Farm Horizons • Aug . 8 , 2016 • Page 28
In addition to applying water and microbubbles through subsurface drip irrigation , Martie also applies fertilizer .
“ I set a meter to what I want , set my timer , and I have a fertilizer pump that injects fertilizer right to the root system ,” Martie said .
Being able to add fertilizer in the summer is key .
“ You know when a plant gets up to the eight- to 10-leaf stage , it uses 75 percent of the fertilizer ,” Martie said . “ I ’ m going to put it on through the water . I ’ ll probably come over every three days and get the fertilizer put on . I really don ’ t need the moisture right now . I just run the moisture to carry the fertilizer .”
To do so , he only needs to run the system for about 2.5 hours , compared to about twice that long when he is watering .
Wicklund believes Martie ’ s techniques will prove to be effective and efficient .
“ We ’ re hoping to be able to show by putting it right in the root zone and being able to apply it right when the plant needs it , spoon-feed application rather than broadcast application , that it can increase yields ,” Wicklund said .
Introducing fertilizer in the root zone prevents runoff and also keeps it from entering the aquifer .
Challenges
Subsurface drip irrigation does not come without its fair share of challenges .
Josh Stamper , an irrigation specialist with the University of Minnesota Extension , said it can be difficult to utilize subsurface drip irrigation in light soil .
“ Where it has worked really well you have heavy- to
Russ Martie built this machine to install irrigation tapes . He used a chisel plow from a junk yard and spent $ 1,200 , compared to the $ 28,000 price to purchase a similar machine .
PHOTO BY GABE LICHT
Solenoids are used as part of the irrigation system .
PHOTO BY GABE LICHT
medium-texture soil ,” Stamper said . “ Most of the irrigated sands in Minnesota are light-texture . When you bury the drip lines , it ’ s hard to pulse the water to drive it up .”
It can also be challenging to determine how deep to bury the lines and how widely to space them to meet the demands of the crop , Stamper said . Burying them too deep could cause a problem . “ When you place the source of irrigation below the soil , it ’ s hard to overcome the gravitational pull ,” Stamper said . “ How do you make it work in course-texture soil , where it ’ s hard to pulse water up into the profile ?”
Martie and Wicklund worked together to answer that question and find the “ sweet spot ,” Stamper said .
Another challenge occurs for farmers who want to use subsurface drip irrigation , but don ’ t want to use no-till or low-till techniques .
“ You have to use GPS to make sure you ’ re not tilling where the tapes are ,” Wicklund said . “ It can be done , but it ’ s another level of complexity and another expense that a smaller operator may not be set up for . Looking at the sand plains north of the metro , a lot of that is conducive to no- or low-till .” That ’ s the system Martie utilizes . “ You can ’ t take a chisel plow to it ,” Martie said . “ I do minimum till . I use a disc and go down 4 to 5 inches .”
An example for others
Martie received a grant from the U of M Extension and another from the Farm Service Agency which require him to compare subsurface drip irrigation to no irrigation and a center pivot .
He has opened his farm up for local farm field days , including a July 21 event , and even hosted some women from the eastern European country of Moldova .
“ Russ ’ farm is a demonstration ,” Stampler said . “ He ’ s been blazing a path toward this . I view what he is doing as a great way to get people excited about new technology that warrants more exploration .” •