Relationships Between Furrow Opener, Corn Plant Spacing, and Yield¹

Abstract

In spite of proven yield advantages for corn (Zea mays L.) planted in narrow rows or at equidistant spacings, equipment expense and weed control disadvantages have slowed acceptance of these cultural practices. Improving plant spacing uniformity by decreasing the intra‐row spacing variance should be as effective in increasing yields as improving spacing uniformity by decreasing row width. To aid in determining what investment may economically be made to improve intra‐row plant spacing uniformity, the effect of such spacing on individual plant yield and total yield was investigated. Yields and plant‐spacing statistics also were obtained for corn planted with V‐type runner and double‐disk furrow openers. A relationship between individual plant yield and distances to adjacent plants was developed from plants harvested individually. This relationship, combined with a frequency function of distances to plants adjacent to the harvested plant, was used to compare yields of corn from conventional plant spacings with the yield of corn from a theoretical uniform intra‐row spacing. The type of planter furrow openers investigated had little effect on yield or on intra‐row plant spacing uniformity. Intra‐row plant spacing accounted for only a small amount of the variance in individual plant yield. The study indicates that on a field scale, with corn planted in 76‐cm rows, improving intra‐row plant spacing may not significantly improve total yield. Therefore, it may not be economical to improve upon the intra‐row plant spacing uniformity obtained with conventional planters.

Response of Maize and Soybean to Variability in Stand Uniformity

“…Important yield decreases in response to uneven seedling emergence were also observed by Nafziger et al (1991) and Liu et al (2004a) Uneven plant spacing tended to result in lower maize yields. Negative effects of unevenness in plant spacing on maize yield were observed by Krall et al (1977) and Vanderlip et al (1988) in contrast to results reported by Erbach et al (1972), Muldoon and Daynard (1981), and Liu et al (2004b) In soybean, yield did not respond to increases in within‐row plant spacing variation nor in seedling emergence variation as it was reported by Egli (1993a) In agreement with these findings, estimations based on Eq. [4] indicated that increases in CV for Vp did not affect soybean yield but reduced maize yield (Fig.…”

“…These genotypic effects would be some of the reasons for the contrasting responses of maize crops to variability in intrarow spacing reported in the literature (Erbach et al, 1972; Krall et al, 1977; Johnson and Mulvaney, 1980; Muldoon and Daynard, 1981; Liu et al, 2004b).…”

“…Negative effects of uneven emergence on grain yield were found in maize (Nafziger et al, 1991; Tollenaar and Wu, 1999; Liu et al, 2004a) but not in soybean (Egli, 1993a). Moreover, nonuniform within‐row plant spacing resulted in lower maize yield in some cases (Krall et al, 1977; Vanderlip et al, 1988) but not in others (Erbach et al, 1972; Muldoon and Daynard, 1981; Liu et al, 2004b). The effects of uneven stands likely vary depending on the species and the genotypes and according to the environmental conditions.…”

Impact of Planter Type, Planting Speed, and Tillage on Stand Uniformity and Yield of Corn

“…The effect of within‐row plant spacing variability on grain yield is somewhat unclear. Various studies have demonstrated a corn yield reduction associated with spacing variability (Krall et al, 1977; Vanderlip et al, 1988; Nielsen, 2001), whereas other studies indicate that spacing variability commonly observed in many commercial fields will not reduce grain yield if plant population is adequate (Erbach et al, 1972; Edmeades and Daynard, 1979; Muldoon and Daynard, 1981; Daynard and Muldoon, 1983; Liu et al, 2004a, 2004b). In contrast, uneven emergence almost always reduces grain yield, with early emerged plants unable to compensate for lower yield of late‐emerging plants (Carter and Nafziger, 1989; Nafziger et al, 1991; Ford and Hicks, 1992; Liu et al, 2004b).…”

Relationships between Sunflower Plant Spacing and Yield: Importance of Uniformity in Spacing

“…For corn, studies on the effect of within‐row plant uniformity on yield are numerous but results are contradictory. Some studies show significant yield decreases due to nonuniform spacing and plant density (Krall et al, 1977; Nielsen, 2001) while others do not (Erbach et al, 1972; Liu et al, 2004). Reconciling the causes leading to these different conclusions is complicated partly by the dramatic improvements in genetics that support higher plant densities and also the confounding role of different growing environments (Martin et al, 2005).…”