Pete Hunter leaves little doubt he’s very concerned about runoff of soil nutrients from his farm into the Mississippi River and the Gulf of Mexico when he speaks to gatherings such as one held by Delta F.A.R.M. in Stoneville, Miss., in late March.
But Hunter is also concerned about his bottom line, and that’s why he’s planning to take another look at polyacrylamide or PAM, a product that helped him achieve an 18-bushel-per-acre increase in grain sorghum yields on his operation near Clarksdale, Miss., in 2015.
Some new ag products have a steeper learning curve. When farmers began applying a plant growth regulator on cotton in the 1980s, there was a debate about whether the product provided any tangible benefits. Eventually, researchers and growers learned how to use PGRs and now most “Pix” their cotton.
The same discussion has been occurring over the use of polyacrylamide – though, in these economic times, the debate seems to have taken on a more somber tone than the one over PGRs as growers seek ways to improve returns.
“First of all, one of my greatest loves is the Gulf of Mexico,” Hunter said in an interview at the Delta F.A.R.M. meeting. “I love to fish down there – I make three to five trips a year to fish in the Gulf. I am very familiar with the dead zone or hypoxia zone in the Gulf and the detrimental effects it has on fisheries and the livelihood there.
“That being said, we used polyacrylamide on the farm on an experimental basis this past year on two fields that were planted in milo, one of the fields being a check and the other receiving applications of polyacrylamide.”
Even distribution with Pipe Planner
Immediately following planting, Hunter flew on an application of Silt Bond, the trade name for PAM. He followed that 28 days later with an injection of polyacrylamide into the poly-pipe that was laid out using Pipe Planner software in the treated field.
“During that time, I was privileged to actually collect water samples coming out of those fields after a rain,” he noted. “In the field treated with polyacrylamide, the water looked very much like drinking water. In the check area, it came out looking like chocolate milk. So something obviously was going on out there.”
The field treated with the two applications of polyacrylamide produced 18 bushels more grain sorghum than the other, Hunter said, adding that a wet spring resulted in excessive moisture across the area.
“I really don’t know if the polyacrylamide contributed to the water percolating down through the ground and getting away from that anaerobic situation on that crop to where the roots could breathe or whether it had to do with irrigation efficiency. It was probably a combination of both.
“But whatever it is, as far as I’m concerned, being a farmer, it really doesn’t matter. Your bottom line is what you look at,” he said. “And an 18-bushel difference is statistically significant to me. I plan to use it this coming year on some soils that really seal hard after a packing rain or to the point it’s hard to get emergence of cotton or soybeans after a packing rain.”
Hunter has seen evidence the infiltration rate of the water in some of those soils “is very much hindered” using conventional irrigation practices.
Water not reaching root depth
“I have some high-dollar moisture testers out in this field, and I have learned I cannot penetrate this soil with irrigation water,” he notes. “It continues to dry out even though I’m irrigating on the soil surface. So I’m really going to try polyacrylamide on that area this year to try to increase irrigation efficiency and also increase profit.”
Buddy Allen, a producer from Tunica, Miss., who has used polyacrylamide on his farm for three seasons, says he’s not surprised at the mixed results researchers reported seeing in the product’s performance during presentations at the Delta F.A.R.M. meeting in Stoneville.
“We’ve done a lot of different things with it; we’ve learned a lot; we’ve made a lot of mistakes, and we’re still making mistakes and learning,” said Allen. “All the variability in you guys’ data just lines up with what I believe as a farmer. There are certain ways to use this that work really well, and there are certain ways that don’t. There are a lot of environments where you see efficacy and others where you don’t.”
The environmental conditions and what’s happening at the time of application have a significant impact, he notes. “If you’re irrigating, is that water carrying a sediment load already or not because of any number of reasons?
Selecting where to use the product and how to use it is important, says Allen. “The first time I applied the product I tried to wash it off my hands with water. You don’t do that. It’s the only product in the world that can be slick and sticky at the same time.”
Aerial application simpler method
Allen says he prefers aerial applications for the product because he can give a custom applicator a rate and get an application scheduled without having to do it on a field-by-field basis of calculating rates for injecting it into an irrigation system.
“I always like to paint with broad strokes in production nowadays. I’m a rice farmer, primarily, and I’ve seen a consistent yield advantage and that’s always encouraging to me, and I believe the correlation between my water efficiency and my yield advantage. Where I’m tailing a bunch of water that’s loaded with nutrients, and I’m not managing my water as I’m seeing a better impact.
“When I’m on my zero grade, and I’m really not wasting any water, and it’s super controlled and super tight, maybe I’m not making as much of an impact.”
For more on polyacrylamide, visit https://en.wikipedia.org/wiki/Polyacrylamide