Evaluation of climatic variables as yield-limiting factors for maize in Kansas

Kansas is situated from the lower Missouri Basin to the high plains lying along the eastern slope of the Rockies so that distinct climates across the state make crop production systems vulnerable to changes in climate. Based on climatic indices such as growing degree-day (GDD), extreme degree-day (EDD), and precipitation (P), this study assessed the sensitivity of maize (Zea mays L.) yield to a changing climate for seven diverse cropping areas from 1981 to 2013 across Kansas. Our results indicated that maize yield increased by 2.4 and 3.4% per annum 100 GDD increase under non-irrigated (i.e. rainfed) and irrigated environments, respectively. Maize yield positive response to changes in GDD during the pre-silking period was more significantly pronounced for irrigated environments than rainfed sites. Rainfed yields showed a significantly negative response to EDD (-3.0% per + 10 EDD) compared with irrigated environments (-1.2% per + 10 EDD). This EDD negative effect was more pronounced during post-silking growth as compared with the pre-silking period for both irrigated and non-irrigated conditions. Yield sensitivity to a unit change of P (mm) was less than the sensitivity to a unit change of GDD (in degrees C days) and EDD (in degrees C days) indices. Nonetheless, maize productivity has a positive response to post-silking P with a greater yield gain at rainfed sites compared with irrigated sites. Irrigation could partially mitigate the effect of extreme heat on maize yield potential. Because the frequency of extreme temperatures and P are predicted to increase in Kansas and the Great Plains region, this study might provide guidelines to farmers, crop consultants, and agronomists to manage maize production thereby providing the ability to mitigate or adapt to climate change impacts.