Planting Speed Effects on Stand Establishment and Grain Yield of Corn

Planting speed can affect a planter's ability to uniformly singulate and deliver seed to the seed furrow. A replicated on-farm strip trial was conducted in 1993 on 22 farms in three states to evaluate the effect of planting speed (4, 5, 6, and 7 mph) on plant population, plant spacing variability, and grain yield of corn (Zea mays L.). Increased planting speed significantly decreased plant population at one site (− 527 plan/acre per mph increase in speed) and increased plant population at nine other sites (207 to 1912 plants/acre per mph). Among the 10 sites where increased planting speed influenced plant population, plant spacing variability significantly increased at four sites and was unaffected at the six other sites. Among the remaining 12 sites where plant population was unaffected by planting speed, plant spacing variability (PSV) significantly increased with increased planting speed at five sites and was unaffected at the seven other sites. Where observed, standard deviation of plant-to-plant spacing increased from 0.22 to 0.37 in./mph increase in planting speed. Grain yield was significantly influenced by increased planting speed at only five of 22 sites. Among the five responsive sites, grain yield decreased linearly from 1.9 to 4.7 bu/acre per mph increase in planting speed. There was no clear relationship between occurrence of grain yield loss and changes in either plant population or plant spacing variability. The possibility for significant grain yield loss with excessive planting speed must be considered when growers contemplate changes in their standard planting speed practices. Research QuestionPlanting speed can affect a planter's ability to uniformly singulate and deliver seed to the seed furrow. An on-farm strip trial was conducted in 1993 to evaluate the effect of planting speed on plant population, plant spacing variability, and grain yield of corn. Literature SummaryPlanter manufacturers usually recommend a range of planting speeds within which their planters are designed to function optimally. Excessive speeds typically result in altered seeding rates for increased variability among plant-to-plant spacings within rows. Plant spacing variability can also occur even if seeding rates have not been altered, if random mixtures of gaps and crowded seeds are delivered by the planter. Variable plant-to-plant spacing within rows can decrease corn grain yield beyond any effect due to altered plant population. Study DescriptionAn on-farm strip trial was conducted in 1993 to evaluate the effect of planting speed on plant population, plant spacing variability, and grain yield of corn. Twenty-two farmers across Indiana, Illinois, and Iowa participated in the study. Plant population, plant spacing variability, and grain yield were measured on plots planted at 4, 5, 6, and 7 mph. Each treatment was replicated three times on each farm. Applied QuestionsDid increased planting speed significantly alter seeding rates (plant population)? Increased planting speed significantly changed final plant population at 10 of 22 sites in this study. Plant population decreased at 1 site (−527 plants/acre per mph increase in speed) and increased at the nine other sites from 207 to 1912 plants/acre per mph increase in planting speed. Did increased planting speed significantly alter plant spacing variability? Among the 10 sites where planting speed influenced population, plant spacing variability (standard deviation of plant-to-plant spacing) significantly increased with increased planting speed at four sites and was unaffected at the six other sites. Among the remaining 12 sites where plant population was unaffected by planting speed, plant spacing variability significantly increased with increased planting speed at five sites and was unaffected at the seven other sites. Where significant, standard deviation of plant-to-plant spacing increased from 0.22 to 0.37 in./mph increase in planting speed. Did increased planting speed significantly alter grain yield? Of the 22 sites in this study, grain yield was significantly influenced by increased planting speed at only five sites. Among the five responsive sites, linear decreases in grain yield ranged from 1.9 to 4.7 bu/acre per mph increase in planting speed. Total yield loss among these five sites from planting at 7 mph instead of 4 mph ranged from 5.7 to 14.1 bu/acre (worth from $14.25 to $35.25 per acre at $2.50/bu corn). RecommendationsFor years, corn growers have been cautioned that excessive planting speeds can alter seeding rates, increase stand establishment variability, and consequently decrease grain yields. This study indicates that these negative effects can occur, resulting in yield losses of at least 2 bu/acre per mph increase in planting speed in the range of 4 to 7 mph. However, the effects are not widespread across all planting systems where well maintained and properly adjusted planters are in use. Because the potential for yield loss exists, growers concerned about the effects of excessive planting speeds should determine their own planter's response to planting speed with on-farm trials similar to that described in this article.