DECEMBER 2018 SEEDWORLD.COM / 53 get outside this range, yield decreases.” Several things happen whenever seed is planted less than 1.5 inches deep. First, he says moisture in the furrow might not be uniform because of the soil close to the surface is drying out. The other thing that typically happens, Goebel explains, is problems with no root formation causing “floppy corn syndrome.” To get good, strong root development, Goebel says it is important to plant at least 1.5 inches deep. Beyond the magic 1.5-inch depth, it is important to plant into uni- form moisture. Ideally, seed is planted into a minimum of 30 percent, preferably 40 per- cent moisture, in the furrow. “Now for the first time, we have the ability to actually measure that with a smart firmer tool,” Goebel shares. AGCO 2016-2017 Planting Depth and ROI Study Planting Depth (inches) Average Corn Yield (bpa) 1.0 186 1.5 204 2.0 209 2.5 203 3.0 204 3.5 190 Downforce Unit Calibration It’s also important that indi- vidual row planting units be calibrated to manage the downforce needed to main- tain a uniform planting depth. A planter row unit will achieve depth if there is appropriate force down on the gauge wheels to hold it in the soil as it encounters different barriers, such as compaction, residue and differences in till- age systems. Downforce is associ- ated with depth control. The researchers analyzed three different levels of downforce to determine its effects of yield. Light downforce pres- sure simulates a very small spring on a planter compara- ble to the springs used in the 1970s and early 1980s before no-till planters became popu- lar. Contrast these planters to heavy duty, no-till downforce systems set at the heaviest setting possible. “We found yield loss due to both too light downforce and excessive downforce,” Goebel says. “Downforce control, in my opinion, is one of the biggest problems for the planter pass.” With too little downforce, he says, planter row units bounce, sometimes going too deep into the ground and sometimes not going into the ground deep enough. The result is variable plant emergence. On the flipside, too much downforce results in “hatchet roots” that follow the seed furrow because the gauge wheels are putting so much pressure on the soil surface which stunts the roots that are trying to grow along the furrow. Ideally, each individual planter row unit should react allowing each row unit to maintain proper depth control without excessive pressure. AGCO 2016-2017 Downforce and ROI Study Average Corn Yield (bpa) Light downforce 195 Proper downforce 209 Excess downforce 204 Singulation AGCO agronomists also performed a singulation study and, according to Goebel, this is one of the first multiyear, multilocation studies to specifi- cally look at singulation with- out the inclusion of population. They blocked off some holes in the planter’s seed disc and then drilled a corre- sponding number of new into the seed disc to maintain the proper population. The effect was to create an uneven seed drop with a poor (93.1 percent) singulation compared to the control (99.6 percent singula- tion). The result was about a 7 bushel per acre difference. AGCO 2016-2017 Seed Spacing Study Yield and ROI Average Corn Yield (bpa) Control singulation (99.6%) 209 Poor singulation (93.1%) 202 Then in 2017, the research team did a closing study. The most aggressive mode resulted in some soil pinching between the closing wheels that in some cases pushed the seed up in the furrow. The result was variable seeding depth. Compaction over the row also prevented some seeds from emerging uni- formly. “The main takeaway is to make sure that you’re clos- ing the furrow well with good seed-to-soil contact, and use only enough pressure to do that consistently,” Goebel says. He tells growers to con- sider adding soil firmers to get a little bit better firming down around that seed, espe- cially in silt loam soils. These firmers can have a payback of just 40 acres, Goebel notes. While equipment plays a large role in helping farmers achieve proper singulation, lubricants are another critical component to success during the planting season. First Is Adherence As soon as seed treatments or any other adjacent tech- nologies are added to seed, the characteristics of the seed surface will change, says Sandy Baker, Syngenta “It’s very important to understand seed lubricants and to use them according to the recommendation of your planter manufacturer.” —Sandy Baker