Corn Row Spacing as a Management Strategy to Reduce Water Runoff and Sediment Losses

Abstract. Corn (Zea mays) is one of the main crops grown in the Midwest. Since large areas of land are in corn production, developing management strategies to minimize environmental impacts of erosion can have a positive impact. Exploring different row configurations, such as increasing the number of plants within a row or narrowing spacing between rows, could help reduce runoff and sediment losses by slowing overland flow water. This study investigated the prospect of using different seeding rates and row spacings as strategies for reducing runoff and sediment losses from land under corn production. Research plots were established using a completely randomized design with six treatments replicated three times on a 5% slope with a silt loam soil in south central Wisconsin. Treatments included corn planted at the typical standard row spacing for the region (76.2 cm) at a normal seeding density of 86,610 seeds/ha (SN), corn planted in narrow 38.1 cm rows with a density of 86,610 seeds/ha (NN), and corn planted at 76.2 cm row spacing with a high seeding rate of 104,543 seeds/ha (SH). In order to investigate the interaction of the row spacing variables with crop residue, these same treatments with corn residue harvested were compared (RH). Runoff and sediment losses were measured using galvanized steel frames (0.5 m wide by 1.0 m long) inserted into the ground with a single collection point oriented downslope acting as a flume. A PVC pipe was attached to the flume in order to collect runoff into a bucket with an 18 L capacity. Buckets were sampled manually after each rainfall event during three growing seasons. Narrow row spacing reduced runoff and sediment losses by about 20%, while increasing the number of plants within a row had no impact. Harvesting corn residue increased runoff by 27% and sediment losses by 19%, however, there was no interaction between row configuration schemes and corn residue removal. Corn yields increased two out of the three years with narrow rows. Results from this work indicate that using narrow rows in corn production in the Midwest has the potential to reduce environmental impacts for surface waters while enhancing productivity.