Dealing with Salt Problems in Soybean Production - January 2013
[University of Arkansas Division of Agriculture Research and Extension University of Arkansas System. Arkansas Soybean Promotion Board. Jeremy Ross, Extension Agronomist - Soybeans, Crop, Soil and Environmental Sciences University of Arkansas System Division of Agriculture]
When we’re dealing with salinity, there are several different factors. Not all of these factors are here in Arkansas or the mid-South, but we do have some that are causing some problems: The geology of the soil, the weathering of the primary material that the soils come from … Climate, I think everybody would agree that our climate has probably changed over the last at least five years.
[Slide – Factors influencing salinity; Geology: weathering of primary minerals, marine sediments, etc.; Climate: evaporation exceeds precipitation; Irrigation: water with moderate to high TDS or SAR; Water Table: near soil surface; Human activity; mines, production plants, or high urban activity; Soil Drainage: poor.]
We’ve probably been hotter and drier than we have been, looking back at the historical weather data. Slide – Symptoms: Pictures showing diseased soybean leaves, plants and fields.
And if your evaporation exceeds your precipitation, you’re going to accumulate these salts.
[Slide – Management Options; Crop Selection; Irrigation, management, controlled leaching, system adjustments; Soil, drainage, tillage/compaction; Continued monitoring.]
Management options we have are, crop selection, as I mentioned before. Cotton and sorghum are a little more tolerant than soybeans and rice to salt problems, so you may have to look at rotation and a different crop.
Irrigation is probably going to be the biggest thing. We have got to manage that water. If you can get another source of water to try to eliminate some of that salt problem, that’s going to be the best thing.
Drainage is a big thing. If we can get that water drained off as quickly as possible and then tillage. Use some of that deep tillage to try to get some of that salt kind of mixed back up into the soil profile where it’s not concentrated in the top two to three inches where the roots are.
[Slide – Management Options; Know levels in water/soil; Switch water sources; Plant Excluder varieties; Plant more tolerant crop; Deep Tillage/Drainage; Fertilizer in fall.]
So really some of the take home messages, know the level which you have in your water and soil. You may have to switch again, water sources, to sources that don’t have near as much salt as you do if you are pumping salty water.
At this point if you are wanting to look at soybeans, the best option that we have are excluder varieties. And we do have quite a number of excluder varieties in the variety update that are high performers, but again, if you get to a point and your salts get real high, those excluders will be overcome with the salt problems, and you’re not going to be able to grow those.
Again, plant the more tolerance crops. Cotton, grain sorghum. Make a deep tillage and then fall fertilizer [is] probably one of the biggest things we can do.
I hope that answers some of the questions. I know a lot of you’ll are probably having some issues with this. Best thing we can do is to monitor our soils and monitor our water to make sure we don’t run into a major problems.