Microclimatic and Rooting Characteristics of Narrow-Row versus Conventional-Row Corn

with corn grown in conventional rows (spacing of 0.76 m) in Michigan. These differences in yield associated with Narrow-row corn (Zea mays L.) has been advocated in recent row spacing appear to be accentuated for corn grown years for bolstering production, but previous studies have failed to elucidate the complexity of factors that promote the production of at more northerly locations within the U.S. Corn Belt. corn sown in narrow rows. This study was undertaken to identify Paszkiewicz (1997), for example, found that corn grown those agronomic and microclimatic factors that influence grain yield in narrow rows to the north of Interstate 90 (44 N of corn grown in narrow and wide conventional rows. A split plot latitude) resulted in an 8% higher grain yield while that experimental design was established near Morris, MN, in 1998 and grown in narrow rows to the south of Interstate 90 1999 with row spacing (0.38, 0.57, and 0.76 m) as the main treatment resulted in a 4% higher grain yield compared with corn and corn hybrid (Pioneer 3893 and DeKalb 417) as the secondary grown in wide conventional rows. Not all studies, howtreatment. Root length density, crop water use, interception of photo- ever, have reported a positive response in yield to growsyntheticallyactive radiation(PAR),soil temperature,and soilevapoing corn in narrower rows (Ottman and Welch, 1989; ration were measured in each row-spacing treatment during the growWestgate et al., 1997). In fact, Pedersen and Lauer (2003) ing season. Grain yield and water use of narrow-row corn equaled, or even exceeded, that of wide, conventional-row corn. Narrow-row found an 11% lower yield for corn grown in 0.19-m corn had a more uniform root distribution and intercepted 5 to 15% rows versus 0.38- and 0.76-m rows in Wisconsin while morePARoncleardays,thelatterofwhichlikelyaidedinsuppressing Farnham (2001) found a 2% lower yield for corn grown soiltemperaturesandevaporationduringvegetativegrowthcompared in 0.38-m rows versus 0.76-m rows in Iowa. with corn grownin conventional rows. The results ofthis study suggest Hybrid and plant population may influence the yield that any yield advantage to growing corn in narrow rows may result response of corn to row spacing (Tollenaar, 1989). Farnfrom establishing a more uniform root and leaf distribution that aids ham (2001) observed a significant hybrid row spacing in exploiting soil water and light resources and reducing soil tempera- interaction among six hybrids grown in narrow and wide tures and evaporation compared with corn grown in wide conven- conventional rows in Iowa. Nielsen (1988) and Widditional rows. combe and Thelen (2002), however, found that higher yields were attained for corn grown in narrow rows versus wide conventional rows irrespective of hybrids S eed row spacing is an agronomic management strat- and plant populations tested in Indiana and Michigan. egy used by producers to optimize the husbandry Crop row spacing influences canopy architecture, of the soil and plant ecosystem from sowing to harvest which is a distinguishing characteristic that affects the with the goal of bolstering the production of crops. Al- utilization of light, water, and nutrients. Earlier canopy