Evaluating Management Factor Contributions to Reduce Corn Yield Gaps

Abstract

ABSTRACTe need to intensify agricultural production due to a growing human population requires yield gaps to be closed. In 2009 and 2010, ve management factors were assessed for their individual and cumulative contributions to reducing the corn (Zea mays L.) yield gap and yield components in a corn-soybean [Glycine max (L.) Merr.] rotation. Five management factors (plant population, transgenic insect resistance, fungicide containing strobilurin, P-S-Zn fertility, and N fertility) were evaluated. An incomplete factorial design with these factors resulted in 12 treatments, including two controls: high technology (HT) and standard technology (ST), comprising all ve factors applied at the supplemental or the standard level, respectively. e HT control yielded 2.9 Mg ha -1 (2.12-3.50 Mg ha -1 across sites and years) more grain (28%) than the ST control, demonstrating the yield gap between traditional farm practice and attainable yield using available technologies. All management factors except plant population were necessary for reducing the yield gap. Fungicide and Bacillius thuringiensis gene (Bt) traits provided the greatest yield increases compared to the ST system. Averaged over sites and years, if each factor was withheld from the HT system, yield decreased by decreasing kernel number. Increased plant population reduced the yield gap when all other inputs were applied at the supplemental level. Kernel number was more signi cant for increasing yield than kernel weight. e yield contribution of each factor was greater when applied as part of a full complement of supplemental inputs than when added individually to the standard input system. Abbreviations: Bt, Bacillius thuringiensis gene; -Bt, HT control system with non-Bt variety; +Bt, ST control with Bt-containing variety added; CU, Champaign-Urbana study site; DS, Dixon Springs Research Center site; -Fung, HT control treatment without fungicide; +Fung, ST control treatment with added fungicide; HT, high technology level; +N, additional side-dress N to ST control; -N, HT control without side-dress application; +Pop, high population treatment added to ST control; -Pop, decreased population treatment within HT control; +P-S-Zn, P, S, and Zn combination fertilizer added to ST control; -P-S-Zn, HT control treatment without P-S-Zn combination fertilizer; ST, standard technology level; VT, tasseling.Numerous recent papers have established that agricultural production must increase substantially to meet the increasing per capita demand for food, feed, fuel, and fi ber of a burgeoning human population (Keyzer et al., 2005, Food and Agriculture Organization, 2009. From a global perspective, it is generally agreed that agricultural intensifi cation (increasing agricultural production per unit area) is preferable to extensifi cation (expanding agriculture onto new areas) as a means of increasing crop production Burney et al., 2010;McLaughlin, 2011;Tilman et al., 2011;Foley et al., 2011). In contrast to the question of whether yield increases are needed, the more practical i...

Yield Stability Differs in Commercial Maize Hybrids in Response to Changes in Plant Density, Nitrogen Fertility, and Environment

“…The yield response of hybrids, averaged across environments, to high N fertilizer (252 kg N ha ‐1 ) ranged from +4.47 to +5.64 Mg ha ‐1 and the yield response to increased plant density ranged from ‐0.60 to +0.58 Mg ha ‐1 . Compared with results from previous studies under similar agronomic conditions, the findings reported here identified substantially greater yield ranges for both response to high N fertilizer (Haegele et al, 2013) and increased plant density (Ruffo et al, 2015), demonstrating greater genetic variability for these traits in current elite maize hybrids. Moreover, four groups of hybrids were identified: group 1B included 25% of the hybrids with below‐average yield response to high N but above‐average response to increased plant density; group 2B included 24% of the hybrids with above‐average yield responses to both high N and increased plant density; group 3B contained 25% of the hybrids with below‐average yield response to both high N and plant density; and group 4B consisted of 26% of the hybrids with above‐average yield response to high N but below‐average response to increased plant density.…”

“…In addition, continued increases in maize yield will depend on a hybrid's ability to utilize resources more efficiently when grown under greater plant densities (Tollenaar and Lee, 2002) and under favorable agronomic conditions (Boomsma et al, 2009). Nonetheless, increased plant density needs to be in synergy with other intensified management factors, such as better soil fertility, to minimize the current maize yield gap that exists in the U.S. Corn Belt (Ruffo et al, 2015).…”

“…To assess the ability of the hybrids to tolerate high plant density conditions (Ruffo et al, 2015), two plant densities (79,000 and 110,000 plants ha -1 , denoted as standard and high plant density, respectively) were used. The standard plant density is based on contemporary farmer practices in the state of Illinois.…”

Exploring soybean management options for environments with contrasting water availability

“…In general, water deficits during reproductive stages impact soybean yield more than deficits during vegetative ones (Ashley & Ethridge, ; Brown, Caviness, & Brown, ; Doss, Pearson, & Rogers, ). Variations in seed number and individual seed weight are used to understand the timing and mechanisms behind yield differences to different stress levels and crop managements (Board & Tan, ; Ruffo, Gentry, Henninger, Seebauer, & Below, ).…”

“…Variations in seed number and individual seed weight are used to understand the timing and mechanisms behind yield differences to different stress levels and crop managements (Board & Tan, 1995;Ruffo, Gentry, Henninger, Seebauer, & Below, 2015).…”