Miller Magazine Issue 109 / January 2019

54 COVER STORY MILLER / JANUARY 2019 tensity precipitation during the growing season to obtain maximum infiltration of precipitation into the soil profile and crop root zone for crop uptake. However, when the precipitation intensity and distribution are considered, precipitation events are getting more intense with larger and unevenly distributed precipitation events that would reduce the infiltration and increase surface run-off and erosion, which would be less beneficial for meeting crop water requirements during the growing season. Thus, changes in all these climate variables indicate that the conditions have been getting drier in Turkiye, which may negatively impact country’s agricultural productivity and water resources, if necessary effective precautions are not developed and implemented immediately. There is substantial evidence that trends in change in climate variables can negatively or positively affect crop yield trends despite advances in technology and other yield-influencing variables. In a study conducted with a climate dataset from 1895 to 1998, Hu and Buyanovsky (2003) found that within-season precipitation and tem- perature variations explained differences in central Mis- souri maize yield. Ferris et al. (1998) found declines in spring wheat yield when plants were exposed to extreme maximum temperatures during the anthesis stage. Hu et al. (2005) found that earlier winter wheat heading dates were associated with warmer spring minimum tempera- tures. Matsui et al. (2001) found that variety selection was crucial to minimizing the effects of extreme heat stress on japonica rice during flowering on grain yield. In addition to other climate variables, increase in minimum air temperature has specific and critical implications to yield productions. Daily Tmin usually occurs during ni- ghttime. For most agronomic crops, Skaggs and Irmak (2012) suggested that Increases in Tmin, which usually occur during the night, may have significant implications in crop productivity. Nighttime increases in temperature can result in greater plant respiration, which is a physi- ological process opposite to trans- piration. Transpiration is mainly driven by sunlight, air tempera- ture, and soil/plant water availa- bility during the daytime and re- sults in dry matter production and accumulation by the plant. Since Tmin is the main driver of respi- ration during nighttime, increases in Tmin can accelerate respiration, increase dry matter consumption by the plants at night, and result in reduction in crop yields. In the literature, there are numerous ot- her data and information related to negative impacts of aforemen- tioned changes in climate variab- les on agricultural yields. Suggestions Remarks: Since agriculture is highly sensi- tive to weather and climate change, agricultural resource management practices and policy decisions require deta- iled information of trends in temperature, precipitation, and other variables, such as carbon dioxide concentration and cloudiness, on relevant spatial and temporal scales (Skaggs and Irmak, 2012). Furthermore, these changes can exhibit substantial deviation for local/regional scales than global values. Thus, trends and magnitudes of chan- ges in these primary climate variables must be quantified for local scales so that relevant mitigation and adoption strategies and best agricultural practices can be researc- hed, developed and implemented to enhance agricultural productivity for a local region. The associated policy and decision-making should also engage in developing these strategies so that research and development and policy and decision-making processes can be established simul- taneously. • While so much discussion and analyses take place on global climate change, it is imperative that the analyses are conducted for local/regional conditions so that local changes can be documented and local best agricultural and water resources management practices can be deve- loped in response to changes in climatic variables. While these increases in air temperature and CO 2 concentration may seem to be small for humans, the implications of these small increases in air temperatures for plant physi- ological functions and, in turn, their impact(s) on agricul- tural practices and productivity can be significant. • Whether it is “man-made” or “natural occurrence,” climate variables are changing and they are having sig- nificant impacts on our agro-ecosystems. This message must be communicated through good quality science and research-based data and information. • Potential changes in climate variables must be quan- tified and studied for all major agriculturally important