Microclimatic and rooting characteristics of narrow-row versus conventional-row corn

Narrow-row corn (Zea mays L.) has been advocated in recent years for bolstering production, but previous studies have failed to elucidate the complexity of factors that promote the production of corn sown in narrow rows. This study was undertaken to identify those agronomic and microclimatic factors that influence grain yield of corn grown in narrow and wide conventional rows. A split plot experimental design was established near Morris, MN, in 1998 and 1999 with row spacing (0.38, 0.57, and 0.76 m) as the main treatment and corn hybrid (Pioneer 3893 and DeKalb 417) as the secondary treatment. Root length density, crop water use, interception of photosynthetically active radiation (PAR), soil temperature, and soil evaporation were measured in each row-spacing treatment during the growing season. Grain yield and water use of narrow-row corn equaled, or even exceeded, that of wide, conventional-row corn. Narrow-row corn had a more uniform root distribution and intercepted 5 to 15% more PAR on clear days, the latter of which likely aided in suppressing soil temperatures and evaporation during vegetative growth compared with corn grown in conventional rows. The results of this study suggest that any yield advantage to growing corn in narrow rows may result from establishing a more uniform root and leaf distribution that aids in exploiting soil water and light resources and reducing soil temperatures and evaporation compared with corn grown in wide conventional rows.