Does Tillage or Fertilizer Provide Resilience to Extreme Weather in Southern Illinois?

CORE IDEAS: Dry weather causes maximum reduction in yields of corn and soybean. Precipitation during silking increases yields of corn. In cold years, no‐till yielded 7.5% higher than alternate tillage and chisel tillage. Fertilizer placement had significant effects on corn yields during normal and dry weather years only. Understanding the influence of past “extreme” weather during critical growth stages of corn (Zea mays L.) and soybean (Glycine max L.) production may help us to predict how management practices could influence yield under climate change scenarios. This study evaluated the influence of tillage (moldboard plow [MP], alternate [AT], chisel [ChT], and no‐till [NT]) and fertilizer (N+NPK starter, NPK+NPKstarter, and NPK) management on yield during extreme weather events (cold, hot, wet, and dry) occurring at critical growth stages of corn and soybean under continuous–corn [CC; 1970–1990] and corn–soybean [CS; 1991–2015] rotations located in a somewhat poorly drained Bethalto silt loam near Belleville, IL. Results showed that during dry years, corn yield was 3.8% higher with NPK treatment as compared to NPK+NPKstarter fertilizer treatment. Soybean yield was not influenced by any type of fertilizer treatments during extreme and normal weather events. Corn yields were significantly affected by tillage in cold years in which NT yielded 7.5% higher than AT and ChT treatments; however, during wet years, ChT and MP yielded 8.5 and 7.3% (respectively) higher than NT. During cold years, soybean yield in AT was higher by 12.3 and 9.4% than MP and ChT treatments, respectively. As compared to normal weather years, corn yield was highest with all tillage treatments during wet years, showing beneficial influence of precipitation on corn yield during critical growth stage (silking). Our study results showed that dry weather has maximum potential for causing a reduction in corn and soybean yields under all tillage treatments.