Missouri farmer John Engram wanted the higher efficiency and yield he could get with narrow-rows, but he didn't want to change his equipment spacing or lose irrigation efficiency due to difficulty of maintaining narrower beds.
He found a way to accomplish both goals with twin-row planting. Engram discussed his experiences with twin-row systems during the Conservation Systems Cotton and Rice Conference in Tunica, Miss.
Engram, who farms cotton, corn and soybeans near Vanduser, Mo., decided to make a change in his row spacing in 1990. He didn't like the yields he was getting in corn on 38-inch rows. “I saw where farmers were getting yield increases on 30-inch configurations, because they were increasing their plant populations and utilizing sunlight and all their inputs better.”
Instead of changing his equipment from 38s to 30s, Engram, a ridge-tiller, came up with the idea for planting two rows on each 38-inch bed.
Engram modified his existing International planter, moving all his row units over 3.75 inches from the center. “I planted down then turned around and planted back, giving me two 7.5-inch rows, each with half the population.”
The system was so successful that Engram soon converted his soybean and cotton acres to the concept. He rotates all three crops on the same beds, which he keeps for a dozen or more years, “which eliminates a lot of my ground preparation costs.”
While the International planter did a good job for Engram, the configuration meant he had to cover the same ground twice. Engram later purchased a Monosem vacuum planter which gave him the ability to plant a 7.5-inch spacing in one pass.
Engram suggests that producers plant the two rows 7.5 inches apart directly in the middle of a bed that has been flattened by a roller. “You don't want the plants falling off the bed on one side.”
To settle on a plant population add 10 percent to the plant population you feel comfortable with, then divide that by two. Engram chose the same population he used for planting single rows on 38-inch beds.
“If you're planting 30,000 plants per acre in corn in a single-row, 38-inch configuration, an extra 10 percent gets you 3,000 more plants, or 33,000 plants. You divide by two to get 16,500 plants per acre for each twin row.
“What you're looking for is more fruit. If you have 3,000 more ears of corn out there and each is just as big as the other 30,000 ears, you make more grain per acre. We've done a lot of studies since 1993 and we're picking up about 19 bushels per acre on the twin-row versus the single-row. We've been picking up 12 to 15 extra bushels per acre on beans and have increased our cotton yields by about 10 percent, to about 1,320 pounds.”
Engram noted that cotton “will tend to grow shorter planted in twin rows. It wants to fruit up faster and it will stay compact. Be sure to pick a variety that will fruit high off the ground. And remember, if you apply too much plant growth regulator, the plants will be too short.”
Engram added that the twin-row soybeans achieve canopy quickly. “I don't lose as much moisture to evaporation. Every time I irrigate, I have a pretty substantial cost. If I can save an irrigation by getting a good canopy on top, that will save me money.”
Engram was able to easily pick his twin-row cotton with a spindle cotton picker. “It picks fine as long as you don't get wider than 7.5 inches. You start tagging cotton a little bit when you go wider and you start losing cotton yield.”
The twin-row planting system “has been very economical for us because of the yield increases,” Engram said. “I will never go back to single row.”