What is in this article?:
- Changing irrigation methods from art to science
- Move from art toward science
• The results of irrigation can often be mixed, depending on factors like rainfall, temperature, soil type and even variety.
• But irrigation methods and research can always be fine-tuned for better results.
Move from art toward science
Mississippi State University agricultural engineer Lyle Pringle, said that soil sensors can provide the type of quality information that moves irrigation away from art and toward science. “The biggest gap for the producer is what's going on below the soil surface,” Pringle said. “How much water is there? What are the critical soil moisture levels where we need to irrigate to prevent a yield-reducing stress?”
For Pringle, the irrigation demonstration on the Bush farm indicated “that the later initiations on deeper soils can save an irrigation without reducing yield and possibly increasing yield. And it doesn’t take an engineer to do this. The producer or consultant, if he has the interest, can install and operate the systems, and understand the data.”
Pringle says the bigger picture is conserving water for future generations.
“We have been put on notice in the Mississippi Delta that we are mining our aquifer. That aquifer is not supporting any drinking water, so it’s mainly our irrigation wells that are pulling those levels down. Static water surveys have shown there is a (cone of depression) that has developed in the middle of the Delta and (it’s) getting deeper and wider every year. Our recharge for the aquifer comes from the bluff hills on the east side and from the Mississippi River on the west side. This is a Delta wide problem, not just for the people who are in the (depression).”
Pringle suggests that agriculture use more surface water and create more surface water supplies. “We can divert water and we can build reservoirs. In the short-term, it’s about conservation. We can increase our water application efficiencies and our water-use efficiencies through irrigation scheduling.”
Irrigation systems are important too, noted Pringle. “A drip system is one of the most efficient systems. A well-managed drip system does not have run-off, deep percolation loss and very little evaporative loss.
“But in the Mississippi Delta, water quality in our shallow water aquifer is not very good for a drip system. We have iron and magnesium in the water, and we tend to have clogging problems. For the cost of a drip system, we have to have the drip system last for 20 to 25 years. Now they last about 10 years.”
A sprinkler system is the next most efficient system, at 80 percent efficiency on average, Pringle noted. “We have to keep those systems maintained so they continue to run at the designed efficiency.”
Furrow irrigation, at 60 percent efficiency, can have losses due to run-off, deep percolation and evaporation, noted Pringle. “There are programs like the PHAUCET program to help size holes (in rollout pipe) and get a more uniform distribution of water down the row. In certain situations, furrow diking, alternate row irrigation and surge flow irrigation can help.”
Pringle noted, “If everybody properly irrigated, we may not save a lot of water, because we have some producers who over-irrigate, and some producers who under-irrigate. But my view is that if you are irrigating properly, you’re maximizing your yields and you have a better bottom line. Then you can invest more in irrigation conservation practices. The goal is to have adequate water for all users in the Delta.”