Compaction may restrict the ability of roots to penetrate the soil to obtain water and nutrients for growth. The number of nodes per plant will be similar, but the early-planted plants will be shorter. This may be an advantage if lodging is reduced, and the shorter plants will seldom be a disadvantage to yield. The tallest plants will occur when the same variety is planted close to June 1 and a normal season follows. The timing of soybean planting is very important to obtain maximum grain yield.
Early planting is one of the most important factors to achieve high yield.
Other factors include the use of high-quality seed, proper adjustment of the planting equipment, appropriate seeding rate, weed management, and soil nutrients. The number of acres to be planted and the size of equipment also affects the decision of when to plant. If the weather cooperates and the above factors are in place, producers should expect yields that they can be proud of at harvest time. Effect of planting date on soybean yield in northern Iowa 1994-1996. Effect of planting date on soybean yield in southern Iowa 1994-1996.