Agronomic Optimum Seeding Rate for Irrigated Maize in Texas is Concomitant to Growing Season Mean Daily Minimum Temperature

Abstract

Our study was conducted to determine agronomic optimum seeding rates (AOSR) for irrigated maize under a range of agroecological conditions in Texas. Environmental factors that affect irrigated maize production vary considerably across Texas. This variability imposes region-specific limitations on statewide maize seeding rate recommendations. Our research examined the efficiency of varying seeding rates on irrigated maize grain yields in five USEPA Level IV Ecoregions that comprise most of the irrigated maize-producing area of Texas. The selected sites span a distance of 1200 km from south to north Texas and elevations from 20 to 1218 m above mean sea level. We conducted the study over three growing seasons from 2005 through 2007 in two Level IV Ecoregions of the High Plains of North Texas (N), one in the East Central Plains (E), one in the Southern Plains and one in Western Gulf Coastal Plains of South Texas (S). We observed that maximum grain yields and AOSR to achieve maximum maize grain yields vary considerably among ecoregions. In South Texas, we observed grain yield response rates of 125-129, 151 kg 1000 seeds À1 in E and 163-199 kg 1000 seeds À1 in N. We show that growing season average daily minimum air temperature (T MIN ) explains most of this variation (r 2 = 0.98, P-value < 0.01) and conclude that seeding rate efficiency is concomitant to T MIN . Maximum grain yields (GY MAX ) determined with seeding rate response analysis also varied among ecoregions and with T MIN from south to north Texas, from a low of 8.3 Mg ha À1 in S to a high of 18.4 Mg ha À1 in N (r 2 = 0.59, P-value < 0.01). We conclude that development of agronomic management models by Level IV Ecoregions of Texas combined with site-specific T MIN climatological data serve as a valid template for delivering robust and agroecozonespecific irrigated maize seeding rate recommendations in Texas.

Row Arrangement, Phosphorus Fertility, and Hybrid Contributions to Managing Increased Plant Density of Maize

“…Thus, it is plausible that narrow row (<0.76 m) or twin row arrangement in maize production may promote greater temperatures in the middle canopy where the leaf subtending the ear and those immediately above and below the ear contribute a greater proportion of assimilates to developing grain tissues relative to other parts of the canopy (Eastin, 1969). Higher temperatures within this stratum of the canopy might promote accelerated leaf senescence (Badu‐Apraku et al, 1983) or increase leaf dark respiration (Kaše and Čatský, 1984; Thompson et al, 2013), thereby reducing photoassimilate availability for kernel development. In our study, differences in leaf senescence below the ear were visible between row arrangements (greater senescence in twin row arrangement) during reproductive stages, particularly during the 2011 growing season at Champaign, IL.…”

Understanding variability in optimum plant density and recommendation domains for crowding stress tolerant processing sweet corn

“…At similar plant densities, lower yield in field corn at higher latitudes can be due to decreased amount of solar radiation and reduced crop growing season [6,7]. In southern climates, Thompson et al [8] found that higher nighttime temperatures were unfavorable for field corn yields and reduced crop yield in above-average plant densities.…”

Optimizing Corn Seeding Rates Using a Field's Corn Suitability Rating

“…Crop yields change from year to year due to local weather and management decisions such as new and improved crop cultivars, changes in tillage methods, improvements in artificial drainage techniques, improved fertilization, and other technological changes (Hofstrand, 2010). Intrarow spacing, competition for water, light, and nutrients, and growing season average daily minimum air temperature determine the optimum plant population for each environment (Hodges and Evans, 1990; Thompson et al, 2013). Ahmadi et al (1993) found quadratic relations between GY and plant population in two experiments and linear relations in another two experiments.…”