like barley, oats or spring wheat.
Next, keep in mind that small grains can’t work miracles on soluble salt levels over 6 millimhos per centimeter, so set expectations for the small grain or go with a perennial grass or cover crop on those areas. Wheatgrasses are a good choice for a perennial and you could mix in some salt-tolerant alfalfa. I have not had luck seeding salt-tolerant alfalfa by itself on saline areas. A grass mixed in with it seems to do the trick.
Keep in mind, give the appropriate level of management to the non-producing saline areas. You likely don’t have to fertilize because there is plenty there from years of application and lack of crop uptake. So, don’t put any more money into those saline areas. The goal is to reduce costs.
Lastly, if you don’t have a soil test from these problematic areas, collect one this fall. If you know how bad the soluble salts are, you can make better decisions.
We have a webinar coming up on May 14 (info and link available at ndsu.edu/soilhealth). There is also plenty of information on salinity on the NDSU Soil Health webpage (ndsu.edu/soilhealth), including sample soil tests and Dave Franzen’s circular (SF 1087) for saline, saline-sodic, and sodic soil issues (Soil Health Tab, Chemistry, Salinity). There are also videos on salinity and creative management approaches (Video tab). You can also call your county Extension agent with questions on management.
Abbey Wick is an Extension soil health specialist at North Dakota State University.