Increased Temperatures Have Dramatic Effects on Growth and Grain Yield of Three Maize Hybrids

Abstract

C limate change impacts on agricultural productivity are linked to the positive effects of increasing carbon dioxide (CO 2 ), negative effects of increasing temperatures, and variable effects of precipitation timing and amounts. Projections of crop productivity under scenarios of climate change have ranged from less than 5% with temperature increases of less than 1°C (Hatfield et al., 2011) to a decrease of more than 50% in maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] (Schlenker and Roberts, 2009). Crop yields decrease with increasing temperatures; a summary by Lobell and Field (2007) showed maize yields decreased 8.3% per 1°C rise without any complicating effect due to water stress. These studies point out the negative impacts of temperature increases. In addition, the review by Hatfield et al. (2011) summarized that rising temperatures increase the rate of phenological development, leading to a smaller plant and reduced productivity because of the shortened growth cycle. One of the most vulnerable stages of plant development to temperature stress is the pollination phase because of pollen's sensitivity to extreme temperatures (Hatfield et al., 2011). The current assessments of temperature impacts on crops have been developed through extrapolation of crop models combined with future climate scenarios, with no direct observations on the effect of rising temperatures on phenological development and growth.There have been projections of the impact of rising temperatures as shown by Asseng et al. (2015) in their evaluation of 30 different wheat (Triticum aestivum L.) models to simulate wheat production. They concluded that grain production would decrease 6% per 1°C rise and become more variable in both space and time. The projected grain yield decrease is similar to that observed for maize by Lobell and Field (2007). The projections by Asseng et al. (2015) are similar to the 5.3% yield reduction per 1°C observed in Australia by Innes et al. (2015) using a combination of experimental results coupled with simulation models. There is a differential response of plants to temperature throughout the growth cycle. The recent results by Laza et al. (2015) for rice (Oryza sativa L.), for example, showed that high night temperatures had no effect during the vegetative stage; however, during the reproductive stage, yields were reduced because of increased dark respiration rate and spikelet degeneration.Warming temperatures have decreased US wheat yields, as observed by Tack et al. (2015) using historical yield and meteorological data. They used statistical analysis for their study specifically for Kansas wheat yields using a Agricultural & Environmental LettersResearch Letter Abstract: Rising temperatures under climate change are projected to have negative impacts on crop growth and production. These conclusions are not based on direct observations but on projected model results. A study conducted comparing normal seasonal temperatures for Ames, IA, to a normal + 4°C environment with the same water vapor defici...

Indicators of climate change in agricultural systems

“…There is a differential response of plants to temperature throughout the growth cycle, and the recent results by Laza et al (2015) for rice showed that high night temperatures had no effect during the vegetative stage; however, high nighttime temperatures during the reproductive stage reduced yields because of the increased dark respiration rate and spikelet degeneration. This is similar to the results of Hatfield and Prueger (2015) and Hatfield (2016) from their controlled environment studies with high nighttime temperatures (plus 3C above normal temperatures) on maize yield which showed reductions of over 50% in maize grain yield.…”

“…The effect of increasing CO 2 on plant productivity is generally positive with enhanced production and improved water use efficiency . Projections of temperature increase showed a large range in crop productivity with estimates of around 5% with temperature increases of 1°C (Schlenker and Roberts 2009;Hatfield et al 2011) to over 50% in maize and soybean under extreme warming (Schlenker and Roberts 2009;Hatfield 2016). Rising temperatures increase the rate of phenological development and reduced productivity because of the shortened growth cycle .…”

Biomass sorghum and maize have similar water-use-efficiency under non-drought conditions in the rain-fed Midwest U.S.

“…When subjected to a 4 °C temperature increase in chamber studies, maize grain yield was found to decrease by 84-100% while vegetative biomass was less affected (Hatfield, 2016). Less severe reductions in maize grain yield have been documented in field studies (Ruiz-Vera et al, 2015).…”

“…The response of maize growth to elevated temperature has been studied in the literature ( -Vera et al, 2015;Hatfield, 2016). When subjected to a 4 °C temperature increase in chamber studies, maize grain yield was found to decrease by 84-100% while vegetative biomass was less affected (Hatfield, 2016).…”

“…Since growth in biomass sorghum is primarily vegetative, it may be less sensitive to the projected increase in consecutive dry days during in the late summer (Aug-Sep), that may coincide with the timing of critical reproductive processes in maize (Harding & Snyder, 2014;Hoffmann & Rooney, 2014;Ruiz-Vera et al, 2015;Hatfield, 2016). Previous research has…”